Study On Funtion Of MurE Genes And Its Molecular Mechanism In Regulating Chloroplast Development

MurE is a key enzyme for peptidoglycan synthesis,which is ubiquitous in plants at various stages of evolution,and play important roles in chloroplast division and development.Previous studies have found that the MurE gene regulates chloroplast division in bryophytes,and participates in chloroplast development in the angiosperm Arabidopsis.Therefore,study on functional conversion mechanism of MurE is of great significance to clarify the origin and evolution of chloroplasts.For analyzing the function of MurE genes in plants at different evolution stages,the MurE genes from the bryophyte Physcomitrella patens,the fern Selaginellae Moellendorfii and the gymnosperm Picea abiese were transformed into Arabidopsis atmure1 mutant,respectively,and phenotype of transgenic plants was identified.Function complementation experiments showed that the Pp MurE gene of P.patens only regulates chloroplast division and does not participate in the development of chloroplasts;the S.moellendorfii Sm MurE protein is located in the chloroplasts,and does not participate in the regulation of chloroplast development;the Pa MurE gene of P.abiese regulates the development of chloroplasts,indicating that the functional conversion of MurE gene may occur in the evolutionary stage of gymnosperms.For exploring the mechanism of MurE gene regulating chloroplast development,transcriptome sequencing was performed on the atmure1 mutant,which showed that the knockout of At MurE gene caused changes in the expression of 3041 genes.The differentially expressed genes were mainly annotated to the ribosome biogenesis process of eukaryotes,phenylpropane biosynthesis pathway,photosynthesis,photosynthesis-antenna protein,plant-MAPK signal transduction and plant hormone signal transduction pathway,indicating that the functional mechanism of MurE gene is closely related to these pathways.According to the prediction of transcriptome data,interaction of At MurE with At FLN2,At TRANS11 and At PRIN2 proteins was confirmed by yeast two-hybrid and Bi FC,suggesting that At MurE protein specifically binds to these proteins to form a complex and to regulate transcription of some chloroplast genes,thereby participating in the development process of chloroplast.The results provide an experimental basis for exploring the functional conversion mechanism of MurEs,and important reference value for further study on the molecular mechanism of chloroplast development regulated by MurE.