Pooja Thakur

Date Approved


Degree Type

Open Access Thesis

Degree Name

Master of Science (MS)

Department or School


Committee Member

Dr. Marianne Laporte PhD, Chair

Committee Member

Dr. James VandenBosch PhD, Member

Committee Member

Dr. Daniel Clemans PhD, Member


Plants lose their water as transpiration by stomatal opening, which is governed by guard cells surrounding the stomata. Influx of ions such as K+, Cl-, from neighboring cells into guard cells, and malate synthesis within guard cells increases turgor pressure opening the stomata. Stomata close when K+ and Cl- efflux out, and the cytosolic isoform of NADP ME convert malate to pyruvate. We hypothesize that stomatal closure can be controlled by increased NADP ME activity in guard cells. More than one of the homozygous transgenic Arabidopsis plants that are transformed with a guard cell promoter driving expression of maize NADP ME have been obtained by herbicide screening. Molecular studies have confirmed presence of the transgene in these transformants. Enzyme assays shows higher ME activity in these transformants, indicating an active form of maize ME. Such transgenic plants would help to determine effects of increased ME activity on plant water loss.

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