Ranbpm homologue genes characterised in the cyst nematodes Globodera pallida and Globodera ‘ mexicana’

Abstract

A homologue of a Ran binding protein to microtubules ( ranbpm) gene, initially known as IC5, was identified and characterised in second-stage juveniles (J2s) of the potato cyst nematode Globodera pallida. The full-length cDNA (937 bp) was obtained by 5′ and 3′ rapid amplification of cDNA ends (RACE) and specific primers were designed to amplify the genomic sequences of 2396 bp containing six introns. The ORF (798 bp) encodes a putative 265 amino acid sequence with a predicted SPRY domain and a signal peptide of 23 amino acids on the N-terminal part of the protein. In situ hybridisation experiments showed that the transcript is located in the dorsal gland of the J2s, suggesting that the encoded protein has an extracellular function and can be involved in the late stages of parasitism such as feeding site establishment. This gene was specifically over-expressed in the juveniles before and during parasitism, but not in adult developmental stages. As this gene is presumed to be involved in plant–nematode interaction, particularly in the development and maintenance of the feeding structure that allows the nematode to achieve parasitic development, homologous genes were sought in other cyst nematode species. One of them was cloned and sequenced in the closely related species Globodera ‘ mexicana’.