Genome Analyses of Two Blueberry Pathogens: <i>Diaporthe</i><i>amygdali</i> CAA958 and <i>Diaporthe eres</i> CBS 160.32

Abstract

The genus Diaporthe includes pathogenic species distributed worldwide and affecting a wide variety of hosts. Diaporthe amygdali and Diaporthe eres have been found to cause cankers, dieback, or twig blights on economically important crops such as soybean, almond, grapevine, and blueberry. Despite their importance as plant pathogens, the strategies of species of Diaporthe to infect host plants are poorly explored. To provide a genomic basis of pathogenicity, the genomes of D. amygdali CAA958 and D. eres CBS 160.32 were sequenced and analyzed. Cellular transporters involved in the transport of toxins, ions, sugars, effectors, and genes implicated in pathogenicity were detected in both genomes. Hydrolases and oxidoreductases were the most prevalent carbohydrate-active enzymes (CAZymes). However, analyses of the secreted proteins revealed that the secretome of D. eres CBS 160.32 is represented by 5.4% of CAZymes, whereas the secreted CAZymes repertoire of D. amygdali CAA958 represents 29.1% of all secretomes. Biosynthetic gene clusters (BGCs) encoding compounds related to phytotoxins and mycotoxins were detected in D. eres and D. amygdali genomes. The core gene clusters of the phytotoxin Fusicoccin A in D. amygdali are reported here through a genome-scale assembly. Comparative analyses of the genomes from 11 Diaporthe species revealed an average of 874 CAZymes, 101 secondary metabolite BGCs, 1640 secreted proteins per species, and genome sizes ranging from 51.5 to 63.6 Mbp. This study offers insights into the overall features and characteristics of Diaporthe genomes. Our findings enrich the knowledge about D. eres and D. amygdali, which will facilitate further research into the pathogenicity mechanisms of these species.

Keywords

• CAZymes
• <i>Diaporthe</i>
• effectors
• Fusicoccin A
• virulence factors
• whole genome sequencing