Regularity Of Accumulated Alkaloids And Influence Of Several Key Enzyme Genes Expression In Catharanthus Roseus Under Weak Red Light Condition

In this paper,tissue culture seedings of Catharanthus roseus under weak red light condition were determined by measuring some index such as variations of chlorophyll content, accumulated alkaloids and the key enzyme genes' expression in C.roseus' MIA's metabolic pathway.In the meantime,we samplinged the same age of seedings as control.The results are as follows:1,Chlorophyll content and chlorophyll a/ chlorophyll b in the leaves of Catharanthus roseus are decreased,when they are in the condition of weak red light.It meams that seeding's photosynthetic capacity is decreased.Meanwhile, carotenoid content is also reduced.Carotenoid is photoprotection pigment.When light is lower,carotenoid content is lower.But carotenoid / chlorophyll have no significant difference,thus we speculate photoprotection capability has no decline.2,The contents of vindoline,catharanthine and vinblastine in the seeding of Catharanthus roseus were measured by HPLC.We found that the contents of vindoline and catharanthine are decreased,and the content of vinblastine is increased in 30 days.And the three total alkaloids are decreased.Only in the 45^th day,the situations are opposite.But this environment is still not suitable for Catharanthus roseus'cultivation.3,The expression levels of the key enzyme genes in C.roseus' MIA's metabolic pathway were studied through RT-PCR.The result is that the expression levels of DXS and DXR in C.roseus' MIA's metabolic pathway just had sightly lower at the beginning of treatmeat,and then returned to normal.In control,as the seedings grow up,the expression level of G10H is up-regulated.It had sightly up-regulated in Catharanthus roseus after treatmeant at previous period,and then it's sightly lower than control at late period.TDCs expression had no obviously regularity.The expression level of STR was up-regulated as the seeding growing up in control,but it had some inhibition after treated in the main.D4H and DAT are the genes which are in vindoline's metabolic pathway.The expression level of D4H in control had no regularity,instead it can steadily express after treated. DAT had steady expression in short time after treated,and it's also higher than control.This result has proportional relationship with vindoline content in gross. There is proportional relationship or negative regulator with alkaloids to STR, D4H and DAT.