Arabidopsis MPK3, a Key Signalling Intermediate in Stomatal Function.
Regulation of stomatal aperture is of critical importance to plants to balance gas exchange and water loss, and also to control ingress of bacterial pathogens. MAP kinase signal transduction pathways are mediators of biotic and abiotic stress, and have been indicted in the control of stomatal movements. Cell-specific antisense was used to down-regulate MPK3 gene expression in Arabidopsis guard cells, resulting in ABA insensitivity during inhibition of stomatal opening, but a normal ABA response in promotion of closure assays. This response is similar to that of the heterotrimeric G protein alpha subunit mutant gpa1, as is the imposition of ABA insensitivity during stomatal closure by butyrate treatment, suggesting that MPK3 and GPA1 are in the same ABA signal transduction pathway and adding further evidence for parallel signalling pathways during ABA-induced closure. By contrast, antisense plants were less sensitive to H(2)O(2) in both promotion of closure and inhibition of opening assays, although H(2)O(2) production in response to ABA was not affected. Regulation of stomatal aperture by PAMPs has recently been shown to be an important plant defense mechanism; since MPK3 is also activated by such pathogen elicitors, we postulate that in addition to a signalling role in guard cell movements, MPK3 is involved in the active prevention of bacterial infection through stomata.
Gudesblat
Gustavo E
GE
Laboratorio de Fisiología, Biología Molecular y Celular; Universidad de Buenos Aires; Buenos Aires, Argentina.
Iusem
Norberto D
ND
Morris
Peter C
PC
Plant J. 2001 Nov;28(4):455-64
11737782
Plant Physiol. 1999 Sep;121(1):147-52
10482669
Science. 2001 Jun 15;292(5524):2070-2
11408655
New Phytol. 2007;173(4):713-721
17286820
Plant Cell. 2005 Mar;17(3):957-70
15705948
Plant Cell. 2005 Jul;17(7):1866-75
15987996
Planta. 1997;202(1):9-17
9177047
Science. 2006 Apr 14;312(5771):264-6
16614222
Plant Cell. 2004 Apr;16(4):897-907
15020743
Plant Physiol. 2001 Aug;126(4):1438-48
11500543
Nature. 2000 Aug 17;406(6797):731-4
10963598
Trends Plant Sci. 2002 Jul;7(7):301-8
12119167
J Exp Bot. 2000 Feb;51(343):197-205
10938826
Cell. 2006 Sep 8;126(5):969-80
16959575
Proc Natl Acad Sci U S A. 2002 Nov 26;99(24):15812-7
12434021
Funct Plant Biol. 2004 Oct;31(9):913-920
32688959
Plant Physiol. 2006 Jan;140(1):210-20
16339801
Nature. 2002 Feb 28;415(6875):977-83
11875555