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Differential activity of plasma and vacuolar membrane transporters contributes to genotypic differences in salinity tolerance in a Halophyte Species, Chenopodium quinoa.

Bonales-Alatorre E, Pottosin I, Shabala L, Chen ZH, Zeng F, Jacobsen SE, Shabala S - Int J Mol Sci (2013)

Bottom Line: Our results suggest that multiple mechanisms contribute towards genotypic differences in salinity tolerance in quinoa.These include: (i) a higher rate of Na+ exclusion from leaf mesophyll; (ii) maintenance of low cytosolic Na+ levels; (iii) better K+ retention in the leaf mesophyll; (iv) a high rate of H+ pumping, which increases the ability of mesophyll cells to restore their membrane potential; and (v) the ability to reduce the activity of SV and FV channels under saline conditions.These mechanisms appear to be highly orchestrated, thus enabling the remarkable overall salinity tolerance of quinoa species.

View Article: PubMed Central - PubMed

Affiliation: School of Agricultural Science and Tasmanian Institute for Agriculture, University of Tasmania, Private Bag 54, Hobart, TAS 7001, Australia. Sergey.Shabala@utas.edu.au.

ABSTRACT
Halophytes species can be used as a highly convenient model system to reveal key ionic and molecular mechanisms that confer salinity tolerance in plants. Earlier, we reported that quinoa (Chenopodium quinoa Willd.), a facultative C3 halophyte species, can efficiently control the activity of slow (SV) and fast (FV) tonoplast channels to match specific growth conditions by ensuring that most of accumulated Na+ is safely locked in the vacuole (Bonales-Alatorre et al. (2013) Plant Physiology). This work extends these finding by comparing the properties of tonoplast FV and SV channels in two quinoa genotypes contrasting in their salinity tolerance. The work is complemented by studies of the kinetics of net ion fluxes across the plasma membrane of quinoa leaf mesophyll tissue. Our results suggest that multiple mechanisms contribute towards genotypic differences in salinity tolerance in quinoa. These include: (i) a higher rate of Na+ exclusion from leaf mesophyll; (ii) maintenance of low cytosolic Na+ levels; (iii) better K+ retention in the leaf mesophyll; (iv) a high rate of H+ pumping, which increases the ability of mesophyll cells to restore their membrane potential; and (v) the ability to reduce the activity of SV and FV channels under saline conditions. These mechanisms appear to be highly orchestrated, thus enabling the remarkable overall salinity tolerance of quinoa species.

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Related in: MedlinePlus

Salinity reduces the final vacuolar FV currents in quinoa. (A,B) Whole vacuolar FV conductance was evaluated in salt-sensitive (Q5206; panel A) and salt-tolerant (Q16; panel B) varieties by taking the first derivative of the whole vacuole I/V relationship, measured 30 min after achieving the whole vacuole configuration. Growth conditions, pipette ion composition and data analysis are the same as in Figure 6; (C) Same data as A,B, but only the points within the physiological tonoplast potential range (±20 mV) are shown.
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f8-ijms-14-09267: Salinity reduces the final vacuolar FV currents in quinoa. (A,B) Whole vacuolar FV conductance was evaluated in salt-sensitive (Q5206; panel A) and salt-tolerant (Q16; panel B) varieties by taking the first derivative of the whole vacuole I/V relationship, measured 30 min after achieving the whole vacuole configuration. Growth conditions, pipette ion composition and data analysis are the same as in Figure 6; (C) Same data as A,B, but only the points within the physiological tonoplast potential range (±20 mV) are shown.

Mentions: The effect of the growth conditions was very pronounced though when FV currents were analysed in their final state (e.g., 30 min after vacuole perfusion and seal formation). Salt grown plants (treated with 400 mM NaCl for four weeks) showed greatly reduced FV currents (Figure 7). While this phenomenon was observed in both genotypes (Figure 7), it was more pronounced in the salt-sensitive Q5206 genotype (4.9 ± 0.2-fold in Q5206 vs. 2.5 ± 0.3-fold in Q16, respectively, within the physiologically relevant range of tonoplast potentials; Figure 8).


Differential activity of plasma and vacuolar membrane transporters contributes to genotypic differences in salinity tolerance in a Halophyte Species, Chenopodium quinoa.

Bonales-Alatorre E, Pottosin I, Shabala L, Chen ZH, Zeng F, Jacobsen SE, Shabala S - Int J Mol Sci (2013)

Salinity reduces the final vacuolar FV currents in quinoa. (A,B) Whole vacuolar FV conductance was evaluated in salt-sensitive (Q5206; panel A) and salt-tolerant (Q16; panel B) varieties by taking the first derivative of the whole vacuole I/V relationship, measured 30 min after achieving the whole vacuole configuration. Growth conditions, pipette ion composition and data analysis are the same as in Figure 6; (C) Same data as A,B, but only the points within the physiological tonoplast potential range (±20 mV) are shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3676782&req=5

f8-ijms-14-09267: Salinity reduces the final vacuolar FV currents in quinoa. (A,B) Whole vacuolar FV conductance was evaluated in salt-sensitive (Q5206; panel A) and salt-tolerant (Q16; panel B) varieties by taking the first derivative of the whole vacuole I/V relationship, measured 30 min after achieving the whole vacuole configuration. Growth conditions, pipette ion composition and data analysis are the same as in Figure 6; (C) Same data as A,B, but only the points within the physiological tonoplast potential range (±20 mV) are shown.
Mentions: The effect of the growth conditions was very pronounced though when FV currents were analysed in their final state (e.g., 30 min after vacuole perfusion and seal formation). Salt grown plants (treated with 400 mM NaCl for four weeks) showed greatly reduced FV currents (Figure 7). While this phenomenon was observed in both genotypes (Figure 7), it was more pronounced in the salt-sensitive Q5206 genotype (4.9 ± 0.2-fold in Q5206 vs. 2.5 ± 0.3-fold in Q16, respectively, within the physiologically relevant range of tonoplast potentials; Figure 8).

Bottom Line: Our results suggest that multiple mechanisms contribute towards genotypic differences in salinity tolerance in quinoa.These include: (i) a higher rate of Na+ exclusion from leaf mesophyll; (ii) maintenance of low cytosolic Na+ levels; (iii) better K+ retention in the leaf mesophyll; (iv) a high rate of H+ pumping, which increases the ability of mesophyll cells to restore their membrane potential; and (v) the ability to reduce the activity of SV and FV channels under saline conditions.These mechanisms appear to be highly orchestrated, thus enabling the remarkable overall salinity tolerance of quinoa species.

View Article: PubMed Central - PubMed

Affiliation: School of Agricultural Science and Tasmanian Institute for Agriculture, University of Tasmania, Private Bag 54, Hobart, TAS 7001, Australia. Sergey.Shabala@utas.edu.au.

ABSTRACT
Halophytes species can be used as a highly convenient model system to reveal key ionic and molecular mechanisms that confer salinity tolerance in plants. Earlier, we reported that quinoa (Chenopodium quinoa Willd.), a facultative C3 halophyte species, can efficiently control the activity of slow (SV) and fast (FV) tonoplast channels to match specific growth conditions by ensuring that most of accumulated Na+ is safely locked in the vacuole (Bonales-Alatorre et al. (2013) Plant Physiology). This work extends these finding by comparing the properties of tonoplast FV and SV channels in two quinoa genotypes contrasting in their salinity tolerance. The work is complemented by studies of the kinetics of net ion fluxes across the plasma membrane of quinoa leaf mesophyll tissue. Our results suggest that multiple mechanisms contribute towards genotypic differences in salinity tolerance in quinoa. These include: (i) a higher rate of Na+ exclusion from leaf mesophyll; (ii) maintenance of low cytosolic Na+ levels; (iii) better K+ retention in the leaf mesophyll; (iv) a high rate of H+ pumping, which increases the ability of mesophyll cells to restore their membrane potential; and (v) the ability to reduce the activity of SV and FV channels under saline conditions. These mechanisms appear to be highly orchestrated, thus enabling the remarkable overall salinity tolerance of quinoa species.

Show MeSH
Related in: MedlinePlus