CASSETTES FOR SEED-SPECIFIC EXPRESSION TESTED IN TRANSFORMED EMBRYOGENIC CULTURES OF SOYBEAN

Soybean (Glycine max [L.] Merrill) lectin is a seed protein that accumulates in protein bodies of cotyledons during seed development. We have constructed two expression cassettes containing the 5' and 3' regions of the soybean lectin gene connected by a Not I restriction site. One vector also contains the 32 amino acid signal sequence. Using polymerase chain reaction (PCR), the coding region of the beta-glucuronidase (uidA) gene was inserted into the Not I site of each vector. We tested the function of the expression cassettes in transformed embryogenic cultures of soybean. Development-specific GUS expression was observed in developing somatic embryos transformed with the chimeric lectin promoter-GUS constructs as determined by histochemical assays. Our data indicate that these cassettes could be used to drive expression of foreign genes to modify embryo-specific traits of soybean as protein quality or quantity in the seed.