Functional Analysis Of Gibberellin Receptor CsGID1from Newhall Navel Orange

In rensent years, the gibberellin insensitive dwarf gene GID1a recpetor of GA, become a hot research point. It has been researched in many plants, such as Arabidopsis、 Rice、Poplar、Cotton and Grapes, but we haven’t seen any report from citrus. To get know the function of the gibberellin recpetor gene GID1in Citrus, the gibberellin receptor gene CsGID1was cloned from Newhall Navel Orang, and then transferred into tobacco, by the commony trangenic technology. The transgeneic tobacco was subjected to paraddin sections, subcellular localization for functional analysis and validation of CsGID1, and to photosynthetic net rate measurement by the CIRAS-2photosynthesis system. Furthermore, the expression of this gene was analyzed by real-time quantity PCR. The main results show as follows:1. Through Blastn analysis, it was found that the sequence similarity between the target, with grape （AFG17072.1） and Arabidopsis GID1（XP₀02874383.1） were81%and79%respectively. Through Blastx analysis, the highest hit was the gibberellin receptor gene GID1of Upland Cotton.2. In this study, the main vein of tobacco leaves was used as reaserch the material. The differences between the transgenic and control plants via paraffin section were observed and compared. The results indicated that leaves’main vein lignin of the transgenic plant catheter was much more and arranged closer but more irregular compared with that in control plants. The results of subcelluar localization indicated that CsGID1with GFP fusion protein expressed in the cytoplasm and the cell nucleus.3. By measuring the plants height, chlorophyll content, net photosynthetic rate of plants under the different hormone treatment, it was indicated that the plant height and net photosynthetic rate of the GA3treatment transgenic positive plants were the highest, however, the chlorophyll content （1.55±0.09mg/g）was the least; as for the paclobutrazol treatment transgenic positive plants, the plant height was the shortest, but the chlorophyll content（1.71±0.15mg/g）and the net photosynthetic rate were higher.4. The expression of the CsGID1gene in transgenic tobacco was analyzed by qPCR. The results declared that the expression level of CsGID1in transgenic tobacco was the highest, in plant under GA3treatment transgenic plants were less than that in transgenice plants, but in plant under paclobutrazol treatment transgenic plants was the least.