抄録
The 6b gene of Agrobacterium tumefaciens is tumorigenic in certain plants. We have shown that the gene induces morphological abnormality and phenylpropanoid metabolism in tobacco. To study further these processes, the 6b gene from AKE10 stain was placed under the control of dexamethazone-inducible promoter and introduced to tobacco. Upon induction, the transgenic seedlings showed;
(1) Developmental abnormalities including high growth rate of whole seedlings, altered morphology of SAM, and multiple outgrowths in cotyledons in which vascular tissues are densely formed.
(2) High accumulation of a number of phenolics,including chlorogenic acid, which could be partly due to increased transcripts of phenylalanine ammonia lyase gene.
(3) Increased sensitivities of growth inhibition to auxin transport inhibitors. This could reflect altered intracellular auxin levels and/or signal transduciton process (under investigation).
From these results we speculate that the 6b gene may induce phenylpropanoid biosynthesis pathway, promoting vascular development in close association with tumorigenic outgrowth.
