Fusarium oxysporum: A “Moving” View of Pathogenicity

Abstract

The genus Fusarium includes a number of important soilborne plant pathogenic and toxicogenic filamentous fungi with worldwide distribution. They have been subjected to considerable research, and availability of tools like transposon tagging, Agrobacterium-mediated transformation and gene disruption has facilitated both forward and reverse genetic studies of plant pathogenesis in Fusarium. Research on Fusarium genetics and genomics accelerated with the availability and analysis of whole genome sequence of four important species, viz. F. graminearum, F. verticillioides, F. oxysporum and F. solani. Detailed bioinformatics and experimental evidence revealed an interesting secret in Fusarium pathogenicity—the existence of lineage-specific (LS) genomic regions in F. oxysporum that could determine pathogenicity. It was proven experimentally that in F. oxysporum transfer of such a lineage-specific chromosome harbouring pathogenicity genes could render a non-pathogenic strain pathogenic. This mobile pathogenicity chromosome opened up a very novel field of research involving horizontal chromosome transfer (HCT) as a basic mechanism in the evolution of Fusarium species.