Table of Content

12 July 2016, Volume 42 Issue 07

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REVIEW

Advances on Methodologies for Genome-wide Association Studies in Plants

FENG Jian-Ying,WEN Yang-Jun,ZHANG Jin,ZHANG Yuan-Ming

Acta Agron Sin. 2016, 42(07):  945-956.  doi:10.3724/SP.J.1006.2016.00945

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Genome-wide association studies (GWAS) have been widely used in human, animal and plant genetics, and many new approaches and their softwares have been developed in recent years. To make a better use of the GWAS methods in applied research, in this study we summarized the advances on methodologies and softwares for GWAS. First, LD score regression was introduced to investigate the effect of population structure on GWAS. Then, the main approaches and their softwares for GWAS in plants were reviewed, including a single-locus model, a multi-locus model, epistasis, and multiple correlated traits. Finally, we prospected the future developments in GWAS. It should be noted that, in real data analysis at present, the methodologies for genome-wide single-marker scan under polygenic background and population structure controls are widely used, and the corresponding results are complementary to those derived from non-parameter approaches with high false discovery rate. However, the future approaches for GWAS should be based on the multi-locus genetic model, QTN-by-environment interaction, epistatic detection and multivariate analysis. Our purpose was to provide beneficial information in theoretical and applied researches.

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Morphological Characterization and Fine Mapping of Zebra Leaf Mutant zebra1349 in Rice (Oryza sativa L.)

GUO Guo-Qiang,SUN Xue-Wu,SUN Ping-Yong,YIN Jian-Ying,HE Qiang,YUAN Ding-Yang,DENG Hua-Feng,YUAN Long-Ping

Acta Agron Sin. 2016, 42(07):  957-965.  doi:10.3724/SP.J.1006.2016.00945

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A new zebra leaf mutant zebra1349 was attained in a restorer line crossing population of [R128//(R318/R1025) F₁] F₆ in Hengyang Agricultural Science Research Institute. This mutant showed normal green leaves at seedlings stage, but a zebra leaf phenotype with green-yellow bands in penpendicular to leaf vein appeared at five days after transplanting, which was most obvious at sixth-leaf stage, and recovered normal green leaves around 30 days (ninth-leaf stage) after transplanting. Until the mature stage, the zebra1349 mutant showed insignificant difference with the wild type in major agronomic traits. The contents of total chlorophyll, chlorophyll a, chlorophyll b and carotenoid in yellow parts of the mutant leaf at sixth-leaf stage decreased by 55.86%, 61.02%, 39.34% and 47.03%, respectively. Transmission Electron Microscopic (TEM) results indicated that the chloroplast of the mutant yellow leaf showed a serious thylakoid membrane degradation and decomposition, and the number of thylakoid grana lamella decreased significantly with larger gap and looser arrangement. Genetic analysis using F₁ and F₂ of the reciprocal crosses between zebra1349 and normal green rice varieties revealed that the zebra-leaf trait was controlled by one pair of recessive nuclear genes. With 1192 recessive plants in a F₂ population from the cross between zebra1349 mutant and normal green variety 02428, the ZEBRA1349 gene was finely mapped between two InDel markers indel39 and indel44 on chromosome 12 with a genetic distance of 0.04 cM and 0.17 cM respectively, and the physical distance was 89 kb based on comparing with the reference genome of Japonica rice Nipponbare. These results provide a foundation for further map-based cloning of ZEBRA1349 and molecular marker-assisted breeding.

Characterization and Gene Fine Mapping of a Rice Dominant Spotted-leaf Mutant

GUO Dan,SHI Yong-Feng,WANG Hui-Mei,ZHANG Xiao-Bo,SONG Li-Xin,XU Xia,HE Yan,GUO Liang,WU Jian-Li*

Acta Agron Sin. 2016, 42(07):  966-975.  doi:10.3724/SP.J.1006.2016.00966

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A stable inherited rice spotted-leaf mutant HM113 was isolated from an EMS-induced IR64 mutant bank. Under natural conditions, brown lesions were observed on the leaves in three weeks after sowing and spread to the sheaths at the initial heading stage. Agronomic traits including the plant height, panicle length, number of panicles, number of filled grain/panicle, seed-setting rate and 1000-grain weight were decreased significantly in HM113. In addition, the photosynthetic pigment contents, net photosynthetic rate and soluble protein content in the mutant were significantly lower than those in the wild type IR64, while the MDA content was similar to that in the wild-type. Activities of CAT and SOD were significantly lower and activity of POD was significantly higher in the mutant than in IR64. Histochemical analysis showed that cell death and ROS accumulation were occurred in and around the lesions in HM113. Furthermore, disease resistance to bacterial blight pathogens was significantly enhanced in the mutant in contrast to that in the wild type IR64. Expression of defense-related genes including AOS2, PAL4, PR10,and PR1b was apparently up-regulated in the mutant. Genetic analysis indicated that the mutant trait was controlled by a novel single dominant nuclear gene, tentatively termedas Spl^HM113, which was detected to be located in a region around 308 kb flanked by RM21605 and RM418 on the long arm of chromosome 7. The data and populations obtained in the present study would facilitate the isolation and functional analysis of Spl^HM113.

Identification and Gene Mapping of an Early Senescent Leaf Mutant esl6 in Oryza sativa L.

YANG Bo,XIA Min, ZHANG Xiao-Bo,WANG Xiao-Wen,ZHU Xiao-Yan,HE Pei-Long,HE Guang-Hua,SANG Xian-Chun*

Acta Agron Sin. 2016, 42(07):  976-983.  doi:10.3724/SP.J.1006.2016.00976

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As an essential process in life, natural senescenceis necessary to adapt plant to environment diversity, while earlier senescence could reduce yield per unit and cause inferior quality in crop production. Therefore, it is significant to elucidate senescence molecular mechanism in plant. Here, we reported a novel rice mutant esl6 derived from the progeny of EMS-induced restorer line Jinhui10, which senescent peculiarity was observed at the early stage of life. In detail, cultivated under the paddy field, the esl6 had no obvious difference with the wild type before the 4-leaf stage, while after that the whole leaf blade of esl6 displayed chlorosis in the tip and kept normal green in the base until the flowering stage. Subsequently, all leaf blades in the esl6 demonstrated chlorosis and senescence, still more severe at the upper position. Observation by scanning electron microscope showed that cell structures in the senescent location of esl6 leaf blade were abnormal and filled with ruptured cell membranes, enlarged vacuoles and broken organelles such as the chloroplasts containing incomplete stroma thylakoids and excessive starch grains. Meanwhile, early senescence significantly lessened photosynthetic pigment contents and photosynthetic rate. The activities of SOD, CAT, and POD raised and the contents of O₂^?, H₂O₂, and ·OH increased in the esl6 leaf tip, and all of the differences led to the extremely significant level compared with those of the wild type. Additionally, the mutational plant showed semi-dwarfism and shorter leaf blades, the first and second internodes decreased to the extremely significant level in statistics. Genetic analysis suggested that the mutational traitswere controlled by a recessive nuclear gene. The gene was finally mapped on chromosome 9 with 203 kb physical distances between Indel markers Sind09-3 and Sind09-4 on the basis of F₂ generation of Xida1A/esl6. All of these provide a foundation for ESL6 cloning and function analysis and then are beneficial to ascertaining the molecular mechanism of senescence in Oryza sativa L.

Detection of the Molecular Marker and Chromosomal Segment linked to Unreduced Gamete Gene in Common Wheat

KOU Chun-Lan,ZHAO Lai-Bin,LIU Meng,HAO Ming,NING Shun-Zong,YUAN Zhong-Wei,LIU Deng-Cai,ZHANG Lian-Quan*

Acta Agron Sin. 2016, 42(07):  984-989.  doi:10.3724/SP.J.1006.2016.00984

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Hexaploid common wheat (Triticum aestivum L., AABBDD, 2n=42) arose fromspontaneous chromosome doubling of the hybrid between T. turgidum and Aegilops tauschii Cosson. The process of chromosomes doubling is mainly determined by unreduced gametes (UG)genes in T. turgidum. The genetic effects on the UG production may vary among T. turgidum lines. In this study, a SSR marker close to the UG geneQTug.sau-3B(Xgpw1146) and high throughput DArTseq genotyping technique were used to screen the UG gene in common wheat lines transferred from T. turgidum via synthetic hexaploid wheat (SHW) as a bridge. Out of the analyzed 105 SHW-derived elite lines, 17 had the Xgpw1146allele from T. turgidum, indicating that the UG gene was probably transferred into these wheat lines. According to the DArTseq genotyping data on 88 lines derived from the synthetic hexaploid wheat SHW-L1, all these lines with the T. turgidumXgpw1146allele contained a chromosomal segment of SHW-L1,probably covering the Xgpw1146 locus. This indicatesthat the adjacent region of the UG gene as a chromosomal segment was transferred into wheat lines. These SHW-derived lines have important application potential on wheat doubled haploid breeding.

Identification, Expression and Variation Analysis of Salt Tolerance Related GmNAC Genes in Soybean

ZHANG Yan-Wei,ZHANG Li-Feng,LI Wei,WANG Cai-Jie,ZHANG Jun,XU Ran

Acta Agron Sin. 2016, 42(07):  990-999.  doi:10.3724/SP.J.1006.2016.00990

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NAC genes play an important role in plant stress tolerance. In this study, bioinformatics method was used to identify the stress related GmNAC gene in soybean; the expression of candidated GmNAC genes in root and leaf was analyzed in soybean with NaCl treatment by Real-time-PCR. Reverse transcription PCR was performed to clone genes with significant difference in expression. The results showed that there were 175 genes in soybean GmNAC gene family. There were 11 GmNACproteins with highly conserved NAC located on the same evolutionary branch with the stress related NAC proteins in rice and Arabidopsis. The expression of 11 GmNAC genes in soybean root was higher than that in leaf. The GmNAC genes were all induced by NaCl stress, but part of the GmNAC genes showed different expression levels between root and leaf in soybean varieties with different salt tolerances. There were three synonymous mutations and one non-synonymous mutation on the CDS region of Glyma06g11970.1 and one synonymous mutation on the CDS region of Glyma06g16440.2 in Qihuang 34, Xudou 10, and Fendou 95.

Cloning and Analyses of Expression and for BnFAD2 Genes in Brassica napus

LIU Rui-Yang,LIU Fang,GUAN Chun-Yun

Acta Agron Sin. 2016, 42(07):  1000-1008.  doi:10.3724/SP.J.1006.2016.01000

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The oil containing high oleic acid is high nutritional. In Brassica napus, the fatty acid desaturase gene (FAD2) is the key gene controlling oleic acid content. In this study, the full-length cDNA sequences of three genes located on chromosome A5, C5 and A1 in Brassica napus were cloned and named BnFAD2-A5, BnFAD2-C5 and BnFAD2-A1. The three genes encode proteins with 384, 384 and 136 amino acid residues, respectively. TMHMM was used to predict transmembrane domain and Clust X software was used to analyze the activity center of FAD2 genes. Both of the results showed that BnFAD2-A1 did not have the function of dehydrogenase. The yeast complementary experiment on four genes (including published BnFAD2-C1 gene) showed that the desaturation capability of BnFAD2-A5 gene was next to that of BnFAD2-C5 gene, and both of them were greater than that of BnFAD2-C1 gene. The expression patterns of the four genes were analyzed by using qRT-PCR technique in different tissues and the protein stability of BnFAD2-C1, BnFAD2-A5 and BnFAD2-C5 was analyzed by using Hemagglutinin labeling method. Both of the results revealed that BnFAD2-A5 and BnFAD2-C5 aremajor genes affecting the accumulation of oleic acid in rape seed.

Genetic Gain of Soybean Breeding for Yield in Henan Summer Soybean Zone Overthe Last 30 Years

HUANGZhong-Wen,XU Xin-Juan,WANGWei,MEIPei-Pei

Acta Agron Sin. 2016, 42(07):  1009-1015.  doi:10.3724/SP.J.1006.2016.01009

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Improvement of yield potential is the main objective for soybean breeding. Studying genetic gain of soybean yield and its related traits is very important for the development of high yield breeding strategies in the future. To this end, this research was conducted a two-year yield evaluation trial using 18 soybean cultivars randomly selected from all the cultivars released during the last 30 years in Henan province. Results showed that the yield presented an increasing trend with the genetic gain of 17.39 kg ha^–1or 0.7% per year. Effective branch, nodes on main stem, seed weight and plant height had a weak positive genetic gain, whereas pods per plant and seeds per pod showed insignificantly negative genetic gain. Yield had a significant genetic and phenotypic correlation with seed weight, nodes on main stem and plant height while an insignificant correlation with their environments,which indicated that the three traits had high genetic heritability. With the genetic improvement of yield traits, the three traits were improved at the same time and not easily affected by environmental conditions. Genetic and phenotypic correlations between yield and effective branch, pods per plant and plant height were not significant because of their significant negative genetic correlation with seed weight, nodes on main stem, and plant height.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Effects of Nutrient Management on Yield and Nitrogen Use Efficiency of Direct Seeding Rice

GUO Jiu-Xin,KONG Ya-Li,XIE Kai-Liu,LI Dong-Hai,FENG Xu-Meng,LING Ning,WANG Min,GUO Shi-Wei

Acta Agron Sin. 2016, 42(07):  1016-1025.  doi:10.3724/SP.J.1006.2016.01016

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The effects of different nutrient management models on the yield and nitrogen (N) use efficiency (NUE) of direct seeding rice were investigated under site-specific farmers cultivate practice situation. We conducted a field experiment at eight farmers’ field in basic farmland protection region with a rice-wheat rotation ecosystem in Xinghua County, Maoshan town, Jiangsu Province, from June 2011 to November 2013. Three different nutrient management models and a control were used in this experiment including fertilizer free treatment (CK), farmers’ fertilizer practice (FFP) and optimal fertilizer management 1 and 2 (OPT1 and OPT2). The rice yield and its components, N accumulation and distribution, and NUE were determined. The results showed that the rice grain yield of OPT treatments (226 kg ha^-1 N) significantly increased 5.5% due to the increase of grains per panicle, seed setting percentage, and 1000-grain weight while the N fertilizer application reduced 32.1% as compared with FFP treatment (333 kg ha^-1 N). The rice grain yield of OPT2 treatment was 3.1% higher than that of OPT1 treatment while resulted from increasing potassium application (18 kg ha^-1 K₂O) at booting stage. The N concentration of different parts of plant, N requirement for 100 kg grain, straw N accumulation and N distribution in vegetative organs of OPT treatment were significantly lower than these of FFP treatment. Compared with FFP treatment, OPT treatment also significantly improved NUE of rice plants, in which partial factor productivity of N (PFP_N), agronomic efficiency of N (AE_N), the recovery efficiency of N (RE_N) and physiological efficiency of N (PE_N) increased by 55.5%, 79.1%, 18.8%, and 48.7%, respectively. There was a significantly positive correlation between plant N accumulation and grain yield in rice, and the effect of yield increase per unit N accumulation in OPT treatment was higher than that in FFP treatment. Therefore, the optimal nutrition management model, including controlling total N rate, regulating application stage of N fertilizer and increasing potassium application, can be need to obtain a comprehensive effect for high grain yield and high N fertilizer use efficiency in direct seeding rice planted by farmers.

Effects of Alternate Wetting and Drying Irrigation on Yield and Water Use Efficiency of Rice

CHU Guang,ZHAN Ming-Fei,ZHU Kuan-Yu,WANG Zhi-Qin,YANG Jian-Chang*

Acta Agron Sin. 2016, 42(07):  1026-1036.  doi:10.3724/SP.J.1006.2016.01026

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Alternate wetting and drying (AWD) irrigation has been widely adopted to replace conventional irrigation (CI) for saving water and increasing water use efficiency (WUE) in irrigated rice systems in China. However, there is limited information about how AWD affects yield, WUE, and root and shoot growth and development. To fill this knowledge gap, we conducted the experiment using three local high-yielding rice cultivars, Wuyunjing 24 (japonica), Yangliangyou 6 (two-line indica hybrid rice) and Yongyou 2640 (three-line indica/japonica hybrid rice) under the two water managements, CI and AWD, during the whole growing season. The results showed that, when compared with CI, AWD increased grain yield by 5.34%, 5.85%, and 6.62% and WUE by 28.9%, 25.3%, and 27.6%, respectively which mainly attributed to greater root oxidation activity, amount of root bleeding sap, content of cytokinins (zeatin + zeatin riboside) in roots and leaves, highten photosynthetic rate of flag leaf, deeper root distribution, increased productive tillers and leaf area, and enhanced activities of enzymes involved in sucrose-to-starch conversion in grains during grain filling. The results demonstrate that AWD is an effective practice to increase grain yield and water use efficiency through enhancing root and shoot growth and development.

Effects of Cotton Straw Returning on Soil Available Nutrients and Microbial Characteristics

LIU Yan-Hui,WANG Shuang-Lei,LI Jin-Pu,QIN Du-Lin,ZHANG Mei-Ling,NIE Jun-Jun,MAO Li-Li,SONG Xian-Liang,SUN Xue-Zhen

Acta Agron Sin. 2016, 42(07):  1037-1046.  doi:10.3724/SP.J.1006.2016.01037

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The experiment with two treatments of cotton straw returning and no straw returning was conducted using Denong 09068 at the Experimental Station of Shandong Agricultural University (Dezhou) to investigate the contents of soil available nutrients and microbial characters under cotton straw returning for four consecutive years. The main results indicated that compared with control (no straw returning), cotton straw returning significantly increased the contents of soil organic matter, alkaline hydrolyzed nitrogen, available potassium, soil microbial C and active microbial biomass by 8.16%, 13.23%, 12.30%, 13.63%, and 11.57% (0–20 cm soil layer), 6.08%, 27.51%, 11.47%, 14.32%, and 15.03% (20–40 cm soil layer), 6.05%, 12.87%, 8.08%, 10.60%, and 20.30% (40–60 cm soil layer) on average, respectively. Soil basal respiration rate of straw returning treatment was 13.14% and 17.44% in 0–20 cm and 20–40 cm soil layers respectively higher than that of no straw returning treatment, while no significant increase in 40–60 cm soil layer. Cotton straw returning significantly increased seed cotton yield (16.86%) and lint yield (15.03%), absolutely owning to larger total boll number (5.99%) and boll weight (10.25%), but there was no change in lint percentage, compared with no cotton straw returning treatment. Returning cotton straw can increase soil fertility, while applying appropriate P fertilizer and controlling obstacles in continuous cropping are necessary for long–term straw returning to enhance yield.

Potassium Nutrition Characteristics in Different Yield Populations of Super Rice Yongyou 12

WEI Huan-He,MENG Tian-Yao,LI Chao,ZHANG Hong-Cheng,DAI Qi-Gen,MA Rong-Rong,WANG Xiao-Yan,YANG Jun-Wen

Acta Agron Sin. 2016, 42(07):  1047-1057.  doi:10.3724/SP.J.1006.2016.01047

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A field experiment was conducted using super rice Yongyou 12 to compare the differences in absorption and accumulation characteristics of potassium among high yield population (HY, 10.5–12.0 t ha^-1), higher yield population (HRY, 12.0–13.5 t ha^-1), and super high yield population (SHY, ≥13.5 t ha^-1) in 2013 and 2014. Results followed that, on an average across two years, grain yield of SHY was 13.9 t ha^-1, significantly higher than that of HRY (12.5 t ha^-1) and HY (10.9 t ha^-1). HY showed higher K content in plants, followed by HRY and SHY, with no significant difference among them. K content at heading and maturity stages, showed a trend of SHY> HRY > HY, whileK uptake amount at jointing stage showed HY>HRY>SHY. K uptake amount at heading stage of SHY was 364.1 kg ha^-1, significantly higher than that of HRY (326.7 kg ha^-1) and HY (282.8 kg ha^-1), respectively. K uptake amount at maturity stage of SHY was 374.6 kg ha^-1, significantly higher than that of HRY (331.1 kg ha^-1) and HY (284.1 kg ha^-1), respectively. With increasing grain yield, K accumulation amount decreased from sowing to jointing stage, while increased from jointing to heading. Very significantly negative linear relationship was observed between K accumulation amount from sowing to jointing and grain yield. Very significantly positive linear relationship was observed between K accumulation amount from jointing to heading and grain yield. Compared with HY and HRY, SHY showed higher K uptake amount in the stem and sheath, leaf, and panicle at heading and maturity stages, which wassignificantly or very significantly and positivelycorrelated with grain yield. SHY showed higher K uptake amount but lower internal nutrient efficiency and K partial productivity, indicating its relatively lower K use efficiency, when compared with HY and HRY. Great attention should be paid for increasing K use efficiency in production of rice. Methods to improve K use efficiency in SHY of Yongyou 12 were discussed.

Measurement of Evapotranspiration for Drip-IrrigatedWinter WheatUsing Large Weighing Lysimeter in Northern Xinjiang

LI Jie,WU Yang-Huan,CHEN Rui,YANG Ping,CHAI Shun-Xi,CUI Jin,MA Fu-Yu

Acta Agron Sin. 2016, 42(07):  1058-1066.  doi:10.3724/SP.J.1006.2016.01058

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Drip-irrigation is a promising water-saving technique in arid agricultural area. To sep up efficient drip-irrigation systems forwinter wheat grown in northern Xinjiang table land, we measured the evapotranspiration (ET) rate ofwheat field using large-scale weighing lysimeter and analyzed the temporal responses of ET (in growing phase, daily and hourly) to air temperature, relative humidity and wind speed. Three treatments were designed with irrigation amounts of 375 (D1), 600 (D2), and 750 mm (D3). During the whole growing period of wheat, daily ET rate varied in different phases, showing heading–milk > jointing–heading > milk–maturity >regreening–jointing > sowing–overwintering > overwintering–regreening. During a day, hourly ET was in high level from 8:00 to 20:00 and stable from 20:00 to 8:00 of next, which varied with weather condition. Under drip-irrigation condition, the ratio of soil evaporation to ET was 25.2–28.3% during the entire growing season. Soil evaporation could be predicted with soil moisture and leaf area index using a bivariate quadratic function(R²> 0.98). Based on a combination of yield and water use efficiency, we suggest 600–650 mm as the optimum irrigation amount under thedrip-irrigated winter wheat field.

RESEARCH NOTES

Expression Patterns of MADS-box Genes Related to Flower Development of Wheat

LI Hai-Feng,HAN Ying,WANG Bing-Hua,SU Ya-Li,SUN Qi-Xin

Acta Agron Sin. 2016, 42(07):  1067-1073.  doi:10.3724/SP.J.1006.2016.01067

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 The objective of this study was to elucidate the molecular mechanism of wheat (Triticum aestivum L.) flower development. According to the phylogenetic tree of MADS- box genes from different species, we found that wheat contained all kinds of genes involved in the ABCDE model for flower development. The expression patterns of A-, B-, C-, D-, and E-class genes were analyzed by semi-quantitative and quantitative RT-PCR (qRT-PCR). Wheat AP1/FUL gene TaFUL (A-class) was expressed in all floral organs with the highest expression level in lemmas and paleas. Genes TaAP3 (B-class), TaAG (C-class) showed conservative expression patterns in specific organs, i.e., TaAP3 was expressed in lodicules and stamens whereas TaAG was expressed in stamens and pistils. The OsMADS13 homologous gene in wheat (D-class) was expressed in both pistils and lodicules, suggesting its function in lodicule and ovule development simultaneously. Gene TaSEP (E-class) was expressed in paleas and the inner-three whorls except for lemmas and glumes. LHS1 is a grass-specific gene family and belongs to E-class. The expression of TaLHS1 was detected in lemmas, paleas, and glumes of wheat. TaDL, the homologous gene of rice DROOPING LEAF (DL) controlling carpel development, was expressed in glumes, lemmas and carpels. These results suggest a conservative molecular mechanism for flower development in wheat, but some genes may have diversified functions due to evolution. The expression evidence of TaDL and TaLHS1 in glumes, in combination with the morphology and structure analyses of glume, lemma and palea, implied that lemma and glume might originate from the same organ in wheat.

Cloning and Expression Analysis of a Ca²⁺/H⁺ Antiporter Gene from Sugarcane

SU Wei-Hua**,LIU Feng**,HUANG Long,SU Ya-Chun,HUANG Ning,LING Hui,WU Qi-Bin,ZHANG Hua,QUE You-Xiong*

Acta Agron Sin. 2016, 42(07):  1074-1082.  doi:10.3724/SP.J.1006.2016.01074

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CAX (Ca²⁺/H⁺ antiporter) is a major category of Ca²⁺ active transport systems in plant cell membrane. In the present study, using a CAX1 mRNA sequence from Sorghum bicolor (GenBank accession number: XM_002441593) as the probe, the full-length cDNA sequence of sugarcane CAX1 gene was cloned by insilico cloning combined with RT-PCR amplification, and named as ScCAX1 (GenBank accession number: KT799799). Bioinformaticsanalysis showed thatScCAX1 has a length of 784 bp and contains a complete open reading frame with a length of 645 bp, which encodes a 214 amino acid residues of sugarcane CAX1 protein. The ScCAX1 protein with stable acidity and hydrophobia was detected to be located in thylakoid membrane of chloroplasts with no signal peptide. It belongs to a conserved Na_Ca_ex.The mainly secondary structure elementof ScCAX1 protein is alpha helix. Real time quantitative PCR (RT-qPCR)analysis revealed that the expression of ScCAX1 was tissue-specific, with constituent expression in different tissues of sugarcane. The highest expression was observed in leaves while the lowest in stems. Besides, the expression of ScCAX1 gene could be regulated by treatments of PEG, NaCl, SA, ABA, and MeJA. The expression level of this genewas up-regulated by ABA, SA and PEG, with the highest inducible expression level in treatment of 24 hours. The expression level was 5.47 times higher than that of control under 24 h stress of SA , and 3.5 times higher than that of control under 24 h stress of ABA. Under 6 h stress of NaCl, the gene had the highest inducible expression level, which was 2.14 times higher than that of control. This study suggested that ScCAX1 could response to stresses, and its expression may be associated with salt resistance and osmotic tolerance in sugarcane.

Genetic Analysis and Taste Quality of Main Conventional Japonica Rice Varieties Grown in Jiangsu

GONG Hong-Bing,ZENG Sheng-Yuan,LI Chuang,ZUO Shi-Min,JING De-Dao,LIN Tian-Zi,CHEN Zong-Xiang,ZHANG Ya-Fang,QIAN Hua-Fei,YU Bo,SHENG Sheng-Lan,PAN Xue-Biao

Acta Agron Sin. 2016, 42(07):  1083-1093.  doi:10.3724/SP.J.1006.2016.01083

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Fifty indica-japonica specific SSR markers were employed to genotype 86 conventional japonica rice cultivars mainly planted in Jiangsu province and 41 loci showed polymorphism among them. After amplifying in 86 rice varieties, a total of 113 alleles were detected at the 41 SSR loci, and the allele number ranged from two to six, with an average of 2.76 in each locus. Polymorphism information content (PIC) value of these 41 SSR markers ranged from 0.02 to 0.84, with an average value of 0.48; Nei’s expected heterozygosity value of the 41 markers ranged from 0.02 to 0.68, and the average value was 0.37. Based on the coefficient index ranged from 0.72 to 1.00, we divided the 86 cultivars into three groups by UPGMA. The analysis of taste quality traits investigated under different environments indicated that the taste quality of conventional japonica rice cultivars in Jiangsu was correlated with the genetic clustering. Under long-day (LD) condition, the amylose content (AC) and protein content (PC) manifested a tendency of group I > group II > group III, while the taste value (TV) was opposites. And under short-day (SD) condition, taste quality traits of group II and group III varied significantly compared with that under LD condition, while the traits of group I had no significant change. In short, the results indicated that the main cultivars grown in Jiangsu have a general taste quality and narrow genetic background, broadening the genetic basis is an important approach to breed japonica rice cultivars with environment-insensitivity and good eating quality.

Cloning and Functional Analysis of Peanut AhDGAT2a Promoter?

ZHENG Ling,SHI Ling-Min,TIAN Hai-Ying,SHAN Lei,BIAN Fei,GUO Feng

Acta Agron Sin. 2016, 42(07):  1094-1099.  doi:10.3724/SP.J.1006.2016.01094

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Diacylglycerol acyltransferase (DGAT) is a rate-limiting enzyme in triacylglycerol (TAG) biosynthesis pathway. In this study, GenomeWalking method was used for cloning the promoter sequence of AhDGAT2a gene from Luhua 14, and finally a 1200 bp fragment flanking 5′-upstream of AhDGAT2a was obtained and named as pAhDGAT2a. The crucial regulatory elements in pAhDGAT2a were further analyzed with software PlantCARE. There were many TATA-box, CAAT-box, light regulation, stress and defense response and hormone response elements. To assess the activity of pAhDGAT2a, we constructed pAhDGAT2a:GUS cassettes and introduced it into the tobacco SR1 genome by Agrobacterium-mediated transformation. Expression pattern was monitored by histochemical staining. Results showed that GUS activity driven by the pAhDGAT2a was detected in almost all vegetative and reproductive tissues, with a higher expression level in stigma, anther and young seeds than in the other organs, indicating thatpAhDGAT2a has a constitutive promoter activity.