Award Abstract #0520548
Stomatal Patterning and Differentiation by Synergistic Interactions of Leucine-rich Repeat Receptor Kinases

NSF Org:	IOS Division of Integrative Organismal Systems
Initial Amendment Date:	July 18, 2005
Latest Amendment Date:	April 27, 2007
Award Number:	0520548
Award Instrument:	Continuing grant
Program Manager:	Zhongchi Liu IOS Division of Integrative Organismal Systems BIO Directorate for Biological Sciences
Start Date:	September 1, 2005
Expires:	August 31, 2008 (Estimated)
Awarded Amount to Date:	$416875
Investigator(s):	Keiko Torii ktorii@u.washington.edu (Principal Investigator)
Sponsor:	University of Washington 4333 Brooklyn Ave NE SEATTLE, WA 98195 206/543-4043
NSF Program(s):	DEVELOPMENTAL BIOLOGY CLUSTER, PLANT FUNGAL & MICROB DEV MECH
Field Application(s):	0000099 Other Applications NEC
Program Reference Code(s):	SMET,BIOT,9251,9183,9178,1111
Program Element Code(s):	7471,1118

ABSTRACT

The successful adaptation of land plants relied on mechanisms that prevent water loss while allowing efficient gas exchange between plants and the atmosphere. Gas exchange takes place through a stomatal complex, which consists of a pair of guard cells that operate as a turgor-driven valve. Isolation of Arabidopsis mutants with elevated stomatal density and stomatal clustering reveals that stomatal patterning is under genetic regulation. This research project focuses on the cell-cell signaling mechanism regulating stomatal patterning and differentiation. A complete loss of three ERECTA-family receptor-like kinases (RLKs) leads to the generation of high-density stomatal clusters. Further analysis of different erecta-family mutant combinations shows that the three RLKs possess overlapping but distinct functions in two critical steps of stomatal differentiation: (1) the initial decision of protodermal cells to enter proliferative division or asymmetric division to generate stomatal complexes; and (2) the decision to maintain stomatal stem cell activity and prevent terminal differentiation of guard cells. Genetic interactions with a known stomatal patterning mutant, too many mouth (tmm), reveals stoichiometric epistasis and combination-specific neomorphism. These findings suggest that negative regulation of ERECTA-family RLKs by TMM receptor-like protein, is critical for proper stomatal differentiation. The specific aims are:

1) to determine the roles of three ERECTA-family receptor kinases during epidermal differentiation.

2) to investigate interactions of three receptor kinases with known players of stomatal differentiation.

3) to identify novel regulators of stomatal patterning and differentiation by taking advantage of a sensitized mutant background.

The proposed research may lead to important agricultural applications, since the ability to manipulate stomatal distribution and patterning may influence photosynthetic efficiency and hence the biomass production of crop plants. A postdoctoral associate, a graduate student and undergraduates, many of whom are women and of diverse ethnic backgrounds, will have excellent opportunities to obtain broad training in plant biology and molecular genetics.

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