Dynamics of plant hormones in plant tumor formation and cell division

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The relation between plant gall formation, such as root nodule, genetic tumor, crown gall and etc., and changes of the content of plant growth hormones has been analyzed mainly by bioassay and/or analytical instruments. However, these methods aren't enough to analyze minute aspects of special and temporal changes of plant hormones due to the restriction of sampling.In this project, in addition to these methods, the construct of plant-hormones-responsive promoter combined with GUS reporter gene, such as DR5-GUS for auxin, was used. The obtained major results are summarized below.1. DR5-GUS was introduced into tumor-proned tobacco F1 plant (Nicotiana glauca x N.langsdorffii). The analysis using the transformants showed the tumors will be induced by wound via increase of auxin content followed the promotion of expression of auxin-induced genes such as NgrolB.2. When the seeds of Lactuca sp. were germinated aseptically in vitro, tumors developed spontaneously at the site between hypocotyl … More and root. As analysis of the seedling of DR5-GUS transformants of Arabidopsis showed the accumulation of auxin at the similar site, transformation of Lactuca sp. by DR5-GUS was attempted. The obtained transformants will be useful for analysis of tumor formation processes.3. GC-MS analysis showed that the content of auxin increased at the early stage of root nodule development in Lotus japonicus. For further analysis of auxin function in the development of root nodule, DR5-GUS transformants were successfully isolated.4. GC-MS analysis showed that in the early stage of the development of, root nodules in Lotus japonicus, GA content increased remarkably. Inhibitors of GA biosynthesis inhibited the root nodule formation. However, the inhibition was recovered by GA. These results suggest that GA involved in root nodule formation at early stage of development.5. High activity of indole-3-acetamide hydrolase, which involve in auxin biosynthesis of crown gall, was detected in rice cells. The enzymatic activity was partially purified and the nature of enzyme was clarified.It was also found that the expression of NgORF13 in tobacco genetic tumor was promoted by wound. Jasmonate was shown to be involved in the promotion. Less