Abstract Detail

Comparative Genomics/Transcriptomics

Purintun, Jordan [1], Andersen, Ethan [1], Neupane, Surendra [1], Nepal, Madhav [1].

Evolution of Resistance Genes in Wheat (Triticum aestivum L.) and its Relatives.

Receptors encoded by plant resistance genes (R genes) detect pathogenic effectors and initiate immune responses. These proteins generally contain three domains essential to their function. The first, the Leucine-Rich Repeat (LRR) domain, detects effectors, and the others, the NB-ARC and Coiled-Coil (CC) domains, initiate signaling to trigger immune responses. The objectives of this study were to identify NB-ARC-encoding genes in wheat (Triticum aestivum L.) and to locate gene clusters that may have evolved through tandem duplication. We analyzed similarities between members of gene clusters, mapped chromosomal locations, constructed phylogenetic trees comparing clustered genes, and aligned chromosomes to assess synteny. Our results show that the wheat genome includes a total of 2,151 NB-ARC-encoding genes, and 1,298 of these were located within at least one of 547 clusters. Many of these clusters include similar genes that we infer to have formed via tandem duplications. Of the 2,151 NB-ARC-encoding genes, 1,552 encode LRR domains but not CC domains, and 802 encode both CC and LRR domains. Three also encode Resistance to Powdery mildew 8 (RPW8) domains (RNL), and five of the NB-ARC-encoding genes encoded a Toll/Interleukin-1 Receptor (TIR) domain without an LRR (TN with no TNL genes) domain. Comparisons of the wheat genome with those of its close relatives, barley (Hordeum vulgare L.) and Tausch's goatgrass (Aegilops tauschii Coss.), found similar locations for homologous NB-ARC-encoding genes, and CNL clades formed phylogenetic nesting patterns similar to those found in these and other species in the grass family. Overall, these results coincide with previous reports that grasses often possess clusters of similar R genes formed by tandem duplications. Future research should characterize these proteins according to which pathogens they detect and determine if these tandem duplications can be associated with known events in wheat's evolutionary history.

1 - South Dakota State University, McFadden Biostress Laboratory, Brookings, SD, 57006, United States

Keywords:
Plant immunity
Disease resistance 
NBS-LRRs
Coiled coiled (CC)
CNL, TNL and RNL.

Presentation Type: Poster
Session: P, Comparative Genomics and Transcriptomics Posters
Location: /
Date: Monday, July 29th, 2019
Time: 5:30 PM This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PGT002
Abstract ID:161
Candidate for Awards:Genetics Section Poster Award