Research On The Effect Of ABA Treatment Involved In Suberin Monomer Biosynthesis In The Russet Fruit Skin Of ’Dangshanjinsu’

The fruit color of ‘Dangshansuli’ is yellow-green,while that of the mutant‘Dangshanjinsu’is russet.Studies have shown that the formation of russet fruit peel is caused by the accumulation of suberin.This study explored the effect and regulation mechanism of exogenous ABA treatments on the suberin formation of ’Dangshanjinsu’peel.1.Measured the content of ABA in the peels of ’Dangshansuli’ and ’Dangshanjinsu’ in different periods.It was found that when the fruit was mature,after the suberin layer was completely formed,the content of ABA in the peel of ’Dangshanjinsu’ was significantly higher than ’Dangshansuli’.2.After studying exogenous ABA treatment of ’Dangshanjinsu’,the structure of the peel was observed to found that suberin layer was thickened,and the quantitative expression of suberin-related genes PbFAD,Pb CYP86A1,Pb CYP86B1,Pb HHT were increased significantly.The Suberin monemers were determinationed and found that Palmitic acid,Cinnamic acid,9,12-octadecadienoic acid(C18: 2),Linolenic acid(C18: 3),Hexadecanedioic acid,Octadecanedioic acid,Eicosanebioic acid were significantly increased.3.Transcriptomics analysis found that most of the KCS family genes involved in fatty acid elongation were repressed;CYP704C1,CYP72A219,FAR3,and CYP94A2 involved in the synthesis of suberin,were increased,and the expression of ECR1 involved in wax biosynthesis was repressed;Increased expression of multiple genes such as 4CL,CAD and POX family in the Phenylpropanoid Biosynthesis;In the pathway of plant pathogens interaction,the stomatal closure was controlled by regulating the CML family genes,and the defense-related genes were induced by regulating WRKY transcription factors.In the plant MAPK signaling pathway,the ABA pathway increases the adaptability of peel pressure by regulating the expression of PYL4 and PP2 C family proteins,and reduces the expression of MLP423;Increased PHO1 and transcription factor ERF1 gene expression in the ETH pathway;In Jasmonic acid(JA)pathways,the expression of b HLH transcription factors is mainly increased or decreased.Increased expression of multiple genes in the ABC transporter family involved in suberin monemers transport,especially the ABCG family.4.Metabolomics analysis found that the contant of unsaturated fatty acids such as C18:1,C18: 2,C18: 4,C20: 2,and C20: 4 and some C16,C18,C20 fatty acid were increased,while C20: 1,C20: 3 and C10,C12,C16 fatty acid were decreased after ABA treatment.5.Subcellular localization showed that the expression of PbFAD was located on the chloroplast;the full-length sequence of the PbFAD gene was obtained by cloning;it was found that the overexpression of PbFAD transgenic Arabidopsis plants increased the content of linolenic acid C18: 3.6.Cloning of the PbFAD gene promoter,and found that the sequences of ’Dangshansuli’and ’Dangshanjinsu’ promoters were different;using transient expression to inject tobacco,GUS staining results showed that there was a difference in promoter activity between’Dangshansuli’ and ’Dangshanjinsu’,and the promoter activity increased significantly after spraying ABA,while the promoter activity decreased significantly after spraying FD.