Modification of vegetable soybean sugar content via gene transformation

In a preliminary study, somatic and zygotic embryos of soybean cv. Jack were analyzed for soluble carbohydrate, total lipids and protein during development. These studies demonstrated that the composition of Jack zygotic embryos is similar to that described for other cvs. during development while the somatic embryo composition and size is markedly different. Glucose, sucrose and the {dollar}alpha{dollar}-galactoside stachyose are found in somatic embryos. These studies have provided provide information concerning the abnormal biochemical changes occurring during development of somatic embryos that might help improve plant regeneration. We can also monitor the effect of genetic engineering approaches that might modify the seed composition using somatic embryos rather than seeds produced after plant regeneration.; To modify soybean sugar content, somatic embryos of soybean cvs. Peterson Jade, Daelip Hakja (PI 157.419), Yakumo Meaka (PI 417.468), Kinshu (PI 549.065) Kaohsiung No.1 (PI 536.546) and Jack were transformed with yeast invertase (SUC 2) and {dollar}alpha{dollar}-galactosidase (agl A) from Aspergillus niger under the control of the lectin promoter using particle bombardment. The transformation was not very successful. In some cultivars, no green clumps were obtained after 8 weeks of selection in FG medium containing 25 {dollar}mu{dollar}g/ml hygromycin B. The green clumps obtained from transformation and selection were subjected to PCR analysis for the transgenes. Some lines were PCR positive for the hygromycin resistance and/or {dollar}alpha{dollar}-galactosidase genes but Southern and northern analysis gave negative results. These results suggest that the transformed genes were lost during the somatic embryo multiplication due to the friability of some green clumps that were discarded during the culture process.