Cloning And Functional Analysis Of Defensin And Jasmonic Acid Carboxyl Methyltransferase Gene From Perilla Frutescens

Perilla frutescens has a history of planting in China for about 2,000 years and is a common edible and medicinal plant.Perilla leaves,stems and fruits can be used as medicines and have good antibacterial activity.Plant defensins are a major member of the antibacterial peptide family and an important part of the plant's innate immune system.They are structurally similar,but the sequence differences are large,which determines the diversity of their functions.Although almost every plant has a series of genes that encode defensins,many are ineffective against specific pathogens,causing plants to become susceptible to disease.Therefore,in-depth study of the nature of plant defensins in plants and the exact role of defensins,and the integration of these data,can provide a reference for the design of resistance genes for specific pathogens.Jasmonic acid carboxyl methyltransferase(JMT)is a key enzyme in the biosynthesis of plant jasmonate.By regulating the concentration of jasmonic acid and its derivatives,JMT plays an important role in plant defense and development and various stress responses.Therefore,the defensin and jasmonic acid hydroxymethyltransferase genes from perilla seeds are applied to improve crop varieties,and in theory have certain food safety and good resistance.In this study,the genes of perilla defensin and jasmonic acid methyltransferase were studied by cloning and expression analysis of perilla defensin and jasmonic acid hydroxymethyltransferase gene,and constructing plant expression vector for genetic transformation.The main findings are as follows:1.Gene cloning resulted in 7 perilla defensin genes,named PfDEF1-PfDEF7.They are all class I plant defensins and are similar to Arabidopsis thaliana AtPDF2.Tissue-specific analysis revealed that PfPDF1,PfPDF2 and PfPDF4 were expressed in stems,leaves,flowers and seeds,PfPDF3 was expressed in leaves and seeds,and PfPDF5,PfPDF6 and PfPDF7 were only expressed in seeds.Genetic transformation yielded transgenic rapeseed of PfDEF2.2.Gene cloning obtained a jasmonic acid hydroxymethyltransferase gene,named PfJMT.The relative expression of PfJMT in roots and stems of Perilla was the lowest,leaves and flowers was slightly higher,5 days after flowering was the highest,and it was gradually down-regulated with the development of seeds.This indicates that JMT plays an important role in seed development.PfJMT expression was significantly down-regulated in Perilla root and leaf tissues treated with MeJA and SA.This result supports the theory that JMT may not directly participate in defense responses,but indirectly participate in plant defense by regulating JA levels.Genetic transformation yielded PfJMT transgenic tobacco.