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A link between magnesium-chelatase H subunit and sucrose nonfermenting 1 (SNF1)-related protein kinase SnRK2.6/OST1 in Arabidopsis guard cell signalling in response to abscisic acid.

Liang S, Lu K, Wu Z, Jiang SC, Yu YT, Bi C, Xin Q, Wang XF, Zhang DP - J. Exp. Bot. (2015)

Bottom Line: Neither mutation nor over-expression of the ABAR gene affects significantly ABA-insensitive phenotypes of stomatal movement in the OST1 knockout mutant allele srk2e.These findings suggest that ABAR shares, at least in part, downstream signalling components with PYR/PYL/RCAR receptors for ABA in guard cells; though cch and rtl1 show strong ABA-insensitive phenotypes in both ABA-induced stomatal closure and inhibition of stomatal opening, while the pyr1 pyl1 pyl2 pyl4 quadruple mutant shows strong ABA insensitivity only in ABA-induced stomatal closure.These data establish a link between ABAR/CHLH and SnRK2.6/OST1 in guard cell signalling in response to ABA.

View Article: PubMed Central - PubMed

Affiliation: Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.

No MeSH data available.


Genetic interaction between ABAR/CHLH and OST1/SnRK2.6/SRK2E: mutation of the ABAR gene does not significantly enhance ABA insensitivity of the OST1/SnRK2.6/SRK2E knockout mutant allele srk2e in stomatal movement. (A) ABA-induced stomatal closure (top) and inhibition of stomatal opening (bottom) in wild-type Col, cch, and srk2e single mutants and srk2e cch double mutant. cch is a mutant allele in the ABAR gene. Values are means ± SE from three independent experiments, and different letters indicate significant differences at P<0.05 (Duncan’s multiple range test) when comparing values within the same ABA concentration. n≥60 apertures per experiment. (B) Status of the detached leaves of the Col, cch, srk2e, and srk2e cch, which were subjected to a 6-h period water loss assay. (C) Water loss rates during a 6-h period from the detached leaves of the different genotypes described in (B). Values are means ±SE from three independent experiments. *P<0.05 (Duncan’s multiple range test) when comparing values within the same time point. (D) Water loss assays with young seedlings of the Col, cch, srk2e, and srk2e cch. Plants were well watered for 5 d then drought-stressed by withholding water for 15 d (bottom). Top panel shows the well watered control plants. The entire experiment was replicated three times with similar results.
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Figure 2: Genetic interaction between ABAR/CHLH and OST1/SnRK2.6/SRK2E: mutation of the ABAR gene does not significantly enhance ABA insensitivity of the OST1/SnRK2.6/SRK2E knockout mutant allele srk2e in stomatal movement. (A) ABA-induced stomatal closure (top) and inhibition of stomatal opening (bottom) in wild-type Col, cch, and srk2e single mutants and srk2e cch double mutant. cch is a mutant allele in the ABAR gene. Values are means ± SE from three independent experiments, and different letters indicate significant differences at P<0.05 (Duncan’s multiple range test) when comparing values within the same ABA concentration. n≥60 apertures per experiment. (B) Status of the detached leaves of the Col, cch, srk2e, and srk2e cch, which were subjected to a 6-h period water loss assay. (C) Water loss rates during a 6-h period from the detached leaves of the different genotypes described in (B). Values are means ±SE from three independent experiments. *P<0.05 (Duncan’s multiple range test) when comparing values within the same time point. (D) Water loss assays with young seedlings of the Col, cch, srk2e, and srk2e cch. Plants were well watered for 5 d then drought-stressed by withholding water for 15 d (bottom). Top panel shows the well watered control plants. The entire experiment was replicated three times with similar results.

Mentions: Next, it was tested whether ABAR and OST1—two positive regulators in guard cell signalling in response to ABA (Mustilli et al., 2002;Yoshida et al., 2002; Shen et al., 2006; Legnaioli et al., 2009; Wu et al., 2009; Jia et al., 2011; Tsuzuki et al., 2011, 2013; Du et al., 2012; Zhang et al., 2013)—functionally interact. It was observed that stomatal apertures of both the cch single and srk2e cch double mutants was slightly larger than that of wild-type Col plants under the exogenous ABA-free conditions, but the differences were not always statistically significant. This seems to be the result of the nuance of changes in environmental conditions among the independent repetitions, which might cause differences in guard cell responses. The intensity of the ABA-insensitive phenotypes of the srk2e cch double mutant in ABA-induced stomatal closure and ABA-inhibited stomatal opening was shown to be comparable with that of both cch and srk2e single mutants with 25 μM (±)ABA application, while in a higher ABA concentration [50 μM (±)ABA], this ABA-insensitive intensity of the srk2e cch double mutant was stronger than that of the cch single mutant and remained similar to that of the srk2e single mutant (Fig. 2A). The detached leaves of the three mutant plants lost water faster than those of wild-type Col plants, where the double mutant srk2e cch showed the highest loss rate, followed by srk2e and cch (Fig. 2B, C). The sensitivities to drought of these mutants showed similar trends to the water loss rates of their detached leaves (Fig. 2D). The observations of the dehydration assays with both the detached leaves and whole plants are consistent with those of stomatal movement.


A link between magnesium-chelatase H subunit and sucrose nonfermenting 1 (SNF1)-related protein kinase SnRK2.6/OST1 in Arabidopsis guard cell signalling in response to abscisic acid.

Liang S, Lu K, Wu Z, Jiang SC, Yu YT, Bi C, Xin Q, Wang XF, Zhang DP - J. Exp. Bot. (2015)

Genetic interaction between ABAR/CHLH and OST1/SnRK2.6/SRK2E: mutation of the ABAR gene does not significantly enhance ABA insensitivity of the OST1/SnRK2.6/SRK2E knockout mutant allele srk2e in stomatal movement. (A) ABA-induced stomatal closure (top) and inhibition of stomatal opening (bottom) in wild-type Col, cch, and srk2e single mutants and srk2e cch double mutant. cch is a mutant allele in the ABAR gene. Values are means ± SE from three independent experiments, and different letters indicate significant differences at P<0.05 (Duncan’s multiple range test) when comparing values within the same ABA concentration. n≥60 apertures per experiment. (B) Status of the detached leaves of the Col, cch, srk2e, and srk2e cch, which were subjected to a 6-h period water loss assay. (C) Water loss rates during a 6-h period from the detached leaves of the different genotypes described in (B). Values are means ±SE from three independent experiments. *P<0.05 (Duncan’s multiple range test) when comparing values within the same time point. (D) Water loss assays with young seedlings of the Col, cch, srk2e, and srk2e cch. Plants were well watered for 5 d then drought-stressed by withholding water for 15 d (bottom). Top panel shows the well watered control plants. The entire experiment was replicated three times with similar results.
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Figure 2: Genetic interaction between ABAR/CHLH and OST1/SnRK2.6/SRK2E: mutation of the ABAR gene does not significantly enhance ABA insensitivity of the OST1/SnRK2.6/SRK2E knockout mutant allele srk2e in stomatal movement. (A) ABA-induced stomatal closure (top) and inhibition of stomatal opening (bottom) in wild-type Col, cch, and srk2e single mutants and srk2e cch double mutant. cch is a mutant allele in the ABAR gene. Values are means ± SE from three independent experiments, and different letters indicate significant differences at P<0.05 (Duncan’s multiple range test) when comparing values within the same ABA concentration. n≥60 apertures per experiment. (B) Status of the detached leaves of the Col, cch, srk2e, and srk2e cch, which were subjected to a 6-h period water loss assay. (C) Water loss rates during a 6-h period from the detached leaves of the different genotypes described in (B). Values are means ±SE from three independent experiments. *P<0.05 (Duncan’s multiple range test) when comparing values within the same time point. (D) Water loss assays with young seedlings of the Col, cch, srk2e, and srk2e cch. Plants were well watered for 5 d then drought-stressed by withholding water for 15 d (bottom). Top panel shows the well watered control plants. The entire experiment was replicated three times with similar results.
Mentions: Next, it was tested whether ABAR and OST1—two positive regulators in guard cell signalling in response to ABA (Mustilli et al., 2002;Yoshida et al., 2002; Shen et al., 2006; Legnaioli et al., 2009; Wu et al., 2009; Jia et al., 2011; Tsuzuki et al., 2011, 2013; Du et al., 2012; Zhang et al., 2013)—functionally interact. It was observed that stomatal apertures of both the cch single and srk2e cch double mutants was slightly larger than that of wild-type Col plants under the exogenous ABA-free conditions, but the differences were not always statistically significant. This seems to be the result of the nuance of changes in environmental conditions among the independent repetitions, which might cause differences in guard cell responses. The intensity of the ABA-insensitive phenotypes of the srk2e cch double mutant in ABA-induced stomatal closure and ABA-inhibited stomatal opening was shown to be comparable with that of both cch and srk2e single mutants with 25 μM (±)ABA application, while in a higher ABA concentration [50 μM (±)ABA], this ABA-insensitive intensity of the srk2e cch double mutant was stronger than that of the cch single mutant and remained similar to that of the srk2e single mutant (Fig. 2A). The detached leaves of the three mutant plants lost water faster than those of wild-type Col plants, where the double mutant srk2e cch showed the highest loss rate, followed by srk2e and cch (Fig. 2B, C). The sensitivities to drought of these mutants showed similar trends to the water loss rates of their detached leaves (Fig. 2D). The observations of the dehydration assays with both the detached leaves and whole plants are consistent with those of stomatal movement.

Bottom Line: Neither mutation nor over-expression of the ABAR gene affects significantly ABA-insensitive phenotypes of stomatal movement in the OST1 knockout mutant allele srk2e.These findings suggest that ABAR shares, at least in part, downstream signalling components with PYR/PYL/RCAR receptors for ABA in guard cells; though cch and rtl1 show strong ABA-insensitive phenotypes in both ABA-induced stomatal closure and inhibition of stomatal opening, while the pyr1 pyl1 pyl2 pyl4 quadruple mutant shows strong ABA insensitivity only in ABA-induced stomatal closure.These data establish a link between ABAR/CHLH and SnRK2.6/OST1 in guard cell signalling in response to ABA.

View Article: PubMed Central - PubMed

Affiliation: Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.

No MeSH data available.