Ectomycorrhizal symbiosis is a cornerstone of ecosystem health, facilitating nutrient uptake, stress tolerance, and biodiversity maintenance in trees. Optimizing Pinus armandii–Tuber indicum mycorrhizal synthesis enhances the ecological stability of coniferous forests while supporting high-value truffle cultivation. This study conducted a pot experiment to compare the effects of three root nutrient regulations—Aolu 318S (containing N-P₂O₅-K₂O in a ratio of 15-9-11 (w/w%)), Aolu 328S (11-11-18), and Youguduo (19-19-19)—on the mycorrhizal synthesis of P. armandii–T. indicum. The results showed that root nutrient supplementation significantly improved the seedling crown, plant height, ground diameter, biomass dry weight, and mycorrhizal infection rate of both the control and mycorrhizal seedlings, with the slow-release fertilizers Aolu 318S and 328S outperforming the quick-release fertilizer Youguduo. The suitable substrate composition in this experiment was as follows: pH 6.53–6.86, organic matter content 43.25–43.49 g/kg, alkali-hydrolyzable nitrogen 89.25–90.3 mg/kg, available phosphorus 83.69–87.32 mg/kg, available potassium 361.5–364.65 mg/kg, exchangeable magnesium 1.17–1.57 mg/kg, and available iron 33.06–37.3 mg/kg. It is recommended to mix the Aolu 318S and 328S solid fertilizers evenly into the substrate, with a recommended dosage of 2 g per plant. These results shed light on the pivotal role of a precise N-P-K ratio regulation in fostering sustainable ectomycorrhizal symbiosis, offering a novel paradigm for integrating nutrient management with mycorrhizal biotechnology to enhance forest restoration efficiency in arid ecosystems.

Tuber is a rare edible and medicinal fungus with a global distribution. The Macrosporum lineage within Tuber is a relatively small and infrequent clade, which has been receiving increasing attention due to the presence of an endangered species, T. gigantosporum. However, the species diversity, phylogenetic relationships, geographic distribution, and ecological characteristics of the Macrosporum group remain poorly understood. Through extensive sampling and combining the accurate and available global specimen and mycorrhizal data, 19 Tuber specimens from Southwest China were studied based on morphology, molecular systematics, and ecology. The specimens were identified as T. calosporum, T. glabrum, and T. sinomacrosporum within the Macrosporum group, with detailed descriptions provided, particularly supplementing the taxonomic features of T. glabrum. A classification key for the Macrosporum group species is also provided. The geographic distribution of specimens and diverse hosts suggest that the Macrosporum clade displays wider ecological adaptability. This study is important to better understand the diversity and conservation measures of Tuber resources throughout the world.

Tuber encompasses ectomycorrhizal fungi (EMF) of significant ecological and economic importance. This study reports the first controlled synthesis of ectomycorrhizae between the near-threatened species T. umbilicatum and Quercus glauca, confirmed through molecular analysis and detailed morphological characterization. Colonization dynamics, assessed over eight months, revealed substantial physiological benefits for the host. At six months post-inoculation, seedling height and above-ground biomass increased by 20.8% and 27.1%, respectively; these increments persisted to eight months, with above-ground biomass remaining 16.9% higher and below-ground biomass elevated by 25.4%. Concomitantly, the photosynthetic performance was markedly improved: a net photosynthetic rate (A) rose by 136.8% and stomatal conductance (g_s) by 36.5% at six months. Available phosphorus (AP) in the mycorrhizosphere was concurrently enhanced, exhibiting a 10.9% increment at eight months. These results underscore the agronomic and conservation utility of T. umbilicatum inoculation for Q. glauca and provide a critically experimental foundation for the ex situ preservation and sustainable truffle cultivation of this threatened fungal taxon.