Effect Of FT On Root Hair Development In Arabidopsis

FT(FLOWERING LOCUS T)is one of important factors in flowering regulation in Arabidopsis thaliana,which is named florigen.The FT shows highly conserved aa sequence and protein structure in different plants species,and integrates signal to promote flowering.At present,the regulation of flowering by FT gene has been studied systematically.However,whether FT plays an important role in vegetative growth remains unknown.Root hair is an important organ for plants to absorb water and nutrients,which is directly involved in the vegetative growth process of plants.In this study,through screening and identifying FT overexpression and mutant plants,we analyzed the effects on the length,density and phenotype of root hair,verified the interaction between FT and FER,and explored the effects of FT gene on the growth and development of Arabidopsis thaliana root hair and its molecular regulatory mechanism.(1)By constructing pCAMBIA2300-FT-GFP recombinant plasmid into Agrobacterium tumefaciens Ag10 and infecting Arabidopsis thaliana flower,We obtained two overexpressed plants FT-GFP-1 and FT-GFP-2.At the same time,ft-10 plants was identified as T-DNA homozygous mutants.(2)By statistical analysis of root hair density,length and phenotype,we found that FT overexpression lines had shoter and sparser root hairs with abnormal phenotypes such as branch,ballooned and wavy types compare with wild type.On the contrary,ft-10 had longer and denser root hairs with normal phenotypes compare with wild type.(3)The fluorescence observation of FT-GFP-1 indicated that the FT gene was expressed in the nucleus and cytoplasm of root hair cells,suggesting that the FT gene was involved in and regulated the growth and development of root hair(4)Quantitative analysis of the genes expression including KOAJK ? AKT1 ?SCN1?RHD2?LRL3?RSL4?RHD6 related to root hair initiation elongation showed that FT overexpression lines were significantly lower than wild type,while ft-10 were slightly higher than wild type.It further indicated that FT gene as a transcription factor significantly affected the polar growth of root hair and the expression of genes related to root hair elongation.(5)The interaction between FT and FER was preliminarily verified by yeasttwo-hybrid.Then the specific interaction in cell membrane and cytoplasm was verified by BiFC.Finally,the interaction between their protein in vitro was further verified by Pull-down assay.The results indicated that FT plays a negative role in the initial elongation of root hairs and affects the polar growth and quantitative distribution of root hairs.We verified the interaction between FT and FER,and speculate that they may participate in the signal network regulating root hair growth and development.This study promoted the understanding of the FT function in the vegetative growth process,and also laid the foundation in research of the root development mechanism.