Abstract: 【Objective】The objective of this study is to analyze the expression characteristics of PMRP (putative membrane related protein)gene (the biological funcion was unknown )in Arabidopsis, and make clear of the regulation function of PMRP in Arabidopsis development process.【Method】Bioinformatics method was used to look for the genes which contain the same domain with PMRP in Arabidopsis and draw the phylogenetic tree. Real-time PCR technique was used to analyze the expression level of PMRP in root and stem tissues of 8 and 21 days Arabidopsis, compare the expression of PMRP gene in the 1st, 2nd, 3rd and the 4th pairs of rosette leaves and cauline leaves in 21 days Arabidopsis, analyze the expression level of PMRP in flower organs (such as sepals, stamens and petals) and seeds of Arabidopsis. The gain-of-function mutant of PMRP were obtained by constructing a vector of PMRP gene driven by the 35S promoter of the cauliflower mosaic virus, and introduced it into wild type Arabidopsis Columbia, then tested the expression level of PMRP by RT-PCR technique. The regulating effect of PMRP gene on the growth sites of leaves and stems was analyzed by observing the phenotype of the 35S:PMRP transgenic plants. The function of PMRP gene in differentiation of vascular xylem and phloem was observed using the paraffin sections of the stem transverse section in the PMRP over-expressing transgenic Arabidopsis. The effect of PMRP on the growth and development of Arabidopsis floral organ was studied through observation of the floral organ anatomy. The effect of PMRP on fertility in Arabidopsis thaliana was analyzed by observing the pod formation in the PMRP over-expressing transgenic Arabidopsis. 【Result】PMRP is a 411 amino acids protein which containing a START domain and have transmenbrane segments, there are 35 START proteins in Arabidopsis. Real-time PCR analysis results showed that the expression level of PMRP was higher in cauline leaves ( the relative expression of PMRP was about 2 935) and then the rosette leaves, the growth time of rosette leaves was longer, the more expression of PMRP was tested (the relative expression of PMRP in the 1st, 2nd, 3rd and 4th pairs of the rosette leaves were 1 650, 1 113, 734, and 507, respectively) , then the sepals floral tissues (PMRP relative expression quantity is about 937), PMRP had distribution in the stem, root and seed , but the relative expression amount was less than 270. The relative expression level of PMRP in stamens was the lowest (about 64), far below the expression quantity of PMRP in sepals (937). The expression level of PMRP gene was increased with the increase of growth time, the relative expression of PMRP were 154 and 222, respectively, in 8 and 21 d roots, and 200 and 264, respectively, in 8 and 21 d stems. The rosette leaves were emerged from the branches, stalk lodging susceptible, vascular had no obvious cambium and the xylem and phloem arranged in disorder, the filaments became shorter in floral organs, the number of pod decreased, and the fertility reduced.【Conclusion】The START domain is extremely conservative in function. PMRP was expressed in different organs of A. thaliana, with the extension of time, the expression level of PMRP was also increased. The level of PMRP in the flower stamens was the lowest, once PMRP was over-expressed in Arabidopsis floral organs, stamens dysplasia, resulting in reduced fertility. PMRP had important function in regulating the origination of leaves, the vascular differentiation and development of floral organs.

Key words: Arabidopsis , PMRP , function analysis