Comparative Study of Secreted Proteins, Enzymatic Activities of Wood Degradation and Stilbene Metabolization in Grapevine Botryosphaeria Dieback Fungi.

Clément Labois,Julie Chong,Mary-Lorène Goddard,Elodie Stempien,Christine Schaeffer-Reiss,Christophe Bertsch,Justine Schneider

doi:10.3390/jof7070568

Abstract

Botryosphaeriaceae fungi are plant pathogens associated with Botryosphaeria dieback. To better understand the virulence factors of these fungi, we investigated the diversity of secreted proteins and extracellular enzyme activities involved in wood degradation and stilbene metabolization in Neofusicoccum parvum and Diplodia seriata, which are two major fungi associated with grapevine B. dieback. Regarding the analysis of proteins secreted by the two fungi, our study revealed that N. parvum, known to be more aggressive than D. seriata, was characterized by a higher quantity and diversity of secreted proteins, especially hydrolases and oxidoreductases that are likely involved in cell wall and lignin degradation. In addition, when fungi were grown with wood powder, the extracellular laccase and Mn peroxidase enzyme activities were significantly higher in D. seriata compared to N. parvum. Importantly, our work also showed that secreted Botryosphaeriaceae proteins produced after grapevine wood addition are able to rapidly metabolize the grapevine stilbenes. Overall, a higher diversity of resveratrol and piceatannol metabolization products was found with enzymes of N. parvum compared to D. seriata. This study emphasizes the diversity of secreted virulence factors found in B. dieback fungi and suggests that some resveratrol oligomers produced in grapevine wood after pathogen attack could be formed via pathogenic fungal oxidases.

Highlights

We investigated the diversity of secreted proteins of N. parvum and D. seriata cultured in media with and without grapevine wood by an MS-based proteomic analysis
Laccase activity was significantly higher for proteins secreted by D. seriata compared to proteins secreted by N. parvum (Figure S1a)
We investigated the diversity of secreted proteins and extracellular enzyme activities involved in wood degradation and stilbene metabolization for N. parvum and D. seriata, which are two major fungi associated with Botryosphaeria dieback

Summary

Introduction

GTDs are associated with the growth of xylem-inhabiting fungi complexes, which eventually leads to the sudden death of the plant. They are characterized by a latent state where fungi are present in the plant as endophytes, and a pathogenic state where they become virulent and colonize the vine wood tissues [4,5]. Many symptoms can be associated to the development of GTDs such as sectorial and/or central necrosis in woody tissues, leaf discoloration, and wilting of berries and inflorescences, leading in the long term to the death of the plant [6,7,8,9,10]

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Discussion

Conclusion