赤霉素响应的苎麻基因鉴定及其参与苎麻茎皮生长调节机制分析

Gibberelline Acids (GA) are important plant hormones. Our study showed that exogenous GA3 significantly influenced the growth of ramie’s bark. Compared with negative control, GA treated ramie reached mostly 186% in the stem length, and had finer fibres. Then, the expression profile of GA was achieved by RNA sequencing. And we found hundreds of candidate genes responded to the GA treatment. Among them, those involed in starch and sucrose metobolism and protein degradation pathway might have direct relationships to plant stem elongation growth. At the same time, the study of these two parthways could improve and supply more imformation to traditional GA signal pathway. The ramie variant sensitive to GA treatment is used as materials, and gene expression patterns which respond to the GA treating and take part in these two pathways are analysed and comfirmed by realtime fluorescence PCR and in situ hybridization technology. Then related full length genes are cloned to express proteins in procaryotes, which then are used to prepare specific antibodies. Subsequently, immunoblot, tissue immunofluorescence and immunoprecipitation are used to study the correlation between the gene function and the ramie bark growth at the protein or the enzyme level. The results of this study would contribute to the molecular mechanism discovery of GA regulating to the ramie bark growth, and provide theoretical basis to ramie’s directional breeding and to improve its fibre quality.

赤霉素（GA）是一类重要的植物激素，对多个性状稳定的苎麻材料外源喷施GA3表明GA对苎麻的茎皮生长有明显的调节。与对照相比GA能够促进苎麻茎杆的伸长达186%；同时对苎麻纤维的细度也有一定的影响。通过进一步表达谱测序，我们发现GA影响到多个基因的转录表达。其中GA对淀粉-蔗糖代谢及蛋白降解途径的影响可能与苎麻株高生长直接相关，对这两条信号通路中GA响应基因的挖掘同时有利于补充经典的GA信号传导途径。本课题选取GA3敏感的苎麻材料，用实时荧光定量PCR和原位杂交技术对参与这两条信号途径的GA响应基因做表达模式分析与鉴定。克隆有关GA响应基因的全长序列，制备特异性抗体。用免疫印记、组织免疫荧光、免疫沉淀等技术在蛋白及酶学水平研究基因与苎麻茎皮生长的相关性，以找出纤维性状决定因子。本研究的成果将有利于阐明GA促进苎麻茎皮生长的分子机制，为实现苎麻定向分子育种及其纤维品质改良提供理论基础。