Arbuscular mycorrhizal fungi contribute to reactive oxygen species homeostasis of Bombax ceiba L. under drought stress

Abstract

Drought stress is one of the major abiotic factors limiting plant growth and causing ecological degradation. The regulation of reactive oxygen species (ROS) generation and ROS scavenging is essential to plant growth under drought stress. To investigate the role of arbuscular mycorrhizal fungi (AMF) on ROS generation and ROS scavenging ability under drought stress in Bombax ceiba, the ROS content, the expression levels of respiratory burst oxidase homologue (Rbohs), and the antioxidant response were evaluated in AMF and NMF (non-inoculated AMF) plants under drought stress. 14 BcRboh genes were identified in the B. ceiba genome and divided into five subgroups based on phylogenetic analysis. The effect of AMF on the expression profiles of BcRbohs were different under our conditions. AMF mainly downregulated the expression of Rbohs (BcRbohA, BcRbohD, BcRbohDX2, BcRbohE, BcRbohFX1, and BcRbohI) in drought-stressed seedlings. For well-water (WW) treatment, AMF slightly upregulated Rbohs in seedlings. AMF inoculation decreased the malondialdehyde (MDA) content by 19.11 and 20.85%, decreased the O2⋅– production rate by 39.69 and 65.20% and decreased H2O2 content by 20.06 and 43.21% compared with non-mycorrhizal (NMF) plants under drought stress in root and shoot, respectively. In addition, AMF inoculation increased the non-enzymatic antioxidants glutathione (GSH) and ascorbic acid (AsA) content in roots by 153.52 and 28.18% under drought stress, respectively. The activities of antioxidant enzymes (SOD, PX, CAT, APX, GPX, GR, MDAR, and DHAR) all increased ranging from 19.47 - 131.54% due to AMF inoculation under drought stress. In conclusion, these results reveal that AMF inoculation can maintain ROS homeostasis by mitigating drought-induced ROS burst, via decreasing ROS generation and enhancing ROS scavenging ability of B. ceiba seedlings.

Physiological and Enzymatic Antioxidant Responses of Solanum tuberosum Leaves to Arbuscular Mycorrhizal Fungal Inoculation under Water Stress

“…Regarding enzymatic antioxidant activities, previous studies have evaluated the effect of AMF inoculation on the response to water stress, showing that in Bombax ceiba , inoculation with AMF under water shortage increased CAT, APX, and GR activities by 318.5%, 34.1%, and 22.8%, respectively [ 46 ], whereas in walnut, these activities were increased by 340.4%, 106.3%, and 77.2%, respectively, compared to those in non-inoculated plants, and these increases were significant for CAT and APX [ 47 ]. Moreover, in tomato plants subjected to water and heat stresses, CAT activity increased by 42% and 57%, respectively, when plants were inoculated with two strains of AMF [ 48 ].…”

Arbuscular mycorrhizal fungal contribution towards plant resilience to drought conditions

“…Oxidative damage and drought stress are closely intertwined. Plants undergo an elevation in reactive oxygen species (ROS) like superoxide anion free radical (O 2 -), hydrogen peroxide (H 2 O 2 ), and hydroxyl radical (OH•) among others, as well as their buildup caused by drought stress (Tiwari et al, 2017;Hasanuzzaman et al, 2021;Li et al, 2022). Drought stress can lead to an overabundance of reactive oxygen species (ROS), which can trigger an "oxidative burst" and oxidative damage in plants (Li et al, 2022).…”

“…Plants undergo an elevation in reactive oxygen species (ROS) like superoxide anion free radical (O 2 -), hydrogen peroxide (H 2 O 2 ), and hydroxyl radical (OH•) among others, as well as their buildup caused by drought stress (Tiwari et al, 2017;Hasanuzzaman et al, 2021;Li et al, 2022). Drought stress can lead to an overabundance of reactive oxygen species (ROS), which can trigger an "oxidative burst" and oxidative damage in plants (Li et al, 2022). This eventually results in the structural damage of essential biomolecules leading to membrane damage and subsequent cell death in plants (Fobert and Despreś, 2005;Rhoads et al, 2006;Gill and Tuteja, 2010;Demidchik, 2015;Bahadur et al, 2019).…”

“…Nevertheless, this production is quickly eliminated by enzymes like superoxide dismutase (SOD), catalase (CAT), and carotenoids (Kapoor and Singh, 2017;Zou et al, 2021). An optimal ROS level is crucial for molecular signaling in plant growth, development, adaptation, and response to different abiotic and biotic stresses (Liu and He, 2016;Mittler, 2017;Li et al, 2022). Thus, maintaining a balance between ROS generation and ROS scavenging in stressful environments is crucial for the survival of plants (Li et al, 2022).…”

“…An optimal ROS level is crucial for molecular signaling in plant growth, development, adaptation, and response to different abiotic and biotic stresses (Liu and He, 2016;Mittler, 2017;Li et al, 2022). Thus, maintaining a balance between ROS generation and ROS scavenging in stressful environments is crucial for the survival of plants (Li et al, 2022). AMF mitigates oxidative damage and enhances drought tolerance through two distinct strategies.…”