A novel class of homoeologous genes targeted by a fungal necrotrophic effector triggers disease susceptibility in wheat

Authors: Zhang, Zengcui; RUNNING, KATHERINE - North Dakota State University; SENEVIRATNE, SUDESHI - North Dakota State University; PETERS HAUGRUD, AMANDA - North Dakota State University; BRUEGGEMAN, ROBERT - North Dakota State University; SZABO-HEVER, AGNES - Orise Fellow; Xu, Steven; Friesen, Timothy; Faris, Justin

Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/11/2020
Publication Date: 1/13/2020
Citation: Zhang, Z., Running, K., Seneviratne, S., Peters Haugrud, A., Brueggeman, R., Szabo-Hever, A., Xu, S.S., Friesen, T.L., Faris, J.D. 2020. A novel class of homoeologous genes targeted by a fungal necrotrophic effector triggers disease susceptibility in wheat [abstract]. Plant and Animal Genome Conference XXVIII. W1106.

Interpretive Summary:

Technical Abstract: Septoria nodorum blotch (SNB), a fungal disease caused by the necrotrophic pathogen Parastagonospora nodorum, is a threat to wheat production worldwide. Multiple inverse gene-for-gene interactions involving the recognition of necrotrophic effectors (NEs) by wheat sensitivity genes have been shown to play major roles in causing SNB. The previously cloned NE sensitivity genes Tsn1 and Snn1 are members of the NLR and wall-associated kinase classes of genes, respectively. Here, we cloned and validated by mutagenesis a pair of homoeologous genes named Snn3-D1 and Snn3-B1, which both mediate recognition of the P. nodorum NE SnTox3 to confer susceptibility to SNB. These genes belong to a class different from Tsn1 and Snn1. Snn3-D1 was not found in hexaploid wheat, and it was recently acquired by Aegilops tauschii through a 200 kb insertion that likely occurred along the west bank of the Caspian Sea. Snn3-B1 is prevalent among hexaploid wheat accessions, but somewhat rare among tetraploids. Like Tsn1 and Snn1, Snn3 transcriptional expression is regulated by light. However, Snn3 expression patterns are the opposite of Tsn1 and Snn1 in that expression increases under darkness and decreases under light. Yeast two-hybrid study indicated that the Snn3-D1 protein does not interact with SnTox3 directly. The cloning of the Snn3 genes and the characterization of their novel features advances our understanding of the wheat-P. nodorum pathosystem and plant-pathogen interactions in general. This work also provides knowledge for strategic development of SNB-resistant wheat varieties through marker-assisted elimination of susceptibility genes or gene editing.