Physiological and Transcriptomic Analysis of A Soybean Drought-tolerant Mutant Under Simulate Drought Stress
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 7 879 differentially expressed genes(DEGs)between Zhechun 3 and ZC-2,including 4 208 up-regulated genes and 3 671 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.