Study On Molecular Mechanism Of The Transcription Factor ABI3 Regulating Seed Dormancy And Germination In Arabidopsis Thaliana

Seed dormancy is a complex adaptive trait that helps plants germinates at a suitable time to ensure that they complete their life cycle in a suitable growing season.Abscisic acid is a key hormone identified early to induce seed dormancy during seed development and maturation,and it is also involved in regulating the response of seed dormancy release and germination after dispersal to environmental factors.The transcription factor ABI3 downstream of ABA signaling pathway is the key gene regulating seed dormancy and germination,and plays a central role in ABA signaling pathway.However,it has long been unclear whether ABI3 regulates DOG1 expression.Our previous study found that auxin signaling pathway downstream transcription factors ARF10,ARF16,ARF17 regulate seed dormancy by activating the expression of DOG1,a key regulator of seed dormancy.Sequence analysis showed that ABI3,ARF10,ARF16 and ARF17 belonged to the B3 family proteins,and contained transcription factors of plant-specific B3 domain.Therefore,we studied whether ABI3 also regulated seed dormancy by activating the expression of DOG1.The main research results are as follows :(1)The expression levels of ABI3 gene and DOG1 gene in seeds of ABI3 overexpression,abi3 mutant and wild type(COL-0)Arabidopsis were detected by real-time fluorescence quantitative analysis.The results showed that the expression level of DOG1 gene in ABI3 overexpression Arabidopsis was higher than that in wild type,while the expression level of DOG1 in abi3 mutant Arabidopsis was lower than that in wild type,indicating that ABI3 regulates the expression of DOG1.(2)Yeast single hybridization results showed that ABI3 could bind to the promoter fragment of DOG1 gene containing RY element.ABI3 cannot bind to the promoter fragment of DOG1 gene when RY element sequence is mutated,indicating that RY element is necessary for this binding.(3)Construction of transgenic Arabidopsis thaliana with wild-type DOG1 promoter-driven GUS(DOG1:Promoter::GUS)and DOG1 promoter-driven GUS(DOG1:Promoter::GUS)with RY element mutation;Construction of hybrid homozygote between ABI3 overexpression A.thaliana and the two transgenic A.thaliana(ABI3-myc-OE/DOG1:Promoter::GUS and ABI3-myc-OE/m DOG1:Promoter::GUS).The GUS staining results of the seed embryos of the above materials showed that when the RY element was mutated,GUS was almost not expressed in either wild type or ABI3 overexpression A thaliana seeds.It indicates that RY element is necessary for DOG1 expression.In summary,ABI3 in A thaliana regulates its expression by directly binding to the RY element in the promoter region of DOG1,thereby regulating seed dormancy.