Abstract Detail



Comparative Genomics/Transcriptomics

Neupane, Surendra [1], Nepal, Madhav [1].

Genome-wide Identification of Disease Resistance Genes in Sunflower (Helianthus annuus L.).

Nucleotide-binding site Leucine-rich repeat (NBS-LRR or NBS in short) genes in plants encode disease resistance proteins (R) involved in plant defense against pathogens. Sunflower crop is affected by many diseases and little is known about the molecular pathogenesis and resistance mechanism against them. Recent availability of sunflower complete genome-sequences allowed us to perform a genome-wide identification of both Toll interleukin-1 receptor-like Nucleotide-binding site Leucine-rich repeat (TNL) and Coiled Coil (CC)-NBS-LRR (CNL) group of proteins in sunflower. We used Arabidopsis thaliana reference sequences to carry out Hidden Markov Model (HMM) profiling of 52,232 sunflower proteins in order to identify NBS-genes in sunflower genome. We identified 352 NBS genes including 100 CNLs (with 64 RX_CC like domains), 77 TNLs and 13 RNLs (resistance to powdery mildew8). We also identified signal peptides and nuclear localization signals present in these NBS proteins including their potential homologs. NBS genes are located on each chromosome forming seventy-five clusters, one-third of which was observed in chromosome 13. Phylogenetic analyses between sunflower and Arabidopsis NBS genes revealed clade-specific nesting pattern in CNL group with RNLs in the CNL-A clade, and species-specific nesting pattern in TNL group. Arabidopsis and sunflower genome showed 87 synteny blocks with 1049 synteny hits with high synteny between chromosomes 5 of Arabidopsis with chromosome 6 of sunflower. Analyses of the available transcriptomic data revealed functional divergence of NBS-genes indicating tissue specific differential expression. This study represents first genome-wide identification of NBS genes in sunflower which could help elucidate the role of these genes in disease resistance pathwayswith potential implication in crop improvement.


1 - South Dakota State University, Biology And Microbiology, McFadden Biostress Laboratory, Brookings, SD, 57006, USA

Keywords:
NBS-genes
Sunflower
TNLs
CNLs
RNLs
Phylogeny of R-genes.

Presentation Type: Poster
Number: PGT003
Abstract ID:106
Candidate for Awards:Genetics Section Poster Award


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