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SnTox5-Snn5: A novel Stagonospora nodorum effector-wheat gene interaction and its relationship with the SnToxA-Tsn1 and SnTox3-Snn3-B1 interactions.

Friesen, Timothy L., Chu, Chenggen, Xu, Steven S., Faris, Justin D.
Molecular plant pathology 2012 v.13 no.9 pp. 1101
Leptosphaeria nodorum, Triticum aestivum, chromosome mapping, chromosomes, epistasis, fungal diseases of plants, genes, host-pathogen relationships, mycotoxins, necrosis, pathogens, plant proteins, tetraploidy, wheat
The Stagonospora nodorum-wheat interaction consists of multiple pathogen - produced necrotrophic effectors that interact directly or indirectly with specific host gene products to induce the disease Stagonospora nodorum blotch (SNB). Here, we used a tetraploid wheat mapping population to identify and characterize a sixth effector-host gene interaction in the wheat-S. nodorum system. Initial characterization of the effector, designated SnTox5, indicated that it is a proteinaceous necrotrophic effector that induces necrosis on host lines harboring the Snn5 sensitivity gene, which we mapped to the long arm of wheat chromosome 4B. Based on ultra-filtration, SnTox5 is likely in the size range of 10 to 30 kDa. Analysis of SNB development in the mapping population indicated that the SnTox5-Snn5 interaction explained from 37 to 63% of the variation, demonstrating that this interaction plays a significant role in disease development. The effects of a compatible SnTox5-Snn5 interaction were additive with those of a compatible SnToxA-Tsn1 interaction, and when the two interactions occurred together the level of SNB was significantly increased. However, the effects of SnTox5-Snn5 were epistatic to the SnTox3-Snn3-B1 interaction. Similar to several other interactions in this system, the SnTox5-Snn5 interaction is light dependent suggesting that multiple interactions may exploit the same pathways to cause disease.