| We used the transgenic wheat lines 08T(1)-27,08T(1)-47and 08T(1)-51 containing the maize C4 Phosphoenolpyruvate Carboxylase(PEPC)gene and parental 'Zhoumai19'(Triticum aestivum L.)as marterials in this study.Then we researched the drought responses and yield characteristics of PEPCtransgenic wheat in booting stage,flowering stage and 20 days after flowing under moderate drought(relative soil water content 45-50%)and severe drought(relative soil water content 30-35%)stress.The main results as follows:1.The expressions of wheat endogenous photosynthetic related genes ppdk,nadp-me,rbcL and rbcS were significantly increased by 1.33,2.53,2.75 and 2.90 fold,respectively,while the pepc was increased by 4.31 fold in PEPC transgenic wheat.And the enzymes activity of phosphoenolpyruvate carboxylase,pyruvate kinase,malic enzyme and ribulose bisphosphate carboxylasewere also greatly increased by 1.07,1.24,0.29 and 0.8 fold in transgenic wheat under drought stress conditions when compared with parental'Zhoumai19'.2.Under drought stress,the decreased magnitude of photosynthetic efficiency was significantly lower in transgenic lines compared with normal growth conditions through importing exogenous maize C4 PEPC gene.The decreased magnitudeof photosynthetic rate,stomatal conductance,transpiration rate and chlorophyll-fluorescence parameters Fv/Fmand Fv/F0were 67.89%,63.95%,33.85%,3.15%and 18.2%in transgenic wheat,which all significantly lowerthan parental control line.The water retaining capacity was enhanced in transgenic wheat,and the decreased magnitudeof relative water content of leaves was 12.5%,that was significantly lower than parental control line.Water use efficiency and osmoregulation substance containing souble sugar,souble protein were greatly increasedby 19.6%,9.5%and 16.2%and malondialdehyde was decreased by 7.3%in transgenic lines when compared with parental control line.The proline of transgenic wheat was increased by 4.95 fold under drought stress compared with normal growth,which was higher than control.The activity of Superoxide dismutase,Peroxidase and catalase was significantly increased by 15.5%,29.2%and 22%which led to enhance of oxidative stress capacity.And root system development ability was enhanced in transgenic lines,and the decreased magnitude of root activity was 19.45%,which was greatly lower than control.Theroot volume and root dry weight were significantly improved by 16.2%and 13.9%in transgenic wheat when compared with control line.3.We separated different protein spots both transgenic line 08T(1)-27 and parental'Zhoumai19' between non-stressed and drought stressed conditions respectively using Two-dimensional electrophoresis technology.The proteins of responsive to transforming PEPC mainly involved in glycolysis and photosynthesis.Among them,the expression of chloroplast glyceraldehyde-3-phosphate dehydrogenase(GAPDH)involving in Calvin cycle,chlorophyll A-B binding protein and pyruvate,phosphate dikinase relevant photosynthesis were induced by transforming PEPC.The proteins of responsive to drought stress mainly involved in pentose phosphate pathway,amino acid synthesis and stress responses.Among them,transketolase,glutamine synthetase(GS)involving in proline synthesis,ascorbate peroxidase(APX)involving in removing reactive oxygen species of intracellular accumulation were induced by drought stress.The proteins of responsive to transforming PEPC and drought stress mainly involved inATP synthesis,photosynthesis and amino acid synthesis.Among them,ATP synthesis subunits,ferredoxin-NADP reductase and S-adenosylmethionine(SAM)involving in methionine synthesiswere induced by transforming PEPC and drought stress,and the degree of increase in transgenic line were higher than parental 'Zhoumai19' under drought stress.4.The results of yield characteristics analysis suggested that the plant height,panicles per plant,above ground biomass,yield per plant and 1000-grain weight were significantly greater,while panicles of infertility was lower,than the values in the parental wheat. |
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