Genome‐wide analysis of fitness data in Ceratocystis albifundus

Abstract

Ceratocystis albifundus is an emerging pathogen of non-native Acacia mearnsii in Southern Africa. Although the fungus generally does not cause disease symptoms on native hosts, disease symptoms have been recently observed on commercial Protea cynaroides. Since laccases, an oxidase enzyme, have been implicated to influence plant-pathogen interactions, this study aimed to use a genome-wide association study (GWAS) approach to identify genes and pathways associated with oxidase activity across a South African C. albifundus population originating from a wide geographic and host range. These individuals were genotyped using low-coverage genome sequencing technologies and laccase activity was determined for each isolate. This study demonstrates that oxidative response represents a quantitative trait in this species and is associated with multiple genomic regions. This implies that oxidative activity may influence plant-pathogen interactions. Correlation between the single nucleotide polymorphism data for the isolates and their corresponding phenotype information allowed for the identification of a collection of genomic regions that were significantly associated with oxidase activity. For example, one of the regions contained a gene that codes for a protein in the multicopper oxidase superfamily, of which laccase is a member. However, further research experiments are required to validate computational study, with the ultimate goal, of improving our knowledge regarding pathogenesis in this economically important fungus.