Isolation and Characterization of Endophyte Bacillus velezensis KOF112 from Grapevine Shoot Xylem as Biological Control Agent for Fungal Diseases.

Kazuhiro Hamaoka,Yoshinao Aoki,Shunji Suzuki

doi:10.3390/plants10091815

Abstract

As the use of chemical fungicides has raised environmental concerns, biological control agents have attracted interest as an alternative to chemical fungicides for plant-disease control. In this study, we attempted to explore biological control agents for three fungal phytopathogens causing downy mildew, gray mold, and ripe rot in grapevines, which are derived from shoot xylem of grapevines. KOF112, which was isolated from the Japanese indigenous wine grape Vitis sp. cv. Koshu, inhibited mycelial growth of Botrytis cinerea, Colletotrichum gloeosporioides, and Phytophthora infestans. The KOF112-inhibited mycelial tips were swollen or ruptured, suggesting that KOF112 produces antifungal substances. Analysis of the 16S rDNA sequence revealed that KOF112 is a strain of Bacillus velezensis. Comparative genome analysis indicated significant differences in the synthesis of non-ribosomal synthesized antimicrobial peptides and polyketides between KOF112 and the antagonistic B. velezensis FZB42. KOF112 showed biocontrol activities against gray mold caused by B. cinerea, anthracnose by C. gloeosporioides, and downy mildew by Plasmopara viticola. In the KOF112–P. viticola interaction, KOF112 inhibited zoospore release from P. viticola zoosporangia but not zoospore germination. In addition, KOF112 drastically upregulated the expression of genes encoding class IV chitinase and β-1,3-glucanase in grape leaves, suggesting that KOF112 also works as a biotic elicitor in grapevine. Because it is considered that endophytic KOF112 can colonize well in and/or on grapevine, KOF112 may contribute to pest-management strategies in viticulture and potentially reduce the frequency of chemical fungicide application.

Highlights

The production of Koshu wine in Japan started in 1874 in Yamanashi Prefecture.Vitis sp. cv
Two hundred and forty-seven colonies were collected from Koshu shoot xylem and subjected to the in vitro bioassay using B. cinerea, C. gloeosporioides, and P. infestans
Large inhibition zones were formed between KOF112 and each phytopathogenic

Summary

Introduction

The production of Koshu wine in Japan started in 1874 in Yamanashi Prefecture.Vitis sp. cv. The production of Koshu wine in Japan started in 1874 in Yamanashi Prefecture. A hybrid of Vitis vinifera L. and V. davidii Foex, is an indigenous wine grape in Japan [1]. Koshu was introduced from Europe to Japan through the Silk. Koshu was recognized as a wine grape cultivar in 2010 by the International Organization for Vine and. Was registered in Vitis International Variety Catalogue by Julius Kühn-InstitutBundesforschungsinstitut für Kulturpflanzen Koshu is one of the most widely cultivated wine grapes in Japan and one of the most important cultivars for white-wine making in Japan [2]. Whole genome analysis demonstrated that Koshu is susceptible to phytopathogenic attack as a result of deletions in genes associated with pathogen response, such as hypersensitive response [3]

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