Molecular mechanism of genetic tumor induction by wound

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Genetic tumors are induced by aging or injury and grow without any plant hormoes in vitro. Since hybrids between Nicotiana glauca and N.langsdorffii (F1) produced typical tumors efficiently, we used them as an experimental materials in this project. Using this material, we have already cloned 17 genetic tumor-specific cDNA (TID clones) by subtraction method. A half of them has a homology to the pathogenesis related proteins and other clones have no homology with any known genes. Ngro1 genes in N.glauca homologous to Agrobacterium rhizogenes have been found to express in genetic tumor specifically.In F1 tissues, by cutting treatments teratomas are formed after dedifferentiation that is followed by continuous cell division. The response which deiffers from the ordinary healing that includes, for example, second cell wall thickening usually observed in plants including the parent plants of F1 pkants, Therefore, we analyzed the way in which each TID transcript responed to stress-related chemicals, such as ABA,methyl-jasmonate and salicylic acid., We also analyzed the responses to plant hormones, an auxin and a cytokinin. The results showed, in general, in F1 tissues transcripts induced by stress-related chemicals were also induced by plant hormones. Ngro1B was found to be induced by auxins. On the other hand, we also obtained three cDNA clones, their transcription was suppressed in genetic tumor cells.