ARS | Publication request: Map-Based Cloning of Sbbmc, a Major Locus Controlling the Profuse Wax Trait of Sorghum: a Case Study in Unlocking the Abiotic Stress Tolerance of Sorghum bicolor via Integrated Physiological and Genomic Approaches

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: February 3, 2008
Publication Date: February 6, 2008
Citation: Burow, G.B., Franks, C.D., Xin, Z. 2008. Map-Based Cloning of Sbbmc, a Major Locus Controlling the Profuse Wax Trait of Sorghum: a Case Study in Unlocking the Abiotic Stress Tolerance of Sorghum bicolor via Integrated Physiological and Genomic Approaches[abstract]. International Meeting on Molecular Mapping and Marker Assisted Selection in Plants. February 3-6, 2008, Vienna, Austria. CDROM.

Technical Abstract: Sorghum bicolor is one of the most valuable “fail safe” cereal crop species and is a rich repository of genes for abiotic stress tolerance that await discovery. As an example, Sorghum exhibits cuticle which produces profuse amount of epicuticular wax (bloom) on sheaths and leaves that serves as key morphological trait contributing to abiotic and biotic stress tolerance. Here, we report the genetic mapping and map-based cloning of a locus controlling profuse wax trait, Sbbmc (S. bicolor bloom-cuticle gene) using a mutant mapping population. The sbbmc mutant locus reduced leaf and sheath wax load by 85-90%, leaf cuticle amount by 70% and significantly increased cuticular permeability and transpiration was derived from a gamma irradiated bloomless mutant (KFS 2021). To map Sbbmc, 100 F2 progenies from a cross of the bloomless KFS2021 to BTx623 (wild type) were genotyped using microsattelite markers. Sbbmc mapped to a 6cM interval in the terminal end of sorghum chromosome10 flanked by Xcup42 and Xsbarslbk7027. High resolution mapping using additional F2 progenies further delineate the locus to 0.5 cM region. Physical mapping is being applied to identify BAC clone corresponding to the interval. An analysis of open reading frames in the region of interest using the newly available sorghum genome sequence (www.phytozome.net) indicates the presence of six candidate genes. Map based cloning of Sbbmc opens new possibilities for dissection of genes in the cuticle-EW pathway of sorghum and their application in enhancing abiotic stress tolerance in other crops.