Expression Of CaCyP2 And The Analysis Of Its Role In Pepper's Stresses Response

Cyclophilin family is a highly conserved protein family which has been found in lots of organisms.There are many functions of Cyclophilin families.Although lots of Cyclophilin genes in some model organisms are isolated and their functions are analyzed.Cyclophilin genes in pepper are rarely reported.A Cyclophilin gene in this paper is cloned from the pepper cDNA.Its structure,expression patterns under stresses and role in stresses response are analyzed.The results are follows:1.Specific primers are designed by Arabidopsis thaliana EST which homologous to Cyclophilin.The pepper cDNA library is screened by 96-well plates.cDNA of the Cyclophilin is cloned by the specific primers from the pepper cDNA library.The cDNA of the Cyclophilin is 1261 bp.Its ORF encodes a deduced protein which contains 208 amino acid residues.There are a transmembrane region of N-terminal and a CsA-PPIase2 domain in the deduced protein.The protein has high identity with Cyclophilins in tobacco and potato,and named it as CaCyP2.2.Total RNA is extracted from functional leaves of peppers treat by different stresses.And the total RNA is reverse transcribed into cDNA as template for fluorescent quantitative PCR.Studies shows that CaCyP2 relative expression level is down-regulated under SA treatment.The expression level is down-regulated under MeJA expect 6h.CaCyP2 relative expression level is up-regulated under Ethephon treatment.CaCyP2 is significantly induced in 1h when treated with ABA.There are no obvious differences of CaCyP2 expression level when treat by NAA,CdCl2 and cold(4?).CaCyP2 is down-regulated under R.solanacearum infection and significantly down-regulated under 45?.But the expression of CaCyP2 is induced under salt and drought.CaCyP2 has a certain lever of constitutive expression in root,stem,leaf,flower and green fruit of pepper.3.The over-expressing vector is constructed and the OE-CaCyP2 transgenic tobacco in T1 generation is cultivated to study the function of CaCyP2.Germination rate,solute sugar content and proline content of CaCyP2 are all higher than K326 when treated with NaCl and mannitol.Solute protein content and SOD activity of CaCyP2 are higher than K326 under salt.CaCyP2 is more sensitive to heat and R.solanacearum than K326.CaCyP2 induced the expression of NtPR2,NtSAM,Ntosmotin,NtGST,NtGPX,NtCA and NtCAT1.CaCyP2 down-regulated NtACC,NtPR4,TOBLTP,NtSOD,NtAPX1,NtAPX2 and NtRbohD expression.In summary,CaCyP2 in pepper is one of Cyclophilin family.It enhances salt and drought tolerance of transgenic tobacco.CaCyP2 improves the sensitivity to high temperature and R.solanacearum of transgenic tobacco.Its expression is affected by ABA,SA,JA and ET signal pathway.