| The effect of activator and inhibitor of the second messenger-mediated signal transduction system in animals was investigated to determine possible interactions with plant cell development. The somatic embryogenesis of rapid cycling Brassica rapa was initiated when immature seeds of different cultivars were cultured on Murashige and Skoog's medium containing 2.5mg/l of 2,4-dichlorophenoxyacetic acid. To determine whether protein kinase C-like isozymes were involved in the development of plant cells the physiological effects of phorbol esters and the distribution of PKC-like proteins were examined in three plant species. Development of adventitious shoots was significantly promoted by treatment with TPA. In contrast, treatment of mature somatic embryos with mTPA, a negative control of TPA, was effective in decreasing kinetin-induced adventitious shoot development. Antibodies raised against the α, β, δ and -PKC polypeptides were used to test for the presence of PKC in the zygotic embryo of Brassica rapa, Zea, mays, and Ginkgo biloba. Western blot analysis with anti-PKC antibodies identified three major bands of 34, 46, and 54 kDa in plant species. Moreover, protein expression and phosphorylation of stathmin-like protein was also investigated in plant species. A single 19 kDa protein was detected in rapid cycling Brassica rapa somatic cells by a 3038 polyclonal antibody prepared against a synthetic polypeptide of rat stathmin. Transgenic rapid cycling Brassica rapa was also used as a tool for studying the mechanism of hormone action in plant cells. |
