title: Molecular and biochemical characterization of the β-1,4-endoglucanase gene Mj-eng-3 in the root-knot nematode Meloidogyne javanica.
abstract: This study describes the molecular and biochemical characterization of the β-1,4-endoglucanase gene (Mj-eng-3) from the root knot nematode Meloidogyne javanica. A 2156-bp genomic DNA sequence of Mj-eng-3 containing six introns was obtained. Mj-eng-3 was localized in the subventral esophageal glands of M. javanica juveniles by in situ hybridization. Real-time RT-PCR assay showed that the highest transcriptional level of Mj-eng-3 occurred in pre-parasitic second-stage juveniles, and this high expression persisted in parasitic second-stage juveniles. Recombinant MJ-ENG-3 degraded carboxymethylcellulose and optimum enzyme activity at 40°C and pH 8.0. EDTA, Mg(2+), Mn(2+), Ca(2+), Co(2+), and Cu(2+) did not affect the activity of MJ-ENG-3; however, Zn(2+) and Fe(2+) inhibited MJ-ENG-3 enzyme activity. In planta Mj-eng-3 RNAi assay displayed a reduction in the number of nematodes and galls in transgenic tobacco roots. These results suggested that MJ-ENG-3 could be secreted by M. javanica to degrade the cellulose of plant cell walls to facilitate its entry and migration during the early stages of parasitism.
authors.affiliation: Laboratory of Plant Nematology, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Hu
authors.forename: Ruqiang
authors.initials: R
authors.lastname: Cui
authors.forename: Longhua
authors.initials: L
authors.lastname: Sun
authors.forename: Borong
authors.initials: B
authors.lastname: Lin
authors.forename: Kan
authors.initials: K
authors.lastname: Zhuo
authors.forename: Jinling
authors.initials: J
authors.lastname: Liao
mesh_terms: D000818:Animals; D002480:Cellulase / Q000235:genetics* / Q000378:metabolism*; D018076:DNA, Complementary / Q000737:chemistry; D018509:DNA, Helminth / Q000737:chemistry; D005091:Exons; D018507:Gene Expression Regulation, Developmental; D006863:Hydrogen-Ion Concentration; D017403:In Situ Hybridization; D007438:Introns; D010935:Plant Diseases / Q000469:parasitology; D018517:Plant Roots / Q000469:parasitology; D034622:RNA Interference; D018510:RNA, Helminth / Q000235:genetics; D016415:Sequence Alignment; D013696:Temperature; D014026:Nicotiana / Q000469:parasitology*; D014431:Tylenchoidea / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development
chemical_list: D018076:DNA, Complementary; D018509:DNA, Helminth; D018510:RNA, Helminth; D002480:Cellulase
keywords: Cellulase; In planta RNAi; Invasion; Meloidogyne javanica; Migration