Cloning Of Gai Gene And Function Analysis Of Dwarf-Related Genes In Pear Dwarfing Mutant

A pear dwarfing mutant was found in the descendant of the Pyrus. ussuriensis Maxim in Yanbian. This research focused on the dwarf mechanism with the pear dwarfing mutant as experiment material. The gene which encoding DELLA named PuGAI was cloned and studied the function of dwarf-related genes,which can lay foundation to the dwarf mechanism. The results are showed as follows:We cloned the PuGAI/PbGAI genes successfully with the pear dwarfing mutant and Pingguoli as templates, which have the typical DELLA protein structure domain. PuGAI contains a ORF encoding584amino acids with a1905bp full-length genome and the other one contains a ORF encoding634amino acids with a1946bp full-length genome. The sequences of PuGAI/PbGAI genes shared a high homology of99%with GAI gene in Pyrus x bretschneideri cultivar (Accession NO. JF304103) and Pyrus betulifolia cultivar Bunge (Accession NO. JF304102) based on the analysis with GenBank database, while shared98%similarity with GAI gene in Malus x domestica(Accession NO. FJ535245、 DQ007885、GQ384423). Besides the overexpression vectors were also established successfully with this a couple of genes.The expression quantity of PuGA20-ox、PuGAI、PuRGL1and PuRGL2dwarfing mutant was measured with semi-quantitative PCR based on leaves sampled every two weeks in order to investigate the relevance between expression quantity of dwarf-related genes with net growth in the pear dwarfing mutant and the sensitivity of pear dwarfing mutant to exogenous plant hormones. The results showed that expression quantity of PuGA20-ox was much lower than the PuGAI、PuRGLland PuRGL2,which maight because of synthesis decreased obviously by themselves. Moreover, branch treated with250mg-L-1GA3had a significant total net growth, which indicates that the dwarf of pear dwarfing mutant was sensitive to exogenous spraying GA and maybe have some relationship with GA20-ox gene or inherent GA of synthesis retardation.Besides we also studied the gene function of PuGA20-ox and PuRGL1gene based on tobacco genetic transformation experiment, which firstly confirmed the genes has successfully transformed to the tobacco genome.In addition, it was obviously observed, form the apparent morphology transformation of tobacco, the dwarf of the transformed tobacco with PuGA20-ox compared with the negative control.