Identification of a C2H2-type zinc-finger transcription factor that binds to the promoter of Parastagonospora nodorum Tox3 and is similar to Con7
S. LIN (1), Y. Chooi (2), P. Solomon (1) (1) Plant Sciences Division, Research School of Biology, The Australian National University, Australia; (2) School of Chemistry and Biochemistry, University of Western Australia, Australia

The wheat pathogen Parastagonospora nodorum secretes host-specific effector proteins to cause disease. One of these effectors, Tox3, interacts with the dominant Snn3 locus and results in necrosis in wheat. Previously, gene expression studies have shown that Tox3 is strongly induced during infection whilst slight induction is observed during growth in vitro. The molecular mechanism regulating expression of the Tox3 gene though is unknown. It is proposed that critical regulatory elements within the promoter of Tox3 control the transcription of this gene during different infection and developmental stages. In this study, a putative transcription factor for Tox3 was identified through deletion analysis of the Tox3 promoter and a yeast-one-hybrid (Y1H) interaction assay. The deletion analysis identified 75 bp of the Tox3 promoter is responsible for Tox3 induction. Furthermore, Y1H identified that a Con7-like transcription factor specifically interacts with a 25 bp binding motif on the 75 bp of promoter. Con7 has been reported as a master regulator of infection-related genes expression in pathogenic fungi. However, how Con7 regulates the expression of these genes is still largely unknown, and as such we have generated Con7-disrupted P. nodorum strains. These mutants are reduced in pathogenicity, with altered morphology and strongly reduced Tox3 expression. This presentation will describe these findings and place them in a broader context of the necrotrophic effector field.

Abstract Number: P7-184
Session Type: Poster