The genome of the butternut canker pathogen, Ophiognomonia clavigignenti-juglandacearum shows an elevated number of genes associated with secondary metabolism and protection from host resistance responses in comparison with other members of the Diaporthales

Abstract

Ophiognomonia clavigignentijuglandacearum (Oc-j) is a plant pathogenic fungus that causes canker and branch dieback diseases in the hardwood tree butternut, Juglans cinerea. Oc-j is a member of the order of Diaporthales, which includes many other plant pathogenic species, several of which also infect hardwood tree species. In this study, we sequenced the genome of Oc-j and achieved a high-quality assembly and delineated the phylogeny of Oc-j within the Diaporthales order using a genome-wide multi-gene approach. We also further examined multiple gene families that might be involved in plant pathogenicity and degradation of complex biomass, which are relevant to a pathogenic life-style in a tree host. We found that the Oc-j genome contains a greater number of genes in these gene families compared to other species in Diaporthales. These gene families include secreted CAZymes, kinases, cytochrome P450, efflux pumps, and secondary metabolism gene clusters. The large numbers of these genes provide Oc-j with an arsenal to cope with the specific ecological niche as a pathogen of the butternut tree.

Two new fungal genera (Diaporthales) found on Dipterocarpaceae in Thailand

“…The pathogenic members cause great economic losses, such as chestnut blight, caused by Cryphonectria parasitica ( Cryphonectriaceae ) (Gryzenhout et al, 2006 ; Rigling and Prospero, 2018 ; Gomdola et al, 2022 ), polar and willow canker on Populus and Salix , caused by Cytospora chrysosperma ( Cytosporaceae ) (Fan et al, 2014 , 2020 ; Wang et al, 2015 ), and stem-end rot of citrus fruits infected by Diaporthe citri (Huang et al, 2013 ). Researchers have carried out their research on secondary metabolites in Diaporthaceae and Gnomoniaceae (Chepkirui and Stadler, 2017 ; Wu et al, 2019 ). As saprobes, they cause the degradation of wood, such as Apiosporopsis carpinea ( Apiosporopsidaceae ) on the overwintered leaves of Carpinus betulus (Senanayake et al, 2017 ) and Pseudoplagiostoma dipterocarpicola on the decaying wood of Dipterocarpaceae (Tang et al, 2022 ).…”