Abstract
Plants must adapt their growth and development to the ambient environment. In higher plants, organ sizes depend on its cell sizes and cell numbers. The correlation between ploidy, nuclear DNA content, and cell size has long been reported in Arabidopsis thaliana and in many other plant species. Our previous study showed that a plant-specific trihelix transcription factor, GT-2-LIKE1 (GTL1) functions as a negative regulator of ploidy-dependent cell growth in Arabidopsis trichomes.
In this study we analyzed the function of GTL1 and its homologs. The expression of GTL1 and its homologs are up-regulated under dark under short day condition (SD). Single mutants of gtl1 and its homologs show no obvious phenotypes in size of leaves and other organs, but double mutants show dwarf phenotypes under continuous light (LL). This dwarf phenotype is enhanced under SD. gtl1 mutant does not show an obvious ploidy phenotype in LL, but display increased ploidy in SD. Based on our progress in these studies, we will discuss how organ size is controlled in plant development.
