Location: Cereal Crops ResearchTitle: Genome-wide association mapping identifies SnTox5 in Parastagonospora nodorum
|KARIYAWASAM, GAYAN - North Dakota State University|
|RICHARDS, JONATHAN - Louisiana State University Agcenter|
|LIU, ZHAOHUI - North Dakota State University|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/31/2019
Publication Date: N/A
Interpretive Summary: .
Technical Abstract: The Parastagonospora nodorum-wheat interaction is comprised of P. nodorum necrotrophic effectors (NEs) and their corresponding host sensitivity genes. To date, nine such interactions have been identified in this pathosystem and three necrotrophic effectors, SnToxA, SnTox1, and SnTox3 have been cloned and functionally validated. In our research, we collected 198 isolates of P. nodorum representing different wheat growing regions of the United States. Whole genome resequencing was done for all the isolates. Isolates were inoculated on the differential line for Snn5 (LP29) that confers sensitivity to SnTox5, and the resulting phenotypic data was used to carry out genome-wide association analysis with the use of 402,612 single nucleotide polymorphisms (SNPs). A single locus was associated with virulence on LP29. A gene that was predicted to encode a small secreted protein was identified as the strongest candidate for SnTox5. The transfer of a functional copy of the candidate SnTox5 into the avirulent isolate Sn79-1087 resulted in virulence on wheat lines harboring Snn5. In addition, mutants of the SnTox5 candidate were developed by deleting the gene in the isolate Sn2000. Inoculation of gene-disruption mutant strains on the LP749 population and subsequent QTL analysis failed to detect the QTL on chromosome 4B that is associated with the SnTox5 -Snn5 interaction. During the infection process SnTox5 was upregulated in planta, reaching its highest expression at 24 hours post inoculation prior to the on-set of symptoms. The evidence presented here validates the identification of SnTox5 that encodes for the NE, SnTox5.