Unveiling the Core Effector Proteins of Oil Palm Pathogen <i>Ganoderma boninense</i> via Pan-secretome Analysis

Ganoderma boninense is the major causal agent for the basal stem rot (BSR) disease in oil palm, causing the progressive rot of the basal part of the stem. Despite its prominence, key pathogenicity determinants for the aggressive nature of hemibiotrophic infection remain unknown. In this study, genome sequencing and annotation of G. boninense T10 were carried out using the Illumina sequencing platform and comparative genome analysis was performed with previously reported G. boninense strains (NJ3 and G3). The pan-secretome of G. boninense was constructed and comprised of 937 core orthogroups, 243 accessory orthogroups, and 84 strain-specific orthogroups. A set of core candidate effector proteins (CEPs) were found to be enriched with catalytic protein classified as the carbohydrate-active enzymes, hydrolases as well as non-catalytic proteins. Differential expression analysis revealed an upregulation of CEP genes which was linked to the suppression of PTI signaling cascade while the downregulation of CEP genes was linked to the inhibition of PTI by preventing host defense elicitation. Genome architecture analysis revealed the one-speed architecture of the G. boninense genome and the lack of preferential association of CEP genes to the transposable elements. The findings obtained from this study would aid in the characterization of pathogenicity determinants and molecular biomarkers of BSR disease.