CHARACTERIZATION OF MORPHOLOGY AND ROOT-FORMATION IN THE MODEL WOODY PERENNIAL SHRUB SOLANUM AVICULARE FORST EXPRESSING ROLABC GENES OF AGROBACTERIUM-RHIZOGENES

Transgenic plants of Solanum aviculare Forst. expressing the rolABC ge nes of Agrobacterium rhizogenes exhibited altered shoot morphologies i n comparison to untransformed plants. Altered growth and development c haracteristics included retarded growth, suppressed apical dominance, shortened internodes; smaller highly lanceolated leaves and smaller, s terile flowers. Pronounced leaf wrinkling was a common feature of the transgenic plants. Shoot slices and leaf fragments of transgenic plant s when cultured in vitro exhibited significantly higher root formation capacities than explants derived from non-transformed plants. Explant s from transgenic plants were able to produce roots in limited manner without exogenous auxin and presented higher sensitivity to promoting effect of IBA. The suppressing effects of light, kinetin, the inhibito r of putrescine synthesis alpha-difluoromethyl-ornithine and gibberell in (GA(3)) on root formation were significantly lower than in control explants. Vanadate (an inhibitor of phosphatases/kinases) strongly blo cked root differentiation in control and in transformant lines. The an tigibberellin paclobutrazol increased the numbers of roots in transfor mant shoot segments and in segments of control plants, whereas the ant iauxin p-chlorophenoxyisobutyric acid, the polyamines putrescine and s permidine, the conjugated auxin indoxyl-beta-glucoside and the conjuga ted cytokinin BAP-9-glucoside had no marked effects on root developmen t. Differences in root formation abilities between transformed lines i n response to the different treatments were found. (C) 1997 Elsevier S cience Ireland Ltd.