Cloning and sequencing of a β-glucosidase of cDNA from Sorghum bicolor (L.) Moench and analysis of expression in seedlings
A full-length β-glucosidase encoding cDNA is isolated and sequenced from Sorghum bicolor (L) Moench. Using 5’- and 3’- end specific probes derived from the cDNA clone, the multiplicity of β-glucosidase genes and their expression in different tissues were studied. Southern blotting data showed that β-glucosidase is encoded by a small multigene family. Northern analysis data indicated that mRNA corresponding to the cloned gene is present at high levels in the node and mesocotyl 2 regions of the seedling and at low levels only in the zone of elongation region in roots. Other seedling parts such as mesocotyl 1, root sections adjacent to the seed and coleoptile sections do not have any detectable expression. The amino acid sequence data show 72% sequence identity between maize and sorghum β-glucosidase precursor proteins. In view of high sequence similarity between maize and sorghum β-glucosidase, immunoblotting analysis was performed with maize-anti-β-glucosidase serum. The immunoblotting results supported the results of Hosel et al., (1987) with respect to the occurrence of two distinct β-glucosidases being present in sorghum.