11. LC-TOF-MS/MSによるIAA生合成中間体の分析(口頭発表)

概要

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Indole-3-acetic acid (IAA) is an active natural auxin that is involved in the most aspects of plant growth and development. Recently, the important roles of the YUCCA pathway in IAA biosynthesis have been reported. In this pathway IAA is generated from tryptophan (TRP) through tryptamine (TAM) and N-hydroxy-tryptamine (HTAM). As for the intermediates between HTAM and IAA, indole-3-acetaldoxime (IAOX), indole-3-acetonitlile (IAN) and indole-3-acetaldehyde (IAAld) have been proposed as candidate compounds. To elucidate the YUCCA pathway in plants, we have developed a new method for the analysis of IAA intermediates by LC-TOF-MS/MS. Using ^^<15>N or ^^2H-labeled IAA intermediates as internal standards, we have detected TAM and IAOX from Arabidopsis seedlings. In addition, the identification of each compound was confirmed by a feeding of [^^<13>C_8, ^^<15>N]indole to the TRP-auxotroph mutants of Arabidopsis. Our data clearly demonstrated that both TAM and IAOX were efficiently labeled from [^^<13>C_8, ^^<15>N]indole. On the other hand, we have not yet detected HTAM and lAAld from this plant due to the unstable property of these indole compounds. We are currently analyzing the IAA intermediates in various IAA biosynthesis mutants.
植物化学調節学会の論文
2007-10-05