Tissue Specificity Of Amylase Of Sweet Potato And Cloning And Expression Of β-Amylase Gene

Amylase isozyme composition of calli and tuberous roots from sweet potato was analyzed by native PAGE and active staining, using amylopectin or soluble starch as substrate. Four amylase bands, two α -amylases and two β -amylases were found in calji, while only one from tuberous roots of sweet potato, The band from tuberous roots is similar with one of bands from calli. Amylase from calli and tuberous roots responded differently to inhibitors. Amylase from tuberous roots is not sensitive to EDTA or thiol-group reagent ,but the four amylase of calli were . These results indicated that there exists polymorphism of amylase isozyme between calli and tuberous roots of sweet potato.The effects of different environmental factors, such as high and low temperature, waterlogging, high temperature-waterlogging, and low temperature-waterlogging, on the main amylases from calli were studied. The activity of amylases from calli in high temperature was approximately equivalent to or slightly lower than normal in 84h. The amylase activity of calli under low-temperature treatment was approximately equal to or slightly higher than normal. Amylase Bl changed acutely compared with others. The amylase activity of calli under waterlogging reduced strongly in 24h, then it recovered to normal level, followed by decreasing rapidly again. The change in amylase activity was almost the same under...