A molecular epidemiology study reveals the presence of identical genotypes on grapevines and ground cover weeds and the existence of separate genetic groups in a Botrytis cinerea population

Abstract

Botrytis cinerea, the grey mould agent, is one of the most important pathogens of grapevine, due to the great yield losses caused and the economic costs related to disease control. Ground cover plants are assumed to have a role in the complex epidemiology of the pathogen, even if no information on the genetic variability of the strains is available. In this study, a molecular epidemiology approach, based on the comparative analysis of the nucleotide sequences of multiple genes (ITS1‐ITS2, G3PDH, NEP1, NEP2, BC‐hch, and sdhB), was used to evaluate whether B. cinerea isolated from herbaceous species contributes to grey mould diffusion on grapevines. From 330 samples collected in two vineyards in Lombardy, Italy, 63 B. cinerea strains were isolated from tissues of grapevine with symptoms (50 strains) and spontaneous ground cover plants (13 strains). Capsella bursa‐pastoris, Cardamine impatiens, Lamium purpureum, and Crepis tectorum were identified as novel B. cinerea hosts. Sequence analysis and phylogeny showed that the same genotypes were present on both grapevines and herbaceous plants, with no fitness (estimated from growth and sporulation on potato dextrose agar) or pathogenicity (on grapevine leaves and berries, and tomato leaves) penalties. This confirms that ground cover plants can be a source of inoculum for B. cinerea on grapevine. Moreover, phylogenetic analysis of the BC‐hch gene allowed the identification of two genetically distinct clusters, characterized by vegetative incompatibility and different distributions of the mating types, fitness, and pathogenicity. Therefore, B. cinerea seems to be composed of two diverging subpopulations that do not differ for host specialization.

Genetic and molecular landscapes of the generalist phytopathogen Botrytis cinerea

“…These large collections of studies provide the ability to conduct a meta‐analysis of the factors influencing B. cinerea's extensive genetic diversity. To summarize findings of these studies, we performed a meta‐analysis by compiling the publicly available data for >10,000 strains across 58 publications (Abdel Wahab, 2015; Acosta Morel et al., 2018; Albertini & Leroux, 2004; Albertini et al., 2002; Aliaga, 2013; Amiri et al., 2018; Asadollahi et al., 2013; Beever & Parkes, 1993; Ben Ahmed & Hamada, 2005; Campia, 2014; Cettul et al., 2008; Ciliberti et al., 2016; DeLong et al., 2020; Diao et al., 2019; Emilda, 2015; Esterio et al., 2011; Fan et al., 2015; Fekete et al., 2012; Fournier et al., 2005, 2013; Giraud et al., 1997; Giraud et al., 1999; Hu et al., 2018; Isenegger et al., 2008; Johnston et al., 2013; Kecskeméti et al., 2014; Kumari et al., 2014; Kuzmanovska et al., 2012; Leyronas et al., 2014; Lorenzini & Zapparoli, 2014; Ma & Michailides, 2005; Makris et al., 2022; Martinez et al., 2003; Mercier et al., 2019; Moparthi et al., 2023; Muñoz & Campos, 2013; Muñoz et al., 2002, 2016; Naegele et al., 2021; Pei et al., 2019; Polat et al., 2018; Rajaguru & Shaw, 2010; Román Ramos, 2013; Tanović et al., 2009, 2014; Testempasis et al., 2020; Toffolatti et al., 2020; Topolovec‐Pintarić et al., 2004; Törün & Biyik, 2022; Vaczy et al., 2008; Vatsa‐Portugal et al., 2014; Vercesi et al., 2014…”