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HKT transporters--state of the art.

Almeida P, Katschnig D, de Boer AH - Int J Mol Sci (2013)

Bottom Line: Here we present an overview of the physiological role of HKT transporters in plant Na⁺ homeostasis.The functions of the most recently characterized HKT members from both HKT1 and HKT2 subfamilies are also discussed.Topics that still need to be studied in future research (e.g., HKT regulation) as well as research suggestions (e.g., generation of HKT mutants) are addressed.

View Article: PubMed Central - PubMed

Affiliation: Vrije Universiteit Amsterdam, Faculty Earth and Life Sciences, Department of Structural Biology, Amsterdam NL-1081 HV, The Netherlands. p.m.fidalgodealmeida@vu.nl.

ABSTRACT
The increase in soil salinity poses a serious threat to agricultural yields. Under salinity stress, several Na⁺ transporters play an essential role in Na⁺ tolerance in plants. Amongst all Na+ transporters, HKT has been shown to have a crucial role in both mono and dicotyledonous plants in the tolerance to salinity stress. Here we present an overview of the physiological role of HKT transporters in plant Na⁺ homeostasis. HKT regulation and amino acids important to the correct function of HKT transporters are reviewed. The functions of the most recently characterized HKT members from both HKT1 and HKT2 subfamilies are also discussed. Topics that still need to be studied in future research (e.g., HKT regulation) as well as research suggestions (e.g., generation of HKT mutants) are addressed.

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Targeted expression of AtHKT1;1 in the roots of both (A) dicotyledonous and (B) monocotyledonous plants. The targeted over-expression of AtHKT1;1 in the roots, regardless of the tissue as both over-expression in the (C) epidermal and cortical cells as well as (D and E) in the pericycle, resulted in enhanced salinity tolerance in Arabidopsis thaliana plants. Also in rice the overexpression of AtHKT1;1 in the (F and G) epidermis and cortical cells resulted also in enhanced salinity tolerance. This might be a useful strategy to use with other HKT genes to ameliorate the salt sensitivity of crop species. Bars: (C) 75 μm, (D and E) 40 μm, (F and G) 100 μm. Figure 3C,F,G reproduced with permission from [20]. Figures 3D,E reproduced with permission from [12].
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f3-ijms-14-20359: Targeted expression of AtHKT1;1 in the roots of both (A) dicotyledonous and (B) monocotyledonous plants. The targeted over-expression of AtHKT1;1 in the roots, regardless of the tissue as both over-expression in the (C) epidermal and cortical cells as well as (D and E) in the pericycle, resulted in enhanced salinity tolerance in Arabidopsis thaliana plants. Also in rice the overexpression of AtHKT1;1 in the (F and G) epidermis and cortical cells resulted also in enhanced salinity tolerance. This might be a useful strategy to use with other HKT genes to ameliorate the salt sensitivity of crop species. Bars: (C) 75 μm, (D and E) 40 μm, (F and G) 100 μm. Figure 3C,F,G reproduced with permission from [20]. Figures 3D,E reproduced with permission from [12].

Mentions: The constant growth of the world population in combination with the increase in salinized land areas make the generation of more salt tolerant cultivars a goal of utmost importance. Research on the physiological roles of class I HKT transporters like AtHKT1;1, and HKT1;4 and HKT1;5 from rice and wheat, as well as all other discovered HKT transporters will give important information that can be used to engineer salinity tolerant cultivars. For example, the studies by Moller et al. and Plett et al. provided evidence that targeted over-expression in the roots of both monocotyledonous and dicotyledonous plants results in increased salinity tolerance (Figure 3) [12,20]. As AtHKT1;1, SlHKT1;1 and HKT1;4 and HKT1;5 from both rice and wheat are orthologous and share the same functions in planta, this strategy might be useful in the engineering of salt tolerant crop plants.


HKT transporters--state of the art.

Almeida P, Katschnig D, de Boer AH - Int J Mol Sci (2013)

Targeted expression of AtHKT1;1 in the roots of both (A) dicotyledonous and (B) monocotyledonous plants. The targeted over-expression of AtHKT1;1 in the roots, regardless of the tissue as both over-expression in the (C) epidermal and cortical cells as well as (D and E) in the pericycle, resulted in enhanced salinity tolerance in Arabidopsis thaliana plants. Also in rice the overexpression of AtHKT1;1 in the (F and G) epidermis and cortical cells resulted also in enhanced salinity tolerance. This might be a useful strategy to use with other HKT genes to ameliorate the salt sensitivity of crop species. Bars: (C) 75 μm, (D and E) 40 μm, (F and G) 100 μm. Figure 3C,F,G reproduced with permission from [20]. Figures 3D,E reproduced with permission from [12].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3821619&req=5

f3-ijms-14-20359: Targeted expression of AtHKT1;1 in the roots of both (A) dicotyledonous and (B) monocotyledonous plants. The targeted over-expression of AtHKT1;1 in the roots, regardless of the tissue as both over-expression in the (C) epidermal and cortical cells as well as (D and E) in the pericycle, resulted in enhanced salinity tolerance in Arabidopsis thaliana plants. Also in rice the overexpression of AtHKT1;1 in the (F and G) epidermis and cortical cells resulted also in enhanced salinity tolerance. This might be a useful strategy to use with other HKT genes to ameliorate the salt sensitivity of crop species. Bars: (C) 75 μm, (D and E) 40 μm, (F and G) 100 μm. Figure 3C,F,G reproduced with permission from [20]. Figures 3D,E reproduced with permission from [12].
Mentions: The constant growth of the world population in combination with the increase in salinized land areas make the generation of more salt tolerant cultivars a goal of utmost importance. Research on the physiological roles of class I HKT transporters like AtHKT1;1, and HKT1;4 and HKT1;5 from rice and wheat, as well as all other discovered HKT transporters will give important information that can be used to engineer salinity tolerant cultivars. For example, the studies by Moller et al. and Plett et al. provided evidence that targeted over-expression in the roots of both monocotyledonous and dicotyledonous plants results in increased salinity tolerance (Figure 3) [12,20]. As AtHKT1;1, SlHKT1;1 and HKT1;4 and HKT1;5 from both rice and wheat are orthologous and share the same functions in planta, this strategy might be useful in the engineering of salt tolerant crop plants.

Bottom Line: Here we present an overview of the physiological role of HKT transporters in plant Na⁺ homeostasis.The functions of the most recently characterized HKT members from both HKT1 and HKT2 subfamilies are also discussed.Topics that still need to be studied in future research (e.g., HKT regulation) as well as research suggestions (e.g., generation of HKT mutants) are addressed.

View Article: PubMed Central - PubMed

Affiliation: Vrije Universiteit Amsterdam, Faculty Earth and Life Sciences, Department of Structural Biology, Amsterdam NL-1081 HV, The Netherlands. p.m.fidalgodealmeida@vu.nl.

ABSTRACT
The increase in soil salinity poses a serious threat to agricultural yields. Under salinity stress, several Na⁺ transporters play an essential role in Na⁺ tolerance in plants. Amongst all Na+ transporters, HKT has been shown to have a crucial role in both mono and dicotyledonous plants in the tolerance to salinity stress. Here we present an overview of the physiological role of HKT transporters in plant Na⁺ homeostasis. HKT regulation and amino acids important to the correct function of HKT transporters are reviewed. The functions of the most recently characterized HKT members from both HKT1 and HKT2 subfamilies are also discussed. Topics that still need to be studied in future research (e.g., HKT regulation) as well as research suggestions (e.g., generation of HKT mutants) are addressed.

Show MeSH