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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

Grain yields of six different wheat genotypes grown under non-stress and stress conditions in the field. The selected wheat genotypes were: Tolerant: Kea, Attila, Florkwa; Sensitive: Simorge; Barbeti; SeriM82. SEN, sensitive group; TOL, tolerant group.
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Figure 1: Grain yields of six different wheat genotypes grown under non-stress and stress conditions in the field. The selected wheat genotypes were: Tolerant: Kea, Attila, Florkwa; Sensitive: Simorge; Barbeti; SeriM82. SEN, sensitive group; TOL, tolerant group.

Mentions: Six spring wheat (Triticum aestivum L.) genotypes were selected and designated as drought-tolerant (DT: Kea, Attila, Florkwa) or drought-sensitive (DS: SeriM32, Simorge, Barbet1) groups based on their stress susceptibility, biomass accumulation and yield potential in the field (Lopes et al., 2012). These groups were selected in such a way that both the DT and DS groups show contrasting yield susceptibility to stress and non-stress conditions (Figure 1). The DS group had higher yield under non-stress (1094 g/m2) while they maintain only 43% of non-stress yields (474 g/m2) under stress conditions. In contrast, DT group had lower grain yield under non-stress (829 g/m2) as compared to DS group but they maintain 73% (606 g/m2) of non-stress yields under stress conditions. Therefore, both groups have differential yield susceptibilities to stress and non-stress conditions. This atypical selection is at marked contrast to a widely accepted breeders conception that selection for high yield potential under non-stress conditions has also improved yield under stress especially for mild to moderate drought stress (Araus et al., 2002, 2008; Trethowan et al., 2002; Cattivelli et al., 2008). However, such genotype selection may be useful to understand the underlying mechanisms of growth and yield responses to the environment.


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)

Grain yields of six different wheat genotypes grown under non-stress and stress conditions in the field. The selected wheat genotypes were: Tolerant: Kea, Attila, Florkwa; Sensitive: Simorge; Barbeti; SeriM82. SEN, sensitive group; TOL, tolerant group.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 1: Grain yields of six different wheat genotypes grown under non-stress and stress conditions in the field. The selected wheat genotypes were: Tolerant: Kea, Attila, Florkwa; Sensitive: Simorge; Barbeti; SeriM82. SEN, sensitive group; TOL, tolerant group.
Mentions: Six spring wheat (Triticum aestivum L.) genotypes were selected and designated as drought-tolerant (DT: Kea, Attila, Florkwa) or drought-sensitive (DS: SeriM32, Simorge, Barbet1) groups based on their stress susceptibility, biomass accumulation and yield potential in the field (Lopes et al., 2012). These groups were selected in such a way that both the DT and DS groups show contrasting yield susceptibility to stress and non-stress conditions (Figure 1). The DS group had higher yield under non-stress (1094 g/m2) while they maintain only 43% of non-stress yields (474 g/m2) under stress conditions. In contrast, DT group had lower grain yield under non-stress (829 g/m2) as compared to DS group but they maintain 73% (606 g/m2) of non-stress yields under stress conditions. Therefore, both groups have differential yield susceptibilities to stress and non-stress conditions. This atypical selection is at marked contrast to a widely accepted breeders conception that selection for high yield potential under non-stress conditions has also improved yield under stress especially for mild to moderate drought stress (Araus et al., 2002, 2008; Trethowan et al., 2002; Cattivelli et al., 2008). However, such genotype selection may be useful to understand the underlying mechanisms of growth and yield responses to the environment.

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