Matsubayashi Y, Takagi L, Omura N, Morita A, Sakagami Y
Laboratory of Bioactive Natural Products Chemistry, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan.
Plant Physiol. 1999 Aug;120(4):1043-8. doi: 10.1104/pp.120.4.1043.
Dispersed zinnia (Zinnia elegans) mesophyll cells cannot differentiate into tracheary elements (TEs) at low cell density conditions even if auxin and cytokinin are present in the medium, indicating the involvement of intercellular interactions during the initiation and/or subsequent progresses in TE differentiation. When zinnia cells were incubated at a low density (2.5 x 10(4) cells mL(-1)) in TE-inductive medium in the presence of various concentrations of phytosulfokine (PSK)-alpha, which was originally identified as an intercellular signal peptide involved in cell proliferation, TE differentiation was strongly stimulated in a dose-dependent fashion; more than 35% of the living cells differentiated into TEs by 5 d of culture in the presence of 10 nM PSK-alpha. Enzyme-linked immunosorbent assay and mass spectroscopy confirmed that cultured zinnia cells produce nanomolar levels of PSKs under inductive conditions. These results suggest that PSK-alpha is a factor responsible for TE differentiation of zinnia mesophyll cells.
即使培养基中存在生长素和细胞分裂素,分散的百日草(百日草)叶肉细胞在低细胞密度条件下也不能分化为管状分子(TEs),这表明细胞间相互作用参与了TE分化的起始和/或后续进程。当百日草细胞在含有不同浓度植物硫肽激素(PSK)-α的TE诱导培养基中以低密度(2.5×10⁴个细胞/mL⁻¹)培养时,PSK-α最初被鉴定为参与细胞增殖的细胞间信号肽,TE分化以剂量依赖的方式受到强烈刺激;在存在10 nM PSK-α的情况下,超过35%的活细胞在培养5天时分化为TEs。酶联免疫吸附测定和质谱分析证实,培养的百日草细胞在诱导条件下产生纳摩尔水平的PSKs。这些结果表明,PSK-α是百日草叶肉细胞TE分化的一个相关因子。