No abstract

A reliable protocol for the transformation of cultivated sunflower (Helianthus annuus L.) has been established, based on microprojectile bombardment of half shoot apices in combination with Agrobacterium tumefaciens coculture. Transgenic shoots have been obtained from 5 inbred lines, although transformation efficiencies varied with the genotype. Plants expressing the transgenes could be recovered from up to 7% of the explants. A minority of plants was shown to be chimaeric for expression of ß-glucuronidase activity while most appeared to be uniformly transformed. Genetic segregation was 3∶1 for both ß-glucuronidase and neomycine phospho transferase in some plants, indicating that the respective mother plants were uniformly transformed. Integration of the foreign genes was also shown by Southern analysis.

The expression of genes encoding conglutin gamma and a leginsulin-like protein has been examined in narrow-leafed lupin, Lupinus angustifolius L. Conglutin gamma is a homologue of basic 7S globulin (Bg), the insulin and leginsulin binding protein from soybean. Accumulation of conglutin gamma mRNA, as assessed by northern assays and reverse-transcription PCR, was tightly regulated both spatially and temporally in lupin plants and was detected almost exclusively in developing seeds. Similar tissue and temporal specificity was demonstrated when 1.8 kb of the promoter region from the conglutin gamma gene was used to drive the expression of a beta-glucuronidase reporter gene in transgenic plants. In stably transformed tobacco the conglutin gamma promoter produced strong, temporally regulated and seed-specific expression of the reporter gene which was localised to the embryo tissues and to a layer of cells adjacent to the seed coat. A truncated 0.29 kb promoter fragment produced much reduced levels of expression and a loss of embryo specificity. Leginsulin-like mRNA was similarly detected in lupins only in developing seeds. The leginsulin-like gene detected in L. angustifolius showed 96% sequence identity to leginsulin from soybean within the 280 bp region amplified from lupin by PCR. The results demonstrate that both components of a Bg-leginsulin putative signal transduction pathway are present in the seeds of lupin.