ELISA na determinaçäo quantitativa e análise genética nas lipoxigenases L1 e L2 em soja / ELISA in the quantification and genetic analysis of lipoxygenases L1 and L2 from soybeans

RESUMO

A soybean breeding program has been undertaken at the Federal University of Viçosa aiming to reduce lipoxygenase lelvels ib the seeds of commercial varieties. A direct ELISA (Enzyme Linked Immunosorbent Assay) procedure has been developed to quantify lipoxygenases L1 and L2 in soybean seeds. Polyclonal antibodies were reised in rabbits against pure L1 and L2 and purified further by affinity chromatography. The best conditions to perform the analaysis were determined as foloow: coating antibody dilution 1:100, crude soybean protein extract 1:2 x 105 and conjugate 1:100 for both L1 and L2 isozymes. The method proved to be sensible enough to identify homozygous and heterozygous genotypes in the breeding program performing single non destructive analysis of seeds or even cotileldones right after germination. Besides, L1 was quantified in about 120 soybean Brazilian cultivars an L2 in some of them. The results showed a significant variability in the level of lipoxygenase-1 among the cultivars analysed. With respect to L2, it was found that the level of this isozyme was significantly greater in the seeds than observed for L1, in spite of its lower "in vitro" specific activity