Expression of the Grape VaSTS19 Gene in Arabidopsis Improves Resistance to Powdery Mildew and Botrytis cinerea but Increases Susceptibility to Pseudomonas syringe pv Tomato DC3000.

Yaqiong Wang,Li Huang,Xiaomin Tian,Xiping Wang,Hua Gao,Steve Van Nocker,Dejun Wang,Fan Wang

doi:10.3390/ijms18092000

Abstract

Stilbene synthase (STS) is a key enzyme that catalyzes the biosynthesis of resveratrol compounds and plays an important role in disease resistance. The molecular pathways linking STS with pathogen responses and their regulation are not known. We isolated an STS gene, VaSTS19, from a Chinese wild grape, Vitis amurensis Rupr. cv. “Tonghua-3”, and transferred this gene to Arabidopsis. We then generated VaSTS19-expressing Arabidopsis lines and evaluated the functions of VaSTS19 in various pathogen stresses, including powdery mildew, B. cinerea and Pseudomonas syringae pv. tomato DC3000 (PstDC3000). VaSTS19 enhanced resistance to powdery mildew and B. cinerea, but increased susceptibility to PstDC3000. Aniline blue staining revealed that VaSTS19 transgenic lines accumulated more callose compared to nontransgenic control plants, and showed smaller stomatal apertures when exposed to pathogen-associated molecular patterns (flagellin fragment (flg22) or lipopolysaccharides (LPS)). Analysis of the expression of several disease-related genes suggested that VaSTS19 expression enhanced defense responses though salicylic acid (SA) and/or jasmonic acid (JA) signaling pathways. These findings provide a deeper insight into the function of STS genes in defense against pathogens, and a better understanding of the regulatory cross talk between SA and JA pathways.

Highlights

Grapevine (Vitis vinifera L.) is one of the most agriculturally and economically important fruit species, and is widely cultivated around the world [1]
We found that expression of VaSTS19 was up-regulated in response to powdery mildew, suggesting that it may be associated with tolerance to biotic stress
VaSTS19 Expression is Induced in Grape Following Powdery Mildew Infection

Summary

Introduction

Grapevine (Vitis vinifera L.) is one of the most agriculturally and economically important fruit species, and is widely cultivated around the world [1]. Plants are exposed to a large variety of pathogens, such as Botrytis cinerea and powdery mildew (Golovinomyces cichoracearum UCSC1 (Erysiphe cichoracearum)), as well as hostile environments, including extremes of temperature, light, and water availability. These biotic and abiotic stresses can severely affect the growth, yield, and fruit quality of cultivated grapevine varieties [2]. Natural resistance of plants to phytopathogens is dependent on a large arsenal of constitutive and inducible defense mechanisms [4]. The best characterized defense mechanisms involve synthesis and accumulation of phytoalexins [5,6]

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