New developments in pathogenicity and virulence of necrotrophs.

It was generally considered that necrotrophic plant pathogenic fungi possessed simplistic pathogenic mechanisms being typically reliant on 'blasting their way through host tissue with a battery of lytic and degradative enzymes. However recent studies have suggested that this is not true and that necrotrophic fungal pathogens can subtly manipulate the host during infection in a manner similar to biotrophic pathogens. For example, it has been demonstrated that the wheat pathogens Stagonospora nodorum and Pyrenophora triticirepentis secrete small unique proteins (effectors) that are internalised by host cells and interact with the host in a gene-for-gene relationship to initiate disease, albeit in an inverse manner compared to biotrophs. This paper reviews recent developments in necrotrophic fungal pathogenicity throughout a critical period that arguably saw this field come of age.