Limits...
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

The association between shoot dry weight (SDW) and endogenous ABA (A), ethylene (B), and ABA:ethylene ratio (C) in drought-tolerant (circles, DT) and drought-susceptible (squares, DS) genotypes grown under well-watered (filled symbols) and mild drought (open symbols) with four replications for each genotype. SEN, drought-susceptible; TOL, drought-tolerant. ETH, ethylene; ABA, abscisic acid.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4834443&req=5

Figure 4: The association between shoot dry weight (SDW) and endogenous ABA (A), ethylene (B), and ABA:ethylene ratio (C) in drought-tolerant (circles, DT) and drought-susceptible (squares, DS) genotypes grown under well-watered (filled symbols) and mild drought (open symbols) with four replications for each genotype. SEN, drought-susceptible; TOL, drought-tolerant. ETH, ethylene; ABA, abscisic acid.

Mentions: Across two treatments, SDW responses of the DT and DS groups to endogenous ABA and ethylene showed a tendency toward two response trends (Figures 4A,B, group effects for ABA: P < 0.0001; group effects for ethylene: P < 0.0001). The DT group showed an increased SDW with increasing concentrations of ABA (round circles, Figure 4A). In contrast, the DS group showed a decreased SDW with increasing concentrations of ABA (squares, Figure 4A). Such SDW responses of the DT and DS groups were consistent with ethylene whereby both the DT and DS groups showed an increased and a decreased SDW response to increasing levels of ethylene, respectively (Figure 4B). Such differential SDW response trends between DT and DS groups were largely driven by WW conditions, suggesting that hormone concentrations may regulate shoot growth even under optimal growing conditions.


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)

The association between shoot dry weight (SDW) and endogenous ABA (A), ethylene (B), and ABA:ethylene ratio (C) in drought-tolerant (circles, DT) and drought-susceptible (squares, DS) genotypes grown under well-watered (filled symbols) and mild drought (open symbols) with four replications for each genotype. SEN, drought-susceptible; TOL, drought-tolerant. ETH, ethylene; ABA, abscisic acid.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 4: The association between shoot dry weight (SDW) and endogenous ABA (A), ethylene (B), and ABA:ethylene ratio (C) in drought-tolerant (circles, DT) and drought-susceptible (squares, DS) genotypes grown under well-watered (filled symbols) and mild drought (open symbols) with four replications for each genotype. SEN, drought-susceptible; TOL, drought-tolerant. ETH, ethylene; ABA, abscisic acid.
Mentions: Across two treatments, SDW responses of the DT and DS groups to endogenous ABA and ethylene showed a tendency toward two response trends (Figures 4A,B, group effects for ABA: P < 0.0001; group effects for ethylene: P < 0.0001). The DT group showed an increased SDW with increasing concentrations of ABA (round circles, Figure 4A). In contrast, the DS group showed a decreased SDW with increasing concentrations of ABA (squares, Figure 4A). Such SDW responses of the DT and DS groups were consistent with ethylene whereby both the DT and DS groups showed an increased and a decreased SDW response to increasing levels of ethylene, respectively (Figure 4B). Such differential SDW response trends between DT and DS groups were largely driven by WW conditions, suggesting that hormone concentrations may regulate shoot growth even under optimal growing conditions.

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