Functional genomics and mycotoxin discovery in the wheat glume blotch pathogen Stagonospora nodorum

Abstract

Stagonospora nodorum is a fungal pathogen of wheat and is responsible for over $100 million in yield losses in Australia each year. Significant progress has recently been made in understanding how S. nodorum causes disease on wheat. These pathogens, known as a necrotrophs, were thought to secrete a battery of lytic and degradative enzymes during infection. These enzymes would simply degrade host tissue, allowing the infecting pathogen to feed off the lysed cellular contents. Recent studies have shown that this is not so, and that these fungi secrete unique effector proteins during the early stages of infection, which appear to be translocated into wheat cells. Once inside, these proteins interact (either directly or indirectly) with the products of dominant susceptibility loci leading to a localised programmed cell death response. Consequently, it is through an intricate gene-for-gene mechanism involving the interaction of pathogen effector proteins and host dominant susceptibility genes that S. nodorum infects its wheat host, not through a crude secretion of cell lysis enzymes. These findings have been recently reviewed by Oliver and Solomon3. This short article focuses on how modern functional genomics techniques have been exploited to reveal a new dimension to the wheat pathogen S. nodorum.