Effect of Bacillus subtilis QM3 on β-amylase Isoenzyme in Early Germination of Wheat Seed

Seed germination is the basis and initial stage in the process of plant growth and development. Bacillus subtilis QM3 is a plant growth promoting rhizobacterium (PGPR) with function of growth promoting, promoting, prevention of pathogens and pests attack and can improve plant resistance to different stress factors. Through the measurement of the early germination rate of wheat (Triticum aestivam L.). seeds under B. subtilis QM3 treatment, the results showed that B. subtilis QM3 can significantly promote the germination of wheat seeds, which has reached a significant level at 6h after seeds sowing or at 6 h of treatment, during imbibition. The β-amylase isoenzyme in early period of wheat seed germination was measured by denaturing polyacrylamide gel electrophoresis. The results showed that the band width and brightness of β-amylase isoenzyme of wheat seeds treated with B. subtilis QM3 increased during three to 6 h of imbibition and especially the effect was significant at 6 h. In the early period, the band of α-amylase isoenzyme could not be detected. It is suggested that the increase of β-amylase isoenzyme early band may be one of the main reasons for B. subtilis QM3 to promote wheat seed germination. Through the combination of B. subtilis QM3 with free and binding states of β-amylase, it was found that the former can increase the activity of β-amylase by either increasing free β-amylase or releasing binding β-amylaseisoenzyme. β-amylaseisoenzyme inhibitors can significantly inhibit β-amylase activity, nevertheless α-amylase activators and inhibitors have no significant effect on β-amylaseisoenzyme, which further proved that the β-amylase exerted the effects in the early period of wheat seed more precisely during the imbibition of the seeds.