Details

Autor(en) / Beteiligte

• Takubo, Eiko
• Kobayashi, Makoto
• Hirai, Shoko
• Aoi, Yuki
• Ge, Chennan
• Dai, Xinhua
• Fukui, Kosuke
• Hayashi, Ken-ichiro
• Zhao, Yunde
• Kasahara, Hiroyuki

Titel

Role of Arabidopsis INDOLE-3-ACETIC ACID CARBOXYL METHYLTRANSFERASE 1 in auxin metabolism

Ist Teil von

• Biochemical and biophysical research communications, 2020-07, Vol.527 (4), p.1033-1038

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2020

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• The phytohormone auxin regulates a wide range of developmental processes in plants. Indole-3-acetic acid (IAA) is the main auxin that moves in a polar manner and forms concentration gradients, whereas phenylacetic acid (PAA), another natural auxin, does not exhibit polar movement. Although these auxins occur widely in plants, the differences between IAA and PAA metabolism remain largely unknown. In this study, we investigated the role of Arabidopsis IAA CARBOXYL METHYLTRANSFERASE 1 (IAMT1) in IAA and PAA metabolism. IAMT1 proteins expressed in Escherichia coli could convert both IAA and PAA to their respective methyl esters. Overexpression of IAMT1 caused severe auxin-deficient phenotypes and reduced the levels of IAA, but not PAA, in the root tips of Arabidopsis, suggesting that IAMT1 exclusively metabolizes IAA in vivo. We generated iamt1 null mutants via CRISPR/Cas9-mediated genome editing and found that the single knockout mutants had normal auxin levels and did not exhibit visibly altered phenotypes. These results suggest that other proteins, namely the IAMT1 homologs in the SABATH family of carboxyl methyltransferases, may also regulate IAA levels in Arabidopsis. •Arabidopsis IAMT1 protein can catalyze the methylation of both IAA and PAA in vitro.•Overexpression of IAMT1 reduces IAA levels and results in auxin-deficient phenotypes.•No reduction in PAA levels was observed following overexpression of IAMT1.•Knockout of IAMT1 did not affect auxin levels in Arabidopsis.•IAMT1 homologs may also participate in Arabidopsis IAA homeostasis.