Interaction Effects of Glomus and Xenobiotic Glutathione Conjugate on the Detoxification Enzymes of the Mycorrhizal Roots in Barley

Symbiotic plants detoxify organic xenobiotics through associations with microorganisms, utilizing conjugation reactions mediated by enzymes like glutathione S-transferases (GST). A significant portion of the resulting metabolites reaches the rhizosphere, potentially impacting other plants' roots and microorganisms in the root zone.

This study investigated the influence of a xenobiotic conjugate, dinitrobenzene-glutathione, on non-mycorrhizal hairy roots of barley (Hordeum vulgare L.) and roots colonized with Glomus hoi. Hairy roots treated with glutathione conjugates showed transient induction of GST-CDNB activity and dichloromethane detoxification within the first 18 hours. Fungi-colonized roots reacted faster than non-mycorrhizal roots. Roots reduced the conjugate DCNB with glutathione at the cost of p-NBOC activity.

These findings are the first to report synergistic effects of soil fungi and xenobiotic conjugates on plant roots. They underscore the significant role of symbiosis in altering plant root detoxification capacities, thereby influencing the plant-mycorrhizosphere metabolism of organic xenobiotics.