Huang Y-W, Tsai Y-J, Cheng T-C, Chen J-J, Chen F-C
Graduate Institute of Plant Science, National Pingtung University of Science and Technology, Pingtung, Taiwan.
Department of Plant Industry, National Pingtung University of Science and Technology, Pingtung, Taiwan.
Genet Mol Res. 2014 Nov 12;13(4):9543-57. doi: 10.4238/2014.November.12.3.
Phalaenopsis orchids have been regenerated by inducing protocorm-like bodies (PLBs) from etiolated leaf sections. However, the physiological and molecular mechanisms of secondary PLB development and subsequent proliferation have not been explored. Bisectionally cutting primary PLBs resulted in more secondary PLBs at 5 weeks, suggesting an embryogenic stem cell property imposed by wounding of primary PLB tissues. The ethylene precursors ethephon and 1-aminocyclopropanecarboxylic acid and the ethylene perception inhibitor silver nitrate increased PLB formation, while aminoethoxyvinylglycine decreased PLB formation. Ethylene content in wounded PLB explants increased over culture time in media containing ethylene precursors or inhibitors. mRNA levels of PhACS2, PhACS3, and PhACO were increased by ethephon and decreased by ethylene inhibitors. Expression of genes in the ethylene signaling pathway was enhanced following ethylene-precursor treatment and was mitigated by ethylene inhibitors during PLB proliferation. Transcription of PhETR and PhEIN3, as well as PhERS, PhCTR, and PhGTP, was significantly increased 12 h after ethylene treatment. Ethylene and physical wounding stimulated secondary PLB formation in Phalaenopsis, probably through ethylene biosynthesis and signal transduction.
通过从黄化叶片切片诱导类原球茎（PLB），已实现蝴蝶兰的再生。然而，二级PLB发育及后续增殖的生理和分子机制尚未得到探索。在5周时，将一级PLB进行二分切割会产生更多的二级PLB，这表明一级PLB组织受伤会赋予其胚胎干细胞特性。乙烯前体乙烯利和1-氨基环丙烷羧酸以及乙烯感知抑制剂硝酸银会增加PLB的形成，而氨基乙氧基乙烯基甘氨酸会减少PLB的形成。在含有乙烯前体或抑制剂的培养基中，受伤PLB外植体中的乙烯含量随培养时间增加。乙烯利会使PhACS2、PhACS3和PhACO的mRNA水平升高，而乙烯抑制剂会使其降低。在PLB增殖过程中，乙烯前体处理后乙烯信号通路中的基因表达增强，而乙烯抑制剂会使其减弱。乙烯处理12小时后，PhETR和PhEIN3以及PhERS、PhCTR和PhGTP的转录显著增加。乙烯和物理创伤可能通过乙烯生物合成和信号转导刺激蝴蝶兰二级PLB的形成。
