Evolutionary analysis of endopolygalacturonase‐encoding genes of Botrytis cinerea

Abstract

Sequence analysis of five of the six endopolygalacturonase-encoding genes (Bcpg1, Bcpg2, Bcpg3, Bcpg4, Bcpg5) from 32 strains of Botrytis cinerea showed marked gene to gene differences in the amount of among-strains diversity. Bcpg4 was almost invariable in all strains; Bcpg3 and Bcpg5 showed a moderate variability, similar to that of non-pathogenicity-associated genes examined in other studies. Conversely, Bcpg1 and Bcpg2 were highly variable and were shown to be under positive selection based on the McDonald-Kreitman test and likelihood ratio test. The evolution of the five endopolygalacturonase genes is explained by their different ecophysiological role. Diversification and balancing selection, as detected in Bcpg1 and Bcpg2, can be used by the pathogen to escape recognition by the host and delay plant reaction in the early phases of infection. The analysis of the polymorphisms and the location of the sites with high probability of being positively selected highlighted the relevance of variability of the BcPG1 and BcPG2 proteins at their C-terminal end. By contrast, the absence of variability in Bcpg4 suggests that the efficiency of the product of this gene is critical for B. cinerea growth in late phases of infection or during intraspecific competition, thus markedly affecting strain fitness.

Evidence for a Common Toolbox Based on Necrotrophy in a Fungal Lineage Spanning Necrotrophs, Biotrophs, Endophytes, Host Generalists and Specialists

“…While we detected no positive selection in pg1 , previous studies among strains of B. cinerea provided evidence consistent with positive selection on both pg1 and pg2 [54], [55]. Direct comparisons to the previous work were not possible because of critical missing information, specifically the model of codon evolution [54], and the d N / d S values [55]. These intraspecific, population scale studies in B. cinerea address a different question than ours.…”

Gray Mold Populations in German Strawberry Fields Are Resistant to Multiple Fungicides and Dominated by a Novel Clade Closely Related to Botrytis cinerea

“…So far, attempts at employing population genetics for the differentiation of subpopulations of B. cinerea according to their host preferences have yielded inconsistent results. Evidence in favor of such a differentiation was reported in some studies (44,45), while no such support was obtained in others (5,46,47). In the present investigation, we have obtained evidence for the existence of a major, previously unknown gray mold subpopulation in German strawberry fields, provisionally called Botrytis group S, which is genetically distinct from B. cinerea sensu stricto.…”

Two Endopolygalacturonase Genes in Trichoderma virens: In Silico Characterization and Expression during Interaction with Plants

“…Evolutionary analyses of B. cinerea endoPG genes in different strains have suggested a role of selective pressure in different ecophysiological roles, such as host preference, pathogenicity and environmental fitness (Cettul et al. ). Although most known endoPGs belong to phytopathogenic fungi, they have also turned out to be crucial for antagonistic fungi (Harman et al.…”

“…In some genomes, they are found as multiple copies: endoPG gene families were first discovered in Aspergillus niger, Sclerotinia sclerotiorum and Botrytis cinerea (Bussink et al 1992;Fraissinet-Tachet et al 1995;Wubben et al 1999). Evolutionary analyses of B. cinerea endoPG genes in different strains have suggested a role of selective pressure in different ecophysiological roles, such as host preference, pathogenicity and environmental fitness (Cettul et al 2008). Although most known endoPGs belong to phytopathogenic fungi, they have also turned out to be crucial for antagonistic fungi (Harman et al 2004).…”