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A Secretory Cellulose-Binding Protein cDNA Cloned from the Root-Knot Nematode (Meloidogyne incognita)

October 1998 , Volume 11 , Number  10
Pages  952 - 959

X. Ding , J. Shields , R. Allen , and R. S. Hussey

Department of Plant Pathology, University of Georgia, Athens 30602-7274, U.S.A.

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Accepted 30 June 1998.

A cDNA encoding a secretory cellulose-binding protein was cloned from the root-knot nematode (Meloidogyne incognita) with RNA fingerprinting. The putative full-length cDNA, named Mi-cbp-1, encoded a 203 amino acid protein containing an N-terminal secretion signal peptide. The C-terminal sequence of the putative MI-CBP-1 was similar to a bacterial-type cellulose-binding domain, whereas the N-terminal sequence did not show significant similarity to any proteins in data bases. Recombinant MI-CBP-1 lacked cellulase activity, but bound to cellulose and plant cell walls. In Southern blot hybridization, Mi-cbp-1 hybridized with genomic DNA from M. incognita, M. arenaria, and M. javanica, but not M. hapla, Heterodera glycines, or Caenorhabditis elegans. Polyclonal antibodies raised against recombinant MI-CBP-1 strongly labeled secretory granules in subventral gland cells of second-stage juveniles in indirect immunofluorescence microscopy. Enzyme-linked immunosorbent assay detection of MI-CBP-1 in stylet secretions of second-stage juveniles with the polyclonal antibodies indicated MI-CBP-1 could be secreted through the nematodes' stylet, suggesting that the cellulose-binding protein may have a role in pathogenesis.

Additional keywords: feeding, giant-cell.

© 1998 The American Phytopathological Society