TRANSFORMATION OF PEANUT WITH A SOYBEAN VSPB PROMOTER-UIDA CHIMERIC GENE - I - OPTIMIZATION OF A TRANSFORMATION SYSTEM AND ANALYSIS OF GUS EXPRESSION IN PRIMARY TRANSGENIC TISSUES AND PLANTS

Direct DNA delivery via microprojectile bombardment has become an esta blished approach for gene transfer into peanut (Arachis hypogaea L.). To optimize our transformation protocol and to simultaneously explore the function of a heterologous promoter whose activity is developmenta lly regulated, embryogenic cultures from three peanut cultivars were b ombarded with two plasmid constructs containing a uidA gene controlled by either a soybean vegetative storage protein gene promoter or a cau liflower mosaic virus 35S promoter. We found that GUS transient expres sion was useful to predict stable transformation and confirmed that im age analysis could provide a quick and efficient method for semi-quant itation of transient expression. One hundred and sixty hygromycin-resi stant cell lines were recovered from and maintained on selective mediu m, and those tested by Southern blot analysis showed integration of th e foreign gene. Over 200 transgenic plants were regenerated from 38 ce ll lines. More than 100 plants from 32 cell lines flowered and 79 plan ts from 19 cell lines produced pods. Over 1000 R-1 seeds were harveste d. Analysis of expression in primary transgenic plants showed that GUS expression driven by the vspB promoter was modulated by chemical and positional information.