Auxin Response Factor2 (ARF2) and Its Regulated Homeodomain Gene HB33 Mediate Abscisic Acid Response in Arabidopsis

Abstract

The phytohormone abscisic acid (ABA) is an important regulator of plant development and response to environmental stresses. In this study, we identified two ABA overly sensitive mutant alleles in a gene encoding Auxin Response Factor2 (ARF2). The expression of ARF2 was induced by ABA treatment. The arf2 mutants showed enhanced ABA sensitivity in seed germination and primary root growth. In contrast, the primary root growth and seed germination of transgenic plants over-expressing ARF2 are less inhibited by ABA than that of the wild type. ARF2 negatively regulates the expression of a homeodomain gene HB33, the expression of which is reduced by ABA. Transgenic plants over-expressing HB33 are more sensitive, while transgenic plants reducing HB33 by RNAi are more resistant to ABA in the seed germination and primary root growth than the wild type. ABA treatment altered auxin distribution in the primary root tips and made the relative, but not absolute, auxin accumulation or auxin signal around quiescent centre cells and their surrounding columella stem cells to other cells stronger in arf2-101 than in the wild type. These results indicate that ARF2 and HB33 are novel regulators in the ABA signal pathway, which has crosstalk with auxin signal pathway in regulating plant growth.

DEXH Box RNA Helicase–Mediated Mitochondrial Reactive Oxygen Species Production in Arabidopsis Mediates Crosstalk between Abscisic Acid and Auxin Signaling

“…As reported previously, we identified several ABA-overly sensitive (abo) mutants for ABA inhibition of primary root growth (Yin et al, 2009;Zhou et al, 2009;Liu et al, 2010;Ren et al, 2010;Wang et al, 2011). Among them, ABO5 encodes a PPR protein required for cissplicing of mitochondrial nad2 intron 3 .…”

“…Arabidopsis plants harboring ProDR5:GUS, ProIAA2:GUS, ProAUX1: AUX1-YFP, ProPIN1:PIN1-GFP, ProPIN2:PIN2-GFP (Wang et al, 2011), and Mito-cpYFP were crossed with abo6. Homozygous plants for the mutant and marker lines were separated from the F2 and F3 population before they were subjected to GUS staining or GFP.…”

The ARF2–ANT–COR15A gene cascade regulates ABA-signaling-mediated resistance of large seeds to drought in Arabidopsis

“…The germinating seedlings at different developmental stages exhibit different physiological responses to ABA signals in Arabidopsis, and the ABA-deficient mutants have significantly reduced cell vigor (Wang et al, 2011). Also, different concentrations of ABA can regulate the root and stem growth by boosting or suppressing cell proliferation and differentiation during Arabidopsis seedling development (Wang et al, 2011;Zhang et al, 2010).…”

“…The germinating seedlings at different developmental stages exhibit different physiological responses to ABA signals in Arabidopsis, and the ABA-deficient mutants have significantly reduced cell vigor (Wang et al, 2011). Also, different concentrations of ABA can regulate the root and stem growth by boosting or suppressing cell proliferation and differentiation during Arabidopsis seedling development (Wang et al, 2011;Zhang et al, 2010). In addition, a number of genotypes with mutations in DNA replication machinery display a hypersensitive response to ABA during seed germination and seedling growth (Yin et al, 2009), strongly implying that ABA signaling suppresses cell proliferation by regulating DNA-replication-related proteins.…”

A Lipid-Anchored NAC Transcription Factor Is Translocated into the Nucleus and Activates Glyoxalase I Expression during Drought Stress

“…The degenerated primers are listed in Supplemental Data Set 8. To analyze the relative immunoprecipitations of samples, mock samples (mock-actin, mock-A, mock-B, and mock-C) were individually set to 1 and the PEG-8000-treated samples were normalized relative to the mock samples, respectively (Wang et al, 2011). Actin was used as a negative control.…”