RT Journal Article SR Electronic T1 First genome of Labyrinthula, an opportunistic seagrass pathogen, reveals novel insight into marine protist phylogeny, ecology and CAZyme cell-wall degradation JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.09.14.297390 DO 10.1101/2020.09.14.297390 A1 Mun Hua Tan A1 Stella Loke A1 Laurence J. Croft A1 Frank H. Gleason A1 Lene Lange A1 Bo Pilgaard A1 Stacey M. Trevathan-Tackett YR 2020 UL http://biorxiv.org/content/early/2020/09/15/2020.09.14.297390.abstract AB Labyrinthula spp. are saprobic, marine protists that also act as opportunistic pathogens and are the causative agents of seagrass wasting disease (SWD). Despite the threat of local- and large-scale SWD outbreaks, there are currently gaps in our understanding of the drivers of SWD, particularly surrounding Labyrinthula virulence and ecology. Given these uncertainties, we investigated Labyrinthula from a novel genomic perspective by presenting the first draft genome and predicted proteome of a pathogenic isolate of Labyrinthula SR_Ha_C, generated from a hybrid assembly of Nanopore and Illumina sequences. Phylogenetic and cross-phyla comparisons revealed insights into the evolutionary history of Stramenopiles. Genome annotation showed evidence of glideosome-type machinery and an apicoplast protein typically found in protist pathogens and parasites. Proteins involved in Labyrinthula’s actin-myosin mode of transport, as well as carbohydrate degradation were also prevalent. Further, CAZyme functional predictions revealed a repertoire of enzymes involved in breakdown of cell-wall and carbohydrate storage compounds common to seagrasses. The relatively low number of CAZymes annotated from the genome of Labyrinthula SR_Ha_C compared to other Labyrinthulea species may reflect the conservative annotation parameters, a specialised substrate affinity and the scarcity of characterised protist enzymes. Inherently, there is high probability for finding both unique and novel enzymes from Labyrinthula spp. This study provides resources for further exploration of Labyrinthula ecology and evolution, and will hopefully be the catalyst for new hypothesis-driven SWD research revealing more details of molecular interactions between Labyrinthula species and its host substrate.Competing Interest StatementThe authors have declared no competing interest.