Root-associated fungal communities of the critically endangered plant Pinus squamata

doi:10.17521/cjpe.2025.0021

Abstract

Abstract:

Aims Pinus squamata is a critically endangered species endemic to China, restricted to Qiaojia County, Yunnan Province. It faces significant challenges such as fragile habitats and difficulties in population recovery. Fungal communities play a vital role in the population maintenance and ecological adaptation of endangered plants. However, studies on the fungal community characteristics within the roots and rhizosphere of P. squamata are currently insufficient.
Methods This study used in-situ sampling and high-throughput sequencing to analyze the fungal community structures and their geographical patterns of both wild and cultivated populations of P. squamata. Additionally, it compared the fungal community structures of Pinus squamata with those of its neighboring plant species.
Important findings (1) There are significant differences in the fungal community structures within the roots and rhizosphere between the wild and cultivated populations of P. squamata. The fungal diversity in the wild populations is lower than that of the ex-situ conserved population. (2) In the wild populations, the fungal communities differ significantly between individuals in the west-slope and east-slope populations. (3) Ectomycorrhizal (ECM) fungi, such as species from the genera Sebacina, Russula, and Xanthoconium, dominate the root systems of P. squamata. Individuals in the west-slope population, which inhabit nutrient-poor soils, exhibit greater dependence on ECM fungi. (4) Pinus squamata shares some ECM fungi with neighboring tree species, highlighting the cooperative role of mycorrhizal fungal networks in resource sharing and ecological stability. This study reveals both abiotic and biotic factors influencing the fungal communities of P. squamata. Results of this study suggest that conservation efforts should combine inoculation with ectomycorrhizal fungi and improvement of the seedling soil to restore the critical ectomycorrhizal networks, thereby promoting the vision of integrated recovery of the “pine-fungus” system.

Key words: endangered plant, extremely small population, Pinus squamata, ectomycorrhizal fungi, root-associated fungal community, conservation strategies

ZHANG Zi-Rui, ZHOU Jing, HU Yan-Ping, LIANG Shuang, MA Yong-Peng, CHEN Wei-Le. Root-associated fungal communities of the critically endangered plant Pinus squamata[J]. Chin J Plant Ecol, 2025, 49(10): 1600-1611.

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URL: https://www.plant-ecology.com/EN/10.17521/cjpe.2025.0021

https://www.plant-ecology.com/EN/Y2025/V49/I10/1600

Figures/Tables 8

Fig. 1 Sampling points distribution map of Yaoshan Nature Reserve in Qiaojia County. ESP, east-slope population; NP, near-situ reintroduced population; WSP west-slope population.

Table 1 Soil physicochemical properties (mean ± SE) at different sampling sites of Pinus squamata

土壤性质 Soil property	野生种群 Wild population		人工繁育种群 Cultivated population
土壤性质 Soil property	西坡种群 WSP	东坡种群 ESP	近地回归 NP	迁地保护 EP
土壤全氮含量 TN content (mg·g^-1)	4.27 ± 1.84^b	7.27 ± 2.44^a	2.22 ± 0.95^c	5.28 ± 2.28^b
土壤全碳含量 TC content (mg·g^-1)	50.62 ± 24.65^b	86.36 ± 32.10^a	30.07 ± 11.53^b	78.42 ± 24.87^a
含水量 SWC (%)	8.09 ± 1.32^b	7.88 ± 2.58^b	7.70 ± 2.35^b	20.44 ± 8.37^a

Fig. 2 Constrained Principal Coordinate (CPCo) analysis based on Bray-Curtis distances was conducted to explore the differences in the structure of endophytic (A) and rhizosphere (D) fungal communities among the wild population, near-situ reintroduced population, and ex-situ conserved population. Shannon-Wiener diversity index and ACE richness index were used to measure the α-diversity of fungal communities in endophytic (B, C) and rhizosphere (E, F). Different lowercase letters indicate significant differences (p < 0.05). EP, ex-situ conserved population; NP, near-situ reintroduced population; WP, wild population.

Fig. 3 Relative abundance (at the genus level) of endophytic (A) and rhizosphere (C) fungal communities in the wild population, near-situ reintroduced population, and ex-situ conserved population, as well as the relative abundance of different functional types in endophytic (B) and rhizosphere (D) fungal communities. EP, ex-situ conserved population; NP, near-situ reintroduced population; WP, wild population. ECM, ectomycorrhizal.

Fig. 4 Shannon-Wiener diversity index and ACE richness index of the endophytic (A, B) and rhizosphere (D, E) fungal communities in the west-slope population and east-slope population were tested for significant differences using the Mann-Whitney U test, and Non-metric Multidimensional Scaling (NMDS) analysis based on Bray-Curtis distances of endophytic (C) and rhizosphere (F) fungal communities in the west-slope population and east-slope population. *, p < 0.05; ***, p < 0.001; ****, p < 0.000 1. ESP, east-slope population; WSP, west-slope population.

Fig. 5 Relative abundance (at the genus level) of endophytic (A) and rhizosphere (C) fungal communities in the west-slope population and east-slope population, as well as the relative abundance of different functional types in endophytic (B) and rhizosphere (D) fungal communities. ESP, east-slope population; WSP, west-slope population. ECM, ectomycorrhizal.

Fig. 6 Non-metric Multidimensional Scaling (NMDS) analysis based on Bray-Curtis distances of the Pinus squamata and four neighboring species for all fungal communities within the roots (A) and ectomycorrhizal (ECM) fungal communities (B), as well as all fungal communities in the rhizosphere (C) and ECM fungal communities (D). LP, Lithocarpus polystachyus; PS, Pinus squamata; PY, Pinus yunnanensis; RC, Rhus chinensis; RL, Rhamnus leptophylla.

Fig. 7 Relative abundance of the top 3 ectomycorrhizal (ECM) fungal genera within the roots (A, C, E) and in the rhizosphere (B, D, F) of the wild west-slope Pinus squamata and four neighboring species. All differences were tested using the Kruskal-Wallis test, with different lowercase letters indicating significant difference (p < 0.001), and ns marked for non-significance. LP, Lithocarpus polystachyus; PS, Pinus squamata; PY, Pinus yunnanensis; RC, Rhus chinensis; RL, Rhamnus leptophylla.

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