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September 1, 2009

Gene controlling plant cell growth discovered

Understanding how plant cells grow and develop is essential to achieving increases in the size and yield of crops, one of the fundamental goals of plant science research. While mechanisms governing plant cell growth are known to exist, the genetic origins of such mechanisms have remained unclear.

With their latest discovery, published in the journal The Plant Cell, research teams at the RIKEN Plant Science Center have marked a major step toward clarifying these origins. The research teams studied mutants of the Arabidopsi leaf trichome, a specialized epidermal cell that forms a small hair-like outgrowth on plants. Unlike earlier studies, the teams focused on later stages in the trichome developmental process, which are accompanied by rapid cell growth and branching.

In their experiments, the researchers discovered that by disrupting the gene encoding a novel protein, GTL1, trichome cells could be induced to grow to twice their normal size, indicating that GTL1 represses cell growth. By measuring the amount of nuclear DNA in young trichomes, they further determined that GTL1, unlike previously-identified growth regulators, functions to suppress DNA reduplication and cell growth entirely at the very last stage of development.

GTL1 is the first transcription factor to have been found to actively down-regulate the growth of plant cells. Its discovery constitutes a key step toward understanding the mechanisms of plant cell growth, offering new directions for research and promising further advances in agricultural production.

Contact

Keiko Sugimoto
Cell Function Research Unit
RIKEN Plant Science Center
Tel: +81-(0)45-503-9575 / Fax: +81-(0)45-503-9591

Jens Wilkinson
RIKEN Global Relations and Research Coordination Office
Tel: +81-(0)48-462-1225 / Fax: +81-(0)48-463-3687
Email: pr@riken.jp

GTL1 suppresses trichome cell growth

Figure 1: GTL1 suppresses trichome cell growth

In the loss-of-function mutants of GTL1 (gtl1 mutants), trichome cells grow further than wild-type since their cell growth is not down-regulated.

Role of GTL1 in trichome development

Figure 2: Role of GTL1 in trichome development

Only a small proportion of leaf epidermal cells, e.g. the one marked in blue, actually differentiate into trichomes and start cell growth. The GTL1 gene is expressed only at the last stage of trichome development to terminate its growth.