The main oxidative inactivation pathway of the plant hormone auxin

Inactivation of the phytohormone auxin plays important roles in plant development, and several enzymes have been implicated in auxin inactivation. In this study, we show that the predominant natural auxin, indole-3-acetic acid (IAA), is mainly inactivated via the GH3-ILR1-DAO pathway. IAA is first converted to IAA-amino acid conjugates by GH3 IAA-amidosynthetases. The IAA-amino acid conjugates IAA-aspartate (IAA-Asp) and IAA-glutamate (IAA-Glu) are storage forms of IAA and can be converted back to IAA by ILR1/ILL amidohydrolases. We further show that DAO1 dioxygenase irreversibly oxidizes IAA-Asp and IAA-Glu into 2-oxindole-3-acetic acid-aspartate (oxIAA-Asp) and oxIAA-Glu, which are subsequently hydrolyzed by ILR1 to release inactive oxIAA. This work established a complete pathway for the oxidative inactivation of auxin and defines the roles played by auxin homeostasis in plant development.

Potato tuber-inducing activities of jasmonic acid and related-compounds (II)

ABSTRACT New information is being accumulated for plant-derived oxylipins, such as jasmonic acid (JA) amino acid conjugates. However, these compounds have not being examined for their activity in promoting potato tuber formation. It was found that (−)-JA had the highest activity followed cis-(−)-OPDA, (+)-4, 5-didehydroJA, cis-(+)-OPDA-l-Ile, and (−)-JA-l-Ile, -Leu, -Phe, -Val, although iso-OPDA and 3,7-didehydroJA did not exhibit activity.

Anticancer Activity of New 1,2,3-Triazole-Amino Acid Conjugates

A multistep synthesis was developed to prepare new 1,2,3-triazole-amino acid conjugates (6 and 7). These compounds contain the diaryl ether moiety and were synthesized via SNAr reaction under mild condition and in good yield. Their structures were confirmed by spectroscopic analyses (HR-MS, NMR, IR). These compounds showed significant antiproliferative activity (>30%) toward the breast MCF7 and liver HepG2 cancer cells lines at <10 µM concentration.