Regulation Of Ethylene Biosynthesis By SlAREB1 Mediated ABA During Tomato Fruit Ripening

As a model plant for studying fruit ripening,the ripening process of tomato fruit has always been a research hotspot.Abscisic acid(ABA)regulates tomato fruit ripening by mediating ethylene biosynthesis,and SlAREB1 is an important transcription factor that regulates the expression of downstream target genes in the ABA signaling pathway,and it can regulate tomato fruit ripening.Studies have shown that SlAREB1 interacts with NOR to mediate ethylene synthesis,thereby regulating tomato fruit ripening,but it may participate in and mediate the regulation of ABA on ethylene biosynthesis through multiple pathways.In this project,exogenous ABA was used to treat cherry tomato fruits in the green ripening stage to clarify the effect of ABA on tomato fruit ripening,and then by measuring the effect of ABA treatment on the expression of ethylene synthesis-related genes,it was clarified that ABA affects ethylene synthesis-related genes in tomato fruit ripening stage.and SlAREB1 gene expression induction rules,and then analyzed the interaction between it and SlAREB1 by yeast single-hybrid and double-luciferase experiments,providing direct evidence for revealing that SlAREB1 mediates ethylene biosynthesis.ChIP-Seq experiments were performed on the fruit to detect its downstream target genes and analyze the downstream regulatory network,aiming to provide a basis for improving the hormone interaction network during tomato fruit ripening,and to further elucidate the molecular mechanism of hormone signaling regulating postharvest ripening of tomato fruit.make fundamental contributions.Below are research findings:(1)Exogenous ABA can regulate the expression of genes related to ethylene synthesis.Exogenous ABA treatment can promote the deepening of tomato fruit color,softening and the increase of ethylene release,which clarifies its promoting effect on tomato fruit ripening.Through q RT-PCR experiments,it was found that SlAREB1 has an impact on tomato fruit ripening and is involved in the regulation of ABA on tomato fruit ripening;exogenous ABA may promote key genes in the ethylene synthesis pathway ACS2,ACS4,ACO1 and positively regulate ethylene biosynthesis The gene expression of regulatory factors Le FUL1,TAGL1,Le MADS-RIN,and CNR induces ethylene biosynthesis,thereby promoting the ripening of tomato fruit;it may also promote the biosynthesis of ethylene by inhibiting the gene expression of MADS1,a regulatory factor that negatively regulates ethylene biosynthesis.Synthesis,thereby promoting the ripening of tomato fruit.(2)SlAREB1 mediates the regulation of ethylene synthesis by ABA by activating the expression of ethylene synthesis related genes ACS2,ACO1,Le FUL1,and MADS1.The interaction between SlAREB1 and ACS2,ACS4,ACO1,Le FUL1 and MADS1 was preliminarily verified by yeast monohybrid technology.Then the yeast monohybrid results were verified again by double luciferase assay,and it was found that SlAREB1 interacted with ACS2,ACO1,Le FUL1 and MADS1.And can activate their transcriptional expression.This indicates that SlAREB1 mediates ABA regulation of ethylene synthesis by binding to ABRE elements in the promoter regions of ACS2,ACO1,Le FUL1 and MADS11,and then promotes the ripening of tomato fruits.Based on these results,a molecular model of SlAREB1-mediated ABA regulation of ethylene biosynthesis was constructed.(3)Analysis of the regulatory network downstream of SlAREB1.Through the analysis of ChIP-Seq results,a total of 972 peaks were obtained,mainly distributed in the intergenic and promoter regions.GO annotation and KEGG pathway analysis showed that the target sequence of SlAREB1 participated in the most biological processes and the least molecular function;and its main metabolic pathways were oxidative phosphorylation and photosynthesis pathways,and involved tomato Ethylene synthesis and signal transduction in fruit,gibberellin synthesis,brassinolide synthesis,cell wall,pigment and antioxidant properties.Based on the analysis of ChIP-Seq results,we initially constructed a model of SlAREB1 regulating tomato fruit ripening,which provided a theoretical basis for further exploring the mechanism of SlAREB1 and ABA on tomato fruit ripening.