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Evolution of carbohydrate and protein metabolism gene families in Colletotrichum spp.

Michael Thon: University of Salamanca, Instituto Hispano-Luso de Investigaciones Agrarias, CIALE

<div><em>Colletotrichum</em> spp. exhibit a broad diversity of host range, host specificity and reproductive behaviors, making the genus an excellent model for studies of the evolution of these traits. We leveraged the growing number of genome sequences available for <em>Colletotrichum</em> spp. to perform a comparative analysis of gene content to find associations with host range and host specificity. Hierarchical clustering of gene families and phylogenetic analyses revealed lineage specific losses of secreted carbohydrate-active enzymes (CAZymes) and protease encoding genes in species that have narrow host range as well as expansions of these families in the acutatum and gloeosporioides species complexes. Members of these species complexes are broad host range pathogens, suggesting that the higher number in CAZy and protease diversity may be associated with the ability to infect multiple host species. This result suggests that the repertoires of CAZymes and peptidases are the product of recent, lineage specific expansions of these families independently in each species complex. Phylogenetic analyses of the CAZyme and peptidase families revealed that, in contrast to our expectations, gene loss is an important force driving the evolution of gene family size. These results are consistent with the idea that different lifestyles, host and host tissues present different types of carbohydrate substrates to the pathogen this is reflected by each species’ CAZyme and peptidase repertoire.</div>