Functional Identification Of Arabidopsis Transcriptional Factor AtOFP19

AtOFP19 is one of the newly discovered members of ovate family protein in Arabidopsis（AtOFPs）.AtOFPs are transcription factors whose members have transcriptional inhibitory activity and can regulate plant growth and development.According to the morphology of overexpressed plants,AtOFPs are divided into 3 sub-groups.As a member of the AtOFPs,AtOFP19has not been classified yet.Existing results show that AtOFPs members have the following functions:AtOFP1 inhibits plant growth,AtOFP4 inhibits epidermal cell growth,AtOFP8 overexpressed plants increases drought resistance of plants,AtOFP15 regulates and controls the morphology of pod.For determining AtOFP19 belonging to which subtribe and identifying biological functions,selecting and getting 35S:HA-AtOFP19 transgenic plants（OE plants）.Comparing OE and wild-type plants（WT plants）it shows that OE plants have small rosette leaves,thin stems,and whole plants is small.It is similar to AtOFPs III genes.For studying the function of AtOFP19 gene,doing bioinformatics analysis,tissue specificity analysis,subcellular localization analysis,transcriptional inhibitory activity analysis and hormone treatment experiment.The main results of this experiment are as follows:1.For exploring AtOFP19 location in cells,transferring recombinant vector to protoplast by transient transfection of protoplast.Using a laser scanning confocal microscope to observed the fluorescence distribution.It shows that AtOFP19-GFP fusion proteins are expressed in the nucleus.Demonstrating that AtOFP19 proteins are localizes in the nucleus.2.Reporter genes LexA-Gal4:GUS,GD-AtOFP19 and LD-VP were co-transfected into protoplasts.Taking GD as control group,GUS expression was measured.The results show that the GUS expression of GD-AtOFP19 group is lower than that in the control group.It shows that AtOFP19 has transcriptional repressor activity.3.AtOFP19 gene is expressing in roots,stems,leaves,flowers and keratocarp of Arabidopsis.The expression is the highest in flowers,relatively high in stem leaves,but less in kerfs,stems and roots.The expression of AtOFP19 gene is higher in the early stage of seedling growth.As plants grow and develop AtOFP19 gene expression decreases and the expression of AtOFP19 gene increases during flowering.4.For determining AtOFP19 belonging to which subtribe,selecting and getting 35S:HA-AtOFP19 transgenic plants.Comparing OE and WT plants it shows OE plants have small rosette leaves,thin stems,and whole plant is small.5.The seeds of OE plants,Atofp19 plants and WT plants were seeded into 1/2 MS medium without hormone and resistance.Satisficing 1d-7d seed germination rate.The results show that Atofp19 seed germination rate is the highest and OE is the lowest.It shows that AtOFP19 has inhibitory effect on the germination of seeds.6.When screening homozygous OE、Atofp19 plants,it was found that Atofp19 plants had the shortest roots and OE plants had the longest roots.It shows that AtOFP19 is associated with root growth.7.Using ABA,6-BA,GA₃,IBA and ethylene treated with OE plant,Atofp19 plant and WT plant.The results show that AtOFP19 gene interacts with 6-BA,GA₃,IBA to promote seed germination and interacts with ABA to inhibit plant growth and development.AtOFP19 gene is also found to respond to 6-BA regulation.As a result,the AtOFP19 gene localizes in the nucleus as a transcriptional repressor.AtOFP19gene has the effect of inhibiting seed germination and is related to the growth of roots,and can interact with plant hormones to regulate seed germination and seedling growth.Its gene expression is responsive to 6-BA.The preliminary study of AtOFP19 function enriches the research results of AtOFPs function and has good theoretical and practical significance.