Expression And Function Of Inositol Metabolism Key Enzyme Gene In Poplar

Abiotic stress such as drought,high salinity,heavy metal stress on plant growth metabolism,in the long-term evolutionary process,the plants produced osmotic regulation and anti-oxidation regulation mechanism to cope with these abiotic stresses.Recent findings,in the process of plant anti-adversity,inositol play an important role.Inositol can be involved in the regulation of cell osmotic potential,the synthesis of cell membrane,cell signal transmission process as well as the accumulation and utilization of auxin to cope with stress.In the process of inositol metabolism,myo-inositol-1-phosphate synthase(MIPS)is the speed limit enzyme of inositol biosynthesis,myo-inositol oxygenase(MIOX)is the key enzyme catalytic decomposition of inositol.At present,the study of metabolism of inositol key enzyme is more of herbaceous plants such as arabidopsis,rice,but the inositol metabolic key enzyme genes of woody plant reported very little.1.In this study,we cloned PdMIPS and PdMIOX sequences through RT-PCR from Populus davidiana,we also compare the amino acid sequence they encoding and analyze evolutionary tree.2.Using Real-time quantitative PCR analyze the gene expression level of PdMIPS and PdMIOX,about the response model of high salt,drought and heavy metal Cu2+ and ABA treatment.The results showed that NaCl,PEG,ABA and Cu2+ can induced a high level expression of PdMIPS genes;NaCl and PEG can induce PdMIOX gene expression,while Cu2+ inhibiting PdMIOX gene expression,PdMIOX gene expression level under the ABA treatment is not obvious.These results suggested that poplar MIPS and MIOX genes plays an important role in poplar adversity stress regulation.3.Using Nicotiana benthamiana epidermal cells transient expression system for PdMIPS protein subcellular localization,the results showed that the protein located in the cytoplasm.4.We build PdMIPS and PdMIOX over expression vector respectively.Then transformed the Populus davidiana by leaf-discs-method.Compared with wild type,the overexpression of transgenic PdMIPS plants showed high salt tolerance.Transgenic PdMIOX gene poplar phenotypes are further identified.5.The transgenic PdMIPS and wild type poplars were treated with NaCl water,result showed that SOD activity of transgenic plants is higher than the wild type,and can inhibit the increase of MDA,the relative conductivity is lower than the wild type.We can deduced that PdMIPS played an important role in plant stress resistance.