Molecular Cloning and Expression Analysis of a Cysteine Proteinase Gene (HbCP2) from Hevea brasiliensis

Based on the EST and genome sequences, a 1056bp cDNA was isolated from the root tissue of Hevea brasiliensis with specific primers via RTPCR. The sequence contains a 1023bp long open reading frame (ORF), 17 bp 5′UTR and 16 bp 3′UTR. The ORF was predicted to encode 340 amino acids with a theoretical molecular weight (Mw) of 3752 kD and isolectric point (pI) of 5.25; The sequence was predicted to be a secretory protein located to vacuoles; the protein contains one Inhibitor_I29 domain and one Peptidase_C1A domain and can be categoried as the papain C1 family; the protein shares a similarity of more than 80% with the homologues in castor bean (Ricinus communis), poplar (Populus trichocarpa), and then this gene was designated as HbCP2. Semiquantitative RTPCR analysis showed that HbCP2 exhibits a rootspecific expression pattern in examed tissues, i.e. root, bark, xylem, bud, leaf, petiole and laticifer.