The nematophagous root endophyte Pochonia chlamydosporia alters tomato metabolome

The endophytic fungus Pochonia chlamydosporia has been used in commercial products to control root-knot nematode infections. Its mutualistic symbiosis also promotes plant growth and development of the plants. We investigated the metabolic changes that occur in tomato roots and leaves when in symbiosis with P. chlamydosporia. The metabolic profiles of roots and leaves were contrasted by liquid chromatograph coupled to mass spectrometry (LC/MS) after 24 and 44 days of plant-fungus interaction. The symbiosis resulted in higher plant biomass than in treatment controls. Phytohormonal profiles indicated that the jasmonic acid regulation appears important for establishing the endophytic interaction. Inoculated plants also showed changes in the root levels of some phenolic and flavonoid compounds. Metabolomic alterations of root tissues occurred in the early stages (24 days after inoculation) of the endophytic interaction, while at later stages profiles were very similar to the control plants. Otherwise, inoculation promoted a systemic response as the leaf metabolome was altered for some defense compounds. These metabolomic changes reinforce the idea that P. chlamydosporia is beneficial to tomato in addition to its nematicide effect.