Identification And Functional Analysis Of The Regulatory Genes At The Early Stage Of Fruit Development In Tomato

Tomato is an important vegetable with good economic value and an ideal model system for fleshy fruit development,which is cultivated in the world wide.The fruit development influences tomato production and quality directly,thus it is necessary to study the mechanism of the fruit development.The cytological observation showed that there are more cell layers in ovary wall of 2 DPA than that of 0 DPAe and 1 DPA,suggesting that the cells in ovary wall started to divide at 2 DPA.The ovary wall significantly thickened at 5 DPA.Besides that,the cell volume in mesocarp of 5 DPA increased,indicating that 5 DPA was a time point when cell expansion started to occur.For the ovary wall and ovule of four developmental stages,we extracted RNA to construct RNA sequencing libraries and sequence.The results indicated that genes displayed the dynamic expression pattern at four developmental stages in two distinct tissues.Some genes related to phytohormone biosynthesis,phytohormone transport,phytohormone response have been identified during early fruit development.On the basis of RNA-seq data,Solyc01g100510,Solyc05g005090,Solyc06g074120,Solyc09g011380 and Solyc11g069890,which were specially expressed in the tomato fruit,were selected to identify their functions.CRISPR/CAS9 was used to edit genes and transform tomato.We have obtained some T1 transgenic lines from two genes,BL2(Solyc06g074120),TKN3(Solyc05g005090).The transgenic plant fruits exhibited the phenotypes different from the wild type plant fruit.We have systematically analyzed the interaction among tomato TALE proteins.The results suggested that KNOX proteins can have different BELL partners,which may lead to diverse combinations with different activities and regulate many aspects of plant development.In conclusion,we clarified the dynamic regulation during tomato early fruit development and found some critical regulatory genes.In addition,the TALE family members were found to play crutial roles in tomato fruit development via interacting with other proteins.