Location: Crop Germplasm ResearchTitle: Evaluation and genome-wide association study of resistance to bacterial blight race 18 in US Upland cotton germplasm
|ELASSBLI, HANAN - New Mexico State University|
|ABDELRAHEEM, ABDELRAHEEM - New Mexico State University|
|ZHU, YI - New Mexico State University|
|TENG, ZONGHUA - New Mexico State University|
|WHEELER, TERRY - Texas A&M Agrilife|
|KURAPARTHY, VASU - North Carolina State University|
|STELLY, DAVID - Texas A&M University|
|WEDEGAERTNER, TOM - Cotton, Inc|
|ZHANG, JINFA - New Mexico State University|
Submitted to: Molecular Genetics and Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2021
Publication Date: 3/29/2021
Citation: Elassbli, H., Abdelraheem, A., Zhu, Y., Teng, Z., Wheeler, T., Kuraparthy, V., Hinze, L.L., Stelly, D., Wedegaertner, T., Zhang, J. 2021. Evaluation and genome-wide association study of resistance to bacterial blight race 18 in US Upland cotton germplasm. Molecular Genetics and Genomics. 296:719-729. https://doi.org/10.1007/s00438-021-01779-w.
Interpretive Summary: In the United States, a resurgence of bacterial blight of cotton has been observed in recent years. Bacterial blight is a yield limiting disease of cotton. Changes in production practices, particularly regarding choice of cultivars, have been noted as modern cultivars are more susceptible to bacterial blight. A survey was conducted to identify sources of resistance to bacterial blight and their genomic associations. Resistance to bacterial blight was identified in 50 cotton cultivars that have not been grown in the United States for more than 15 years. Five chromosome locations were discovered as linked to resistance. This survey identified sources of germplasm resistant to bacterial blight that may be used to develop new cultivars. The results will assist in breeding cotton for bacterial blight resistance and developing studies to better understand the genetics of resistance to this disease.
Technical Abstract: Bacterial blight (BB), caused by Xanthomonas citri pv. malvacearum (Xcm), is a destructive disease in many cotton-producing countries. In the US, Xcm race 18 is the most virulent and widespread race and can cause serious yield losses. Planting BB resistant cotton cultivars is the most effective method of controlling this disease. In this study, 339 US Upland cotton accessions were evaluated for resistance to race 18 using artificial inoculations by scratching cotyledons on an individual plant basis in the greenhouse. The analysis of variance detected significant genotypic variation in disease incidence, and 50 accessions were resistant including 38 lines with no symptoms on both cotyledons and true leaves. Many of the resistant lines were developed in the MAR breeding program at Texas A&M University, while others were developed before race 18 was first reported in the US in 1973, suggesting a broader base of resistance to race 18 than expected. A genome-wide association study (GWAS) based on 26,301 single nucleotide polymorphic (SNP) markers detected 11 quantitative trait loci (QTL) anchored by 79 SNPs, including three QTL on each of the three chromosomes- A1, A5 and D2 and one QTL each on D8 and D10. This study has identified a set of obsolete Upland germplasm with resistance to race 18 and specific chromosomal regions delineated by SNPs for resistance. The results will assist in breeding cotton for BB resistance and facilitate genomic studies in fine mapping resistance genes to enhance the understanding of the genetic basis of BB resistance in cotton.