Expression of a Grape VqSTS36-Increased Resistance to Powdery Mildew and Osmotic Stress in Arabidopsis but Enhanced Susceptibility to Botrytis cinerea in Arabidopsis and Tomato.

Li Huang,Jinhua Yang,Xiangjing Yin,Xiping Wang,Xiaomeng Sun,Mohammad Rahman,Zhiping Chen

doi:10.3390/ijms19102985

Abstract

Stilbene synthase genes make a contribution to improving the tolerances of biotic and abiotic stress in plants. However, the mechanisms mediated by these STS genes remain unclear. To provide insight into the role of STS genes defense against biotic and abiotic stress, we overexpressed VqSTS36 in Arabidopsis thaliana and tomato (Micro-Tom) via Agrobacterium-mediated transformation. VqSTS36-transformed Arabidopsis lines displayed an increased resistance to powdery mildew, but both VqSTS36-transformed Arabidopsis and tomato lines showed the increased susceptibility to Botrytis cinerea. Besides, transgenic Arabidopsis lines were found to confer tolerance to salt and drought stress in seed and seedlings. When transgenic plants were treated with a different stress, qPCR assays of defense-related genes in transgenic Arabidopsis and tomato suggested that VqSTS36 played a specific role in different phytohormone-related pathways, including salicylic acid, jasmonic acid, and abscisic acid signaling pathways. All of these results provided a better understanding of the mechanism behind the role of VqSTS36 in biotic and abiotic stress.

Highlights

Stilbene synthase (STS) is a key enzyme for the synthesis of phytoalexin stilbenoids through the polyphenol biosynthetic pathway [1]
Observation of leaf surfaces of transgenic lines displayed that the lesion coverage area was smaller than WT at 7 days post-inoculation, see Figure 1B, VqSTS36 enhanced the disease resistance of transgenic Arabidopsis
To figure out the potential pathways causing the difference between VqSTS36 transgenic Arabidopsis and WT in response to powdery mildew, we measured the cell death and superoxide anions (O2−) in inoculated leaves

Summary

Introduction

Stilbene synthase (STS) is a key enzyme for the synthesis of phytoalexin stilbenoids through the polyphenol biosynthetic pathway [1]. Powdery mildew is a biotrophic pathogen, while the fungus B. cinerea is a necrotrophic pathogen which colonizes dead plant tissues and leads to gray mold in fruits. These fungi release a set of effector proteins into host cells to intervene the host immunity [10], including activating a hypersensitive response and changing the expression profile of defense-related genes [10,11]. Exogenous SA can reduce the cytosine DNA methylation of certain STS genes, which results in significant increase in the expression of STS genes and the accumulation of resveratrol in the cell cultures of V. amurensis [16]

Methods

Results

Conclusion