Mycorrhiza–induced resistance against the root-knot nematode Meloidogyne incognita involves priming of defense gene responses in tomato
Date
2013Author
Vos, C.
De Waele, D.
Van Tuinen, D.
Chatagnier, O.
Schouteden, N.
Metadata
Show full item recordAbstract
Arbuscular mycorrhizal fungi (AMF) have great potential as biocontrol organisms against the rooteknot
nematode Meloidogyne incognita which causes severe gall formation in plants, but knowledge about the
underlying molecular mechanisms involved in the biocontrol of nematodes is scarce. In the present
study, suppression subtractive hybridization (SSH) was used to investigate plant genes that are specifically
up-regulated in tomato roots (Solanum lycopersicum cv. Marmande) pre-colonized by the AMF
Glomus mosseae (BEG 12) and 12 days after soil inoculation with M. incognita juveniles. Nematode
infection was significantly lower in the mycorrhizal roots as compared to the non-mycorrhizal roots, and
identified genes were classified mainly in the categories of defense, signal transduction and protein
synthesis and modification. The higher expression of a selection of defense-related plant genes specifically
in the biocontrol interaction compared to in plants that were only mycorrhizal or only nematodeinfected
was confirmed, which pleads for the existence of mycorrhiza-induced priming of plant defense
responses. In conclusion, by focusing on up-regulated gene expression in the biocontrol interaction
between mycorrhizal tomato and M. incognita, new insights were found into the molecular mechanisms
underlying the mycorrhiza-induced resistance against rooteknot nematodes. In particular, the involvement
of the phenylpropanoid pathway and reactive oxygen species (ROS) metabolism could explain the
reduced rooteknot nematode infection in mycorrhizal tomato roots, processes that have also been
reported to play a pivotal role in plant resistance to nematodes