The tomato DELLA protein PROCERA acts in guard cells to promote stomatal closure

Ido Nir, Hagai Shohat, Irina Panizel, Neil Olszewski, Asaph Aharoni, David Weiss*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

78 Scopus citations


Plants employ stomatal closure and reduced growth to avoid water deficiency damage. Reduced levels of the growth-promoting hormone gibberellin (GA) lead to increased tolerance to water deficit, but the underlying mechanism is unknown. Here, we show that the tomato (Solanum lycopersicum) DELLA protein PROCERA (PRO), a negative regulator of GA signaling, acts in guard cells to promote stomatal closure and reduce water loss in response to water deficiency by increasing abscisic acid (ABA) sensitivity. The loss-of-function pro mutant exhibited increased stomatal conductance and rapid wilting under water deficit stress. Transgenic tomato overexpressing constitutively active stable DELLA proteins (S-della) displayed the opposite phenotype. The effects of S-della on stomatal aperture and water loss were strongly suppressed in the ABA-deficient mutant sitiens, indicating that these effects of S-della are ABA dependent. While DELLA had no effect on ABA levels, guard cell ABA responsiveness was increased in S-della and reduced in pro plants compared with the wild type. Expressing S-della under the control of a guard-cell-specific promoter was sufficient to increase stomatal sensitivity to ABA and to reduce water loss under water deficit stress but had no effect on leaf size. This result indicates that DELLA promotes stomatal closure independently of its effect on growth.

Original languageAmerican English
Pages (from-to)3186-3197
Number of pages12
JournalPlant Cell
Issue number12
StatePublished - Dec 2017

Bibliographical note

Publisher Copyright:
© 2017, American Society of Plant Biologists. All rights reserved.


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