Study On The Relationship Between The Key Gene Of Ethylene Synthesis ZjACO And Related Regulatory Genes With The Fruit Ripening Of “Gou Tou Zao”

Jujube has high economic value and wide cultivation area,and is an important part of the agricultural economy.The quality of jujube fruit directly affects its economic value,and the fruit maturity is closely related to the quality of jujube fruit.Ethylene is clearly recognized as a major factor in regulating fruit ripening.At present,ethylene synthesis-related genes and ethylene receptor genes have made important progress in the regulation of fruit ripening,but the molecular regulation mechanism involved in fruit ripening is still unclear.In this study,the fruit of the "Gou tou zao" in Yanchuan,Shaanxi Province was used as the material to analyze the changes of the color of the peel in seven different growth and development stages,and to help determine the maturity of the jujube fruit.The ZjACO1 gene was cloned in the “Gou tou zao”,and the two homologous genes ZjACO2 and ZjACO3 were compared in genome database and their promoter sequences were analyzed to predict the potential related genes.The expression levels of these genes in seven different stages of the development of the “Gou tou zao” fruit were detected.The main experimental results are as follows:1.Jujube fruit color difference analysis shows that during the growth and development of the “Gou tou zao”,the change of the color of the peel mainly shows the process of changing from cyan(blue-green superimposed color)to jujube red(red-yellow superimposed color),indicating that the mature appearance of the “Gou tou zao” fruit changes from cyan to magenta.2.The detection of ZjACO1,ZjACO2 and ZjACO3 in seven different developmental stages of jujube fruits showed that the relative expression of ZjACO1-ZjACO3 was positively correlated with fruit maturity,and ZjACO1 was the most relevant.In order to verify the function of ZjACO1 gene in 7 different growth and development processes of jujube fruits,agrobacterium transformation method was used,and established a genetictransformation system,then the transgenic callus of “Gou tou zao” was induced.3.The results of gene expression of ethylene receptor genes ZjERS1,ZjERS2,ZjETI,ZjETR1 and ZjETR2 in 7 different developmental stages of jujube fruits showed that ZjETR1 was not detected in the fruit of “Gou tou zao”,and ZjETR2 was positively correlated with jujube fruit maturity;ZjERS1,ZjERS2 and ZjETI were negatively correlated with fruit maturity,suggesting that ZjETR2 is a potential receptor gene for ethylene to regulate jujube ripening.4.In this study,the 2000 bp sequence of ZjACO1,ZjACO2 and ZjACO3 genes was searched from the jujube genome as the corresponding promoter region,and the cis-acting elements were predicted analyzing.It showed that it mainly contained ethylene response element ERE,salicylic acid response element TCA-element,auxin response element TGA-element,drought response element MBS and HD-zip etc.Since ERF is a transcription factor that specifically responds to ethylene signaling,HD-Zip and TCP family genes are transcription factors involved in stress,So ERF,HD-Zip and TCP may be potential regulators of ACO gene expression transcription factors.5.The results of gene expression of ERF,HD-Zip and TCP in 7 different developmental stages of jujube fruits showed that ZjTCP19 was highly correlated with the fruit ripening of “Gou tou zao”;ZjHD-Zip1 and ZjHD-Zip6 were significantly positively correlated with fruit ripening.(P ? 0.01),ZjHD-Zip2 and ZjHD-Zip4 were significantly negatively correlated with fruit ripening(P ? 0.01),ZjERF1 was significantly positively correlated with the maturity of the “Gou tou zao” fruit(P?0.01),and the ripening period decreased slightly.It is speculated that ZjERF1 is related to the regulation of ethylene maturity in the fruit of “Gou tou zao”;ZjERF3 is significantly negatively correlated with the fruit ripening of “Gou tou zao”(P?0.01).It is speculated that ZjERF3 may be involved in delaying the regulation of the fruit ripening of “Gou tou zao”.In summary,during the development and maturity of jujube fruits,the expression of ZjACO1,ZjACO2 and ZjACO3 genes were positively correlated with the maturity ofjujube fruits;the expression of ZjETR2 gene was positively correlated with the maturity of jujube fruits,and the expression of ZjERS1 and ZjETI genes were negatively correlated with the maturity of jujube fruits;ZjTCP19,ZjHD-Zip1,ZjHD-Zip6 and ZjERF3 may regulate the ripening of the fruit of the “Gou tou zao” by participating in the synthesis of ethylene or ethylene signal transduction.The fruit ripening process is not regulated by a single factor.This study preliminarily showed that the maturation of the“Gou tou zao” may affect the synthesis of ethylene by regulating the expression of ACO gene,and regulate the expression of ethylene receptors,as well as transcription factors regulating ethylene biosynthesis,or it is involved in ethylene signal transduction to regulate fruit ripening.In this study,the mechanism of maturation of “Gou tou zao” fruit was studied through gene regulation strategy,which provided a reference for the storage and preservation of “Gou tou zao” fruit,and provided a theoretical reference for the selection of high quality “Gou tou zao” varieties by molecular breeding methods.