Expression of rice promotes cell proliferation, leading to enhancement of growth in transgenic tobacco.

An increase in plant biomass production is desired to reduce emission of carbon dioxide emissions and arrest global climate change because it will provide a more source of energy production than fossil fuels. Recently, we found that forced expression of the rice gene increased aboveground growth by . 2-fold in the transgenic plants. Here, we created transgenic tobacco plants harboring the rice driven by the maize promoter (UbiP::) or cauliflower mosaic virus 35S promoter (35SP::). In 35SP:: and UbiP:: transgenic tobacco plants, the leaf length and size were increased compared with control plants, leading to an increase of aboveground growth (dry weight) up to 2-fold at the early stage of seedling development. Conversely, leaf physiological traits, such as photosynthetic capacity, stomatal characteristics, and chlorophylls and RuBisCO protein contents, were similar between the transgenic and control plants. Flow cytometry analysis indicated that the transgenic plants had enhanced cell-proliferation especially in seedling root and leaf primordia. Microarray analysis revealed that genes encoding transcription factors, such as GIGANTEA-like, were more than 2-fold up-regulated in the transgenic plants. Although the mechanism underlying the increased growth has yet to be elucidated, this strategy could be used to increase biomass production in cereals, vegetables, and bio-energy plants.