Abstract
Plant organ growth is regulated by two distinct processes, first, the cell number which is controlled by cell proliferation, and second, the size of individual cells, which is regulated by cell expansion and cell growth. In Arabidopsis, various studies have shown a strong positive correlation between cell size and cell ploidy. In this respect, we have previously identified GT-2-LIKE1 (GTL1), a member of the GT2 trihelix transcription factor family, as a repressor of ploidy-dependent cell growth in trichomes. GTL1 is a nuclear protein, and further expression analysis revealed that GTL1 is expressed during late developmental stages of cells throughout the plant, suggesting that GTL1 might function as a general transcriptional regulator of plant cell growth. To confirm this experimentally, we are now using ectopic cell- and tissue-specific promoters to assess the potential role of GTL1 in controlling growth, ploidy and size of plant cells.
