Alfa-amylase inhibitors of legume seeds and their involvement in the resistance to bruchid beetles

RESUMO

The presence of inhibitors of alfa-amylases from several sources (bacterial, plant, insect and mammallian) was investigated in seeds of several food legumes. No inhibitor of any of the tested enzymes was found in Phaseolus lunatus (Lima bean) seeds while the presence of inhibitors of insect (bruchid), porcine pancreas and human saliva alfa-amylases was confirmed in the seeds of P. vulgaris (common bean). Glycine max (soybean) seeds showed alfa-als for all the tested enzymes except for the porcine pancreatic amylase. Although we have found low levels of alfa-als in both bruchid-susceptible and resistant cowpea (Vigna unguiculata) seeds their presence does not correlate with the resistance shown by the seeds of some cultivars to the cowpea weevil Callosobruchus maculatus. The results reported here suggest that alfa-Als are not involved in the resistance of seeds of some cowpea lines to C. maculatus and that variant vicilins, the 7 S storage proteins involved in this resistance, do not show any inhibitory towards bruchi alfa-amylases