Molecular Cloning and Sequence Analysis of a Tonoplast Aquaporin Gene TIP1 Associated with Tapping Panel Dryness in Hevea brasiliensis

[Objective]To address the role of aquaporins(AQPs) in the occurrence of Tapping Panel Dryness(TPD),a syndrome with tapping incision blocked partly or entirely during latex exploiting in the rubber tree(Hevea brasiliensis) that causes great losses on rubber production,a tonoplast aquaporin gene associated with TPD occurence was cloned and analyzed. [Methed]Based on a EST down-regulated in the TPD-affected rubber trees,a 774 bp cDNA designated HbTIP1 was isolated from the bark tissue of rubber tree with a combination of in silico cloning and RTPCR. Furthermore,the sequence features of HbTIP1,the biochemical features of its deduced protein and the evolutionary relationship were also analyzed via bioinformatics tools.[Result]The cDNA contains a 759 bp long ORF,8 bp 5'UTR and 7 bp 3'UTR. Sequence analysis indicated that HbTIP1 encodes 252 amino acids with a theoretical molecular weight(Mw) of 25. 88 kDa and isolectric point(pI) of 4. 96. Bioinformatics analysis suggested the deduced protein is predicted to have six transmembrane helices located to the vacuolar membrane,and harbour one MIP domain that can be grouped into the tonoplast intrinsic proteins(TIPs) of Aquaporin family. Homology search revealed that the protein shares a similarity of more than 90% with the homologues in Theobroma cacao,Prunus persica,Citrus sinensis and Ricinus communis,supportting a highly conserved evolution. [Conclusion]This study provided a basis for uncovering the regulatory role of AQPs in TPD occurrence in the future.