Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: CHARACTERIZATION OF HOST-PATHOGEN INTERACTIONS IN BARLEY AND WHEAT

Location: Cereal Crops Research

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

Authors
item Friesen, Timothy
item Chu, Chenggen -
item Xu, Steven
item Faris, Justin

Submitted to: Molecular Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 20, 2012
Publication Date: December 1, 2012
Repository URL: http://handle.nal.usda.gov/10113/58119
Citation: Friesen, T.L., Chu, C., Xu, S.S., Faris, J.D. 2012. SnTox5-Snn5: A novel Stagonospora nodorum effector-wheat gene interaction and its relationship with the SnToxA-Tsn1 and SnTox3-Snn3-B1 interactions. Molecular Plant Pathology. 13(9):1101-1109.

Interpretive Summary: Stagonospora nodorum blotch of wheat is a destructive disease of wheat worldwide. The pathogen S. nodorum produces several necrotrophic effectors (host selective toxins) that interact with wheat gene products to induce disease. Here, we used a wheat mapping population to identify and characterize a new interaction in the wheat-S. nodorum system. This effector, designated SnTox5, induces necrosis on host lines harboring the Snn5 sensitivity gene, which we mapped to the long arm of wheat chromosome 4B. We also showed that the SnTox5-Snn5 interaction explained from 37 to 63% of the variation, demonstrating that this interaction plays a significant role in disease development. When the SnTox5-Snn5 interaction was combined with other interactions, disease increased significantly. Similar to several other interactions in this system, the SnTox5-Snn5 interaction is light dependent suggesting that multiple interactions use the same mechanism to induce disease.

Technical Abstract: 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.

Last Modified: 4/16/2014