title: Arbuscular mycorrhizal fungi affect both penetration and further life stage development of root-knot nematodes in tomato.
abstract: The root-knot nematode Meloidogyne incognita poses a worldwide threat to agriculture, with an increasing demand for alternative control options since most common nematicides are being withdrawn due to environmental concerns. The biocontrol potential of arbuscular mycorrhizal fungi (AMF) against plant-parasitic nematodes has been demonstrated, but the modes of action remain to be unraveled. In this study, M. incognita penetration of second-stage juveniles at 4, 8 and 12 days after inoculation was compared in tomato roots (Solanum lycopersicum cv. Marmande) pre-colonized or not by the AMF Glomus mosseae. Further life stage development of the juveniles was also observed in both control and mycorrhizal roots at 12 days, 3 weeks and 4 weeks after inoculation by means of acid fuchsin staining. Penetration was significantly lower in mycorrhizal roots, with a reduction up to 32%. Significantly lower numbers of third- and fourth-stage juveniles and females accumulated in mycorrhizal roots, at a slower rate than in control roots. The results show for the first time that G. mosseae continuously suppresses root-knot nematodes throughout their entire early infection phase of root penetration and subsequent life stage development.
authors.affiliation: Laboratory of Tropical Crop Improvement, Department of Biosystems, University of Leuven (K.U. Leuven), Kasteelpark Arenberg 13, Leuven, Belgium. christine.vos@biw.kuleuven.be
authors.forename: Christine
authors.initials: C
authors.lastname: Vos
authors.forename: Katleen
authors.initials: K
authors.lastname: Geerinckx
authors.forename: Rachel
authors.initials: R
authors.lastname: Mkandawire
authors.forename: Bart
authors.initials: B
authors.lastname: Panis
authors.forename: Dirk
authors.initials: D
authors.lastname: De Waele
authors.forename: Annemie
authors.initials: A
authors.lastname: Elsen
mesh_terms: D000818:Animals; D005260:Female; D055137:Glomeromycota / Q000502:physiology*; D018551:Solanum lycopersicum / Q000382:microbiology* / Q000469:parasitology*; D008297:Male; D038821:Mycorrhizae / Q000502:physiology*; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000469:parasitology*; D018517:Plant Roots / Q000382:microbiology / Q000469:parasitology; D014431:Tylenchoidea / Q000254:growth & development* / Q000502:physiology