Development of pathogenicity assay and characterization of Fusarium oxysporum f. sp. elaeidis (FOE) based on Secreted In Xylem genes and EF-1α

Abstract

The pathogenicity of four Fusarium oxysporum isolates collected from symptomatic oil palm (Elaeis guineensis Jacq.) from Ghana were tested for the first time to develop a new pathogenicity assay for Fusarium oxysporum f. sp. elaeidis (FOE) infection in oil palm seedlings. All four FOE isolates used for pathogenicity assay were pathogenic to oil palm seedlings within a relatively short time compared to other pathogenicity studies, for which infection/symptoms in oil palm seedlings was time consuming. FOE and “presumed-FOE” (i.e. Fusarium isolates collected from symptomatic oil palm trees whose pathogenicity is not confirmed) were characterised based on partial sequences of a housekeeping gene EF-1α and three Secreted In Xylem genes (SIX8, SIX9 and SIX11). All the phylogenetic trees generated for EF-1α, SIX8, SIX9 and SIX11 showed some variation between FOE, and “presumed-FOE”, but could not cluster isolates based on geographical location. Phylogenetic trees for EF-1α and SIX (SIX9 and SIX11) genes clustered both FOE and “presumed-FOE” from FUSARIUM-ID from GenBank, but SIX8 could not.