Characterization Of Gibberellin Receptor And Aquaporin Genes In Galega Orientalis

Leguminosae Galega Genus, Galega orientalis is an important perennial legume forage, with greateconomic and ecological purpose. Improve forage biomass and resistance is the main target of foragebreeding. Based on the demands in selection and utilization of excellent genetic resource, gibberellinreceptor and water channel protein was selected for gene function analysis and transgenic research.The main results of this study are as following:1. In present of GA3, GoGID can interact with Arabidopsis DELLA proteins by YeastTwo-Hybrid system. Complementation with genetic strategies showed that GoGID can partly restoredmutant gid1ac and completely restored mutant gid1ab. These results suggested that GoGID a dedicatedgibberellin receptor can partly replace AtGIDs.2. The coding region of GoGID was inserted into the Binary expression vector pBI121toconstruct the recombined vector pBI121-GoGID-GUS. The recombinant vector was transformed intoArabidopsis by floral dip method. The height, fresh weight, dry weight and seeds yield in transgenicArabidopsis lines were increased compared with control. And more important, the transgenic plantsexhibited90%-160%higher in dry biomass yield than control.3. An alfalfa (Medicago sativa) genotype Zhongmu NO.1was used for Agrobacterimtumefaciens-mediated transformation to produce transgenic plants. Both transgenic and wild-type alfalfaplants were vegetatively propagated using shoot cutting. The biomass of transgenic alfalfa GroupⅠ、GroupⅡlines were increased by8%-46%than the control, GroupⅢ lines had similar dry weight withcontrol, but had higher leaf/stem ratio.4. A cDNA sequence homologous to AQP gene family was cloned based on an EST from G.orientalis salt-induced SSH cDNA library. This gene was encoded289amino acids, highly homologousto PIPs genes, and belonged to PIP1subfamily by phylogenetic tree analysis. The corresponding genewas designated as GoPIP1(Genbank accession no. HM991477).5. Quantitative RT-PCR analysis results showed that the expression level of GoPIP1was higherin the root than in the leaf and stem. Salt stress and PEG treatment induced GoPIP1expressionsignificantly and rapidly. Subcellular localization analysis showed that GoPIP1was localized in plasmamembrane. The transgenic plants had a higher rosette/root ratio, and had higher transpiration ratecompared with control under normal condition. In salt condition, there was no difference in phenotypeand ion content between transgenic lines and the control plants, implying that GoPIP1was notfacilitated ion transport. Under dehydration treatment, the transgenic plants had faded leaves comparedwith the control, and had a lower rosette weight, rosette water content and root dry weight. Transgenicplants had higher transpiration rate and osmolality, and higher MDA content and lower proline content.The genes involved in ABA-biosynthesis and ABA-induction were increased in transgenic lines. Theseresutls showed that GoPIP increased drought sensitivity.