Gamarada debralockiae gen. nov. sp. nov.-the genome of the most widespread Australian ericoid mycorrhizal fungus.

Abstract

This study describes a novel ericoid mycorrhizal fungus (ErMF), Gamarada debralockiae Midgley and Tran-Dinh gen. nov. sp. nov. Additionally, catabolism was explored from a genomic perspective. The nuclear and mitochondrial genomes of G. debralockiae were sequenced. Morphological characteristics were assessed on various media. Catabolic genes of G. debralockiae were explored using SignalP and dbCAN. Phylogenetic comparisons were undertaken using Phylogeny.fr. The 58.5-Mbp draft genome of G. debralockiae contained 17,075 putative genes. The complete mitochondrial genome was 28,168bp in length. In culture, G. debralockiae produces slow-growing non-sporulating colonies. Gamarada debralockiae has many putative secreted catabolic enzymes. Phylogeny indicated G. debralockiae was distinct from known ascomycetous ErMF: Pezoloma ericae, Meliniomyces spp., Oidiodendron spp., and Cairneyella variabilis. It is closely related to many undescribed plant root-associated fungi and its nearest described relative is Hyphodiscus brevicollaris. Gamarada debralockiae has been recovered from virtually all Australian ericoid mycorrhizal studies and biogeographic data suggests the taxon is widespread in Australia. Gamarada debralockiae has similar catabolic potential to C. variabilis and co-occurs with C. variabilis at Australian sites. Plants that host multiple ErMF may benefit from subtle differences in catabolism that improve access to nitrogen and phosphorus from within recalcitrant organic matter.