Overexpression of TMAC2, a novel negative regulator of abscisic acid and salinity responses, has pleiotropic effects in Arabidopsis thaliana

Ming Der Huang, Wen-Luan Wu

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

Phytohormone abscisic acid (ABA) regulates many aspects of plant development and growth. To explore the molecular mechanism of ABA, we identified the novel ABA-regulated genes in Arabidopsis thaliana by searching for genes possessing two or more ABREs (ABA-responsive elements). One of these genes, two or more ABREs-containing gene 2 (TMAC2) is highly induced by ABA and NaCl. Database searches revealed that TMAC2 encodes a protein with no domains of known function. Expression of TMAC2-GFP fusion protein in Arabidopsis mesophyll protoplasts indicated that TMAC2 is targeted to the nucleus. Although the gene has a basal level of expression in various Arabidopsis organs/tissues except for adult leaves, a high expression level was detected in roots. Constitutive overexpression of TMAC2 in plants resulted in the insensitivity to ABA and NaCl, suggesting that TMAC2 plays a negative role in ABA and salt stress responses. Furthermore, TMAC2-overexpressing plants exhibited the short roots, late flowering and starch-excess phenotypes. RT-PCR analysis showed that decreased expression of two floral- and one starch degradation-related genes, SOC1/AGL20 and SEP3/AGL9, and SEX1, respectively, may lead to altered phenotypes of TMAC2-overexpressing plants. Taken together, our data reveal that TMAC2 acts in the nucleus and is an important negative regulator of ABA and salt stress responses, and could play a critical role in controlling root elongation, floral initiation and starch degradation.

Original languageEnglish
Pages (from-to)557-569
Number of pages13
JournalPlant Molecular Biology
Volume63
Issue number4
DOIs
Publication statusPublished - 2007 Mar 1

All Science Journal Classification (ASJC) codes

  • Agronomy and Crop Science
  • Genetics
  • Plant Science

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