Xu Lingjie, He Jiadong, Meng Yu, Zheng Yanyan, Lu Bin, Zhang Jiawen, Zhou Yong
Country College of Landscape Architecture and Tourism, Hebei Agricultural University, Baoding, China.
Earth and Life Institute, Université catholique de Louvain-UCLouvain, Louvain-la-Neuve, Belgium.
Front Plant Sci. 2024 Aug 20;15:1446437. doi: 10.3389/fpls.2024.1446437. eCollection 2024.
Drought constitutes a major abiotic stress factor adversely affecting plant growth and productivity. Plant-microbe symbiotic associations have evolved regulatory mechanisms to adapt to environmental stress conditions. However, the interactive effects of different fungi on host growth and stress tolerance under drought conditions remain unclear.
This study explored the effects of varying polyethylene glycol (PEG-6000) concentrations (0%, 15%, 25%, and 35%) on the growth and physiological responses of two ectomycorrhizal fungi ( (Sg) and (Pt)) and two dark septate endophytes ( (Po) and sp. (Ps)) isolated from the root system of . Specifically, the study aimed to evaluate six inoculation treatments, including no inoculation (CK), single inoculations with Sg, Pt, Po, Ps, and a mixed inoculation (Sg: Pt : Po: Ps = 1:1:1:1), on the growth and physiological characteristics of seedlings under different water regimes: well-watered at 70% ± 5%, light drought at 50% ± 5%, and severe drought at 30% ± 5% of the maximum field water holding capacity.
All four fungi exhibited the capacity to cope with drought stress by enhancing antioxidant activities and regulating osmotic balance. Upon successful root colonization, they increased plant height, shoot biomass, root biomass, total biomass, and mycorrhizal growth response in seedlings. Under drought stress conditions, fungal inoculation improved seedling drought resistance by increasing superoxide dismutase and catalase activities, free proline and soluble protein contents, and promoting nitrogen and phosphorus uptake. Notably, mixed inoculation treatments significantly enhanced antioxidant capacity, osmotic adjustment, and nutrient acquisition abilities, leading to superior growth promotion effects under drought stress compared to single inoculation treatments.
All four fungi tolerated PEG-induced drought stress, with increased antioxidant enzyme activities and osmotic adjustment substances and they promoted the growth and enhanced drought resistance of seedlings.
干旱是一种主要的非生物胁迫因素，对植物生长和生产力产生不利影响。植物与微生物的共生关系已经进化出调节机制以适应环境胁迫条件。然而，在干旱条件下不同真菌对宿主生长和胁迫耐受性的交互作用仍不清楚。
本研究探讨了不同浓度聚乙二醇（PEG-6000）（0%、15%、25%和35%）对从 的根系分离出的两种外生菌根真菌（ （Sg）和 （Pt））以及两种深色有隔内生真菌（ （Po）和 种（Ps））生长和生理反应的影响。具体而言，该研究旨在评估六种接种处理，包括不接种（CK）、单独接种Sg、Pt、Po、Ps以及混合接种（Sg:Pt:Po:Ps = 1:1:1:1），对不同水分条件下 幼苗生长和生理特征的影响：最大田间持水量的70%±5%充分浇水、50%±5%轻度干旱和30%±5%重度干旱。
所有四种真菌都表现出通过增强抗氧化活性和调节渗透平衡来应对干旱胁迫的能力。成功定殖于根系后，它们增加了 幼苗的株高、地上生物量、根系生物量、总生物量和菌根生长响应。在干旱胁迫条件下，真菌接种通过增加超氧化物歧化酶和过氧化氢酶活性、游离脯氨酸和可溶性蛋白含量以及促进氮和磷吸收来提高幼苗抗旱性。值得注意的是，混合接种处理显著增强了抗氧化能力、渗透调节和养分获取能力，与单独接种处理相比，在干旱胁迫下具有更好的促生长效果。
所有四种真菌都能耐受PEG诱导的干旱胁迫，抗氧化酶活性和渗透调节物质增加，并且它们促进了 幼苗的生长并增强了其抗旱性。
