Faculty and research guide

Flower and Horticulture Laboratory

Takashi Nakatsuka (Tenure-track faculty members)

 Laboratory of Floricultural Science is studying on characterization of molecular mechanism of the important floral traits, including flower color, floral morphogenesis, flowering time, and vase life. Therefore, we are investigating them using culture practice, molecular biological and biochemical analyses, and tissue culture. These research will be used to develop novel culture system and new cultivars.

 Flower color is one of the most important traits in floricultural plants. Plant pigments, including anthocyanins (flavonoids), carotenoids, chlorophylls and betalains, accumulated in their petals are responsible for flower colors. Especially, anthocyanins are responsible for wide range of flower colors (red, orange, pink, purple and blue). We are studying on molecular mechanisms of flower color, color intensity and color pattern using Japanese gentians and cymbidiums. In addition, we are attempted the metabolic engineering by productions of transgenic floricultural plants. For example, we try to produce the transgenic floricultural plants accumulated betalain pigments.
 Nakatsuka et al. (2014) Plant Biotechnology 31: 389-399.
 Nakatsuka et al. (2013) Plant Cell Reports 32:1925-1937.
 Nakatsuka et al. (2013) Scientific Reports 3: 1970.

Double flowers are also popular trait for floricultural plants, and they are selected by conventional breeding. The identity of floral organ has been known as ABC model based on basic study using Arabidopsis thaliana and Antirrhinum majus. The deficiency of C-class gene leads to double flower phenotype, which converted stamen/pistil to petals. The double flower phenotypes of most floricultural plants are also contributed to the deficiency of C-class gene. In Japanese gentian, we identified two C-class genes, GsAG1 and GsAG2. Silencing of GsAG1 by virus-induced gene silencing (VIGS) was converted stamen into petal organs in Japanese gentians. We also are investigating on double flowers of common stock (Matthiola incana).
 Nakatsuka et al. (2016) Plant Cell Reports 35: 895-904.
 Nakatsuka et al. (2015) BMC Plant Biology 15: 182.

 Other than these above, we are also studying on control of flowering time and quality of vase life.