Study On The Mechanism Of The Seed Desiccation Tolerance And Dormancy Regulated By A DOG1 Interaction Protein

Seed germination is the foundation of plant growth and development.Seed development will experience fertilization,morphogenesis,maturation and drying process.The establishment of seed desiccation tolerance has an important influence on the germination in the next stage.The phenomenon that seeds with normal germination vigor cannot germinate under suitable conditions is called dormancy.In agricultural production,if the dormancy is too strong,it will affect the germination speed and uniformity,and if the dormancy is too weak,it will lead to early germination,or even germination before harvest,reducing the yield and quality.Therefore,it is of great significance to study the mechanism of seed desiccation tolerance and seed dormancy so as to improve seed quality through molecular breeding.DOG1(Delay of Germination 1)is the main gene controlling dormancy in Arabidopsis.The gene is specifically expressed in developing seeds,and its expression level determines the degree of seed dormancy.However,the mechanism by which DOG1 regulates seed dormancy is still largely unknown.In our previous study,we found a gene with similar expression pattern to DOG1,which was also expressed in seeds during seed maturation,and its expression was induced by osmotic pressure,suggesting that it may be involved in the establishment of seed desiccation tolerance and dormancy.Through the analysis of protein-protein interaction,we found that there is interaction between them.The Protein encoded by this gene is called DIP(DOG1 Interaction Protein).We further analyzed how DIP interacts with DOG1 to regulate desiccation tolerance and seed dormancy through phenotypic analysis of transgenic plants,biochemical and genetic analysis,and explored the relationship between seed dormancy and seed desiccation tolerance.Here are our main findings:1.According to the germination rate test of dog1-3 and dip mutant seeds,we found DIP can promote the germination.2.Through the hormone sensitivity experiments of dog1-3 and dip mutant seeds,we found DIP and DOG1 are not specifically involved in ABA / GA signaling pathway to regulate seed dormancy.3.DIP was induced by osmotic pressure.We analyzed the desiccation tolerance of dog1-3 and dip mutants.We found that DIP promoted the establishment of desiccation tolerance,while DOG1 inhibited it.DOG1 can negatively regulate the expression of DIP.Therefore,DOG1 may be located in the upstream process of regulating seed drying tolerance establishment.4.By analyzing the expression of DOG1 protein in dip mutant seeds,it was found that DIP could inhibit the expression of DOG1 protein,thus regulating seed dormancy.5.By analyzing the homologous proteins of DOG1 and DIP in soybean and their interaction,we found that the protein encoded by DOG1 homologous genes reserved DOG1 conservative domain in soybean,and there was also interaction between DOG1 and DIP homologous proteins.Therefore,we speculate that the function of DIP homologous genes in soybean is conservative.In conclusion,DIP is a protein expressed during seed maturation,which can promote the establishment of seed desiccation tolerance,and regulate the accumulation of DOG1 protein in seeds by interacting with DOG1,and then regulate seed dormancy.These results reveal the new mechanism of DOG1 regulating seed dormancy,and provide a new explanation for the relationship between seed desiccation tolerance and seed dormancy at the molecular level.