Developmental expression of lipoxygenases in soybeans

The developmental expression of lipoxygenase(s) (LOX) was investigated in different soybean Glycine max L. Merr. tissues. Both LOX 1 and LOX 2 + 3 were observed to be present at high levels in axes and cotyledons as determined by Ouchterlony double diffusion, Western immunoblotting and conjugate diene activity assays. LOX 1 was not detectable in any other tissue. Axes and cotyledons contained high levels of LOX 2 + 3 as did pods, small leaves and in lesser amounts medium leaves, large leaves, roots ad stems. Northern analysis that the steady state level of mRNA coding for all three seed LOXs was high only in embryos. This very high expression of LOX in axes in comparison to cotyledons, which is the tissue generally thought to have the highest LOX activity, suggest that lipoxygenase might play a role in embryo development, growth or germination. Unlike LOX 1 or LOX 2, LOX 3 was present in a number of forms with slightly different pI values. A LOX isozyme from leaves was found too be different immunologically and had an altered pI when compared to the three seed LOXs, indicating that soybean leaves contain a LOX that is different that any of the previously characterized seed LOXs.