Map-based cloning and expression analysis of BMR-6 in sorghum

作者：Li Jieqin; Wang Lihua; Zhan Qiuwen^*; Liu Yanlong

来源：Journal of Genetics, 2015, 94(3): 445-452.

DOI：10.1007/s12041-015-0550-9

• bmr-6
• cinnamyl alcohol dehydrogenase
• lignin biosynthesis
• sorghum

Brown midrib mutants in sorghum are associated with reduced lignin content and increased cell wall digestibility. In this study, we characterized a bmr-6 sorghum mutant, which shows reddish pigment in the midrib and stem after the fifth-leaf stage. Compared to wild type, Kalson lignin content of bmr-6 is decreased significantly. We used histological analysis to determine that the mutant exhibited a modified pattern of lignin staining and found an increased polysaccharide content. We cloned BMR-6 gene, a gene encoded a cinnamyl alcohol dehydrogenase (CAD), using a map-based cloning approach. Genetic complementation confirmed that CAD is responsible for the BMR-6 phenotype. BMR-6 gene was expressed in all tested sorghum tissues, with the highest being in midrib and stem. Transient expression assays in Nicotiana benthamiana leaves demonstrated cytomplasmic localization of BMR-6. We found that the expression level of bmr-6 was significantly decreased in the mutant but expression of SbCAD3 and SbCAD5 were significantly increased. Our results indicate that BMR-6 not only affects the distribution of lignin but also the biosynthesis of lignin in sorghum.

• 出版日期2015-9
• 单位安徽科技学院