The symbiosis between Nicotiana tabacum and the endomycorrhizal fungus Funneliformis mosseae increases the plant glutathione level and decreases leaf cadmium and root arsenic contents

Abstract

a b s t r a c tOver time, anthropogenic activities have led to severe cadmium (Cd) and arsenic (As) pollution in several environments. Plants inhabiting metal(loid)-contaminated areas should be able to sequester and detoxify these toxic elements as soon as they enter roots and leaves. We postulated here that an important role in protecting plants from excessive metal(loid) accumulation and toxicity might be played by arbuscular mycorrhizal (AM) fungi. In fact, human exploitation of plant material derived from Cd-and As-polluted environments may lead to a noxious intake of these toxic elements; in particular, a possible source of Cd and As for humans is given by cigarette and cigar smoke. We investigated the role of AM fungus Funneliformis mosseae (T.H. Nicolson & Gerd.) C. Walker & A. Schüßler in protecting Nicotiana tabacum L. (cv. Petit Havana) from the above-mentioned metal(loid) stress. Our findings proved that the AM symbiosis is effective in increasing the plant tissue content of the antioxidant glutathione (GSH), in influencing the amount of metal(loid)-induced chelators as phytochelatins, and in reducing the Cd and As content in leaves and roots of adult tobacco plants. These results might also prove useful in improving the quality of commercial tobacco, thus reducing the risks to human health due to inhalation of toxic elements contained in smoking products.

Endophytic Paecilomyces formosus LHL10 Augments Glycine max L. Adaptation to Ni-Contamination through Affecting Endogenous Phytohormones and Oxidative Stress

“…This implies the beneficial interaction with endophytic fungal enables plants to cope with oxidative stress induced by Ni toxicity. The findings of the present study are consistent with those reported by Degola et al (2015) and Wang et al (2016), who found enhanced antioxidant activities in maize and Nicotiana tabacum plants inoculated with endophytic fungi under heavy-metal stress. GSH is an important antioxidant owing to its reducing potential, which can respond directly as a free radical scavenger.…”

Effects of a root-colonized dark septate endophyte on the glutathione metabolism in maize plants under cadmium stress

“…For instance, the inoculation of endophytic Sphingomonas SaMR12 increased the GSH concentration and subsequently improved Cd tolerance and accumulation in the roots of Sedum alfredii (Pan et al 2016). The endophytic F. mosseae reduced the Cd content in the leaves and roots by increasing the GSH content in tobacco plants (Degola et al 2015). In addition, the endophytic fungi colonization altered the heavy metals' distribution in the host plant.…”

“…For instance, the endophyte Sphingomonas SaMR12 up-regulates the expression of GSH synthesis-relevant genes (ATPS, GS and GSH1), increases GSH concentrations and subsequently enhances both Cd tolerance and accumulation (Pan et al 2016). Similarly, the AM fungus Funneliformis mosseae decreases leaf Cd contents with increasing GSH levels in tobacco (Degola et al 2015).…”

Arsenic Uptake, Toxicity, Detoxification, and Speciation in Plants: Physiological, Biochemical, and Molecular Aspects

“…The complexation of As with ligands and its vacuolar compartmentation is another mechanism of As detoxification in plants [ 6 , 50 ]. Thiol-reactive cysteine-rich peptides such as phytochelatins (PCs) and metallothioneins strongly bind with As and convert it to a non-toxic form [ 32 , 51 ].…”