Abstract: Auxin, a kind of phytohormone discovered quite earlier, affects many processes of plant growth. If we identify the receptor interplaying with auxin directly and find out how the signal transfered into the tissue cells, it can help us to learn the mechanism of auxin effection, detecting many processes about plant’s growth deeply. ABP1 (auxin binding protein 1) was cloned from upland cotton (Gossypium hirsutum Linn.), capsicum, etc. But there is not any report about the auxin binding protein of ramie. In this paper the ABP1 cDNA core sequence was cloned by PCR with the primers designed using Boehmeria nivea(Linn.) Gaud as material. The identical molecules were cloned through 5’ and 3’ RACE and the whole sequence of the cDNA was cloned and sequenced which was a 849 bp molecule and could be translated into putative protein with 189 amino acids. BLAST analysis confirmed that this cDNA sequence shared a high homology with reported ABP gene of plants. It was designated as BnABP1 according to the auxin binding protein gene nomination habit and was submitted to GenBank with an accession number EU195804. In order to investigate the expression and regulation roles of BnABP1 in different tissues of ramie, the non-conservative sequence at 3’-end of BnABP1 was selected as target and its expression was detected by semi-quantitative RT-PCR with 18S rRNA as internal control. After running the PCR with various cycles the products electrophoresed in agarose gel and the integrating optic density (IOD) of bands was detected with gel analysis software. We take the ratio of IOD as relative ex-pressive quantity. The results indicated the expression of BnABP1 could be found in leaf, stem and bud but not in root in ramie. The expression level in bud, leaf and stem was with the relative content of 0.755, 0.632, and 0.360 respectively compared with that of 18S rRNA. Thus BnABP1 maybe expresses mostly in the tender tissues of plant.

Key words: Ramie(Boehmeria nivea), Auxin-binding Proteins 1(ABP1), cDNA cloning, Expression analysis