Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2007
Publication Date: 1/10/2008
Citation: Faris, J.D., Lu, H., Zhang, Z., Reddy, L., Fellers, J.P., Friesen, T.L. 2008. Genomic analysis of the Tsn1 locus and the identification of candidate genes. Plant and Animal Genome ConferenceXVI abstracts pg. 305 Interpretive Summary:
Technical Abstract: The wheat Tsn1 gene on wheat chromosome arm 5BL confers sensitivity to the host-selective proteinaceous toxins Ptr ToxA and SnToxA produced by the pathogenic fungi Pyrenophora tritici-repentis and Stagonospora nodorum, respectively. Compatible Tsn1-ToxA interactions lead to extensive cell death and disease susceptibility. Toward the map-based cloning of Tsn1 on chromosome 5B, we sequenced and assembled chromosome 5A and 5B BAC contigs spanning the gene. Evaluation of gene content and micro-colinearity between the orthologous regions of 5A, 5B, and rice chromosome 9 indicated the 5A region and rice share a higher level of micro-colinearity than the 5B region does with rice due to the presence of numerous transpositions, deletions, and rearrangements present in the wheat 5B region. In addition, the 5B Tsn1 candidate region is nearly 4 times larger than the corresponding region of 5A due to the presence of additional genes and transposable elements. At least ten genes exist within the 350 kb Tsn1 candidate gene region, and they are currently being validated by comparative sequence analysis of Tsn1-disrupted mutants and virus-induced gene silencing (VIGS). An important applied by-product of this research is the development of efficient PCR-based markers for Tsn1, which are being used to introgress SnToxA insensitivity into adapted germplasm. The isolation of Tsn1 will allow us to begin deciphering the molecular interactions and mechanisms associated with the wheat-P. tritici-repentis and wheat-S. nodorum pathosystems.