Mapping and characterization of sorghum bicolor thick leafed mutant



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The importance of generating economically desirable varieties of sorghum either, decreasing lignin content or cellulose crystalline enhances crop efficiency (Xu et al., 2009). Therefore, new varieties with distinct favorable phenotypes need to be produced. However, increasing plant height becomes a mechanical obstacle to harvesting and to other agronomic practices in commercial sorghum production. Further, improving foliage quality of grain sorghum would be added advantage to future sorghum cultivation. Therefore, enhancing the foliage quality of grain sorghum would add benefit to future sorghum cultivation. Endo - 1,4 β - glucanase enzyme plays an important role in plant cellulose biosynthesis. The present research was performed to characterize the protein Endo - 1, 4 β – glucanase encoding, SBTHL2 gene in sorghum bicolor physiologically and functionally. Histological and biochemical analysis was performed to observe the impact of the SBTHL2 gene on plant cell wall. The crystalline cellulose analysis of the SBTHL 2 stem showed a decrease in crystalline cellulose content due to endo - 1,4 β – glucanase only in SBTHL 2 stem. In addition, KORRIGAN gene expression was noted to be greater in immature plants compared to mature plants. This is further supported by increasing the crystalline cellulose content of SBTHL 2 leaves and roots. Arabidopsis is an excellent model system for evaluating the function of the genes from other plant species because of its small genome, short life cycle, wide seed production, and easy floral dip transformation capability. Taking consideration of the similarity of Arabidopsis sequence similarity, SBTHL 2 gene was transformed to Arabidopsis rsw 2-1 temperature- sensitive mutant to functionally characterize the SBTHL gene of sorghum. The full length of KORRIGAN cDNA 620 bp was amplified and characterized from Sorghum bicolor sequence alignment with Arabidopsis korrigan Endo - 1,4 β – glucanase gene showed 74% sequence similarity. The SBTHL 2 genes were successfully transformed to sorghum bicolor using agrobacterium mediated floral dip transformation. RT-pcr analysis was conducted to observe presence of Transgenic SBTHL 2 gene. Overexpression of SBTHL 2 restored into Arabidopsis performs a similar function, restored the mutant phenotype back to the Col 0 phenotype. However, SBTHL 2 complement gene using native promoter has not recovered the phenotype back to wild type.



Sorghum, Endo-1,4 β-glucanase enzyme, KORRIGAN, Overexpression