Cloning, Characterization, and Functional Investigation of VaHAESA from Vitis amurensis Inoculated with Plasmopara viticola.

Shaoli Liu,Chi Zhang,Yali Zhang,Nan Chao,Jiang Lu

doi:10.3390/ijms19041204

Abstract

Plant pattern recognition receptors (PRRs) are essential for immune responses and establishing symbiosis. Plants detect invaders via the recognition of pathogen-associated molecular patterns (PAMPs) by PRRs. This phenomenon is termed PAMP-triggered immunity (PTI). We investigated disease resistance in Vitis amurensis to identify PRRs that are important for resistance against downy mildew, analyzed the PRRs that were upregulated by incompatible Plasmopara viticola infection, and cloned the full-length cDNA of the VaHAESA gene. We then analyzed the structure, subcellular localization, and relative disease resistance of VaHAESA. VaHAESA and PRR-receptor-like kinase 5 (RLK5) are highly similar, belonging to the leucine-rich repeat (LRR)-RLK family and localizing to the plasma membrane. The expression of PRR genes changed after the inoculation of V. amurensis with compatible and incompatible P. viticola; during early disease development, transiently transformed V. vinifera plants expressing VaHAESA were more resistant to pathogens than those transformed with the empty vector and untransformed controls, potentially due to increased H2O2, NO, and callose levels in the transformants. Furthermore, transgenic Arabidopsis thaliana showed upregulated expression of genes related to the PTI pathway and improved disease resistance. These results show that VaHAESA is a positive regulator of resistance against downy mildew in grapevines.

Highlights

Downy mildew is caused by the oomycete Plasmopara viticola and is one of the major diseases affecting grapevines worldwide
A phylogenetic analysis revealed that the leucine-rich repeat (LRR)-receptor-like kinases (RLKs) that we identified in the present study (VaHAESA) clustered with HAESA and HAESA homologs from Arabidopsis and five other species (Figure 4)
It has become apparent that pattern recognition receptors (PRRs) exist in the plasma membrane within intricate protein complexes resembling supramolecular structures and require numerous regulators to initiate and fine-tune plant immune responses [17,18,19]

Summary

Introduction

Downy mildew is caused by the oomycete Plasmopara viticola and is one of the major diseases affecting grapevines worldwide. Grapevines possess natural resistance against P. viticola as a result of disease resistance synergy. These resistance mechanisms involve physiological, ecological, and morphological changes in the plant [1,2]. An important mode of active defense in plant immunity is the detection of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs) [3], otherwise known as PAMP-triggered immunity (PTI) [4,5]. PTI plays a major role in preventing the pathogenic invasion of plants

Methods

Results

Conclusion