Abstract
Developmental program that stops cell proliferation plays an important role in the determination of leaf size. To investigate this regulation genetically, we have isolated three lines of grandifolia-D mutants of Arabidopsis thaliana that produce larger leaves than wild-type plants do by extending the duration of cell proliferation. Unexpectedly, our genetic mapping revealed that each gra-D loci has genetic linkages with two different chromosomal regions: depending on the lines used, the gra-D loci are mapped on the top part of either chromosome 2 or 4, and all three lines shows a second linkage at the lower part of chromosome 4. Curiously, this region contains the AINTEGUMENTA (ANT) gene that is known to positively control the duration of cell proliferation in leaf primordia. RT-PCR analysis revealed that ANT is overepressed in the gra-D mutants backgrounds. We are now characterizing the relationship between ANT overexpression and gra-D phenotype in more details.
