Isoenzyme Expression in Bean Seed Germination Treated with Thiamethoxam with and without Drought Stress

Abstract

The thiamethoxam acts as enhancer, allowing maximizing the expression of seed vigor. Isozymes are products of gene expression, highly influenced by the environment, because genes that control its expression are manifested in certain stages of development and in specific organs and tissues, or even under the action of certain stimulus. This study evaluated the isoenzyme expression in bean seedlings from seeds treated with thiamethoxam. Bean seeds were used, cultivar Pérola and IAPAR Siriri, submitted or not to drought stress. Seeds were treated at doses of thiamethoxam: 0, 1, 2, 3, 4 and 5 mL·kg -1 of seed. Isozymes were extracted from seedlings collected five days after sowing. We evaluated the expression of isoenzymes: Glutamate Oxalacetate transaminase (GOT), acid phosphatase (FAC), peroxidase (PO), Esterase (EST), malate dehydrogenase (MDH) and glutamate dehydrogenase (GTDH). Interpretation of the results was based on visual analysis of electrophoresis gels, considering the presence/absence and the intensity of each electrophoretic band. Bean seeds treated with thiamethoxam with doses up 3 mL·kg -1 of seed are higher germination untreated, even when submitted to drought stress. The expression of isozymes GOT, FAC, PO, EST, MDH and GTDH is not affected significantly in bean seedlings of Pérola and IPR Siriri under different doses of thiamethoxam with and without drought stress.