4.オーキシン生合成変異体におけるIAA代謝調節機構の解析(口頭発表)

概要

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Auxins have critical roles in plant growth and development. Arabidopsis has multiple pathways for biosynthesis of a naturally occurring auxin, indole-3-acetic acid (IAA): the YUCCA (YUC) pathway, the CYP79B pathway, the indole-3-pyruvic acid (IPA) pathway and the indole-3-acetamide pathway. The YUC and IPA pathways widely exist in plant kingdom. Recently, we found that the CYP79B pathway operates in the crucifer plants producing indole glucosinolates like Arabidopsis, but may not in non-crucifers. It has been demonstrated that cyp79b2 cyp79b3 mutants show IAA-deficient phenotype, but IAA levels are not greatly reduced in these mutants under the normal growth condition. yuc1D mutants show IAA-overproduction phenotype, but IAA levels are slightly increased in yuc1D. To address this question, we analyzed IAA metabolites in Arabidopsis IAA biosynthesis mutants. We found that IAA-amino acid conjugates were significantly decreased in the CYP79B-deficient mutants. In contrast, the levels of IAA-amino acid conjugates were dramatically increased in the YUC-overexpression lines. These results indicate that the IAA-amino acid conjugates may have important roles to maintain IAA levels in IAA biosynthesis-deficient mutants.
2010-10-01