Arbuscular Mycorrhizal Fungi Regulate Polyamine Homeostasis in Roots of Trifoliate Orange for Improved Adaptation to Soil Moisture Deficit Stress

Abstract

Soil arbuscular mycorrhizal fungi (AMF) enhance the tolerance of plants against soil moisture deficit stress (SMDS), but the underlying mechanisms are still not fully understood. Polyamines (PAs) as low-molecular-weight, aliphatic polycations have strong roles in abiotic stress tolerance of plants. We aimed to investigate the effect of AMF (Funneliformis mosseae) inoculation on PAs, PA precursors, activities of PA synthases and degrading enzymes, and concentration of reactive oxygen species in the roots of trifoliate orange (Poncirus trifoliata) subjected to 15 days of SMDS. Leaf water potential and total chlorophyll levels were comparatively higher in AMF-inoculated than in non-AMF-treated plants exposed to SMDS. Mycorrhizal plants recorded a significantly higher concentration of precursors of PA synthesis such as L-ornithine, agmatine, and S-adenosyl methionine, besides higher putrescine and cadaverine and lower spermidine during the 15 days of SMDS. AMF colonization raised the PA synthase (arginine decarboxylase, ornithine decarboxylase, spermidine synthase, and spermine synthase) activities and PA-degrading enzymes (copper-containing diamine oxidase and FAD-containing polyamine oxidase) in response to SMDS. However, mycorrhizal plants showed a relatively lower degree of membrane lipid peroxidation, superoxide anion free radical, and hydrogen peroxide than non-mycorrhizal plants, whereas the difference between them increased linearly up to 15 days of SMDS. Our study concluded that AMF regulated PA homeostasis in roots of trifoliate orange to tolerate SMDS.

Physiological responses of mycorrhizal symbiosis to drought stress in white clover

“…AMF are a kind of beneficial soil microorganisms that can form mutualistic symbiosis with more than 80% of terrestrial plants including white clover. Under environmental stresses including DS, AMF can induce various responses in plants to improve stress tolerance (He et al, 2020a;Meng et al, 2020;Zou et al, 2021).…”

Inoculation with Clariodeoglomus etunicatum improves leaf food quality of tea exposed to P stress

“…Among them, AMF in soil can form symbiotic arbuscular mycorrhizas (AMs) with most terrestrial plants. In AM symbiotic system, AM fungi can not only directly improve the absorption of soil nutrients through external hyphae (Mei et al, 2019;He et al, 2020a;Wu et al, 2020), enhance the ability of plants to resist abiotic stresses (Wu et al, 2019a;He et al, 2020b;Zhang et al, 2020;Zou et al, 2020Zou et al, , 2021, but also improve the disease resistance of plants (Zhang et al, 2019b), thus improving the yield and quality of plants (Wu et al, 2020). In sustainable agricultural development, the role of AMF in improving plant growth and quality has been widely concerned (Wu et al, 2020).…”

Arbuscular Mycorrhiza-Mediated Regulation of Polyamines and Aquaporins During Abiotic Stress: Deep Insights on the Recondite Players

“…GABAT converts GABA into a subsequent substrate, succinate, which is consumed in the tricarboxylic acid cycle (TCA) cycle to synthesize carbohydrates. In a recent study by Zou et al (2021), AMF-regulated PA homeostasis in the roots of P. trifoliata plants was found to be associated with enhanced tolerance against soil moisture deficit stress (SMDS). Mycorrhizal plants exhibited a significantly higher concentration of PA precursors, L-ornithine, agmatine, and SAM, increased Put and Cad, and reduced Spd content.…”