Characterisation of mjap genes encoding novel secreted proteins from the root-knot nematode, Meloidogyne javanica

Abstract

AbstractTwo homologues of map-1, which encodes a putative avirulence factor, were found in a single egg mass line of the root-knot nematode Meloidogyne javanica that was virulent to the Mi-resistant gene. The main difference between the two encoded proteins of these homologues, MJ-MAP-1 and MJ-MAP-2, was the position of a 13 amino acid repeat region. Genes encoding two related but novel proteins, MJAP-1 and MJAP-2 (290 and 283 amino acids, respectively, including a potential signal secretion peptide), were also isolated from M. javanica. They have high similarity to MAP at the C-terminus. MJAP-1 and MJAP-2 differ from each other in the number and position of a seven-amino-acid repeat and in five other amino acids. The mjap genes are expressed in the subventral pharyngeal glands of second-stage juveniles of M. javanica, and transcription analysis in different developmental stages showed expression in the juvenile stage but not in eggs or adult females. Both mjap-1 and mjap-2 were expressed in both Mi-virulent and avirulent lines of M. javanica.