Fusarium oxysporum f. sp. passiflorae infecting passionfruit in New Zealand in a changing taxonomic landscape

Fusarium oxysporum f. sp. passiflorae (FOP) is reported for the first time in Northland, New Zealand. The identity of this host-specific pathogen was confirmed by pathogenicity testing, morphological characters, and DNA sequencing. Pathogenic strains of Fusarium oxysporum secrete unique proteins or effectors, 'secreted in xylem' (SIX), which are likely to contribute to host-specific virulence. Sequence analysis of the EF-1a gene, beta-tubulin and the effector genes SIX6 and SIX9 confirmed that New Zealand isolates belong to FOP. This study confirmed that the three New Zealand EF-1 alpha haplotypes of FOP had identical SIX6 and SIX9 sequences, indicating that the same homolog of each gene, SIX6a and SIX9a, is shared by both haplotypes of FOP. SIX genes are rarely detected in non-pathogenic strains of Fusarium oxysporum species complex (FOSC) and pathogenicity tests are necessary to confirm its pathogenicity status.

Automated summary

The study confirmed the presence of Fusarium oxysporum f. sp. passiflorae (FOP) in Northland, New Zealand, through pathogenicity testing and DNA sequencing. The FOP isolates in New Zealand were found to have identical SIX6 and SIX9 sequences, indicating a shared homolog of these effector genes among different haplotypes.