Functional Analysis Of The Stilbene Synthase VqSTS21 And VqSTS36 Genes In Chinese Wild Vitis Quinquangularis

Stilbene synthase(STS)gene is a key gene in the biosynthesis of various stilbenoids,including resveratrol and its derivative glucosides(such as piceid),that has been shown to contribute to disease resistance in plants.However,the mechanism behind such a role has yet to be elucidated.Furthermore,the function of STS genes in osmotic stress tolerance remains unclear.As such,we sought to elucidate the role of STS genes in the defense against biotic and abiotic stress in the model plant Arabidopsis thaliana(Columbia,wild type)or tomato(Micro-Tom).1.Expression profiling of 31 VqSTS genes from Vitis quinquangularis revealed that VqSTS21 was up-regulated in response to powdery mildew(PM)infection.Overexpression of this gene in Arabidopsis thaliana via Agrobacterium-mediated transformation,we found that the VqSTS21 Arabidopsis lines produced trans-piceid as their main stilbenoid product detected by HPLC,and the content was about 216-531?g g-1 FW.But the infection of Botrytis cinerea,the transgenic Arabidopsis lines improved disease resistance to PM and Pseudomonas syringae pv.tomato DC3000,but after transgenic plants infected with Botrytis cinerea,the leaves showed more increasement of large spots,and heavier disease symptom than CoL-0.Therefore we made a conclusion that VqSTS21 increased transgenic plants' susceptibility to Botrytis cinerea.In addition,transgenic Arabidopsis lines were found to confer tolerance to salt and drought stress from seed germination through plant maturity.Intriguingly,qPCR assays of defense-related genes involved in salicylic acid,jasmonic acid,and abscisic acid-induced signaling pathways in these transgenic lines suggested that VqSTS21 plays a role in various phytohormone-related pathways,providing insight into the mechanism behind VqSTS21-mediated resistance to biotic and abiotic stress.2.Heterologous expression of VqSTS36 transgenic tomato and Arabidopsis inoculated with Botrytis cinerea showed that the diameter of the transgenic plant was larger than that of the wild type,and the transgenic tomato and Arabidopsis were susceptible to Botrytis cinerea.After transgenic Arabidopsis leaves inoculated with powdery mildew,active oxygen accumulation and dead cells in leaveswere moreseriousthan wild type.Real time quantitative PCR results showed that the invasion of Botrytis cinerea,powdery mildew mainly induced in response to the SA signal pathway in transgenic tomato and Arabidopsis thaliana,in response to the SA biosynthetic pathway,transgenic Arabidopsis not only increased the resistance to powdery mildew,but also increased the susceptibility to Botrytis cinerea.When treated with salt and drought stress,the transgenic Arabidopsis seed germination rate and seedling root length werehigher than thoseof the wild type,real-time quantitative PCR showed that the important genes in ABA signaling pathway were up-regulated in transgenic Arabidopsis seedlings,suggesting that VqSTS36 may improve plant resistance by participating in ABA signaling pathway.Furthermore,according to the SMART website that VqSTS36 contains predicted domains might be associated with biotic and abiotic stresses.Analysis of the transmembrane domain by using the tmrpres2 d software,1 transmembrane segment was found,it may indicate that VqSTS36 gene may keep activity in the cell membranefor signal transduction.