Study On The Mechanism Of Exogenous H₂S Donor NaHS In Improving Drought Resistance Of Wheat

In this study,indoor wheat solution culture were carried out at temperature-controlled chamber to investigate the effect of applying exogenous H2 S on the physiological characters,ABA signaling pathway,and differential protein expression profile of wheat seedling leaves.Pot experiments were carried out at Henan Agricultural University Research Station to study the effect of applying exogenous H2 S on the physiological characters of the flag leaves and grain yield under drought stress.The main results were as follows:(1)Compared with PEG treated plant,Na HS pretreated wheat seedling significantly increased the plant height,fresh weight and the leaf relative water content of seedlings.Additionally,the contents of MDA and H2O2 were significantly reduced under Na HS treatment than under drought alone.And antioxidant enzyme activities SOD,POD and CAT were significantly increased with H2 S treatment than that of non-treated plant.At the same time,the contents of starch,sucrose and soluble sugar contents were also increased under drought stress and Na HS pretreatment.(2)Ten genes that involved the ABA signaling pathway were selected to inveatigate the expression levels with H2 S treatment under drought stress using quantitative real-time reverse transcription polymerase chain reaction(q PCR).The results showed that Na HS pretreatment increased the expression levels of ABA biosynthesis and ABA reactivation genes in leaves;whereas the expression levels of ABA biosynthesis and ABA catabolism genes were up-regulated in roots.And pretreatment Na HS,the content of H2 S was increased under drought,while the content of ABA was decreased under drought stress.This maybe have complex crosstalk between H2 S and ABA metabolism pathway.(3)Using i TRAQ(isobaric tags for relative and absolute quantitation)technique to investigate the inner mechanism of H2 S in alleviating the drought stress on wheat seedlings.We identified a total of 4296 proteins in leaves of wheat,and pretreatment with Na HS identified 120 significanly differential proteins including 57 up-regulated proteins and 63 down-regulated.Function analysis showed that these proteins involved in CHO metabolism,photosynthesis,signal transduction,amino acid metabolism,protein metabolism,stress and second metabolism.Nine proteins that involved in starch synthesis,serine metabolism,flavonoids and cell wall formation and other metabolic pathway were selected to examine the transcript expression levels by using q RT-PCR analysis.We found that most of them performed the similar tendency as proteins expression.These results implied that Na HS could alleviated the drought stress by regulating multiple pathway in leaves of wheat.(5)Foliar spraying with Na HS in wheat under drought stress was used to investigate the effect of exogenous H2 S on improving the drought resistance at late growth stages of wheat..The results showed that spraying Na HS could significantly increased chlorophyll content and the SOD,POD and CAT activities,reduced the contents of MDA and H2O2 of flag leaf.And improved the panicle number per plant,hundred-grain weight and grain yield of wheat under drought stress.These results showed that exogenous H2 S could improve the drought resistance of wheat plant at late growth stages of wheat.