AUTHOR=Plesken Cecilia , Pattar Patrick , Reiss Bianka , Noor Zinnia Naoshin , Zhang Lisha , Klug Klaus , Huettel Bruno , Hahn Matthias 

TITLE=Genetic Diversity of Botrytis cinerea Revealed by Multilocus Sequencing, and Identification of B. cinerea Populations Showing Genetic Isolation and Distinct Host Adaptation

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.663027

DOI=10.3389/fpls.2021.663027

ISSN=1664-462X

ABSTRACT=<p><italic>Botrytis cinerea</italic> is a world-wide occurring plant pathogen, causing pre- and post-harvest gray mold rot on a large number of fruit, vegetable, and flower crops. <italic>B. cinerea</italic> is closely related to <italic>Botrytis pseudocinerea</italic>, another broad host range species which often occurs in sympatry with <italic>B. cinerea</italic>, and to several host-specific species including <italic>Botrytis fabae</italic> and <italic>Botrytis calthae</italic>. <italic>B. cinerea</italic> populations have been shown to be genetically heterogeneous, and attempts have been made to correlate genetic markers to virulence and host adaptation. Here, we present the development of a multilocus sequence typing (MLST) scheme, with 10 genes selected for high variability and phylogenetic congruence, to evaluate the genetic diversity of <italic>B. cinerea</italic>, <italic>B. fabae</italic>, and <italic>B. pseudocinerea</italic>. Using PacBio-assisted simultaneous mass sequencing of PCR products, MLST analysis of about 100 strains from diverse geographical origins and years of isolation was performed, which resulted in high-resolution strain differentiation and robust species separation. Several <italic>B. cinerea</italic> strains formed an as yet unknown population, referred to as group B, which was well separated from all other <italic>B. cinerea</italic> strains. Furthermore, the gene cluster for biosynthesis of the phytotoxin botcinic acid was missing in <italic>B. cinerea</italic> B strains. <italic>B. cinerea</italic> strains from the monocot <italic>Iris pseudacorus</italic> were found to form a genetically distinct population, and contained an intact gene cluster for production of the red pigment bikaverin, which is usually degenerated in <italic>B. cinerea</italic>. Remarkably, these strains were much more aggressive on <italic>Iris</italic> than other <italic>B. cinerea</italic> strains, which is the first unequivocal example for host specialization in <italic>B. cinerea</italic>. Our data reveal new insights into the genetic diversity of <italic>B. cinerea</italic> and provide evidence for intraspecific differentiation and different degrees of host adaptation of this polyphagous necrotrophic pathogen.</p>