cDNA Cloning and Sequencing of β-galactosidase Genes in Banana(Musa spp.) Fruit

Degenerate primers were designed according reported conservative sequence of β-galactosidase genes and amplified by RT-PCR so that a fragment of about 900 bp were obtained;The fragment was named MA-gal and its sequencing indicated that MA-gal was 927 bp in its full length,encoded 309 amino acids and contained GGPIILSQIENEY(F) motif,the presumptive catalytic domain which was shared by all β-galactosidase genes;The amino acid sequence of MA-gal is similar to those of the corresponding gene fragments of asparagus,strawberry,tomato,mango and avocado with their homologies standing at 85.8%,80.9%,80.5%,79.0% and 76.3%,respectively.