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.

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;CHITARRA, WALTER;VITALI, MARCO;PAGLIARANI, CHIARA;RICCOMAGNO, NADIA;SCHUBERT, Andrea;LOVISOLO, Claudio
2012

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.
PLANT PHYSIOLOGY
160
965
977
http://www.plantphysiol.org/content/160/2/965
ABA; aquaporin; water channel; PIP; water stress
Irene Perrone; Giorgio Gambino; Walter Chitarra; Marco Vitali; Chiara Pagliarani; Nadia Riccomagno; Raffaella Balestrini; Ralf Kaldenhoff; Norbert Uehlein; Ivana Gribaudo; Andrea Schubert; Claudio Lovisolo.
File in questo prodotto:
File Dimensione Formato  
Perrone 12 PP aperto.pdf

embargo fino al 01/01/2014

Tipo di file: POSTPRINT (VERSIONE FINALE DELL’AUTORE)
Dimensione 7.56 MB
Formato Adobe PDF
7.56 MB Adobe PDF Visualizza/Apri
Perrone et al 2012 Plant Physiol.pdf

non disponibili

Tipo di file: PDF EDITORIALE
Dimensione 1.1 MB
Formato Adobe PDF
1.1 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2318/121664
Citazioni
  • ???jsp.display-item.citation.pmc??? 29
  • Scopus 85
  • ???jsp.display-item.citation.isi??? 80
social impact