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This review highlights the key role that mycorrhizal fungi play in making phosphorus (Pi) more available to plants, including pathways of phosphorus absorption, phosphate transporters and plant-mycorrhizal fungus symbiosis, especially in conditions where the level of inorganic phosphorus (Pi) in the soil is low. Mycorrhizal fungi colonization involves a series of signaling where the plant root exudates strigolactones, while the mycorrhizal fungi release a mixture of chito-oligosaccharides and liposaccharides, that activate the symbiosis process through gene signaling pathways, and contact between the hyphae and the root. Once the symbiosis is established, the extraradical mycelium acts as an extension of the roots and increases the absorption of nutrients, particularly phosphorus by the phosphate transporters. Pi then moves along the hyphae to the plant root/fungus interface. The transfer of Pi occurs in the apoplectic space; in the case of arbuscular mycorrhizal fungi, Pi is discharged from the arbuscular to the plant’s root symplasm, in the membrane that surrounds the arbuscule. Pi is then absorbed through the plant periarbuscular membrane by plant phosphate transporters. Furthermore, plants can acquire Pi from soil as a direct absorption pathway. As a result of this review, several genes that codify for high-affinity Pi transporters were identified. In plants, the main family is Pht1 although it is possible to find others such as Pht2, Pht3, Pho1 and Pho2. As in plants, mycorrhizal fungi have genes belonging to the Pht1 subfamily. In arbuscular mycorrhizal fungi we found L1PT1, GiPT, MtPT1, MtPT2, MtPT4, HvPT8, ZmPht1, TaPTH1.2, GmosPT and LYCes. HcPT1, HcPT2 and BePT have been characterized in ectomycorrhizal fungi. Each gene has a different way of expressing itself. In this review, we present diagrams of the symbiotic relationship between mycorrhizal fungi and the plant. This knowledge allows us to design solutions to regional problems such as food production in soils with low levels of Pi.
相似文献Salicylic acid (SA) is a plant hormone that stimulates the growth and metabolism of plants, also acting as an abiotic elicitor. This study aimed to evaluate the effect of SA on leaf production, leaf area and synthesis of secondary compounds in yarrow plants. The experiments were conducted under field conditions in two consecutive years and f-received SA foliar applications (T1-control; T2-1.0 mmol L−1 applications at 20, 60 and 100 days after planting (DAP) and T3-1.0 mmol L−1 applications at 100 DAP during 3 days). The exogenous application of SA resulted in increases in leaf area (total and specific), number of leaves and leaf mass ratio of yarrow plants, polyphenolic compounds, phenylalanine ammonia-lyase and chalcone synthase enzymes and the antioxidant activity of the plant extract. The HPLC–DAD–MS/MS analysis of phenolic compounds revealed increases in the amounts of quinic acid and rutin. The results of this research lead us to affirm that SA exerted both the hormonal effect on number of leaves and leaf area, and also acted as eliciting substance.
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