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. (1st September 2020)

• Record Type: Journal Article
• Authors: Toffolatti, Silvia L.; Maddalena, Giuliana; Marcianò, Demetrio; Passera, Alessandro; Quaglino, Fabio
• Is Part Of: Plant pathology. Volume 69:Number 9(2020)
• Page Start: 1695
• Page End: 1707
• Publication Date: 2020-09-01
• Subjects: host specialization -- inter‐row vegetation -- MAT 1‐1 -- MAT 1‐2 -- viticulture -- Vitis vinifera; Agricultural pests -- Periodicals; Plant diseases -- Periodicals; 632
• DOI: 10.1111/ppa.13257
• Languages: English
• ISSNs: 0032-0862

Abstract

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 sdh B ), 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. Abstract : Botrytis cinerea isolates from vines and herbaceous species are phylogenetically related and show analogous fitness and pathogenicity, therefore grey mould inoculum is circulating among different plant species in vineyard.