模拟干旱胁迫下大豆耐旱突变体的生理和转录组分析

Physiological and Transcriptomic Analysis of A Soybean Drought-tolerant Mutant Under Simulate Drought Stress

为了明确大豆苗期响应干旱胁迫的关键基因,解析其耐旱机制,本研究以浙春3号及其突变体Gm-lpa-ZC-2(ZC-2)为材料,利用20%PEG6000胁迫处理其幼苗后,对比两品种表型差异并测定相关生理生化指标,再利用RNA-seq技术进行转录组学分析。结果表明:突变体ZC-2的耐旱性强于浙春3号,随着干旱胁迫时间的延长,突变体ZC-2的最大光化学效率(Fv/Fm)、相对含水量、可溶性糖和可溶性蛋白含量均显著高于亲本浙春3号,相对电导率和丙二醛(MDA)含量低于浙春3号。转录组数据分析表明:PEG6000胁迫后,浙春3号和ZC-2之间共存在7879个差异表达基因,其中上调表达的差异基因有4208个,下调表达的差异基因有3671个;胁迫处理2和4 d共同表达的差异基因为571个。KEGG富集分析表明,这571个基因主要富集在84条代谢途径,包括光合作用-天线蛋白、半乳糖代谢、内质网中的蛋白质加工、类黄酮生物合成等通路。进一步筛选到光合作用和糖代谢相关通路基因以及可能与干旱胁迫相关的基因,包括TIFY10A、ZAT10、RD22、PM19L和XTH6等。研究结果可为挖掘大豆苗期耐旱候选基因和解析大豆耐旱机制提供一定基础。

In order to identify the key genes responsive to drought stress and to elucidate the underlying mechanism in drought tolerance of soybean seedlings,Zhechun 3 and its mutant Gm-lpa-ZC-2(ZC-2)were test in this research.The phenotype,relevant physiological and biochemical indexes were observed and determined after stress treatment under 20%PEG6000,and RNA-seq technology used for transcriptomic analysis.The results showed that the relative water content,the maximum quantum yield of PSII(Fv/Fm),soluble sugar content and soluble protein content of the mutant ZC-2 were significantly higher than those of Zhechun 3,and relative electrolyte leakage rate(REC)and malondialdehyde(MDA)content were lower than those of Zhechun 3,which could indicate that the mutant ZC-2 was more drought tolerant than Zhechun 3.The transcriptomic data indicated that there were totally 7879 differentially expressed genes(DEGs)between Zhechun 3 and ZC-2,including 4208 up-regulated genes and 3671 down-regulated genes.There were 571 differential genes expressed on both day 2 and day 4 under treatment.In addition,the 571 DEGs were involved in 84 metabolic pathways.KEGG enrichment analysis indicated that DEGs were mainly enriched in pathways such as photosynthesis-antenna proteins,galactose metabolism,protein processing in endoplasmic reticulum,and flavonoid biosynthesis.Moreover,genes related to photosynthesis and sugar metabolism pathway as well as gene associated with drought stress,including TIFY10A,ZAT10,RD22,PM19L and XTH6,were detected.This study provided a foundation for mining candidate genes related to drought tolerance in soybean seedlings and studying the mechanism of soybean drought tolerance.