POLYGALACTURONASE INVOLVED IN EXPANSION3 Functions in
Seedling
Development, Rosette Growth, and Stomatal Dynamics in Arabidopsis thaliana
Yue Rui, Chaowen Xiao, Hojae Yi, Baris Kandemir, James Z. Wang,
Virendra M. Puri, and Charles T. Anderson
The Pennsylvania State University
Abstract:
Plant cell separation and expansion require pectin degradation by
endogenous pectinases such as polygalacturonases, few of which have
been functionally characterized. Stomata are a unique system to study
both processes because stomatal maturation involves limited separation
between sister guard cells and stomatal responses require reversible
guard cell elongation and contraction. However, the molecular
mechanisms for how stomatal pores form and how guard cell walls
facilitate dynamic stomatal responses remain poorly understood. We
characterized POLYGALACTURONASE INVOLVED IN EXPANSION3 (PGX3), which
is expressed in expanding tissues and guard cells. PGX3-GFP localizes
to the cell wall and is enriched at sites of stomatal pore initiation
in cotyledons. In seedlings, ablating or overexpressing PGX3 affects
both cotyledon shape and the spacing and pore dimensions of developing
stomata. In adult plants, PGX3 affects rosette size. Although stomata
in true leaves display normal density and morphology when PGX3
expression is altered, loss of PGX3 prevents smooth stomatal closure,
and overexpression of PGX3 accelerates stomatal opening. These
phenotypes correspond with changes in pectin molecular mass and
abundance that can affect wall mechanics. Together, these results
demonstrate that PGX3-mediated pectin degradation affects stomatal
development in cotyledons, promotes rosette expansion, and modulates
guard cell mechanics in adult plants.
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Citation:
Yue Rui, Chaowen Xiao, Hojae Yi, Baris Kandemir, James Z. Wang,
Virendra M. Puri and Charles T. Anderson, ``POLYGALACTURONASE INVOLVED
IN EXPANSION3 Functions in Seedling Development, Rosette Growth, and
Stomatal Dynamics in Arabidopsis thaliana,'' The Plant Cell,
vol. 29, no. 10, pp. 2413-2432, 2017.
© 2017 American Society of Plant Biologists.
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Last Modified:
November 10, 2017
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