A guard-cell-specific MYB transcription factor regulates stomatal movements and plant drought tolerance.
Stomatal pores located on the plant epidermis regulate CO(2) uptake for photosynthesis and the loss of water by transpiration. The opening and closing of the pore is mediated by turgor-driven volume changes of two surrounding guard cells. These highly specialized cells integrate internal signals and environmental stimuli to modulate stomatal aperture for plant survival under diverse conditions. Modulation of transcription and mRNA processing play important roles in controlling guard-cell activity, although the details of these levels of regulation remain mostly unknown. Here we report the characterization of AtMYB60, a R2R3-MYB gene of Arabidopsis, as the first transcription factor involved in the regulation of stomatal movements. AtMYB60 is specifically expressed in guard cells, and its expression is negatively modulated during drought. A null mutation in AtMYB60 results in the constitutive reduction of stomatal opening and in decreased wilting under water stress conditions. Transcript levels of a limited number of genes are altered in the mutant, and many of these genes are involved in the plant response to stress. Our data indicate that AtMYB60 is a transcriptional modulator of physiological responses in guard cells and open new possibilities to engineering stomatal activity to help plants survive desiccation.
Cominelli
Eleonora
E
Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.
Galbiati
Massimo
M
Vavasseur
Alain
A
Conti
Lucio
L
Sala
Tea
T
Vuylsteke
Marnik
M
Leonhardt
Nathalie
N
Dellaporta
Stephen L
SL
Tonelli
Chiara
C
D000222:Adaptation, Physiological / Q000235:genetics* / Q000502:physiology; D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D003681:Dehydration / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins; D046228:Microarray Analysis; D009154:Mutation / Q000235:genetics; D018515:Plant Leaves / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D017931:DNA Primers; C504084:MYB61 protein, Arabidopsis; D014157:Transcription Factors; D049452:Green Fluorescent Proteins