Table of Content

12 March 2019, Volume 45 Issue 3

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REVIEW

A review for impacts of climate change on rice production in China

Xiao-Xia LING,Zuo-Lin ZHANG,Jing-Qiu ZHAI,Shu-Chun YE,Jian-Liang HUANG

Acta Agronomica Sinica. 2019, 45(3):  323-334.  doi:10.3724/SP.J.1006.2019.82044

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Rice production system is one of the most sensitive agricultural ecosystems in response to climate change. Here, we reviewed the effects of current and future climate change on rice production in China. Over the past few decades, the thermal resources during rice growing seasons showed an increasing trend, while solar radiation resources showed a decreasing trend and the precipitation’s heterogeneity increased. The frequencies of high temperature stress, heavy precipitation, drought and flood increased, which may lower down the effectiveness of hydrothermal resources. Climate change has led to a significant northward shift of potential planting boundaries for single and double rice production systems, resulted in a negative impact on the length of growth period for single rice, early rice and late rice. The researches based on statistical models and process-based crop models showed that climate change hampered rice production of China. Most reports indicated a reducing trend of yield caused by climate change for single rice, early rice and late rice, but there were still some differences in results from different methods and rice cropping regions. The trends of prolonging growth period and increasing yield are a reflection of the capability of rice production system in China to adapt to climate change, through regulating planting regionalization and improving variety and culture technics. The impact assessment with different climate scenarios showed that the projected growth period of rice would shorten and projected yield would decrease in future. That means climate change will seriously challenge the rice production and food security in China. For further study, deeper understanding of abiotic stress physiology and its incorporation into ecophysiological models, reducing the uncertainty and extending the systematicness of impact assessment are the important research areas that require much attention.

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Introducing qSS-9 ^Kas into Ningjing 4 by molecular marker-assisted selection to improve its seed storage ability

Ping ZHANG,Yi-Mei JIANG,Peng-Hui CAO,Fu-Lin ZHANG,Hong-Ming WU,Meng-Ying CAI,Shi-Jia LIU,Yun-Lu TIAN,Ling JIANG,Jian-Min WAN

Acta Agronomica Sinica. 2019, 45(3):  335-343.  doi:10.3724/SP.J.1006.2019.82035

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In this paper, the chromosome segment substitution line SL36 was used as the donor parent with the Kasalath allele at the qSS-9 locus. Ningjing 4, a commercial cultivar with ideal agronomic traits, was used as a recurrent parent, through continuous self-pollination and backcrossing for four consecutive years. Four molecular markers Y-10, Y-11, Y-14, Y-13 closely linked to qSS-9 were used to screen genotypes, and molecular marker-assisted selection (MAS) was used for seed storage ability breeding for Ningjing 4. Through genetic improvement, we obtained inheritable lines with high seed storage ability. Most agronomic traits of the lines were nearly the same as those of Ningjing 4. These lines showed significantly higher germination rate, lower malondialdehyde content and more obvious TTC staining effects under artificial aging and natural aging conditions compared with Ningjing 4, indicating that the new lines with qSS-9 ^Kas have high seed storage ability.

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Cultivation of herbicide tolerant transgenic rice by gene spliting technique

DONG Yu-Feng, WANG Xu-Jing, SONG Ya-Ya, JIN Xi, and WANG Zhi-Xing

Acta Agronomica Sinica. 2019, 45(3):  344-353.  doi:10.3724/SP.J.1006.2019.82029

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The environmental risk caused by gene flow from herbicide-tolerant rice to normal rice is focused by the public and has become a key factor affecting the use of herbicide-tolerant rice in rice production. Gene splitting technique can effectively resolve the problem of the environmental risk and be applied on the development of herbicide-tolerant rice. In this study, the herbicide-tolerant gene G2-aroA was separated into N-terminal (EPSPSn) and C-terminal (EPSPSc) and were fused with Ssp DnaE intein, N-terminal (Intein-N) and C-terminal (Intein-C), to form fusion genes EPSPSn-In and Ic-EPSPSc, respectively. EPSPSn-In and Ic-EPSPSc were separately transferred into Zhonghua11 by Agrobacterium-mediated method. Southern hybridization demonstrated that the transgenic lines En-12 and Ec-22 were integrated with a single copy of insertion. The flanking sequence analysis demonstrated that the foreign genes in the transgenic lines En-12 and Ec-22 were respectively inserted into chromosomes 2 and 6. The homozygous lines of En-12 and Ec-22 were screened using the optimized four-primer method, and the hybrid En×Ec containing both EPSPSn-In and Ic-EPSPSc was obtained through sexual hybridization. Glyphosate resistance analysis revealed that transgenic rice containing only one gene fragment did not possess glyphosate tolerance, while transgenic rice En×Ec containing both gene fragments showed glyphosate tolerance. The glyphosate tolerance of the hybrid En×Ec was slightly weaker than that of the transgenic lines containing whole G2-aroA, but could meet the requirement in rice production. The results of this study provide a scientific basis for the use of gene splitting technology to develop safe transgenic glyphosate-tolerant rice, and also a new technology platform for genetically engineering safe transgenic hybrid rice.

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Identification and expression analysis of PEBP gene family in oilseed rape

Hong-Ju JIAN,Bo YANG,Yang-Yang LI,Hong YANG,Lie-Zhao LIU,Xin-Fu XU,Jia-Na LI

Acta Agronomica Sinica. 2019, 45(3):  354-364.  doi:10.3724/SP.J.1006.2019.84095

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The plant phosphatidylethanolamine-binding protein (PEBP) genes play an important role in controlling flowering time. Rapeseed, as one of the most important oil crops in the world, has similar flowering habits with Arabidopsis thaliana. In this study, the PEBP family protein sequences of A. thaliana were used to perform BlastP analysis in the rapeseed genome. The members of the rape PEBP family were obtained, and the gene structure analysis, motif prediction, duplication analysis, phylogenetic tree construction, selective pressure analysis and tissue expression analysis were carried out on the family members. A total of 26 rapeseed PEBP gene members were identified, and most of them contained four exons and three introns, and motif-1 and motif-2 were the characteristics of PEBP members. Over 76.9% members were segmental duplicated. Phylogenetic tree analysis showed that PEBP was divided into three subfamilies. The tissue-specifics analysis based on RNA-Seq data showed that 26 PEBP members of rapeseed had very obvious tissue expression characteristics. All these results greatly enrich our understandings of flowering genes and regulation patterns in Brassica napus, and provide a theoretical basis for further molecular breeding in B. napus.

Bioinformatics analysis and response to nitrate-cadmium stress of NRT1.5 and NRT1.8 family genes in Brassica napus

Gui-Hong LIANG,Ying-Peng HUA,Ting ZHOU,Qiong LIAO,Hai-Xing SONG,Zhen-Hua ZHANG

Acta Agronomica Sinica. 2019, 45(3):  365-380.  doi:10.3724/SP.J.1006.2019.84099

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The absorption and transportation of nitrate in plants require the assistance of nitrate transporters (NRTs). The expression of two members of the NRT1 family, including NRT1.5 and NRT1.8 genes was strongly induced by nitrate, and regulated the long-distance transport and distribution of nitrate between roots and shoots in Arabidopsis. NRT1.5 and NRT1.8 homologous genes in B. rapa, B. oleracea, and B. napus were identified by bioinformatics with the basic sequences of AtNRT1.5 and AtNRT1.8 and analyzed in gene structures and proteins molecular characterization, gene copy number variations, chromosome locations, evolutionary relationship tree, proteins conservative sequence alignment and the transmembrane domains. NRT1.5 and NRT1.8 responsive to the low concentration nitrate and cadmium stress were also determined by transcriptome analysis and co-expression network analysis, showing that NRT1.5 and NRT1.8 proteins belong to major facilitator superfamily (MFS) and peptide transporter (PTR) with the conservative transmembrane domains and motifs (F-Y-L-A-L-N-L-G-S-L) in B. rapa, B. oleracea, and B. napus. High-throughput transcriptome analysis showed that the expression of NRT1.5 gene was up-regulated and the NRT1.8 was down-regulated by low concentration nitrate treatment for 72 h in roots, which caused more nitrate transferred from roots to shoots. On the contrary, the ethylene/jasmonic acid-NRT signaling module could promote NRT1.8 up-regulation and inhibit the expression of NRT1.5 by cadmium treatment. So that more nitrate transported from shoots to roots and improved the ability of plants to resist cadmium stress. This study is valuable for the research of biological functions of NRT1.5 and NRT1.8 family genes in B. napus and the responses to nitrate-cadmium stress. Our results also provide references for the bioinformatic study of NRT1.5 and NRT1.8 family genes in other plant species.

Transcriptional regulation of oil biosynthesis in different parts of Wanyou 20 (Brassica napus) seeds

Yu-Ting ZHANG,Shao-Ping LU,Cheng JIN,Liang GUO

Acta Agronomica Sinica. 2019, 45(3):  381-389.  doi:10.3724/SP.J.1006.2019.84105

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Brassica napus is one of the main oil crops and the seed oil content is generally between 35% and 50%. Oil is mainly stored in the seed embryo. Embryo is composed of cotyledons (including outer and inner cotyledons) and embryonic axis. The oil content and fatty acid composition of different parts of low erucic Brassica napus WY20’s seed were analyzed. There was a significant difference in oil content in different parts of the seed. The oil content in the outer cotyledon was the highest while embryonic axis had the lowest oil content. At the same time, the fatty acid composition also showed significant difference in different parts of the seed. The ratio of C16:0, C18:2, and C20:0 in embryonic axis was significantly higher than that in cotyledon. The ratio of C16:0 in the embryonic axis was about twice more than that of the cotyledons. The ratio of C18:1 and C20:1 in cotyledons was significantly higher than that in embryonic axis. C18:0 had the lowest content in the outer cotyledon and no difference in the inner cotyledons and embryonic axis. C18:3 had the highest content in the outer cotyledons and no difference between inner cotyledons and embryonic axis. Transcriptome analysis was performed for the inner cotyledon, outer cotyledon and embryonic axis of the 34-day-old seed. A total of 7192 differentially expressed genes (DEGs) were identified after pairwise comparison of gene expression of the three parts. There were much fewer DEGs between cotyledons and more DEGs between cotyledon and embryonic axis. These DEGs were enriched in biological processes such as photosynthesis, fatty acid metabolism and chlorophyll metabolism. Gene function annotations revealed that there were 355 genes involved in lipid metabolism, especially in the de novo fatty acid biosynthesis in plastid. This study suggests that transcriptional regulation of key genes involved in oil biosynthesis results in different oil contents and fatty acid compositions in different parts of seed in Brassica napus.

Structure and expression analysis of the members of peanut annexin gene family

Hui-Min WANG,Xin-Guo LI,Shu-Bo WAN,Zhi-Meng ZHANG,Hong DING,Guo-Wei LI,Wen-Wei GAO,Zhen-Ying PENG

Acta Agronomica Sinica. 2019, 45(3):  390-400.  doi:10.3724/SP.J.1006.2019.84056

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Annexin is a kind of calcium-dependent phospholipid binding proteins involved in the regulation of plant metabolism, growth and development, drought resistance and salt tolerance, and its structure is species-specific in different plants. In order to have a systematic analysis of the annexin gene family of peanut, we identified 30 annexin genes from the peanut genome database, and analyzed their characteristics using bioinformatics method. Peanut annexin (annexin of Arachis hypogaea, AnnAh) genes were unevenly distributed on 13 chromosomes, with 13 in A genome and 17 in B genome. There were 2 to 8 introns in the AnnAhs, with 5 to 6 introns in most AnnAhs. Phylogenetic analysis showed that the clustering relationship was complex. The annexins of lower plant, monocotyledonous and dicotyledonous plants were distributed at interval, with AnnAhs inserting in each branch. However, in each small branch, AnnAhs were basically clustered with the dicotyledonous plant annexins, and close to soybean, alfalfa and sunflower, followed by Arabidopsis; but several AnnAhs were associated with monocotyledonous and lower plant annexins. All 30 AnnAhs had no transmembrane domain, and 16 of them were located in cytoplasm, and the others’ localization was uncertain. Results of alternative splicing (AS) analysis of AnnAhs showed that only 11 AnnAhs experienced AS, which accounted for about 38% of all AnnAhs; the AS events occurred most in roots, followed by leaves, and the least in seeds. The expression level of AnnAhs was high in seed2 and root, followed by seed1, and lower in leaf. The comprehensive analysis of AnnAhs can provide some theoretical support for peanut resistance breeding.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Effect of organic fertilizer and rotational tillage practices on soil carbon and nitrogen and maize yield in wheat-maize cropping system

Kai SUN,Zhen LIU,Heng-Yu HU,Geng LI,Wen-Tao LIU,Liu YANG,Tang-Yuan NING,Yan-Ling WANG

Acta Agronomica Sinica. 2019, 45(3):  401-410.  doi:10.3724/SP.J.1006.2019.83028

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Quantitatively analyzing the effects of different tillage rotations and organic fertilization practices on soil carbon, nitrogen and their enzyme activities is of great importance to improve soil fertility and promote maize yield. This study was intended to explore changes of soil organic carbon, total nitrogen, urease and sucrase activities under different tillage rotations and organic manure patterns in wheat-maize cropping system of North China Plain. Six treatments were compared, which were straw returning with rotary tillage-subsoiling (PRS), straw returning with subsoiling-no tillage (PSN), straw returning with conventional tillage-no tillage (PCN), cow manure with rotary tillage-subsoiling (FRS), cow manure with subsoiling-no tillage (FSN), and cow manure with conventional tillage-no tillage (FCN). The tillage mode, organic manure and their interactions had significant effects on soil fertility. The RS and SN patterns had higher contents of soil organic carbon and total nitrogen, and higher enzyme activities of urease and sucrase in 0-10 cm and 10-20 cm soil layers compared with the CN pattern. In rotation tillage mode of RS, straw returning significantly increased the soil organic carbon contents in 10-20 cm, 20-30 cm, and 30-40 cm soil layers, and increased the total nitrogen content and sucrase activity in 10-20 cm soil layer. In rotation tillage mode of SN, the soil organic carbon, total nitrogen content, and sucrase activity in 0-10 cm and 10-20 cm soil layers, and urease enzyme activity in each soil layer, were significantly increased by applying cow manure compared with straw returning. Compared with PCN, PRS and FSN could significantly increase the soil fertility. The soil organic carbon, total nitrogen, urease and sucrase activities in FSN treatment were the highest in 0-10 cm and 10-20 cm soil layers in all treatments. The tillage mode, organic manure and their interactions had significant effects on maize yield. Compare with CN pattern, maize yield of the RS and SN patterns were averagely increased by 1.89%-10.49% and 5.44%-11.99%, respectively. In rotation tillage mode of RS, the yield under straw returning was significantly increased by 2.91%-3.11% compared with that under using cow manure; while in rotation tillage mode of SN, the yield under straw returning was 5.02%-9.07% lower than that under applying cow manure. The average yields of two years were in the order of FSN>PRS>FRS>PSN>FCN>PCN. This study demonstrates that cow manure with subsoiling-no tillage can increase the soil organic carbon, total nitrogen, and urease and sucrase activities, and increase the crop yield as a result. Thus, cow manure with subsoiling-no tillage management practice is a better mode for increasing soil fertility and crop productivity, which should be expected to be adopted in the North China Plain.

Exogenous MeJA improves cold tolerance of tobacco by inhibiting H₂O₂ accumulation

Xiao-Han MA,Jie ZHANG,Huan-Wei ZHANG,Biao CHEN,Xin-Yi WEN,Zi-Cheng XU

Acta Agronomica Sinica. 2019, 45(3):  411-418.  doi:10.3724/SP.J.1006.2019.84090

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Methyl jasmonate (MeJA) is an elicitor evolving in a variety of physiological and biochemical processes. To explore the effects of exogenous MeJA on tobacco seedlings under low temperature conditions, we used the tobacco variety “Yuyan 10” and sprayed four concentrations (1, 10, 100, 1000 μmol L ^-1) of MeJA for 3 days on plants. Under low temperature with the treatment under normal temperature as positive and that under low temperature on negative control. The growth indicators, relative electrolyte permeability, photosynthetic pigment content, antioxidant enzyme activity and hormone content of each treatment were measured, showing that the treatment with 10 μmol L ^-1 methyl jasmonate could reduce the damage of tobacco seedlings caused by low temperature. The effect of H₂O₂ was then verified by applications of DPI, 10 μmol L ^-1 MeJA, and DPI+MeJA with the same material and growth period, while low temperature treatment was used as a control. The contents of H₂O₂, O ^2-, CAT, MDA, and ASA-GSH cycle were determined. In conclusion, H₂O₂ in tobacco plants mainly exists as a poison molecule instead of a second messenger under the treatment of exogenous methyl jasmonate combined with low temperature.

Evaluation of drought tolerance and screening for drought-tolerant indicators in sweetpotato cultivars

Hai-Yan ZHANG,Bei-Tao XIE,Bao-Qing WANG,Shun-Xu DONG,Wen-Xue DUAN,Li-Ming ZHANG

Acta Agronomica Sinica. 2019, 45(3):  419-430.  doi:10.3724/SP.J.1006.2019.84087

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Field experiments were conducted under a rain proof shelter using 15 sweetpotato cultivars with drought stress treatment and well-watered treatment. The yield and agronomic traits of different sweetpotato cultivars under drought stress were studied. The sweetpotato cultivars were classified according to the drought resistance coefficient of each cultivar. The drought-tolerant cultivars (DC ≥ 0.6) included Jishu 21, Jishu 25, Jixu 23, Jishu 15, and Yanshu 25. The moderate drought-tolerant cultivars (0.4 ≤ DC < 0.6) included Xushu 18, Jishu 26, Beijing 553, Jizishu 2, and Jishu 18. The drought-sensitive cultivars (DC < 0.4) included Zhengshu 20, Jizishu 3, Jishu 22, Jizishu 1, and Ayamaraski. Drought stress caused the decline of leaf number per plant, vine length, leaf area index and biomass which was different among cultivars. The impact of drought stress on drought-tolerant cultivars was lower than that of drought-sensitive cultivars. Under drought stress, these were significant positive correlations of drought resistance with leaf number per plant, vine length, leaf area index and biomass of different cultivars. All the agronomic traits could be used as a comprehensive evaluation index for identifying drought resistance of sweetpotato cultivars. Xushu 18 could be used as a control cultivar in the identification and screening of drought tolerance.

Increasing spring maize yield by basic application of PASP chelating nitrogen fertilizer in northeast China

Hui-Hui TANG,Yan-Li XU,Qing-Yan WANG,Zheng-Bo MA,Guang-Yan LI,Hui DONG,Zhi-Qiang DONG

Acta Agronomica Sinica. 2019, 45(3):  431-442.  doi:10.3724/SP.J.1006.2019.83056

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The randomized block field experiments were conducted using maize variety of Zhongdan 909 with different nitrogen treatments of polyaspartic acid chelating nitrogen fertilizer (PASP-N) and commonly used nitrogen fertilizer (CN) in Gongzhuling Experimental Station (43o29°55°°N, 124o48°43°°E) in Jilin province in 2016 and 2017. The PASP-N increased maize yield, ear length and leaf area index (LAI) by 0.9%-3.0%, 0.5%-2.9%, and 18.5%-22.3% respectively, and decreased bare top length, plant height and ear height by 13.8%-46.7%, 1.5%-2.5%, and 0.7%-8.4%, respectively, compared with CN. Moreover, PASP-N significantly influenced activity of enzymes related to nitrogen metabolism: nitrate reductase (NR) activity decreased by 1.4%-19.8% at anthesis stage, glutamine synthetase (GS) activity increased by 18.5%-33.1% at 30 days after anthesis, and glutamic oxalacetic transaminase (GOT) activity increased by 0.8%-6.4% at 20 days after anthesis. The total nitrogen inputs of PASP-N and CN for the highest maize yield were 185.3 kg ha ^-1 and 219.1 kg ha ^-1, respectively, with 108.9 kg ha ^-1 higher in PASP-N treatment than in CN treatment. Nitrogen fertilizer partial productivity, agronomic efficiency, apparent utilization and physiological efficiency of nitrogen fertilizer in PASP-N treatment increased by 51.3%-54.4%, 2.9%-104.2%, 28.9%-126.6%, and 48.0%-405.2%, respectively, compared with these in CN treatments. In conclusion, PASP could enhance nitrogen metabolism during middle and late grain-filling stage, resulting in increased yield and nitrogen use efficiency in maize.

Effects of drip irrigation pattern and water regulation on the accumulation and allocation of dry matter and nitrogen, and water use efficiency in summer maize

Ming-Da YANG,Xiao-Kang GUAN,Ying LIU,Jing-Yu CUI,Chao-Ming DING,Jing-Li WANG,Jing-Li HAN,Huai-Ping WANG,Hai-Ping KANG,Tong-Chao WANG

Acta Agronomica Sinica. 2019, 45(3):  443-459.  doi:10.3724/SP.J.1006.2019.83026

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A split-plot experiment was conducted to explore the dry matter and nitrogen accumulation and allocation characteristics, and water use efficiency of maize in response to different drip irrigation regimes. Drip underground (DU) and drip surface (DS) were applied with three levels of water treatment [W40, W60, and W80 referring to 40%-50% field water capacity (FWC), 60%-70% FWC, and 80%-90% FWC, respectively]. The nitrogen accumulation and water use efficiency of DU treatment has been significantly increased by 6.18% and 4.85%-8.61% respectively compared with DS treatment. The response of dry matter and nitrogen characteristics to drip irrigation patterns was depended on soil water regulation levels. Under W40 and W60 conditions, DU significantly increased the net photosynthetic rate of summer maize, improved dry matter and nitrogen accumulation after silking and their contribution to grains. At last, DU increased the dry matter accumulation, nitrogen accumulation in grains, yield and nitrogen partial factor productivity by 3.29% to 19.94%, -1.10% to 20.65%, 3.29% to 19.94%, and 3.31% to 23.64% respectively. While under W80 condition, dry matter and nitrogen accumulations, yield and crop evapotranspiration were 6.80% to 12.24%, 5.93%, 8.39% to 14.91%, and 9.73% to 14.57% respectively higher in DS than in DU. In conclusion, drip underground could improve dry matter and nitrogen translocated to grain, and increase yield under limited irrigated condition (W40 and W60), while under adequate water supply (W80), drip surface could enhance the dry matter and nitrogen accumulation with lower water use efficiency due to excessive water consumption.

Effects of photoperiods and temperatures on physiological characteristics and chlorophyll synthesis precursors of adzuki bean seedlings

Ning HE,Xue-Yang WANG,Liang-Zi CAO,Da-Wei CAO,Yu LUO,Lian-Zi JIANG,Ying MENG,Chun-Xu LENG,Xiao-Dong TANG,Yi-Dan LI,Shu-Ming WAN,Huan LU,Xu-Zhen CHENG

Acta Agronomica Sinica. 2019, 45(3):  460-468.  doi:10.3724/SP.J.1006.2019.84002

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The aim of this study was to discuss the mechanism of chilling injury and the blocked site of chlorophyll synthesis in primary leaf, providing theoretical basis for breeding and cultivation of cold-resistant cultivars. Two Japanese adzuki bean varieties with different temperature and light reactions were used to study the effects of short-term (18 d) and long-term (28 d) low temperature shading treatments (10-13°C, 2% shading) on H₂O₂, SOD, CAT, APX, and Chl of seedlings in the artificial climate chamber, and the effects of the treatment durations of low temperature (1 d, 3 d, 5 d, 7 d, 10°C, 50 μmol m ^-2 s ^-1) and dark (25°C, 1 d, 3 d, 5 d, 7 d) under chlorophyll synthesis blocked site (25°C, and under illumiation at 62.5 μmol m ^-2 s ^-1for 24 h). The content of H₂O₂ and activity of SOD had significant difference between cold resistant and susceptible varieties during seedling stage. The content of H₂O₂ in susceptible variety was 66 folds of the resistant one, and with the greening treatment antioxidant activity and content of chlorophyll were rapidly dropped until totally vanished after 8 h. The main cause of difference in chlorophyll synthesis between the two varieties was the dark treatment but not the low temperature treatment. It was suggested that the transformation from δ-ALA to Proto IX might be blocked in chloroplast stroma, which eventually inhibited chlorophyll synthesis and decreased chlorophyll content. It is suggested that H₂O₂ content and SOD activity may be more closely related to the cold tolerance of adzuki bean at seedling stage. The transformation of Proto IX is the blocking site in chlorophyll synthesis which causes etiolated seedlings of adzuki bean.

RESEARCH NOTES

Expression and promoter activity of GhTFL1a and GhTFL1c in Upland cotton

Xiao-Hong ZHANG,Gen-Hai HU,Han-Tao WANG,Cong-Cong WANG,Heng-Ling WEI,Yuan-Zhi FU,Shu-Xun YU

Acta Agronomica Sinica. 2019, 45(3):  469-476.  doi:10.3724/SP.J.1006.2019.84082

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In this study, we cloned the phosphatidylethanolamine-binding protein GhTFL1a and GhTFL1c genes from Upland cotton, and analyzed their expression and promoter activity. The results of promoter structure prediction revealed that GhTFL1a promoter contains abscisic acid (ABA) responsiveness elements, drought-induced MYB binding sites and shoot-specific expression and light responsiveness elements, and the promoter region of GhTFL1c contains ethylene-responsive element, drought-induced MYB binding sites and salicylic acid (SA) responsiveness elements. Thus, we constructed the fusion vector pBI121-GhTFL1a-GUS and pBI121-GhTFL1c-GUS, respectively. Transient transformation of tobacco showed that both promoters had the activity to drive the expression of target gene GUS. Quantitative Real-time PCR result indicated that the expression profile of GhTFL1a and GhTFL1c was opposite during different photoperiod treatments of cultivated and semi-wild cotton. Meanwhile, the expression of GhTFL1a was induced by ABA, SA, and salt (NaCl), while GhTFL1c expression was induced by SA, gibberellin (GA) and ABA. Taken together, the results suggest that GhTFL1a and GhTFL1c might be involved in the regulation of response to abiotic stresses (SA and ABA), which could provide a solid foundation for further function identification.

Mapping of quantitative trait loci conferring resistance to brown spot in cigar tobacco cultivar Beinhart1000-1

Zhi-Jun TONG,Yi-Han ZHANG,Xue-Jun CHEN,Jian-Min ZENG,Dun-Huang FANG,Bing-Guang XIAO

Acta Agronomica Sinica. 2019, 45(3):  477-482.  doi:10.3724/SP.J.1006.2019.84035

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Tobacco brown spot (TBS) caused by Alternaria alternata is one of the most destructive foliar diseases affecting tobacco (Nicotiana tabacum L.) production and quality in China. Breeding TBS-resistant cultivars is difficult by traditional method because the resistance has proved to be quantitatively inherited. To facilitate marker-assisted selection, we carried out a study of mapping quantitative trait loci (QTLs) for TBS resistance. We developed an F₂ population consisting of 362 individuals from a cross between a TBS-susceptive flue-cured tobacco Honghua Dajinyuan (HD) and a TBS-resistant cigar tobacco cultivar Beinhart1000-1, and constructed a genetic map consisting of 670 SSR markers based on this population. Using disease index (DI) as the indicator of TBS resistance, we detected two QTLs located between SSR markers TMs05179 and TMs04022, and TM61049 and TM62212 on linkage group (LG) 20 and LG23, respectively. The resistant alleles of the two QTLs were all from the resistant parent Beinhart1000-1. The two QTLs together could explain 81% of the DI difference between the two parents in total, and 64% of their additive effects. Therefore, the two QTLs will be useful for TBS resistance breeding.