Characterisation of the cellulose-binding protein Mj-cbp-1 of the root knot nematode, Meloidogyne javanica

The cellulose-binding protein gene, cbp, of Meloidogyne javanica encodes a protein that contains a signal secretion peptide and is expressed in the eggs and pre-invasive stage J2s but not from adult females. Several highly similar forms were found in the three root knot nematode species, M. javanica, Meloidogyne incognita and Meloidogyne arenaria indicating very limited divergence of the orthologues and paralogues. The genomic sequences included three introns which differed in size between species and between isolates of M. incognita and M. arenaria, however, the coding regions of the various forms were highly similar. In M. javanica only one form of cbp was found. Treatment of pre-invasive stage J2 nematodes with cbp-dsRNA resulted in a reduction in the ability of J2s to penetrate tomato roots and consequently in a reduction in the number of egg masses produced by the cpb-dsRNA treated nematodes compared to the control nematodes, consistent with an important role of CBP in the early stages of penetration and invasion.