一个新的调控生长、开花和低温响应的基因功能研究

低温是限制牧草生长的主要逆境。我们曾从黄花苜蓿发现了一个未知功能新基因，它受低温诱导，过量表达后提高了转基因烟草生物量和抗寒性。其同源基因的蒺藜苜蓿突变体具有植株矮小、叶片小、开花时间提前等表型，因而将该基因暂命名为GFC。本项目拟获得表达MfGFC的转基因蒺藜苜蓿，鉴定转基因蒺藜苜蓿及gfc突变体的表型，筛选、鉴定MfGFC的互作蛋白，进一步筛选鉴定互作蛋白的突变体，比较该突变体与gfc突变体表型的异同。在此基础上，分析比较转基因蒺藜苜蓿、gfc突变体及互作蛋白突变体在基因表达 谱和生理生化等方面的差异，从而揭示MfGFC及其互作蛋白调控植物生长、开花时间和抗冷的机理。将MfGFC过量表达到柱花草中，以改良柱花草生物量和抗冷性。生物量、开花和抗寒性是3个重要农艺性状，本项目研究不仅有望揭示一个重要新基因的功能，具有重要的科学意义，所获得的提高生物量和抗冷性的转基因柱花草也有潜在应用价值。

Low temperature is one of the major environmental stresses limiting forage growth. It is important to understand the molecular mechanism of cold tolerance in forage plants. In our previous investigations a novel gene encoding an unknown protein was identified in Medicago falcata, a cold tolerant forage legume germplasm. Transcript of the new gene is highly induced by low temperature, while transgenic tobacco plants overexpressing the gene showed an enhanced biomass and cold tolerance. In addition, Medicago trancatula mutants by Tnt1 insertions showed a phenotype of smaller plant size and leaves with early flowering. Thus we named it GFC (growth, flowering time and cold responsive). The objective of this project is to study the function of MfGFC. MfGFC gene is to be overexpressed in M. trancatula to analyse phenotype in comparison to the gfc mutants as well as the wild type plants. MfGFC interaction proteins will be screened and identified using yeast two hybrid analysis, followed by confirmation with bimolecular fluorescence complementation (BiFC) assay and immunoprecipitation experiments. On the basis of the above studies, transcript profiling and biochemical and physiological changes will be analyzed in transgenic M. trancatula, mutants of gfc and GFC interaction proteins as compared with wild type plants for understanding of the key role of MfGFC and its interaction proteins in regulation of growth, flowering time and cold tolerance. In addition, transgenic Stylosanthes guianensis overexpressing MfGPC will also be generated for improving biomass and chilling tolerance.