Fungal endophyte associations have been suggested as a possible strategy of Antarctic vascular plants for surviving the extreme environmental conditions of Antarctica. However, the mechanisms by which this occurs are still poorly understood. The role of root fungal endophytes in nitrogen mineralization and nutrient uptake, as well as their impact on the performance of Antarctic plants, were studied. We tested root endophytes, isolated from Colobanthus quitensis and Deschampsia antarctica, for lignocellulolytic enzyme production, nitrogen mineralization, and growth enhancement of their host plants. Penicillium chrysogenum and Penicillium brevicompactum were identified using a molecular approach as the main root endophytes inhabiting C. quitensis and D. antarctica, respectively. Both root endophytes were characterized as psychrophilic fungi displaying amylase, esterase, protease, cellulase, hemicellulase, phosphatase and urease enzymatic activities, mainly at 4 °C. Moreover, the rates and percentages of nitrogen mineralization, as well as the final total biomass, were significantly higher in symbiotic C. quitensis and D. antarctica individuals. Our findings suggest that root endophytes exert a pivotal ecological role based not only to breakdown different nutrient sources but also on accelerating nitrogen mineralization, improving nutrient acquisition, and therefore promoting plant growth in Antarctic terrestrial ecosystems.

中文翻译：

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根内生青霉通过增强氮矿化促进南极维管植物的生长。

真菌内生菌群被认为是南极维管植物在南极极端环境条件下生存的一种可能策略。然而，发生这种情况的机制仍然知之甚少。研究了根真菌内生菌在氮矿化和养分吸收中的作用，以及它们对南极植物性能的影响。我们测试了从Colobanthus quitensis和Deschampsia antarctica 中分离出来的根内生菌，用于它们宿主植物的木质纤维素分解酶的产生、氮矿化和生长增强。使用分子方法鉴定了Penicillium chrysogenum和Penicillium brevicompactum作为主要的根内生菌。分别为C.quitensis和D. antarctica。两种根内生菌都被表征为嗜冷真菌，显示淀粉酶、酯酶、蛋白酶、纤维素酶、半纤维素酶、磷酸酶和脲酶酶活性，主要在 4°C 下。此外，共生C.quitensis和D. antarctica个体的氮矿化速率和百分比以及最终总生物量显着更高。我们的研究结果表明，根内生菌发挥着关键的生态作用，不仅可以分解不同的营养来源，还可以加速氮矿化，改善营养获取，从而促进南极陆地生态系统中的植物生长。