MAPKK kinase and stomata

Photo credit: Science

Interactions between YDA and other stomatal pattern genes in the abaxial epidermis of 7-dpg cotyledons: (A) wild type, (B) ΔN-YDA/+, (C) sdd1-1, (D) sdd1-1;ΔN-YDA/+, (E) tmm-1, (F) tmm-1;ΔN-YDA/+, (G) flp-1, and (H) flp-1;ΔN-YDA/+. Brackets indicate clusters. All images are the same magnification. Scale bar, 50 μm.

Stomatal development and pattern controlled by a MAPKK kinase.

by Bergmann D. C., Lukowitz W., Somerville C. R. (2004)

in Science 304:1494–1497. – 10.1126/science.1096014. –

Abstract/FREE Full Text – View ArticlePubMed – PubMed Abstract | CrossRef Full Text | Google Scholar

http://science.sciencemag.org/content/304/5676/1494.abstract?ijkey=577388e406e343563532353474c6da2ee7c6b3cf&keytype2=tf_ipsecsha

Abstract

Stomata are epidermal structures that modulate gas exchange between a plant and its environment. During development, stomata are specified and positioned nonrandomly by the integration of asymmetric cell divisions and intercellular signaling.

The Arabidopsis mitogen-activated protein kinase kinase kinase gene, YODA, acts as part of a molecular switch controlling cell identities in the epidermis. Null mutations in YODA lead to excess stomata, whereas constitutive activation of YODA eliminated stomata.

Transcriptome analysis of seedlings with altered YODA activity was used to identify potential stomatal regulatory genes. A putative transcription factor from this set was shown to regulate the developmental behavior of stomatal precursors.

MAPK signaling in Arabidopsis stomata

 

Novel and expanded roles for MAPK signaling in Arabidopsis stomatal cell fate revealed by cell type-specific manipulations

by Lampard G. R., Lukowitz W., Ellis B. E., Bergmann D. C. (2009)

in Plant Cell 2009,21:3506-3517.

(PubMed Abstract | Publisher Full Text|PubMed Central Full Text) – 

PMID: 19897669 

http://www.plantcell.org/content/21/11/3506/F1.medium.gif

Figure 1.

Diagram of Stomatal Lineage Development and Gene Expression Patterns.

Arabidopsis stomatal development follows a three-step stereotyped pathway that involves a series of asymmetric and symmetric cell divisions. Entry into the stomatal lineage is negatively regulated by a MAPK module containing YDA (MAPKKK), MKK4 and MKK5 (MAPKKs), and MPK3 and MPK6 (MAPKs). Progression through the developmental pathway is positively influenced by sequentially acting bHLH transcription factors, SPCH, MUTE, and FAMA, which regulate entry (1), progression through (2), and terminal differentiation of guard cell development (3), respectively. The expression of green fluorescent protein (GFP)-tagged transcriptional reporters of each of SPCH (A), MUTE (B), andFAMA (C) coincides with each major developmental transition. Bars = 50 μm.

Abstract

Mitogen-activated protein kinase (MAPK) signaling networks regulate numerous eukaryotic biological processes. In Arabidopsis thaliana, signaling networks that contain MAPK kinases MKK4/5 and MAPKs MPK3/6 function in abiotic and biotic stress responses and regulate embryonic and stomatal development.

However, how single MAPK modules direct specific output signals without cross-activating additional downstream processes is largely unknown.

Studying relationships between MAPK components and downstream signaling outcomes is difficult because broad experimental manipulation of these networks is often lethal or associated with multiple phenotypes.

Stomatal development in Arabidopsis follows a series of discrete, stereotyped divisions and cell state transitions. By expressing a panel of constitutively active MAPK kinase (MAPKK) variants in discrete stomatal lineage cell types, we identified a new inhibitory function of MKK4 and MKK5 in meristemoid self-renewal divisions.

Furthermore, we established roles for MKK7 and MKK9 as both negative and (unexpectedly) positive regulators during the major stages of stomatal development. This has expanded the number of known MAPKKs that regulate stomatal development and allowed us to build plausible and testable subnetworks of signals. This in vivo cell type-specific assay can be adapted to study other protein families and thus may reveal insights into other complex signal transduction pathways in plants.

See the text: NCBI

Read the full article: The Plant Cell

MAPKK kinase and stomata

Photo credit: Google

Stomata Vicia Faba Leaf

Stomatal development and pattern controlled by a MAPKK kinase

by Bergmann D.C., Lukowitz W., Somerville C.R. (2004)

in Science 304:1494–1497.

PMID: 15178800

Abstract

Stomata are epidermal structures that modulate gas exchange between a plant and its environment. During development, stomata are specified and positioned nonrandomly by the integration of asymmetric cell divisions and intercellular signaling.

The Arabidopsis mitogen-activated protein kinase kinase kinase gene, YODA, acts as part of a molecular switch controlling cell identities in the epidermis. Null mutations in YODA lead to excess stomata, whereas constitutive activation of YODA eliminated stomata. Transcriptome analysis of seedlings with altered YODA activity was used to identify potential stomatal regulatory genes.

A putative transcription factor from this set was shown to regulate the developmental behavior of stomatal precursors.

See the text: NCBI