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Foliar Abscisic Acid-To-Ethylene Accumulation and Response Regulate Shoot Growth Sensitivity to Mild Drought in Wheat.

Valluru R, Davies WJ, Reynolds MP, Dodd IC - Front Plant Sci (2016)

Bottom Line: We concluded that SDW of the DT and DS groups might be distinctly regulated by specific ABA:ethylene ratio.Furthermore, the DT group accumulated a significantly higher galactose while a significantly lower maltose in the shoot compared to the DS group.Taken all together, these results suggest an impact of ABA, ethylene, and ABA:ethylene ratio on SDW of wheat seedlings that may partly underlie a genotypic variability of different shoot growth sensitivities to drought among crop species under field conditions.

View Article: PubMed Central - PubMed

Affiliation: Global Wheat Program, International Maize and Wheat Improvement Center (CIMMYT)El Batan, Mexico; Plant Biology Department, Lancaster Environmental Center, Lancaster UniversityLancaster, UK.

ABSTRACT
Although, plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA) and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT) group maintained or increased shoot dry weight (SDW) while the drought-susceptible (DS) group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous ABA and ethylene concentrations under mild drought compared to control. The DT and DS groups exhibited different SDW response trends, whereby the DS group decreased while the DT group increased SDW, to increased concentrations of ABA and ethylene under mild drought, although both groups decreased ABA/ethylene ratio under mild drought albeit at different levels. We concluded that SDW of the DT and DS groups might be distinctly regulated by specific ABA:ethylene ratio. Further, a foliar-spray of low concentrations (0.1 μM) of ABA increased shoot relative growth rate (RGR) in the DS group while ACC (1-aminocyclopropane-1-carboxylic acid, ethylene precursor) spray increased RGR in both groups compared to control. Furthermore, the DT group accumulated a significantly higher galactose while a significantly lower maltose in the shoot compared to the DS group. Taken all together, these results suggest an impact of ABA, ethylene, and ABA:ethylene ratio on SDW of wheat seedlings that may partly underlie a genotypic variability of different shoot growth sensitivities to drought among crop species under field conditions. We propose that phenotyping based on hormone accumulation, response and hormonal ratio would be a viable, rapid, and an early-stage selection tool aiding genotype selection for stress tolerance.

No MeSH data available.


Related in: MedlinePlus

Shoot ABA concentration (A) and ethylene production (B) of drought-tolerant (DT) and drought-susceptible (DS) genotypes grown under well-watered (WW) or mild water-deficit (MWD) conditions with four replications for each genotype. *, **, *** Indicate p < 0.001, < 0.01, and < 0.05, respectively.
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Figure 3: Shoot ABA concentration (A) and ethylene production (B) of drought-tolerant (DT) and drought-susceptible (DS) genotypes grown under well-watered (WW) or mild water-deficit (MWD) conditions with four replications for each genotype. *, **, *** Indicate p < 0.001, < 0.01, and < 0.05, respectively.

Mentions: Previous studies have reported that wheat genotypes differ in the accumulation of, and their sensitivity to, ABA (Ji et al., 2011). We, therefore, measured endogenous ABA and ethylene in DT and DS genotypes grown under WW and MWD conditions. The DS and DT groups showed similar pattern of ABA and ethylene accumulation with both groups showing significantly higher ABA concentration (129% and 95%, respectively; P < 0.001) and ethylene production (160 and 138%, respectively; P = 0.001) in response to MWD (Figure 3, Supplementary Figures S3A,B). The main group effect on ABA was not significant (P > 0.05) but was significant for ethylene production (P = 0.01), indicating that both groups (DT and DS) significantly differed for ethylene production.


Foliar Abscisic Acid-To-Ethylene Accumulation and Response Regulate Shoot Growth Sensitivity to Mild Drought in Wheat.

Valluru R, Davies WJ, Reynolds MP, Dodd IC - Front Plant Sci (2016)

Shoot ABA concentration (A) and ethylene production (B) of drought-tolerant (DT) and drought-susceptible (DS) genotypes grown under well-watered (WW) or mild water-deficit (MWD) conditions with four replications for each genotype. *, **, *** Indicate p < 0.001, < 0.01, and < 0.05, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834443&req=5

Figure 3: Shoot ABA concentration (A) and ethylene production (B) of drought-tolerant (DT) and drought-susceptible (DS) genotypes grown under well-watered (WW) or mild water-deficit (MWD) conditions with four replications for each genotype. *, **, *** Indicate p < 0.001, < 0.01, and < 0.05, respectively.
Mentions: Previous studies have reported that wheat genotypes differ in the accumulation of, and their sensitivity to, ABA (Ji et al., 2011). We, therefore, measured endogenous ABA and ethylene in DT and DS genotypes grown under WW and MWD conditions. The DS and DT groups showed similar pattern of ABA and ethylene accumulation with both groups showing significantly higher ABA concentration (129% and 95%, respectively; P < 0.001) and ethylene production (160 and 138%, respectively; P = 0.001) in response to MWD (Figure 3, Supplementary Figures S3A,B). The main group effect on ABA was not significant (P > 0.05) but was significant for ethylene production (P = 0.01), indicating that both groups (DT and DS) significantly differed for ethylene production.

Bottom Line: We concluded that SDW of the DT and DS groups might be distinctly regulated by specific ABA:ethylene ratio.Furthermore, the DT group accumulated a significantly higher galactose while a significantly lower maltose in the shoot compared to the DS group.Taken all together, these results suggest an impact of ABA, ethylene, and ABA:ethylene ratio on SDW of wheat seedlings that may partly underlie a genotypic variability of different shoot growth sensitivities to drought among crop species under field conditions.

View Article: PubMed Central - PubMed

Affiliation: Global Wheat Program, International Maize and Wheat Improvement Center (CIMMYT)El Batan, Mexico; Plant Biology Department, Lancaster Environmental Center, Lancaster UniversityLancaster, UK.

ABSTRACT
Although, plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA) and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT) group maintained or increased shoot dry weight (SDW) while the drought-susceptible (DS) group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous ABA and ethylene concentrations under mild drought compared to control. The DT and DS groups exhibited different SDW response trends, whereby the DS group decreased while the DT group increased SDW, to increased concentrations of ABA and ethylene under mild drought, although both groups decreased ABA/ethylene ratio under mild drought albeit at different levels. We concluded that SDW of the DT and DS groups might be distinctly regulated by specific ABA:ethylene ratio. Further, a foliar-spray of low concentrations (0.1 μM) of ABA increased shoot relative growth rate (RGR) in the DS group while ACC (1-aminocyclopropane-1-carboxylic acid, ethylene precursor) spray increased RGR in both groups compared to control. Furthermore, the DT group accumulated a significantly higher galactose while a significantly lower maltose in the shoot compared to the DS group. Taken all together, these results suggest an impact of ABA, ethylene, and ABA:ethylene ratio on SDW of wheat seedlings that may partly underlie a genotypic variability of different shoot growth sensitivities to drought among crop species under field conditions. We propose that phenotyping based on hormone accumulation, response and hormonal ratio would be a viable, rapid, and an early-stage selection tool aiding genotype selection for stress tolerance.

No MeSH data available.


Related in: MedlinePlus