Str And Pme Gene Expression In Catharanthus Roseus Leaves Under Drought Stress

The enzyme encoded by the Strictosidine synthase gene(Str) catalyses a key step in the biosynthesis of indole alkaloids in Catharanthus roseus.And pectinmethylesterase(Pme) is closely related with the enhancement of cell wall by hydrolyzing pectin,which is the main cell wall component.The expression of Str gene was studied using leaves of C.roseus as experimental materials during continuous drought process.The activity of Peroxidase was measured to detect the extent of drought. And the expression of Pine gene was studied under the combined stresses of drought and light.The results showed that the activity of Peroxidase decreased slightly and then increased markedly with the increase of the drought stress extent.It reached the highest level(2.19 times its original value) on day 19.The decrease in Peroxidase activity after day 19 suggested that the samples were under severe stress.The expression of Str gene was downregulated and then upregulated significantly by moderate drought treatment.The level of expression of Str was the highest on day 22 and then declined to the normal level.The study revealed the correlation between the expression ofStr gene in C.roseus and drought stress.In this experiment,combined effect of drought and light on the expression of Pme genes in leaves of Croseus was investigated.Present results revealed that the expression of Pme gene from C.roseus was more significantly influenced under light stress than that under drought stress.A good positive correlation was observed between Pme gene expression and the light stress.The expression of Pine gene increased under the combined stresses of drought and light.