Study On MiSVP Homologus Gene Family Mining And Its Expression Pattern In Mango(Mangifera Indica L.)

SHORT VEGETATIVE PHASE(SVP)gene can inhibit flowering time,regulate flowering formation and development in plants.In this experiment,SiJiMi mango(multiple blooming for one year)and TaiNong Nol mango(one blooming for one year)were used as experimental materials to explore the molecular mechanism and expression pattern of SVP homologous genes in mango flowering regulation.Here are the results of the experiment:1.The full-length cDNA of four mango SVP homologues genes were cloned by RT-PCR and named MiSVPl,MiSVP2,MiSVP3 and MiSVP4.Sequence analysis revealed that the open reading frames(ORFs)of the four AiSVP genes were 675 bp,657 bp,684 bp and 591 bp,respectively,encoding 225,219,228 and 197 amino acids.2.Nucleotide homology analysis showed that the highest homology between MiSVP3 and MiSVP4 was 910%,a,nd the homology between MiSVP 1 and MiSVP2 was 90%.It can be seen from the results of phylogenetic tree that homologous proteins have been divided into two branchs,MiSVP1,AMiSVP3 and MiSVP4 belong to the same branch,MiSVP4 belongs to another branch.The homology of MiSVP3 and MiSVP4 is closer,and the homology between MiSVP1 and Glycine max is closer,MiSVP2 has closer homology with Daucus carota subsp.Sativus.3.The real-time fluorescence quantification technique(qRT-PCR)was used to analyze gene expression patterns of the four MiSVP genes in SiJi Mi and TaiNong Nol mangoes different tissues and different times during the period from flower bud differentiation to flowering was analyzed,as well as the treatment of mangoes with paclobutrazol,low temperature of 2?,drought and salt stress,and analysis of the expression of four mango MiSVP genes.(1)MiSVPl,MiSVP2,MiSVP3 and MiSVP4 were expressed in the stems,leaves and flowers of SiJi Mi mango and TaiNong Nol mango,as well as the leaves of young mango trees.Among them,in SiJi Mi mango the highest expression level were in leaves,followed by the stems,the least expressed part was the floral organ.However,in TaiNong Nol mango cultivars,the highest amount of gene expression were found in the mango leaves of young trees,followed by the stems,and the least expressed part was in mango flowers.The expression level of MiSVP3 in SiJi Mi mango and TaiNong Nol mango were significantly higher than those in other genes,and the expression level of MiSVP4 was the least.(2)In the mango flower bud differentiation period to flowering stage of expression analysis,The largest amount of expression of the four genes in SiJi Mi mango and TaiNong Nol mango leaves were both peaked in December,and followed by February.The expression level of MiSVP3 in SiJi Mi mango and TaiNong Nol mango were significantly higher than those in other genes,and the expression level of MiSVP4 was the least.(3)Treatment with 1000ppm paclobutrazol in SiJi Mi mango.The expression level in leaves and flowers of the four MiSVP genes was lower than that in control group,and the expression in stems were significantly more than that in control group.(4)The tender trees growing in ten months of SiJiMi mango were treated under 2 ??30%PEG and 300mmol/L NaCl separately,the expression level of MiSVP4 gene was very few,almost close to zero,and the changes of treatment and control were not obvious.After 2 ? hypothermia treatment,the expression level of MiSVP 1,MiSVP 2 and MiSVP 3 genes were all improved,and it has a certain persistence in the response process of resisting the low temperature.During 30%PEG treatment for 0?72 h,MiSVP1 and MiSVP2 genes were always at work,the effect of NIiSVP3 gene is weak after 48h.After 300mmol/L NaCl treatment,the expression of MiSVP3 was always more than that of other genes,and the function of all genes declined with the prolongation of time.4.Construction of four eukaryotic expression vectors pBI121-MiSVP-GUS of mango MiSVP genes,The extracted plasmids were transferred into Agrobacterium.