LAUSR

Ganoderma butt rot of palms is caused by a white rot basidiomycete fungus, Ganoderma zonatum. Typical symptoms include wilting of fronds that start in lower canopy and move to the top. As wilting symptoms are associated with other diseases/disorders, appearance of basidiomata on the trunks is necessary to confirm this disease. Basidiomata develop late in the disease cycle making early diagnostics challenging. Here we describe a DNA-based molecular diagnostic assay that could be used to confirm the presence of G. zonatum in palm trunks before conks are observed. Primers tailored to end on SNPs, that differentiate G. zonatum from fourteen other Ganoderma taxa, were designed from multiple regions in four genes, ITS, rpb1, rpb2, and tef1α. A set of three primer pairs could successfully determine the incidence of G. zonatum with high specificity and sensitivity in different environmental samples such as sawdust collected from naturally infected palm trunks and soil samples containing G. zonatum basidiospores. This rapid PCR-based assay can be used to detect inoculum sources of the fungus and track its movement and survival in different palm tissues and environments. Early detection of G. zonatum is a crucial step towards building and implementing better disease management strategies and mitigating potential risks from palm failures due to decay.