The Effect Of Transcription Factor MYB14 On Defense Mechanisms In Vitis Quinquangularis-pingyi

Grape is an important crop with rich edible and economic value,but its yield is often affected by pathogenic bacteria.The viticultural area in China is extensive,and some of the wild grapes in China have resistance to pathogenic bacteria.Stilbenes is a class of secondary metabolite in grape,and it is one of the main defense mechanisms to resist the pathogen infection in plants,and resveratrol is the main antibacterial constituents.Transcription factor MYB14 plays an indispensable role in the biosynthesis of stilbenes,and it can activate the Stilbene synthase/Resveratrol synthase to regulate the biosynthesis of stilbenes.In the current study,we identified a transcription factor,MYB14,from Chinese wild grape,Vitis quinquangularis-Pingyi(V.quinquangularis-PY),which could enhance the main stilbene contents and expression of stilbene biosynthesis genes(St Sy)by overexpression of Vq MYB14.The promoter of Vq MYB14(p Vq MYB14)was shown to be induced as part of both basal immunity(also called PAMP-triggered immunity,PTI)and effector-triggered immunity(ETI),triggered by the elicitors flg22 and harpin,respectively.This was demonstrated by expression of p Vq MYB14 in Nicotiana benthamiana and Vitis.We identified sequence differences,notably an 11 bp segment in p Vq MYB14 that is important for the PTI/ETI,and particularly for the harpin-induced ETI response.In addition,we showed that activation of the MYB14 promoter correlates with differences in the expression of MYB14 and stilbene pattern induced by flg22 and harpin.An experimental model of upstream signaling in V.quinquangularis-PY is presented where early defense responses triggered by flg22 and harpin partially overlap,but where the timing and levels differ.This translates into a qualitatively different with respect to patterns of stilbene accumulation.