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Scientia Silvae Sinicae ›› 2023, Vol. 59 ›› Issue (12): 117-124.doi: 10.11707/j.1001-7488.LYKX20220253

• Research papers • Previous Articles     Next Articles

Effects of Arbuscular Mycorrhizal Fungi on Phosphorus Uptake of Walnut Seedling Roots under Low Phosphorus Stress and the Potential Mechanisms

Ming'ao Cao1,Fei Zhang2,Guangming Huang1,Ruicheng Liu1,Liping Liu1,Qiangsheng Wu1,*,Yongjie Xu3   

  1. 1. College of Horticulture and Gardening/Tibet Plateau Walnut Industry Research Institute, Yangtze University Jingzhou 434025
    2. Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization Huanggang Normal University Huanggang 438000
    3. Hubei Academy of Forestry Science Wuhan 430075
  • Received:2022-04-16 Online:2023-12-25 Published:2024-01-08
  • Contact: Qiangsheng Wu

Abstract:

Objective: Walnut is a high-quality economic forest tree. Arbuscular mycorrhizal (AM) fungi can promote plant growth and phosphorus (P) uptake, however, the mechanisms by which AM fungi enhance nutrient utilization and plant growth in walnuts are not clear. This study aims to explore the effect of AM fungi on P uptake of walnuts under low P conditions and the associated mechanisms. Method: In this study, an effective AM fungal strain, Diversispora spurca, screened earlier, was used to inoculate Juglans regia cv. Liaohe 1 seedlings, and the effects of D. spurca on plant growth, root system architecture, root P, root and soil phosphatase activities, and the relative expression of root acid phosphatase secretion genes (JrPAP10 and JrPAP12) and phosphate transporter protein genes (JrPT3;1 and JrPT3;2) of J. regia cv. Liaohe 1 seedlings under appropriate P (100 μmol·L?1) and low P (1 μmol·L?1) level conditions were studied. Result: After three months of inoculation with D. spurca, the mycorrhizal colonization of walnut root system reached 45.6%–53.2%, and low P treatment significantly increased root mycorrhizal colonization, compared with appropriate P treatment. Inoculation of D. spurca significantly increased plant biomass and soil acid, neutral, and alkaline phosphatase activities under both low and appropriate P levels conditions. D. spurca also significantly improved root morphology as well as increased root P content and root acid phosphatase activity under low P condition. Root JrPAP10 expression was up-regulated by D. spurca under both low and appropriate P levels conditions, while JrPAP12 expression was induced by D. spurca only under low P level condition. In addition, D. spurca up-regulated the relative expression of JrPT3;1 in roots under both low P and appropriate P level conditions, while the expression of JrPT3;2 was inhibited by D. spurca. Conclusion: The AM fungus, D. spurca, can induce up-regulated expressions of JrPAP10, JrPAP12, and JrPT3;1 in roots of walnut seedlings under low P levels conditions, increase soil phosphatase, root acid phosphatase, and improve root morphology, and thereby enhancing P uptake and biomass accumulation of walnut seedlings.

Key words: walnut, mycorrhiza, phosphorus, phosphatase, phosphate transporter gene

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