Identification Of Polypeptide Hormones And Transcription Factors Related To Senescence Of Plant Leaves And Bioinformatic Analysis Of Downstream Signal Factors

Leaf senescence is the last important process of leaf growth and development.When leaves enter the senescence stage,photosynthesis will decline,chlorophyll,protein and other high molecular substances in mesophyll cells will decompose and redistribute to the organs with vigorous growth.In recent years,studies have shown that the timing of leaf senescence directly affects the material accumulation and quality of plants.Therefore,a systematic and in-depth study on leaf senescence is of great theoretical significance in developmental biology and also has key practical value in agricultural production.Leaf senescence is regulated by external factors(e.g.biotic stress)and internal factors(e.g.plant hormones).In recent years,a variety of studies have shown that polypeptides in plants can play a key role in the regulation of plant growth,development and stress resistance as important signal molecules.So far,studies have proved that many signal polypeptides exist in Arabidopsis.However,the function of these polypeptides,especially their regulatory function on leaf senescence,is not clear.Our research team has found that CLE14 polypeptide participates in the regulation of leaf senescence of Arabidopsis,which provides evidence for the regulatory role of polypeptide in leaf senescence for the first time.In order to further study the molecular mechanism of polypeptides regulating leaf senescence,in this study,we used Arabidopsis as the research material,through bioinformatics analysis and molecular biology research technology,systematically screened the polypeptides in Arabidopsis that play a regulatory role in leaf senescence.The results showed that there were 1,453 signal peptide coding genes in Arabidopsis.Through the interaction analysis of the identified peptide hormones with the polypeptide group data and transcriptome data,we identified 83 candidate genes encoding aging related signal polypeptides.Compared with the wild type,some leaves showed the phenotype of delayed senescence,which indicated that there were indeed signal polypeptides in the selected polypeptides.It laid a foundation for further analysis of the function of signal peptide coding genes in the process of leaf senescence and the mechanism of regulating leaf senescence.Tobacco is an important economic crop and model plant.As an important regulator of plant growth and development,transcription factors play an important role in the process of leaf aging.Therefore,it is of great significance to study the regulatory function of tobacco transcription factors on tobacco leaf senescence to improve tobacco quality.In this study,we identified 1,359 transcription factor genes in tobacco leaves.Through co-expression network analysis,21,35 and 183 transcription factor genes were identified as the early,middle and late tobacco leaf senescence response transcription factor genes,respectively.In addition,797,756 and 4,552 genes were predicted to be the targets of these transcription factors.The regulatory networks were constructed.The function and metabolic pathway of the transcription factor genes and their target genes were analyzed in order to provide clues for the research on the regulation of transcription factors on tobacco leaf senescence.