Preliminary Study On Arabidopsis Transcription Factor ERF014 Regulating The Formation Of Petal Conical Cells

During the development of plants,organs and cells can adjust the corresponding morphology,size and other characteristics to adapt to changes in the external environment.Studies have found that the cells on the adaxial surface of the petal epidermis of many angiosperms are not ordinary flat,but some kind of conical or papillary structure.This phenomenon rarely occurs on the epidermis of leaves or other plant organs,so conical cells are considered as a typical feature of petals.At the same time,conical cells have many functions,such as maintaining the humidity and temperature of the petal surface,and providing a foothold for the pollinator.ERF014 is a nuclear-localized transcription factor encoding the AP2 domain and is a member of the DREB subfamily of the ERF family of AP2/ERF transcription factors.AP2/ERF transcription factor plays an important role in plant development and stress resistance through specific binding to cis-elements in response to stress.So far,the research direction of ERF014 has mainly focused on plant immune effects,JA-related regulatory processes and pectin synthesis.There is little research on the molecular mechanism of how ERF014 regulates the formation of petal epidermal conical cells.Therefore,studying the effect of ERF014 on the morphological formation of petal epidermal conical cells is a novel direction and has very important significance.There are only a few cell types and simple laminar structure in the petals of Arabidopsis,which have great advantages for analyzing the process of organogenesis.So,this study uses the petals of Arabidopsis as a model to explore the regulatory effect of ERF014 on the growth of petal conical cells.Through research,it was found that in the ERF014over-expressing plant ACT2pro::GFP-ERF014/rdr6,the plant development was slow and obvious dwarfing.At the same time,in the flowers,the stigma was higher than the pistil and there was a phenomenon of abortion.The petals as a whole become smaller,and the blade and claw parts also become significantly smaller.Observe the petal conical cells under a microscope using the living folding method,and the top of the conical cells will obviously swell.In the ERF014 chimeric inhibitor mutant p Super::SRDX-ERF014-GFP/Col-0,it was also found that the apical angle of the petal conical cells of Arabidopsis thaliana becomes larger.GUS staining revealed that ERF014 was hardly expressed in the early stages of petal development(stage 7-8),and only began to be expressed in the middle and late stages of development(after stage 9).Therefore,ERF014 may affect the growth and development of conical cells in the middle and late stages of petal development(after the9 th stage).Because the shape and structure of petal conical cells are closely related to the cell wall,10 genes related to cell wall synthesis were screened as downstream candidate target genes of ERF014 by transcriptome analysis of the inflorescences of ACT2pro::GFP-ERF014/rdr6 and ACT2pro::GFP/rdr6.At the same time,the interaction between ERF014 and BIN2 was proved by Spill Luciferase and pull-down.Therefore,it is speculated that ERF014 may affect the growth and development of cone cells by regulating the BR signal pathway,which provides an important basis for the study of the morphogenesis mechanism of conical cells in the future.