Arbuscular mycorrhizal fungi enhance antioxidant defense in the leaves and the retention of heavy metals in the roots of maize

Abstract

In this study, we investigated the effects of the arbuscular mycorrhizal fungi (AMF) Funneliformis mosseae and Diversispora spurcum on the growth, antioxidant physiology, and uptake of phosphorus (P), sulfur (S), lead (Pb), zinc (Zn), cadmium (Cd), and arsenic (As) by maize (Zea mays L.) grown in heavy metal-polluted soils though a potted plant experiment. F. mosseae significantly increased the plant chlorophyll a content, height, and biomass; decreased the HO and malondialdehyde (MDA) contents; and enhanced the superoxide dismutase (SOD) and catalase (CAT) activities and the total antioxidant capacity (T-AOC) in maize leaves; this effect was not observed with D. spurcum. Both F. mosseae and D. spurcum promoted the retention of heavy metals in roots and increased the uptake of Pb, Zn, Cd, and As, and both fungi restricted heavy metal transfer, resulting in decreased Pb, Zn, and Cd contents in shoots. Therefore, the fungi reduced the translocation factors for heavy metal content (TF) and uptake (TF') in maize. Additionally, F. mosseae promoted P and S uptake by shoots, and D. spurcum increased P and S uptake by roots. Moreover, highly significant negative correlations were found between antioxidant capacity and the HO, MDA, and heavy metal contents, and there was a positive correlation with the biomass of maize leaves. These results suggested that AMF alleviated plant toxicity and that this effect was closely related to antioxidant activation in the maize leaves and increased retention of heavy metals in the roots.

Overexpression of a novel microRNA IamiR-4-3p from water spinach (Ipomoea aquatica Forsk.) increased Cd toxicity and accumulation in Arabidopsis thaliana

“…T-AOC is an important antioxidant for plants under heavy metal stresses, and the lower the content of T-AOC in plants, the more oxidative damage will plants suffer (Sytar et al 2013). In the present study, we also found that there was a signi cant negative correlation between T-AOC and Cd concentration in plants, which was consistent with the research of (Zhan et al 2018), who found that a signi cant negative correlation (-0.856, p < 0.01) existed between T-AOC and Cd contents in maize. Therefore, the IamiR-4-3p overexpression reduced the antioxidation ability in Arabidopsis, which should be one of the reasons of the increases of MDA and H 2 O 2 contents in the p35S::miR-4-3p plant.…”

Arbuscular mycorrhizal fungi alleviate negative effects of arsenic‐induced stress on crop plants: A meta‐analysis

“…(2015), Zhang et al. (2018)), others used As‐contaminated soils (Bai et al., 2008; Cattani et al., 2015; Neagoe et al., 2013; Ultra Jr, Tanaka, Sakurai, & Iwasaki, 2007a, 2007b; Xia et al., 2007; Zhan et al., 2018). Importantly, when As is added to natural soil, the resulting As stress on crops grown therein will always comprise both the amount added and the soil's background concentration.…”

“…The Four subgroups were introduced for the colonization rate: very low (< 25%), low (25% to 50%), medium (> 50% to 75%), and high (> 75%). Note that other mycorrhizal parameters (e.g., evaluating the development of arbuscules and extraradical hyphae) might be more suitable to monitor the vitality of AM fungi under As stress (Orłowska, Godzik, & Turnau, 2012) Ultra Jr, Tanaka, Sakurai, & Iwasaki, 2007a, 2007bXia et al, 2007;Zhan et al, 2018). Importantly, when As is added to natural soil, the resulting As stress on crops grown therein will always comprise both the amount added and the soil's background concentration.…”

Arbuscular Mycorrhizal Symbiosis Enhances Photosynthesis in the Medicinal Herb Salvia fruticosa by Improving Photosystem II Photochemistry

“…Naturally appearing soil microbes may be used as inoculants to maintain crop yields despite reduced resource (water and nutrient) inputs [ 7 ]. Several studies revealed that AMF could increase plant biomass and help host plants to improve their nutrient uptake and their tolerance/resistance to biotic and abiotic stresses [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. Under drought stress AMF inoculation increased the content of compatible solutes, assisting in maintaining the relative water content, and upregulated the antioxidant system of maize plants, facilitating alleviation of oxidative effects through elimination of reactive oxygen species (ROS) [ 12 ].…”