RESUMO
A new kind of curcin (curcin 2), induced by several kinds of stresses from Jatropha curcas leaves, under the control of the 35S CaMV (cauliflower mosaic virus) promoter, was introduced into tobacco genome by Agrobacterium tumefaciens-mediated transformation method. Curcin 2 protein was only detected in the transgenic tobacco plants transformed with the cur2p fragment (coding premature curcin 2 protein), but not in the plants transformed with cur2m fragment (coding mature curcin 2 protein). The transgenic lines expressing curcin 2 showed increased tolerance to tobacco mosaic virus (TMV).
RESUMO
The open reading frame (ORF) encoding curcin 2 was cloned from total genomic and cDNA of Jatropha curcas leaves, which were treated by drought, temperature stress and fungal infection, by polymerase chain reaction (PCR) and reverse transcriptase (RT)-PCR amplification. The ORF has 927 bp that encodes a precursor protein of 309 amino acid residues. There are high similarities with curcin and the conserved domain of ribosome inactivating proteins (RIPs). Antiserum to curcin recognized one band of 32 kDa on Western blot of the leaves treated by temperature stresses at 4 degree C and 50 degree C and by fungal infections of Pestalotia funerea, Curvularia lunata (Walk) Boed, Gibberelle zeae (Schw.) Petch. Two bands of 32 kDa and 65 kDa were recognized on Western blot of the leaves treated by 10--40 percent polyethylene glycol (PEG). In addition, the 32 kDa band is nearly the molecular weight of curcin 2. This finding suggests that the protein of 32 kDa should be related to curcin 2. The presence of this protein molecular marker under stresses may provide an experimental foundation to study the stress proteins in J. curcas.