The analysis of auxin biosynthetic pathway using metabolic intermediates

本研究通过对生长素生物合成基因的转录分析和对拟南芥幼苗生长素过剩和缺乏条件下的代谢分析，研究了生长素生物合成的反馈调控机制。通过向野生型拟南芥中添加人工合成的生长素和生长素生物合成抑制剂，以及利用生长素生物合成基因突变体，研究了生长素过量和缺乏的情况。结果表明，生长素的生物合成在生长素合成的限速步骤YUCCA中以负反馈的方式受到调控。这表明生长素的生物合成以及结合和降解有助于生长素的稳态。我们认为本研究结果对促进生根和稳定结果等农业技术有一定的指导意义。

In this research, a feedback regulatory mechanism of auxin biosynthesis has been studied by transcription analysis of auxin biosynthetic genes and metabolic analysis in auxin excess and deficient condition of Arabidopsis seedlings. Auxin excess and deficient conditions were produced by feeding of synthetic auxin and auxin biosynthesis inhibitors to wild type Arabidopsis and by using genetic mutants in auxin biosynthesis. As a result, auxin biosynthesis has been demonstrated to be regulated at the step of YUCCA, a rate-limiting step of auxin biosynthesis, through the negative feedback manner. This suggests that auxin biosynthesis as well as conjugation and degradation contributes to auxin homeostasis. We consider that our results may be useful for agricultural technology such as promotion of rooting and stable fruiting.