Pan Gao, Hu Jiayao, Zi Zhen, Wang Wenying, Li Xinhang, Xu Xiaoli, Liu Wensheng
College of Life and Environmental Sciences, Central South University of Forestry and Technology, Changsha, China.
Hunan Research Center of Engineering Technology for Utilization of Environmental and Resources Plant, Central South University of Forestry and Technology, Changsha, China.
Front Plant Sci. 2024 Nov 27;15:1470063. doi: 10.3389/fpls.2024.1470063. eCollection 2024.
Arbuscular mycorrhizal fungi (AMF) can relieve manganese (Mn) phytotoxicity and promote plant growth under Mn stress, but their roles remain unclear.
In this study, inoculated with or without AMF () under different Mn concentrations (0 mmol/L, 1 mmol/L, 5 mmol/L, 10 mmol/L, and 20 mmol/L) was cultivated via a pot experiment, and plant biomass, physiological and biochemical characteristics, manganese absorption, subcellular distribution, and chemical forms of Mn were examined.
The results showed that root biomass, stem biomass, leaf biomass, and total individual biomass decreased under high Mn concentrations (above 10 mmol/L), and the inoculated plants had higher biomass than the uninoculated plants. With the increasing Mn concentration, the contents of soluble sugar, soluble protein, free proline, superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) increased first and then decreased, while the malondialdehyde (MDA) content increased. The contents of soluble sugar, soluble protein, free proline, SOD, POD, and CAT in the inoculated group were higher than those in the uninoculated group at the Mn concentration of 20 mmol/L. The content of MDA in the inoculated plants was lower than that in the uninoculated plants. AMF inoculation enriched most of the manganese in the root system when compared with the non-mycorrhizal treatment. Subcellular distribution of Mn indicated that most of the Mn ions were stored in the cell wall and the vacuoles (the soluble fractions), and the proportion of Mn content in the cell wall components and the vacuole components in leaves in the inoculated group was higher than that in the uninoculated group. Furthermore, the proportions of Mn extracted using ethanol and deionized water in the uninoculated group in stems and roots were higher than those in the inoculated group, which suggested that AMF could convert Mn into inactive forms.
The present study demonstrated that AMF could improve the resistance of to Mn toxicity by increasing the activity of antioxidant enzymes and altering the subcellular distribution and chemical forms of Mn.
丛枝菌根真菌（AMF）在锰胁迫下可缓解锰（Mn）的植物毒性并促进植物生长，但其作用仍不明确。
本研究通过盆栽试验，在不同锰浓度（0 mmol/L、1 mmol/L、5 mmol/L、10 mmol/L和20 mmol/L）下接种或不接种AMF（）来培育植物，并检测植物生物量、生理生化特性、锰吸收、亚细胞分布以及锰的化学形态。
结果表明，在高锰浓度（高于10 mmol/L）下，根生物量、茎生物量、叶生物量和单株总生物量均下降，且接种植物的生物量高于未接种植物。随着锰浓度的增加，可溶性糖、可溶性蛋白、游离脯氨酸、超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）的含量先增加后降低，而丙二醛（MDA）含量增加。在20 mmol/L的锰浓度下，接种组中可溶性糖、可溶性蛋白、游离脯氨酸、SOD、POD和CAT的含量高于未接种组。接种植物中MDA的含量低于未接种植物。与非菌根处理相比，接种AMF使大部分锰富集在根系中。锰的亚细胞分布表明，大部分锰离子储存在细胞壁和液泡（可溶性部分）中，接种组叶片中细胞壁成分和液泡成分中锰含量的比例高于未接种组。此外，未接种组茎和根中用乙醇和去离子水提取的锰的比例高于接种组，这表明AMF可以将锰转化为无活性形式。
本研究表明，AMF可通过提高抗氧化酶活性以及改变锰的亚细胞分布和化学形态来提高植物对锰毒性的抗性。
