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A mechanism of growth inhibition by abscisic acid in germinating seeds of Arabidopsis thaliana based on inhibition of plasma membrane H+-ATPase and decreased cytosolic pH, K+, and anions.

Planes MD, Niñoles R, Rubio L, Bissoli G, Bueso E, García-Sánchez MJ, Alejandro S, Gonzalez-Guzmán M, Hedrich R, Rodriguez PL, Fernández JA, Serrano R - J. Exp. Bot. (2014)

Bottom Line: Concerning the latter effect, several mutants of Arabidopsis thaliana with improved capability for H(+) efflux (wat1-1D, overexpression of AKT1 and ost2-1D) are less sensitive to inhibition by ABA than the wild type.The mechanism of inhibition of the H(+)-ATPase by ABA and its effects on cytosolic pH and membrane potential in roots were different from those in guard cells.ABA did not affect the in vivo phosphorylation level of the known activating site (penultimate threonine) of H(+)-ATPase in roots, and SnRK2.2 phosphorylated in vitro the C-terminal regulatory domain of H(+)-ATPase while the guard-cell kinase SnRK2.6/OST1 did not.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Camino de Vera, 46022 Valencia, Spain.

No MeSH data available.


Related in: MedlinePlus

Germination and early seedling growth of Arabidopsis mutants wat1-1D, OE AKT1, and ost2-1D are less sensitive to inhibition by ABA than in the wild type. (A) Visual result of a typical experiment with Col-0 and wat1-1D. (B) statistical data from three independent experiments. Values are the average percentages of seedlings with green, expanded cotyledons (reflecting seedling establishment) after 7 d in plates with 0.75 µM ABA. In the absence of ABA, 95–100% of planted seeds had green cotyledons in all genotypes. Two independent lines of OE AKT1 gave similar results. The mutants wat1-1D and OE AKT1 were in the Columbia (Col-0) background, while ost2-1D was in the Landsberg erecta (L.er) background. Error bars correspond to the standard error. * indicates a significant difference (P<0.01 by Student’s t-test) compared with wild type. (This figure is available in colour at JXB online.)
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Figure 1: Germination and early seedling growth of Arabidopsis mutants wat1-1D, OE AKT1, and ost2-1D are less sensitive to inhibition by ABA than in the wild type. (A) Visual result of a typical experiment with Col-0 and wat1-1D. (B) statistical data from three independent experiments. Values are the average percentages of seedlings with green, expanded cotyledons (reflecting seedling establishment) after 7 d in plates with 0.75 µM ABA. In the absence of ABA, 95–100% of planted seeds had green cotyledons in all genotypes. Two independent lines of OE AKT1 gave similar results. The mutants wat1-1D and OE AKT1 were in the Columbia (Col-0) background, while ost2-1D was in the Landsberg erecta (L.er) background. Error bars correspond to the standard error. * indicates a significant difference (P<0.01 by Student’s t-test) compared with wild type. (This figure is available in colour at JXB online.)

Mentions: Several mutants with improved pH homeostasis because of increased capability for proton extrusion (as determined in roots) have been identified in A. thaliana. These include ost2-1D (a constitutively hyperactive plasma membrane AHA1 H+-ATPase; Merlot et al., 2007), wat1-1D (loss of function of AP-3 β-adaptin affecting localization of transporters; Niñoles et al., 2013) and the overexpression of the K+ uptake channel AKT1 (OE AKT1; Niñoles et al., 2013). In wat1-1D and OE AKT1, an increased rate of K+ influx allows a higher rate of H+ efflux mediated by the PM H+-ATPase through electrical balance. These mutants are tolerant of inhibition of germination and early seedling growth by weak organic acids such as acetic acid, which induces cytosolic acidification in root epidermal cells of the wild type but not in the wat1-1D mutant (Niñoles et al., 2013). As indicated in Fig. 1, all these mutants were less sensitive than the wild type to inhibition by ABA during germination and early seedling growth (appearance of green cotyledons). These results suggested that one mechanism of inhibition of growth by ABA at this stage could be cytosolic acidification. The ABA insensitivity of the wat1-1D mutant was much less apparent during plantlet growth (Supplementary Fig. S1 at JXB online).


A mechanism of growth inhibition by abscisic acid in germinating seeds of Arabidopsis thaliana based on inhibition of plasma membrane H+-ATPase and decreased cytosolic pH, K+, and anions.

Planes MD, Niñoles R, Rubio L, Bissoli G, Bueso E, García-Sánchez MJ, Alejandro S, Gonzalez-Guzmán M, Hedrich R, Rodriguez PL, Fernández JA, Serrano R - J. Exp. Bot. (2014)

Germination and early seedling growth of Arabidopsis mutants wat1-1D, OE AKT1, and ost2-1D are less sensitive to inhibition by ABA than in the wild type. (A) Visual result of a typical experiment with Col-0 and wat1-1D. (B) statistical data from three independent experiments. Values are the average percentages of seedlings with green, expanded cotyledons (reflecting seedling establishment) after 7 d in plates with 0.75 µM ABA. In the absence of ABA, 95–100% of planted seeds had green cotyledons in all genotypes. Two independent lines of OE AKT1 gave similar results. The mutants wat1-1D and OE AKT1 were in the Columbia (Col-0) background, while ost2-1D was in the Landsberg erecta (L.er) background. Error bars correspond to the standard error. * indicates a significant difference (P<0.01 by Student’s t-test) compared with wild type. (This figure is available in colour at JXB online.)
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
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getmorefigures.php?uid=PMC4321545&req=5

Figure 1: Germination and early seedling growth of Arabidopsis mutants wat1-1D, OE AKT1, and ost2-1D are less sensitive to inhibition by ABA than in the wild type. (A) Visual result of a typical experiment with Col-0 and wat1-1D. (B) statistical data from three independent experiments. Values are the average percentages of seedlings with green, expanded cotyledons (reflecting seedling establishment) after 7 d in plates with 0.75 µM ABA. In the absence of ABA, 95–100% of planted seeds had green cotyledons in all genotypes. Two independent lines of OE AKT1 gave similar results. The mutants wat1-1D and OE AKT1 were in the Columbia (Col-0) background, while ost2-1D was in the Landsberg erecta (L.er) background. Error bars correspond to the standard error. * indicates a significant difference (P<0.01 by Student’s t-test) compared with wild type. (This figure is available in colour at JXB online.)
Mentions: Several mutants with improved pH homeostasis because of increased capability for proton extrusion (as determined in roots) have been identified in A. thaliana. These include ost2-1D (a constitutively hyperactive plasma membrane AHA1 H+-ATPase; Merlot et al., 2007), wat1-1D (loss of function of AP-3 β-adaptin affecting localization of transporters; Niñoles et al., 2013) and the overexpression of the K+ uptake channel AKT1 (OE AKT1; Niñoles et al., 2013). In wat1-1D and OE AKT1, an increased rate of K+ influx allows a higher rate of H+ efflux mediated by the PM H+-ATPase through electrical balance. These mutants are tolerant of inhibition of germination and early seedling growth by weak organic acids such as acetic acid, which induces cytosolic acidification in root epidermal cells of the wild type but not in the wat1-1D mutant (Niñoles et al., 2013). As indicated in Fig. 1, all these mutants were less sensitive than the wild type to inhibition by ABA during germination and early seedling growth (appearance of green cotyledons). These results suggested that one mechanism of inhibition of growth by ABA at this stage could be cytosolic acidification. The ABA insensitivity of the wat1-1D mutant was much less apparent during plantlet growth (Supplementary Fig. S1 at JXB online).

Bottom Line: Concerning the latter effect, several mutants of Arabidopsis thaliana with improved capability for H(+) efflux (wat1-1D, overexpression of AKT1 and ost2-1D) are less sensitive to inhibition by ABA than the wild type.The mechanism of inhibition of the H(+)-ATPase by ABA and its effects on cytosolic pH and membrane potential in roots were different from those in guard cells.ABA did not affect the in vivo phosphorylation level of the known activating site (penultimate threonine) of H(+)-ATPase in roots, and SnRK2.2 phosphorylated in vitro the C-terminal regulatory domain of H(+)-ATPase while the guard-cell kinase SnRK2.6/OST1 did not.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Camino de Vera, 46022 Valencia, Spain.

No MeSH data available.


Related in: MedlinePlus