Department of Microbiology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University (NCU), Lwowska 1, 87-100, Torun, Poland.
Department of Natural Resources and the Environment, Cornell University, 111 Fernow Hall, Ithaca, NY, 14853, USA.
Sci Rep. 2023 Dec 20;13(1):22831. doi: 10.1038/s41598-023-49447-w.
The tolerance of European alder (Alnus glutinosa Gaertn.) to soil salinity can be attributed to symbiosis with microorganisms at the absorptive root level. However, it is uncertain how soil salinity impacts microbial recruitment in the following growing season. We describe the bacterial and fungal communities in the rhizosphere and endosphere of A. glutinosa absorptive roots at three tested sites with different salinity level. We determined the morphological diversity of ectomycorrhizal (ECM) fungi, the endophytic microbiota in the rhizosphere, and the colonization of new absorptive roots in the following growing season. While bacterial diversity in the rhizosphere was higher than that in the absorptive root endosphere, the opposite was true for fungi. Actinomycetota, Frankiales, Acidothermus sp. and Streptomyces sp. were more abundant in the endosphere than in the rhizosphere, while Actinomycetota and Acidothermus sp. dominated at saline sites compared to nonsaline sites. Basidiomycota, Thelephorales, Russulales, Helotiales, Cortinarius spp. and Lactarius spp. dominated the endosphere, while Ascomycota, Hypocreales and Giberella spp. dominated the rhizosphere. The ECM symbioses formed by Thelephorales (Thelephora, Tomentella spp.) constituted the core community with absorptive roots in the spring and further colonized new root tips during the growing season. With an increase in soil salinity, the overall fungal abundance decreased, and Russula spp. and Cortinarius spp. were not present at all. Similarly, salinity also negatively affected the average length of the absorptive root. In conclusion, the endophytic microbiota in the rhizosphere of A. glutinosa was driven by salinity and season, while the ECM morphotype community was determined by the soil fungal community present during the growing season and renewed in the spring.
欧洲桤木（Alnus glutinosa Gaertn.）对土壤盐分的耐受性可归因于其与吸收根水平的微生物共生。然而，目前尚不清楚土壤盐分如何影响下一季微生物的招募。我们描述了在三个不同盐度水平的测试点，桤木吸收根的根际和根内的细菌和真菌群落。我们确定了外生菌根（ECM）真菌、根际内生微生物区系以及下一季新吸收根的定植的形态多样性。虽然根际的细菌多样性高于吸收根的根内，但真菌则相反。放线菌门、弗兰克氏菌目、酸热菌属和链霉菌属在根内比在根际更丰富，而放线菌门和酸热菌属在盐渍地比非盐渍地更丰富。担子菌门、层孔菌目、红菇目、蜡壳耳目、红菇科和乳菇科在根内占主导地位，而子囊菌门、腔孢纲和镰孢菌属在根际占主导地位。层孔菌目（栓孔菌属、拟层孔菌属）形成的 ECM 共生体构成了春季与吸收根共生的核心群落，并在生长季节进一步定植新的根尖。随着土壤盐分的增加，真菌的总丰度降低，红菇属和蜡壳耳科完全不存在。同样，盐度也对吸收根的平均长度产生负面影响。总之，桤木根际的根内微生物群受盐分和季节的驱动，而 ECM 形态型群落则由生长季节存在的土壤真菌群落决定，并在春季更新。
