Amplification, sequence and expression of the harpin encoding gene of the bacterial canker pathogen, Pseudomonas syringae pv. syringae strain NV

DNA fragments containing a putative harpin elicitor encoding (hrpZ) gene we re amplified from genomic DNA of the South African stone fruit pathogen, Ps eudomonds syringae pv. syringae strain NV, using primers based on the hrpAZ B sequences of the wheat pathogen, P s. pv syringae strain 61. Sequencing o f these amplification products revealed a hrpZ open reading frame, which sh owed 96.2% identity with the hrpZ gene of P. s. pv. syringae 61. A similar degree of identity (96.4%) was obtained when the predicted amino acid seque nce of the P s. pv. syringae NV harpin elicitor protein (HrpZ) was aligned with that of the P s. pv. syringae 61 harpin. The P s. pv. syringae NV hrpZ gene was subsequently cloned into the pMAL-c2 vector and expressed in Esch erichia call. This system proved useful for the production of purified, bio logically active recombinant HrpZ protein.