The Preliminary Investigation Of Arabidopsis Transcription Factor JAGGED In Regulating The Morphogenesis Of Petal Conical Cells

Plant epidermal cells have different shape which facilitates completion of their specific biological function.In nature world,nearly 79%angiosperms petals have papillate-conical epidermal cells.This special structure can provide a powerful landing platform for insect pollinators staying on the petals,which can improve pollination efficiency.In Arabidopsis thaliana,conical cells can affect a series of biological properties of the petals,such as the temperature,humidity,and color of the petal surface.Arabidopsis JAGGED(JAG)is a single-chain C2H2 zinc finger motif containing transcription factor that plays an important role in the regulation of plant organ development and polarity growth.At present,the molecular mechanism of how JAG regulates the conical cells is not very clear.Therefore,it is of great significance to study the action of JAG on the conical cells of petals.In this study,we used the petals of the model plant Arabidopsis thaliana as an ideal material to study the morphology of conical cells,and explored JAG function in conical cell development.The results showed that JAG has a higher expression level in the early stage of seedling and petal development.The jag-1 mutant petals are smaller,and the white parts of petals also significantly reduced.The petals and sepals have uneven size phenotypes,indicating that JAG can regulate the development of floral organs generally.The observation of jag-1 petal adaxial epidermal cells showed that the tip of the conical cell is obviously swollen,the height of the cell decreased,and the cells size on the same petal are different.It was further found that the alignment of microtubules in jag-1 conical cells are almost identical to wild type,both of which show an orderly helical ascending arrangement,thus indicating that JAG does not affect the development of conical cells by modulating the arrangement of microtubules.Reactive oxygen species(ROS)staining experiments showed that there was a remarkable ROS accumulation in the early stage of jag-1 petal development and using exogenous hydrogen peroxide directly treated wild type early buds could cause large area abnormal conical cells with more swollen and uneven morphology.Based on transcriptome comparative analysis of WS and jag-1 inflorescence,11 candidate JAG target genes were identified,and those candidate genes were further verified by real-time quantitative PCR,and their expression change between WS and jag-1 were consistent with the the results of RNA-seq data.These genes included auxin-related genes(IAA27,ARF18)and ROP related gene(ROPGAP2),which are associated with ROS signaling.Therefore,JAG is likely to influence the accumulation of ROS by regulating the auxin signaling pathway and the ROP signaling pathway,which in turn regulates the morphogenesis of the petal conical cells.This project provided a new basis for further analyzing the molecular mechanism of JAG regulated petal conical cell morphogenesis.