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The grapevine root-specific aquaporin VvPIP2;4N controls root hydraulic conductance and leaf gas exchange under well watered conditions but not under water stress.

Perrone, Irene and Gambino, Giorgio and Chitarra, Walter and Vitali, Marco and Pagliarani, Chiara and Riccomagno, Nadia and Balestrini, Raffaella and Kaldenhoff, Ralf and Uehlein, Norbert and Gribaudo, Ivana and Schubert, Andrea and Lovisolo, Claudio (2012):
The grapevine root-specific aquaporin VvPIP2;4N controls root hydraulic conductance and leaf gas exchange under well watered conditions but not under water stress.
In: Plant physiology, pp. 965-977, 160, (2), ISSN 1532-2548, [Article]

Abstract

We functionally characterized the grape (Vitis vinifera L.) VvPIP2;4N aquaporin gene. Expression of VvPIP2;4N in Xenopus laevis oocytes increased their swelling rate 54-fold. Northern blot and qRT-PCR analyses showed that VvPIP2;4N is the most expressed PIP2s gene in root. In situ hybridisation confirmed root localization in the cortical parenchyma and close to the endodermis. We then constitutively overexpressed VvPIP2;4N in Vitis vinifera L. 'Brachetto' and in the resulting transgenic plants we analysed i) the expression of endogenous and transgenic VvPIP2;4N and of four other aquaporins, ii) whole-plant, root, and leaf ecophysiological parameters, and iii) leaf abscisic acid content. Expression of transgenic VvPIP2;4N inhibited neither the expression of the endogenous gene nor that of other PIP aquaporins in both root and leaf. Under well-watered conditions, transgenic plants showed higher stomatal conductance, gas exchange, and shoot growth. The expression level of VvPIP2;4N (endogenous + transgene) was inversely correlated to root hydraulic resistance. The leaf component of total plant hydraulic resistance was low and unaffected by overexpression of VvPIP2;4N. Upon water stress, the overexpression of VvPIP2;4N induced a surge in leaf abscisic acid content, and a decrease in stomatal conductance and leaf gas exchange. Our results show that aquaporin-mediated modifications of root hydraulics play a substantial role in the regulation of water flow in well-watered grapevine plants, while they have a minor role upon drought, probably because other signals, such as ABA, take over control of water flow.

Item Type: Article
Erschienen: 2012
Creators: Perrone, Irene and Gambino, Giorgio and Chitarra, Walter and Vitali, Marco and Pagliarani, Chiara and Riccomagno, Nadia and Balestrini, Raffaella and Kaldenhoff, Ralf and Uehlein, Norbert and Gribaudo, Ivana and Schubert, Andrea and Lovisolo, Claudio
Title: The grapevine root-specific aquaporin VvPIP2;4N controls root hydraulic conductance and leaf gas exchange under well watered conditions but not under water stress.
Language: English
Abstract:

We functionally characterized the grape (Vitis vinifera L.) VvPIP2;4N aquaporin gene. Expression of VvPIP2;4N in Xenopus laevis oocytes increased their swelling rate 54-fold. Northern blot and qRT-PCR analyses showed that VvPIP2;4N is the most expressed PIP2s gene in root. In situ hybridisation confirmed root localization in the cortical parenchyma and close to the endodermis. We then constitutively overexpressed VvPIP2;4N in Vitis vinifera L. 'Brachetto' and in the resulting transgenic plants we analysed i) the expression of endogenous and transgenic VvPIP2;4N and of four other aquaporins, ii) whole-plant, root, and leaf ecophysiological parameters, and iii) leaf abscisic acid content. Expression of transgenic VvPIP2;4N inhibited neither the expression of the endogenous gene nor that of other PIP aquaporins in both root and leaf. Under well-watered conditions, transgenic plants showed higher stomatal conductance, gas exchange, and shoot growth. The expression level of VvPIP2;4N (endogenous + transgene) was inversely correlated to root hydraulic resistance. The leaf component of total plant hydraulic resistance was low and unaffected by overexpression of VvPIP2;4N. Upon water stress, the overexpression of VvPIP2;4N induced a surge in leaf abscisic acid content, and a decrease in stomatal conductance and leaf gas exchange. Our results show that aquaporin-mediated modifications of root hydraulics play a substantial role in the regulation of water flow in well-watered grapevine plants, while they have a minor role upon drought, probably because other signals, such as ABA, take over control of water flow.

Journal or Publication Title: Plant physiology
Volume: 160
Number: 2
Divisions: 10 Department of Biology
10 Department of Biology > Applied Plant Sciences
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Date Deposited: 03 Sep 2012 08:57
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