Table of Content

12 August 2024, Volume 50 Issue 8

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REVIEW

Research progress on the intensification of agroecosystem functions through legume-based crop rotation

LIU Chun-Yan, ZHANG Li-Ying, ZHOU Jie, XU Yi, YANG Ya-Dong, ZENG Zhao-Hai, ZANG Hua-Dong

Acta Agronomica Sinica. 2024, 50(8):  1885-1895.  doi:10.3724/SP.J.1006.2024.34195

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Although intensive agriculture plays a crucial role in ensuring global food security, the conflict between its environmental costs and sustainable development is becoming increasingly prominent. Legume inclusion into agroecosystem is vital for improving soil health, enhancing agroecosystem stability, and achieving resource utilization efficiency. This paper provides a systematic summary of the main effects of the legume-based rotation on crop production and soil function as follows: 1) Legume enhance soil nitrogen (N) content through biological N fixation, high-quality rhizosphere exudates input, and straw incorporation, resulting in positive legacy effects. This, in turn, benefits the subsequent crop yields, particularly in agroecosystems with low soil fertility. 2) Although the biological N fixation of legumes poses the risk of increasing CO₂ emissions, it can mitigate greenhouse gas emissions by reducing N fertilization in the rotation. 3) The low C/N ratio and high N content of legume straw promote soil microbial activity and microbial residue accumulation, thereby improving soil carbon sequestration efficiency. However, the limited amount of straw for legumes restricts C sequestration. 4) Legumes can improve water and fertilizer utilization efficiency of subsequent crops, and optimizing the root depth between legume and subsequent crop can enhance the overall efficiency of water and fertilizer usage in the rotation. In conclusion, the inclusion of legumes in crop rotation can achieve a reduction in N fertilizer usage and an increase in yield. However, the effects of soil carbon sequestration and greenhouse gas emission reduction are influenced by various factors such as crop type, fertilizer input, soil, and climate conditions. Exploring the coupling mechanisms between the effects of legumes on subsequent crop yield and belowground ecological functions is of great significance. Developing field management technologies for legume-based crop rotation and designing new ecological and efficient cropping systems suitable for various regions in China will facilitate the construction and implementation of legume-based rotations, contributing to agricultural green development.

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Superior allele genes mining for drought tolerance in maize based on introgression line from a cross between maize and teosinte

LIU Shuang, LI Shen, WANG Dong-Mei, SHA Xiao-Qian, HE Guan-Hua, ZHANG Deng-Feng, LI Yong-Xiang, LIU Xu-Yang, WANG Tian-Yu, LI Yu, LI Chun-Hui

Acta Agronomica Sinica. 2024, 50(8):  1896-1906.  doi:10.3724/SP.J.1006.2024.43007

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Drought is one of the major abiotic stresses affecting maize production. In order to explore new genes for drought tolerance in maize, the BC2F6 population constructed on the basis of teosinte and PH4CV was screened for the drought-tolerant introgression lines TP180 through the preliminary identification of drought tolerance at seedling stage. After drought stress, the TP180 was less wilting than its recurrent parent PH4CV, and the survival rate of TP180 was significantly higher than PH4CV after rehydration. Genome-wide genotypic identification revealed that introgression line TP180 contained 0.6% of the teosinte genome. By transcriptomic analysis of TP180 and PH4CV under different water conditions, a total of 2307 differentially expressed genes were identified between TP180 and PH4CV, and 122 of the differentially expressed genes were identified under both two drought stresses conditions. These genes were related to the growth hormone pathway, jasmonic acid pathway, etc., and contained multiple transcription factors. Integrating the differentially expressed genes and the analysis of introgression region containing the teosinte genome, two drought-resistant candidate genes (Zm00001d033050 and Zm00001d002025) were identified and further validated by RT-PCR. This study provides an important germplasm and information for mining drought-resistant gene of the teosinte.

Screening, evaluation, and utilization of low nitrogen tolerance for the selected introgression lines in rice with Huanghuazhan background

SHAO Mei-Hong, ZHAO Ling-Ling, CHENG Chu, CHENG Si-Ming, ZHU Shuang-Bing, ZHAI Lai-Yuan, CHEN Kai, XU Jian-Long

Acta Agronomica Sinica. 2024, 50(8):  1907-1919.  doi:10.3724/SP.J.1006.2024.42002

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Nitrogen deficiency in medium-yield and low-yield fields is an important factor restricting the high yield in rice. It is one of effective ways to solve the problem by screening and developing rice variety with low nitrogen tolerance (LNT). In this study, the selected introgression lines (SILs) from germplasms in Huanghuazhan (HHZ) background were used to evaluate the performance of yield and its related traits under low and normal nitrogen conditions for successive three seasons. Low nitrogen had least effect on heading date, seed fertility, and 1000-grain weight (TGW) with the average low nitrogen tolerance index (LNTI) around 1.0, whereas had greatest effect on grain yield per plant (GYP) and panicle number per plant (PN) with the respective average LNTI of 0.45 and 0.62, indicating that GYP and PN were useful indicator of LNT. Based on LNTI of GYP, nine LNT lines were selected with LNTI ranging from 0.87 to 1.04. Five of the selected LNT lines verified by multiple-site trials, one line (M281) had low LNT with GYP-LNTI of 0.66 and the other four had high LNT with the average GYP-LNTI of 0.94, indicating that LNT was a characteristic with the differences at individual and population levels, thus emphasizing the importance of population verification for LNT materials which were screened from segregation population. Among the four LNT lines, M85 was mainly achieved by higher PN and TGW under low nitrogen condition, whereas the other three lines (M382, M563, and M79) were mainly supported by more filled grains per panicle (FGP) and higher TGW. Therefore, an important way was proposed to achieve high yield under low nitrogen condition through increasing FGP based on a relatively high PN. In view of salt tolerance at seedling stage, drought tolerance at reproductive stage and LNT at all growth duration of SILs, it was discussed how to simultaneously improve multiple complex abiotic stress tolerances using SILs derived from diverse donors by molecular design.

Functional study on the regulation of root growth and development and stress tolerance by maize transcription factor ZmEREB180

LIU Chen-Ming, ZHAO Ke-Yong, YUE Man-Fang, ZHAO Yan-Ming, WU Zhong-Yi, ZHANG Chun

Acta Agronomica Sinica. 2024, 50(8):  1920-1933.  doi:10.3724/SP.J.1006.2024.33070

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The AP2/ERF (APETALA2/ethylene-responsive factor) family is one of the largest families of transcription factors in plants, and plays an important role in regulating a variety of biological processes such as plant growth and development, respond-ing to adversity stress, and regulating hormone signaling and substance metabolism. The biological functions of AP2/ERF family genes in many plant species have been validated, but fewer studies have been reported in maize (Zea mays L.). In the previous work, there was significant difference in the relative expression level of the ZmEREB180 transcription factor in root system between the identified critical developmental stages of maize at the six-leaf (V6), the twelve-leaf (V12), and tasseling (VT) stages, the tissue expression analysis revealed that this gene was mainly expressed in maize root system and was significantly higher in young roots than in mature roots, and it was hypothesized that this gene might be involved in the regulation of maize root growth and development. In this study, we cloned the ZmEREB180 (Gene ID: 100192457) transcription factor gene, and preliminarily analyzed the relative expression pattern and biological functions of ZmEREB180 by bioinformatics, RT-qPCR, subcellular localization, and stress-resistant phenotype identification of transgenic Arabidopsis (Arabidopsis thaliana L.) lines. This gene contained two exons and the full-length cDNA was 1023 bp, encoding 340 amino acids. The gene had a conserved domain unique to the AP2/ERF family, which expressed most highly in root system of maize; and the gene had different degrees of induced expression under high salt, drought, high nitrogen, and low nitrogen treatment conditions, with a more rapid and higher expression in response to low nitrogen than high nitrogen; root length of ZmEREB180 transgenic Arabidopsis lines were all significantly longer than the wild type (WT) on 1/2 MS medium containing 0.10 mol L^-1, 0.15 mol L^-1 NaCl, and 0.15 mol L^-1, 0.20 mol L^-1, 0.30 mol L^-1 mannitol (MNT). Under high salt and drought stress conditions in soil environments, transgenic Arabidopsis lines had healthier growth status, higher green leaf percentage, lower malondialdehyde (MDA) content, and higher peroxidase (POD) activity than WT. The transcription factor ZmEREB180 may play a positive and promotional role in regulating the growth and development of maize root system and enhance the tolerance of maize plants under high salt, drought, osmosis, low nitrogen, and other adversity stresses. This study lays a good foundation for further identification of the biological function and molecular mechanism of transcription factor ZmEREB180 in maize.

OsRPTA18 participated in the regulation of leaf inclination in rice

HE Dan-Dan, SHU Ya-Zhou, ZHOU Hai-Lian, WU Song-Guo, WEI Xiao-Shuang, YANG Ming-Chong, LI Bo, WU Zheng-Dan, HAN Shi-Jian, YANG Juan, WANG Ji-Bin, WANG Ling-Qiang

Acta Agronomica Sinica. 2024, 50(8):  1934-1947.  doi:10.3724/SP.J.1006.2024.32046

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The regulatory particle triple-A ATPase (RPTA) gene family is closely related to plant growth and development, hormone regulation and stress response. In this study, a total of 33 members of the gene family were identified in rice and their gene locations, gene structures, motifs composition, and cis-elements in the promoter regions were revealed. Then, the relative expression patterns of the gene members in OsRPTA family were investigated with the data downloaded from rice CREP database. Most of the OsRPTA genes expressed highly in panicle, endosperm and callus tissues. β-D-glucuronidase (GUS) staining further indicated that one of the members, OsRPTA18, was expressed in collar, root, leaf, leaf sheath, stem node, vascular bundles of glume and lemma. Subcellular localization indicated that OsRPTA18 protein was in nucleus. Two knock-out mutants (osrpta18-1 and osrpta18-2) were generated by CRISPR/Cas9 editing technology and both exhibited reduced plant height, leaf inclination, accompanied by the decreased grain width and 1000-grain weight compared to the wild type Zhonghua 11. Transverse section staining of the lamina joints of the plants indicated the changes in the cell wall thickness and vascular bundle size, causing the obvious proliferation of thick-walled cells at adaxial side, thus decreasing asymmetric development of the lamina joints and the leaf angel in the osrpta18 mutants. These results of this study are valuable for further functional analysis of RPTA genes and utilization of the OsRPTA18 gene for the genetic improvement of rice varieties with ideal plant architecture.

Genome-wide association study of major grain quality traits in wheat based on 55K SNP arrays

PENG Xiao-Ai, LU Mao-Ang, ZHANG Ling, LIU Tong, CAO Lei, SONG You-Hong, ZHENG Wen-Yin, HE Xian-Fang, ZHU Yu-Lei

Acta Agronomica Sinica. 2024, 50(8):  1948-1960.  doi:10.3724/SP.J.1006.2024.31052

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To meet people's demand for wheat quality, exploring relevant candidate genes can provide a theoretical basis for genetic improvement and molecular marker-assisted selection of high-quality wheat cultivars. In this study, phenotypic values of eight wheat grain quality traits, including water absorption, grain protein content, volume weight, wet gluten content, dough stability time, dough development time, sedimentation value, and flour yield, were detected in 118 wheat genotypes in three environments. The genotypes were analyzed using 55K SNP arrays, and a genome-wide association study was conducted using the Q+K mixed model. In three different environments, the eight grain quality traits had extensive variation, the maximum variation coefficient of sedimentation value was 16.47%-17.03%, and the heritability of each quality trait was 0.71-0.85. The 118 wheat genotypes were divided into three subgroups: subgroup I, consisting of 41 (34.75%) genotypes, mainly from Anhui; subgroup II, consisting of 32 (27.12%) genotypes, predominantly from Anhui, Jiangsu, and Sichuan provinces; and subgroup III, consisting of 45 (38.13%) genotypes, mainly from Anhui and Jiangsu provinces. 22 stable loci significantly associated with wheat grain quality traits (P < 0.001) were repeatedly detected in two or three environments, distributed on chromosomes 1B (4), 1D (1), 2B (1), 2D (1), 3B (2), 3D (1), 4D (1), 5A (1), 5B (1), 5D (3), 6B (2), 7B (3), and 7D (1), explaining 8.53% to 16.32% of the phenotypic variation. Among the stable loci, three exhibited significant pleiotropic effects, 14 were identified as novel loci for controlling wheat quality traits, and 11 candidate genes possibly associated with wheat grain quality traits were screened. The higher the number of favorable alleles, the higher the phenotypic values of quality traits. Furthermore, it was discovered that several genotypes carried favorable alleles for all eight major quality traits. Among them, the wheat cultivars Huacheng 859 and Jimai 44 contained the highest number of favorable alleles, making them valuable breeding parents for improving wheat quality. The results of this study provide a theoretical basis, parental materials, and molecular markers for the breeding of high-quality wheat.

Construction and verification of the CRISPR/Cas9 system containing DsRed fluorescent expression cassette for editing of ZmCCT10, ZmCCT9, and ZmGhd7 genes in maize

CAO Xiao-Qing, QI Xian-Tao, LIU Chang-Lin, XIE Chuan-Xiao

Acta Agronomica Sinica. 2024, 50(8):  1961-1970.  doi:10.3724/SP.J.1006.2024.33050

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The CCT family genes affect plant flowering time. In maize, ZmCCT10 and ZmCCT9 are photoperiod sensitive genes, and ZmGhd7 is a gene related to the flowering time. Targeted editing of ZmCCT10, ZmCCT9, and ZmGhd7 genes using CRISPR/Cas9 technology provides the possibility to study the function of three genes and to rapidly improve the flowering time of maize. In this study, maize ZmCCT10, ZmCCT9, and ZmGhd7 were used as editing objects. The inbred line KN5585 was used as a stable transforming receptor, and CML312SR, LCL-1, and LCL-2 were used as pre-modified late-flowering lines. Firstly, the conservation of the target regions of the three genes in four maize lines was verified by Sanger sequencing. Secondly, one sgRNA was selected to co-edit three genes based on sgRNA design principles. The CRISPR/Cas9 gene editing knockout vector CCT-CPD was constructed using homologous recombination, which contained the DsRed expression cassette driven by embryo-specific promoter Zm3896 and the sgRNA expression cassette driven by the ZmU6-2 promoter. Next, the mutation rate and mutation type of the three genes in T₀ generation KN5585 were analyzed by enzyme digestion method and Sanger sequencing, and the gene editing effect of the CRISPR/Cas9 system was verified. Finally, the seeds produced by stable genetic transformation plants were verified by the DsRed fluorescent labeling phenotype at the kernel level and tissue level. On this basis, F₁ was obtained by cross breeding using late flowering lines as female parent and T₁ generation KN5585 positive plant as male parent, and late flowering lines containing effective edited transgenic elements were obtained by DsRed fluorescence screening. The CRISPR/Cas9 system for editing ZmCCT10, ZmCCT9, and ZmGhd7 genes containing DsRed fluorescent expression cassette constructed, in this study, laid a foundation for the creation of single-gene mutants, double-gene mutants, and/or triple-gene mutants. The application of DsRed fluorescent screening markers in this system can quickly screen and distinguish corn kernels with or without transgenic components, which has the potential of large-scale kernels screening with low cost and high identification efficiency. This study laid a material foundation and efficient technical basis for identifying the functions of ZmCCT10, ZmCCT9, and ZmGhd7 and creating photoperiod insensitive materials in maize.

Cloning and functional analysis of ubiquitin-conjugating enzymes TaUBC16 gene in wheat

GAO Wei-Dong, HU Chen-Zhen, ZHANG Long, ZHANG Yan-Yan, ZHANG Pei-Pei, YANG De-Long, CHEN Tao

Acta Agronomica Sinica. 2024, 50(8):  1971-1988.  doi:10.3724/SP.J.1006.2024.31080

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E2 ubiquitin-conjugating enzyme plays an important role in regulating plant growth and development, and stress signal transduction. In this study, the TaUBC16 gene encoding E2 ubiquitin-conjugating enzyme was cloned from the cDNA of the drought-tolerant wheat cultivar Jinmai 47. The gene was 447 bp in length and encoded 148 amino acids. The cis-acting element analysis showed that the promoter region of TaUBC16 contained various cis-acting elements related to meristem development, stress responses, and plant hormone responses. By the wheat RNA-seq transcriptome data analysis combined with qRT-PCR validation, it was found that TaUBC16 was generally expressed in different tissues/organs and at different growth stages of wheat, whereas the highest expression level was exhibited in developing grains at 30 days after anthesis. The relative expression level of TaUBC16 was highly induced by PEG, mannitol, and ABA stresses. The subcellular localization in tobacco leaves and wheat protoplasts showed that TaUBC16 proteins were located in both cytoplasm and nucleus. The phenotypic analysis of the heterologous expression of TaUBC16 in transgenic Arabidopsis revealed that the transgenic lines had earlier flowering time than the wild type, and its seeds were more plumpness with higher 1000-grain weight than the wild type. Based on the polymorphism of the promoter region -388 bp site (T-A), a kompetitive allele-specific PCR (KASP) marker of TaUBC16 gene was developed and its haplotypes were identified. The haplotype TaUBC16-Hap I had higher thousand-kernel weight, kernel length and width than TaUBC16-Hap II, and had been subjected to positive selection in wheat breeding processes in China. The results of this study provide a theoretical basis for further revealing the involvement of the TaUBC16 gene in the regulation of wheat growth and development and the molecular mechanism responding to adverse stresses.

Genetic diversity analysis of Chinese faba bean (Vicia faba L.) germplasm resources using 130K liquid phase chips

ZHANG Hong-Yan, MIN Yu-Xia, TENG Chang-Cai, PENG Xiao-Xing, CHEN Zhi-Kai, ZHOU Xian-Li, LOU Shu-Bao, LIU Yu-Jiao

Acta Agronomica Sinica. 2024, 50(8):  1989-2000.  doi:10.3724/SP.J.1006.2024.34059

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A comprehensive understanding of the genetic diversity and population structure of faba bean (Vicia faba) germplasm resources is of great significance for the mining and innovative utilization of excellent resources. In this study, to analyze the genetic diversity, 822 Chinese faba bean germplasm resources were genotyped using 130K liquid phase chips, resulting in a total of 30,946 high-quality SNP loci by high-standard filtering. The polymorphism information content (PIC) and Nei’s gene diversity were 0.0905-0.3750 and 0.0950-0.5000, with the averages of 0.2600-0.3222, respectively. After evaluating the genetic diversity of 822 accessions using Nei’s gene diversity and PIC, based on their geographical origin, the faba bean accessions from Jiangsu and Sichuan had rich genetic diversity, while those from Xinjiang were low. Population structure analysis showed that 822 faba bean accessions were divided into two subpopulations, and when Q was ≥ 0.6, the genetic background of 717 accessions was relatively simple. However, the same subpopulation contained materials from different geographical origins, indicating that gene flow or introgression occurred among the accessions. Results from NJ clustering based on Nei’s (1972) genetic distance and principal component analysis (PCA) indicated that the 822 accessions were also divided into two subpopulations, which was basically consistent with the structure analysis results. In general, the genetic relationships among the faba bean groups with similar ecological environments and geographic origins in neighboring regions or countries were closer and frequently grouped into the same group, while genetic variation among individuals was the main source of the total genetic variation.

Functional analysis of maize N-acetyltransferase ZmNAT1 gene in response to abiotic stress

GUO Si-Yu, ZHAO Ke-Yong, DAI Zheng-Gang, ZOU Hua-Wen, WU Zhong-Yi, ZHANG Chun

Acta Agronomica Sinica. 2024, 50(8):  2001-2013.  doi:10.3724/SP.J.1006.2024.33059

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The GNAT (Gcn5-related N-acetyltransferase) family proteins play a crucial role in regulating plant growth and development, and responding to stress. At present, the biological functions of GNAT family genes have been reported in many species, but there are few studies on its function validation in maize (Zea mays L.). Exploring the functions of maize GNAT family genes not only enriches the genetic resources for maize breeding in China, but also provides an important basis for the creation of new germplasm resources of maize. In this study, the ZmNAT1 gene (Gene ID: 541936, GRMZM2G123159) was cloned. Bioinformatics analysis showed that the CDS of this gene was 519 bp, encoding 172 amino acids. ZmNAT1 contained a conserved domain unique to GNAT family. The relative expression level of ZmNAT1 gene in different tissues of maize at different stages under different stress conditions showed that the expression level of ZmNAT1 was the highest in mature roots, and the relative expression of ZmNAT1 gene could be induced in different degrees under different abiotic adversity stress conditions. Three independent transgenic Arabidopsis (Arabidopsis thaliana L.) pure lines with higher expression were obtained by heterologous expression, and phenotypic characterisation experiments under different adversity stress treatments were carried out on them, the results showed that transgenic Arabidopsis had a better phenotype relative to wild-type Arabidopsis, and the roots of transgenic plants under salt stress, osmotic stress, and drought were significantly longer than those of the wild-type,and the plants showed higher green leaf rate and chlorophyll content, and lower malondialdehyde content than the wild-type plants, which were significant difference. We speculated that ZmNAT1 gene may be involved in response to abiotic stress such as drought and salt in maize. This study provides an important reference for further analysis of the biological functions of ZmNAT1 in maize.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Effect of nitrogen application on water consumption characteristics and grain yield of winter wheat under wide width sowing

YAN Fei-Long, ZHANG Zhen, ZHAO Jun-Ye, SHI Yu, YU Zhen-Wen

Acta Agronomica Sinica. 2024, 50(8):  2014-2024.  doi:10.3724/SP.J.1006.2024.41004

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In order to clarify the optimal nitrogen application rate for sustainable and efficient utilization of water and nitrogen under wide width sowing, a field experiments were conducted at the Wheat Experiment Station in Yanzhou, Shandong province, during the growth period of 2020?2022, and using the variety Jimai 22 as the experimental material. The effects of nitrogen application on water consumption characteristics, flag leaf senescence and fluorescence characteristics, and grain yield of winter wheat were investigated by five treatments including no N (N0), 150 (N1), 180 (N2), 210 (N3), and 240 (N4) kg N hm^-2, under wide width sowing. The results showed that the N2 treatment significantly increased the absorption and utilization of soil water in the 60?120 cm soil layer. Compared with N3 and N4 treatments, the N2 treatment effectively reduced the water consumption of ineffective tillers before anthesis and reduced the total water consumption. The high daily water consumption after anthesis in the N2 treatment significantly increased the antioxidant enzyme activities of the flag leaf, and its fluorescence parameters of the flag leaf were significantly higher than those of the other treatments from 14 to 28 days after anthesis. Grain yield and water use efficiency of N2 and N3 treatments were significantly higher than those of the other treatments, while N2 treatment had the highest nitrogen fertilizer agronomic efficiency, which was 6.88%, 10.60%, and 45.37% (2020?2021) and 7.03%, 13.56%, and 43.71% (2021?2022) higher than N1, N3, and N4 treatments, respectively. In conclusion, the N2 treatment can improve the absorption and utilization of deep soil water of winter wheat, increase the water consumption from anthesis to maturity, delay the senescence of flag leaves, and improve grain yield and water and nitrogen use efficiency, which is the optimal treatment under this experiment.

Effects of nitrogen fertilization levels on matter accumulation and nutrient uptake in rice cultivar with different nitrogen efficiency under drip irrigation

SONG Zhi-Wen, ZHAO Lei, BI Jun-Guo, TANG Qing-Yun, WANG Guo-Dong, LI Yu-Xiang

Acta Agronomica Sinica. 2024, 50(8):  2025-2038.  doi:10.3724/SP.J.1006.2024.32061

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The objective of this study is to explore the effects of nitrogen application levels on dry matter accumulation, nitrogen absorption and transport, and yield of rice varieties with different nitrogen efficiency during key growth stages under drip irrigation conditions, which can provide the technical reference for high-yield and efficient rice production under drip irrigation in arid and semi-arid areas. The experiment was conducted from 2021 to 2022, using high nitrogen efficient cultivar (T-43) and low nitrogen efficient cultivar (LX-3) as the test materials. The split zone design was conducted with four nitrogen application levels, namely N0 (0 kg hm^-2), N1 (150 kg hm^-2), N2 (300 kg hm^-2), and N3 (450 kg hm^-2). The differences in dry matter accumulation, nitrogen absorption and utilization, and yield response to nitrogen application in drip irrigated rice at heading and maturity stages were analyzed. The results showed as follows: (1) Applying nitrogen fertilizer can increase the dry matter accumulation (1.99%-26.02%) and nitrogen accumulation (25.67%-97.69%) of rice under drip irrigation, and increase rice yield (23.75%-66.75%). However, the excessive nitrogen application (450 kg hm^-2) reduced the promoting effect on dry matter accumulation, leading to a decrease in seed setting rate and grain number per spike, mainly concentrating nitrogen in straw, ultimately reducing the nitrogen utilization efficiency of rice. (2) Under the same nitrogen application conditions, the effective number of panicles, seed setting rate, dry matter and nitrogen accumulation in leaves and panicles of T-43 were higher than LX-3 by 1.65%-5.19%, 0.42%-8.47%, 7.61%-19.68%, 19.81%-40.73%, 19.81%-30.23%, and 20.14%-49.65%, respectively, and the final yield was higher than LX-3 by 4.23%-28.47%. (3) The response of nitrogen utilization efficiency varies among varieties at P < 0.05. Compared with LX-3, T-43 had higher N Agronomic efficiency, N recovery efficiency, and N partial factor productivity higher by 1.05%-25.23%, 5.86%-20.05%, and 10.09%-18.01%, respectively. In conclusion, under drip irrigation cultivation, the selection of high nitrogen efficient cultivar (T-43) and the application of 300 kg hm^-2 nitrogen showed better nitrogen uptake and transport capacity and higher yield, and could better utilize nutrient resources, which was the best combination of variety and nitrogen application rate in this experiment.

Evolution characteristics of rhizosphere microorganisms in response to ratoon rice senescence and underlying carry-over effect mechanism

GUO Chun-Lin, LIN Man-Hong, CHEN Ting, CHEN Hong-Fei, LIN Wen-Fang, LIN Wen-Xiong

Acta Agronomica Sinica. 2024, 50(8):  2039-2052.  doi:10.3724/SP.J.1006.2024.32047

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The objective of this study is to investigate the ecological strategies and evolutionary patterns of rhizosphere microorganisms at the late stages of ratoon rice growth, which is crucial for preventing premature crop senescence, enhancing crop productivity, and improving soil fertility in cultivated land. In this study, two genetically related conventional ratoon rice varieties, namely Huanghuazhan (HHZ) and Fenghuazhan (FHZ), were selected as the experimental materials. We employed high throughput sequencing and correlation analysis to explore the changes in diversity, ecological strategies, and inter-species niche relationships of rhizosphere microbiota at the late growth stage of ratoon rice with respect to plant aging. The results demonstrated a consistent trend in the natural aging changes at the late growth stages of both varieties. However, under identical fertilization conditions, FHZ exhibited a significantly higher decay rate of all relevant physiological indicators compared to HHZ at the late growth stage. This observation suggested that the premature aging greatly impacted dry matter accumulation, grain filling, and seed-setting in both seasons, ultimately leading to reduced crop yield. Further analysis confirmed a close relationship between rhizosphere microorganism diversity and the aging process of ratoon rice. Specifically, FHZ showed a significant decrease in rhizosphere microbial diversity index and niche width during the development of ratoon rice’s late growth period. Conversely, Agrobacterium (0.61%), Halocystium (0.17%), Nitrite Oxidizing Bacteria (0.42%), and Nitrospiridium genera (0.045%) were more prominent in HHZ during main crop maturity period (HMR) compared to FHZ’s main crop maturity period (FMR). On the other hand, Bradyrhizobium (0.29%), Sphingomonas (0.76%), and Gemmatimonas (0.15%) displayed an opposite pattern for these genera. Furthermore, we observed that up-regulated microorganisms in HHZ's rhizosphere played a crucial role in nutrient cycling and availability as well as soil transformation processes. Additionally, the niche breadth of rhizosphere soil microorganisms was 36.81% higher in HHZ compared to FHZ, indicating their adaptive response to soil stress environments. This phenomenon reflected the variations in resource utilization by rhizosphere microorganisms, thereby elucidating the evolutionary dynamics and competitive ability for resources among them, ultimately impacting the growth, development, and yield of ratoon rice plants. This study suggests that plant premature senescence is a consequence of an ecological strategy employed by rhizosphere microorganisms. Furthermore, differences in the structure of rhizosphere soil microbial communities during the initial season significantly delay their regeneration season in ratoon rice cultivation. In conclusion, enhancing regulation within the rhizosphere environment, establishing a rational construction of rhizosphere soil microbial communities, and promoting positive effects on plant growth are crucial processes for activating soil nutrients, preventing premature senescence in ratoon rice plants, and further improving its yield.

Root and shoot growth of different maize varieties in response to soil compaction stress

LIANG Lu, ZHOU Bao-Yuan, GAO Zhuo-Han, WANG Rui, WANG Xin-Bing, ZHAO Ming, LI Cong-Feng

Acta Agronomica Sinica. 2024, 50(8):  2053-2066.  doi:10.3724/SP.J.1006.2024.33071

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Soil compaction has become a limiting factor for further increasing maize yield as the development of intensification and mechanization in agriculture in the Huang-Huai-Hai region. Understanding the characteristics of root and shoot growth of different maize varieties under soil compaction stress is benefit for maize high-yield cultivation. To analyse the root and shoot growth and yield of different maize varieties under different levels of soil compaction stress, in this study, three maize varieties were selected, and three soil compaction levels [no compaction stress (NC: no compaction stress, bulk density 1.0-1.3 g cm^-3), moderate compaction stress (MC: moderate compaction stress, bulk density 1.4-1.5 g cm^-3), and heavy compaction stress (HC: heavy compaction stress, bulk density > 1.6 g cm^-3)] were simulated by mechanical rolling in the same field. The results showed that compared with NC, maize yield under MC and HC treatments decreased by 3.8%-10.3% and 12.5%-33.3%, respectively. There were differences in maize root and shoot growth and yield formation under soil compaction stress among three varieties. Under MC treatment, root length, root dry matter, and root-shoot ratio of DK517 increased by 6.0% and 14.0%, 15.7% and 29.6%, 18.8% and 24.8%, respectively, compared to ZD958 and DH605. However, there was no significant difference in the maximum leaf area index, total dry matter, and yield. Under HC treatment, root length and root dry matter of DK517 increased by 8.4% and 22.5%, 29.6% and 57.8%, respectively, compared to ZD958 and DH605, and the maximum leaf area index, total dry matter, and root-shoot ratio increased by 4.6% and 15.5%, 3.7% and 20.9%, 28.0% and 32.1%, respectively, resulting in an increase in yield of 7.5% and 27.2%, respectively. The correlation analysis showed that soil bulk density and penetration resistance were negatively correlated with maize root and shoot growth and yield (P < 0.01). In summary, soil compaction stress could significantly inhibit the growth of maize roots and shoot, resulting in the reduced yields. However, there were differences in maize root and shoot growth under soil compaction stress among different varieties, and the variety with advantages in both root and shoot growth and coordination could maintain higher yields under heavy soil compaction stress. The results provide the theoretical basis for maize breeding improvement and cultivation measures optimization with root architecture as the goal.

Effects of nitrogen fertilizer application levels on yield and nitrogen absorption and utilization of oilseed rape under maize-oilseed rape and rice-oilseed rape rotation fields

LIU Chen, WANG Kun-Kun, LIAO Shi-Peng, YANG Jia-Qun, CONG Ri-Huan, REN Tao, LI Xiao-Kun, LU Jian-Wei

Acta Agronomica Sinica. 2024, 50(8):  2067-2077.  doi:10.3724/SP.J.1006.2024.34181

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Continuous upland and paddy-upland anniversary multiple cropping rotations are typical planting patterns of winter rape in the Yangtze River basin in China, and nitrogen nutrient deficiency is the main limiting factor for rapeseed yield. To provide a basis for scientific nitrogen application, a comparative positioning experiment of split area was conducted in Wuhan City, Hubei Province from 2016 to 2023, and the effects of nitrogen fertilizer application on rapeseed yield and nitrogen uptake and utilization under different rotation patterns was explored. The main treatments of the experimental design were two rotation modes of upland-oilseed rape (maize-oilseed rape rotation) and paddy-oilseed rape (rice-oilseed rape rotation), and the secondary treatments were four nitrogen application rates (0 kg N hm^-2, 75 kg N hm^-2, 150 kg N hm^-2, and 225 kg N hm^-2). The related indexes such as rapeseed yield, yield components, and nitrogen absorption were analyzed. The average results of seven-year experiment showed that there were differences in response to the yield and nitrogen uptake of rapeseed in upland and paddy fields under different nitrogen fertilizer inputs. When there was no nitrogen application or low nitrogen application (75 kg N hm^-2), the yield of rapeseed in paddy fields was significantly higher than that in upland fields, which was higher by 53.9% and 20.8%, and the nitrogen accumulation was higher by 57.8% and 18.3%, respectively. When the nitrogen application rate was 150 kg N hm^-2, there was no significant difference between the two rotations. When the nitrogen application rate reached 225 kg N hm^-2, the yield and nitrogen accumulation of rapeseed in dry land were higher by 11.2% and 16.0% than those in paddy fields, respectively. The agronomic utilization efficiency, contribution rate, and apparent utilization rate of nitrogen fertilizer in upland rapeseed were higher on average by 16.5%, 20.5%, and 22.0% than those in paddy field rapeseed, respectively. Nitrogen fertilizer had a greater yield increase effect on upland-rapeseed, but the soil background nitrogen supply in paddy field rapeseed season was 61.5% higher than that in upland, and its dependence on nitrogen fertilizer was less. In conclusion, the increase in nitrogen fertilizer application significantly increased rapeseed yield and nitrogen accumulation. There were differences in the response of rapeseed yield to nitrogen fertilizer between maize-oilseed rape rotation and rice-oilseed rape rotation. Paddy-oilseed rape exhibited higher stability under low nitrogen input, while upland-oilseed rape achieved higher yield under high nitrogen input. Therefore, the nitrogen application rate of rapeseed should be adjusted according to different crop rotation modes in actual production. The nitrogen application rate of upland rapeseed can be appropriately increased to achieve high yield, while the nitrogen application rate of rapeseed in paddy field should be properly controlled by making full use of the nitrogen supply capacity to achieve the high yield and efficient production of rapeseed and efficient utilization of nitrogen fertilizer.

Effects of deep fertilization on ecological stoichiometric characteristics and photosynthetic carbon assimilation of flag leaves of spring wheat under drought conditions

LIANG Jin-Yu, YIN Jia-De, HOU Hui-Zhi, XUE Yun-Gui, GUO Hong-Juan, WANG Shuo, ZHAO Qi-Zhi, ZHANG Xu-Cheng, XIE Jun-Hong

Acta Agronomica Sinica. 2024, 50(8):  2078-2090.  doi:10.3724/SP.J.1006.2024.31074

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Deep fertilization can improve the water and fertilizer use efficiency of dryland crops, which is one of the important technical ways to increase crop yield, but there is a lack of systematic research on its nutritional physiological mechanism, especially from the perspective of ecological stoichiometric characteristics of flag leaves. In this study, three treatments, 30 cm deep fertilization (D30), 15 cm shallow fertilization (D15) and no fertilization (CK) were conducted in 2021 and 2022 with ‘Longchun 35’ as the test cultivar. The effects of different treatments on the contents of carbon (C), nitrogen (N), phosphorus (P), and ecological stoichiometric characteristics (C/N, C/P, N/P) of spring wheat flag leaves from booting to filling stage were studied. The effects of nutrient content and ecological stoichiometric characteristics of flag leaves on SPAD value, P_n, shoot growth rate, dry matter accumulation, and yield formation of flag leaves in spring wheat were revealed. The results showed that the C/N value of D30 flag leaves at the grain filling stage was 2.1%?6.4% and 5.4%?10.2% lower than D15 and CK, respectively. The C/P values decreased by 3.8%?5.2% and 5.4%?6.0%, respectively. In 2021, the distribution of N/P values increased by 1.4% and 4.1%, and in 2022, the N/P values decreased by 1.6% and 0.2%, respectively. Compared with D15 and CK, the SPAD values of D30 flag leaves increased by 1.8%?6.5% and 15.5%?18.2%, respectively. P_n increased by 21.6%, 27.0%, 28.5%?36.6%, respectively. Compared with D15 and CK, the growth rate of D30 shoots increased by 22.1%?41.2% and 68.4%?80.8%, respectively. The dry matter accumulation of D30 at maturity stage increased by 10.6%?11.1% compared with D15 and CK, respectively. The output increased by 15.7%?15.9% and 46.5%?49.3%, respectively. The contribution rate of nitrogen fertilizer in D30 increased by 46.6%?52.4% compared with D15. The partial productivity of nitrogen fertilizer increased by 15.7%?16.0%. The agronomic efficiency of nitrogen fertilizer increased by 69.6%?76.7%. Correlation analysis showed that the contents of C, N, and P in flag leaves of spring wheat at grain filling stage were positively correlated with SPAD value, P_n, and dry matter accumulation in flag leaves. The ecological stoichiometric characteristics of flag leaf were negatively correlated with SPAD value, P_n and dry matter accumulation of flag leaf. Therefore, 30 cm deep fertilization under drought conditions increased the contents of C, N and P in flag leaves from booting to filling stage, delayed the decrease of N and P contents in flag leaves after flowering, optimized the ecological stoichiometric characteristics of flag leaves, reduced the restriction of N and P on the photosynthesis of flag leaves of spring wheat, increased the growth rate of P_n and shoots of flag leaves of spring wheat, delayed the senescence of flag leaves, and promoted the increase of yield.

Optimal allocation of sowing date and sowing rate of late-sowing rapeseed in the Yangtze River Basin

LOU Hong-Xiang, HUANG Xiao-Yu, JIANG Meng, NING Ning, BIAN Meng-Lei, ZHANG Lei, LUO Dong-Xu, QIN Meng-Qian, KUAI Jie, WANG Bo, WANG Jing, ZHAO Jie, XU Zheng-Hua, ZHOU Guang-Sheng

Acta Agronomica Sinica. 2024, 50(8):  2091-2105.  doi:10.3724/SP.J.1006.2024.34166

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To solve rice-rapeseed-stubble contradiction in the Yangtze River Basin and to improve the utilization rate of wintering idle field, it is urgent to carry out the research on supporting technologies for late-sowing rapeseed (sown after October 25). In this study, the early-maturing variety ‘Huayouza 137’ was used as the material, while two one-way experiment on sowing date (S1-S8, each sowing date was delayed by three days from October 25 to November 15) and sowing rate (R1-R5, 2.5, 5.0, 7.5, 10.0, and 12.5 kg hm^-2) was set in Wuhan, Hubei, in two years. The growth period, seedling dynamics, agronomic traits, the yield, and lodging related indexes were investigated. The effective accumulated temperature was counted. Linear regression and smooth curve fitting analysis were carried out. The allocation parameters of sowing date and sowing rate at late-sowing stage rapeseed were optimized, which provided technical support for the production of late-sowing rapeseed. The results showed as follows: (1) With the sowing date delaying, the growth period was shortened, the root neck diameter, the number of branches and yield was reduced, the lodging index was increased at late-sowing stage in rapeseed. Among the four growth periods of rapeseed, the effective accumulated temperature during seedling and flowering stage was positively correlated with the actual yield. (2) With the sowing rate increasing at late-sowing stage in rapeseed, the number of seedlings and the harvest density was increased, but the growth period was shortened, the total effective accumulated temperature and silique-layer thickness were decreased, lodging index was first decreased and then increased, and the yield showed a trend of the first increasing and then decreasing. (3) Regression analysis on the yield data of different sowing dates in two years was carried out. The results showed that the effective accumulated temperature before wintering and at seedling stage could be maintained above 317.1℃ and 401.1℃, respectively, when the sowing date was postponed to S3-S4, and the yield of 35 days after final flowing reached 2700.0 kg hm^-2, while lodging index was above 1.5. The smooth-curve-fitting analysis on the yield data of different sowing rates in two years was carried out. The results showed that the harvest density was parabolic with yield under different sowing rates, and the average peak yield of 35 days after final flowing was 2948.5 kg hm^-2 under harvest density of 64.2×10⁴ plants hm^-2, while lodging index was 1.6. In summary, the sowing rate of 7.5-10.0 kg hm^-2 (harvest density of 64.2×10⁴ plants hm^-2) and sowing against the clock (the average effective accumulated temperature before wintering of 317.1℃) could improve the yield and lodging index of late-sowing rapeseed.

Effects of straw returning methods and sowing depth on soil physical properties and emergence characteristics of summer peanut

ZHU Rong-Yu, ZHAO Meng-Jie, YAO Yun-Feng, LI Yan-Hong, LI Xiang-Dong, LIU Zhao-Xin

Acta Agronomica Sinica. 2024, 50(8):  2106-2121.  doi:10.3724/SP.J.1006.2024.34215

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To explore the effects of sowing depth and different wheat straw returning methods on soil physical properties, peanut hypocotyl growth dynamics and seedling emergence rate, a wheat-peanut annual positioning experiment was conducted. Peanut season was designed with a split-plot experiment. The main area was wheat straw returning methods, including moldboard plow tillage with wheat residue returning (P), rotary tillage with wheat residue returning (R), no tillage with wheat residue mulching (N). The split area was peanut varieties, which were large-seed peanut variety Shanhua 108 (B) and small-seed peanut variety Shanhua 106 (S). The split zone was the sowing depth, with 3 cm (3), 5 cm (5), 9 cm (9), 15 cm (15) in 2021 and 3 cm (3), 6 cm (6), 9 cm (9) in 2022. The results showed that moldboard plow tillage and rotary tillage increased soil temperature, but decreased soil water content. The no tillage with wheat residue mulching treatment significantly increased the soil compactness of soil layer below 6 cm. Under the same straw returning method, both varieties showed that the appropriate shallow sowing (sowing depth of 3 cm, 6 cm) significantly increased the emergence rate, deep sowing (sowing depth > 9 cm) increased hypocotyl elongation rate, increased cotyledon lipase activity, and decreased cotyledon dry weight, sucrose and soluble sugar content in cotyledons. Compared with PB3, the contents of soluble sugar and sucrose in cotyledons of PB6 and PB9 decreased by 19.72%, 39.43% and 14.15%, 40.23%, respectively. Compared with PS3, the contents of soluble sugar and sucrose in cotyledons of PS6 and PS9 decreased by 10.08%, 24.84% and 20.04%, 37.08%, respectively, indicating that deep sowing increased the nutrient consumption of cotyledons during seedling emergence. The grain yield of tillage and rotary tillage was significantly higher than that of no-tillage. With the increase of sowing depth, the number of plants per unit area and the number of pods per plant decreased significantly under different straw returning methods. Compared with PB6, the pod yield of PB3 and PB9 decreased by 7.47% and 14.94%, respectively. Compared with PS3, the pod yield of PS6 and PS9 decreased by 11.66% and 24.03%, respectively. Therefore, moldboard plow tillage with wheat residue returning treatment was conducive to improving soil structure, shortening peanut emergence time, increasing emergence rate and peanut pod yield. Under this condition, the suitable sowing depth of large-grain peanut varieties and small-small peanut varieties was 5-6 cm and 3 cm, respectively.

RESEARCH NOTES

Establishment of screening method for salt tolerance at germination stage and identification of salt-tolerant germplasms in soybean

LIU Xin-Yue, GUO Xiao-Yang, WANG Xin-Ru, XIN Da-Wei, GUAN Rong-Xia, QIU Li-Juan

Acta Agronomica Sinica. 2024, 50(8):  2122-2130.  doi:10.3724/SP.J.1006.2024.44006

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Salinity tolerance is prioritized for soybean because salt can affect soybean germination and growth. Screening for salt-tolerant soybean germplasms is of great significance for the breeding salt-tolerant soybean varieties and the utilization of saline lands for production. In this study, eight representative soybean germplasms were used as the experimental materials, soybean seeds were planted in vermiculite and treated with 150 mmol L^-1 NaCl or water as the control. The germination rate and radicle length of soybean were measured after 2 days and 3 days treatment, aiming to establish the identification index and evaluation method of soybean salt tolerance at germination stage. In comparison to control, the germination rate and radicle length of soybean decreased under salt stress. No significant difference was observed in the germination rate and relative radicle length (RRL) between germplasms after 2 days salt treatment. Significant difference was observed in RRL after 3 days salt stress. Therefore, RRL was selected as the evaluation indicator to distinguish salt tolerance of 48 soybean germplasms. The 48 germplasms were divided into 5 levels by using RRL after 3 days salt treatment. Level 1, level 2, level 3, level 4, and level 5 was high tolerant, tolerant, medium sensitive, sensitive, and most sensitive, respectively. Five high salt-tolerant germplasms and 12 salt-tolerant germplasms were identified at germination stage. These germplasms were screened for salt tolerance at both emergence and seedling stages Three soybeans were identified for salt tolerance from germination stage to seeding stage, namely Zhonghuang 685, Heinong 94, and Dongsheng 104. In conclusion, a screening method for salt tolerance at germination stage under controlled condition was established, which laid a foundation for the identification and utilization of salt tolerant germplasms.

Identification of nitrate transporter protein 1/peptide transporter protein family 6.4 gene (ScNPF6.4) and functional analysis of its regulation of tillering in sugarcane

LI Xu-Juan, LI Chun-Jia, TIAN Chun-Yan, KONG Chun-Yan, XU Chao-Hua, LIU Xin-Long

Acta Agronomica Sinica. 2024, 50(8):  2131-2142.  doi:10.3724/SP.J.1006.2024.44002

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Sugarcane is an important sugar and energy crop, and tillering is one of the important traits affecting its yield. Nitrate transporter 1 (NRT1) / peptide transporter (PTR) family (NPF) protein plays an important role in plant vegetative growth and development, mining and exploitation of NPF genes in sugarcane could lay an important foundation for genetic regulation of tillering in sugarcane. In this study, the full-length cDNA sequence of the NPF6.4 gene (ScNPF6.4) was obtained from sugarcane variety ROC22 by combining pre-transcriptomic data with RT-PCR. Subsequently, the sequence structure, physicochemical properties and phylogeny were analyzed. The tissue-specific expression of the gene in sugarcane at seedlings stage, the expression in axillary bud germination, and the expression pattern in responsive to hormone treatments were analyzed. Finally, the gene was genetically transformed into rice to verify the over-expression for functional verification. The results showed that the cDNA of ScNPF6.4 contained an open reading frame of 1806 bp encoding 601 amino acids, which belonged to the major facilitator superfamily (MFS) protein with a molecular weight of 63.9 kD and a theoretical isoelectric point of 9.23, and included 12 transmembrane helical regions. The protein was hydrophobic in nature and had no signal peptide, whereas it belonged to a class of stable non-secretory proteins. In addition, phylogenetic analysis illustrated that it belonged to the NPF family and 6.4 subfamily of proteins. Likewise, subcellular localization indicated that the protein was localized in the endoplasmic reticulum. The tissue-specific analysis revealed that the relative expression level of ScNPF6.4 was the highest in roots and lower in leaf and stem bases of sugarcane seedling. Moreover, ScNPF6.4 was up-regulated at the axillary bud sprouting stage of different sugarcane varieties, and appropriate concentrations of exogenous plant hormones such as 6-BA, ABA, GA₃, IBA, ethylene, and SLs could induce the up-regulated its expression in sugarcane at seedling stage, while ectopic over-expression of ScNPF6.4 increased the tillering number and induced early heading in rice. Thus, it could be inferred that ScNPF6.4 could regulate the germination of sugarcane tiller buds, and its expression was up-regulated by exogenous phytohormones, whereas the over-expression of this gene could increase the tillering numbers and induce early heading in rice. This study provides an important genetic resource for the breeding of sugarcane to improve tillering ability, which is beneficial for the early and rapid growth and high cane yield formation.

Comparative transcriptome profiling of leaf in curled-leaf cassava and its mutant

XIAO Ming-Kun, YAN Wei, SONG Ji-Ming, ZHANG Lin-Hui, LIU Qian, DUAN Chun-Fang, LI Yue-Xian, JIANG Tai-Ling, SHEN Shao-Bin, ZHOU Ying-Chun, SHEN Zheng-Song, XIONG Xian-Kun, LUO Xin, BAI Li-Na, LIU Guang-Hua

Acta Agronomica Sinica. 2024, 50(8):  2143-2156.  doi:10.3724/SP.J.1006.2024.34168

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The objective of this study is to elucidate the molecular regulatory mechanisms and metabolic pathways underlying the abnormal development in the leaf of curled-leaf cassava. Normal curled cassava leaf (JY), mutant expanded leaf (ZY), and mutant curled leaf (BJ) were used as the experimental materials, and bioinformatics analysis was conducted based on transcriptome sequencing (RNA-seq) data. DESeq differential analysis showed that there were 327 (255 up-regulated, 72 down-regulated) DEGs for ZY vs BJ, 1085 (337 up-regulated, 748 down-regulated) DEGs for JY vs ZY, and 689 (381 up-regulated, 308 down-regulated) DEGs for JY vs BJ, and 19 DEGs were co-expressed by three comparative groups. GO functional analysis showed that DEGs had significant differences in the pathways of stimulus response, components of membranes, and transmembrane transporter protein activity. KEGG enrichment analysis indicated that the DEGs were more active in pathways such as phenylpropanoid biosynthesis, phytohormone signaling, and protein processing in the endoplasmic reticulum. Further analysis of the DEGs in the mutated leaf expansion, curled leaves of the same plant, and normal curled leaves of other plants, demonstrated that the DEGs were concentrated in the phenylpropanoid biosynthesis pathways, starch and sucrose metabolism, and plant hormone signal transduction, which may be the key factors causing leaf expansion mutants. There were 9 main KEGG metabolic pathways and 9 important differentially expressed genes involved in leaf expansion and leaf curling. Microscopic analysis of different types of leaf revealed an increase in the number of epidermal cell layers, a loosening of sponge tissue structure, and a decrease in vascular bundle cells in mutated expanded cassava. The results of this study provide theoretical guidance for further understanding the molecular mechanisms underlying the abnormal development of cassava leaf, as well as genetic resources and improvement strategies for cassava genetic improvement and germplasm innovation.