Roman Ivan, Khylchuk Oleksandr, Fedorenko Victor, Gromyko Oleksandr
Department of Genetics and Biotechnology, Ivan Franko National University of Lviv, Lviv, 79000, Ukraine.
Microbial Culture Collection of Antibiotic Producers, Ivan Franko National University of Lviv, Lviv, 79000, Ukraine.
Folia Microbiol (Praha). 2025 Jun 7. doi: 10.1007/s12223-025-01282-4.
The rhizosphere microbiota plays a crucial role in plant growth and resilience, particularly in extreme environments such as Antarctica. This study explores the diversity and plant growth-promoting properties of actinomycetes associated with the rhizosphere of Deschampsia antarctica on Galindez Island, Maritime Antarctica, under varying microclimatic conditions and human-impacted sites. Using direct inoculation and selective pretreatment methods, a diverse array of actinomycete strains was isolated, representing genera such as Amorphoplanes, Embleya, Kribbella, Lentzea, Micromonospora, Nocardia, Rhodococcoides, Rhodococcus, Saccharopolyspora, Streptomyces, and Winogradskya. Sites influenced by human activity exhibited reduced actinomycete abundance and altered genus ratios compared to less disturbed areas. Among the isolated strains, many demonstrated the ability to produce siderophores for metals such as iron, nickel, copper, zinc, and manganese. Notably, five strains produced siderophores capable of binding all tested metals. Additionally, three strains exhibited the capacity to solubilize insoluble forms of both zinc and phosphorus while producing siderophores for all metals tested. Genomic analysis of one of these strains, namely, Streptomyces sp. Da 82-17, revealed an array of secondary metabolite gene clusters, including those for ectoine, paenibactin, and lidamycin, highlighting its significant biotechnological potential. Functional genomics identified genes encoding phytohormones, such as indole-3-acetic acid (IAA), and siderophores, which are critical for improving plant nutrient uptake and stress tolerance. These findings underscore the high biosynthetic potential of Antarctic actinomycetes for applications in agriculture, medicine, and biotechnology. Further research into microbiota from both human-impacted and pristine regions on Galindez Island will enhance understanding of microbial adaptation and inform strategies to mitigate anthropogenic impacts, preserving the unique Antarctic ecosystem.
根际微生物群在植物生长和恢复力方面发挥着关键作用，尤其是在南极洲等极端环境中。本研究探讨了在不同微气候条件和受人类影响的地点下，与南极德尚草（Deschampsia antarctica）根际相关的放线菌的多样性及其促进植物生长的特性。采用直接接种和选择性预处理方法，分离出了多种放线菌菌株，代表的属包括无定形放线菌属（Amorphoplanes）、恩布勒亚菌属（Embleya）、克里贝拉菌属（Kribbella）、伦茨菌属（Lentzea）、小单孢菌属（Micromonospora）、诺卡氏菌属（Nocardia）、红球菌属（Rhodococcoides）、红球菌属（Rhodococcus）、糖多孢菌属（Saccharopolyspora）、链霉菌属（Streptomyces）和维诺格拉茨基氏菌属（Winogradskya）。与受干扰较少的地区相比，受人类活动影响的地点放线菌丰度降低，属比例发生变化。在分离出的菌株中，许多菌株表现出为铁、镍、铜、锌和锰等金属产生铁载体的能力。值得注意的是，有五个菌株产生的铁载体能够结合所有测试金属。此外，三个菌株在为所有测试金属产生铁载体的同时，还表现出溶解锌和磷的不溶性形式的能力。对其中一个菌株，即链霉菌属（Streptomyces sp.）Da 82 - 17进行基因组分析，发现了一系列次生代谢物基因簇，包括那些编码埃托因、泛菌素和力达霉素的基因簇，突出了其巨大的生物技术潜力。功能基因组学鉴定出了编码植物激素（如吲哚 - 3 - 乙酸（IAA））和铁载体的基因，这些基因对于改善植物养分吸收和胁迫耐受性至关重要。这些发现强调了南极放线菌在农业、医学和生物技术应用方面具有很高的生物合成潜力。对加林德兹岛受人类影响和原始地区的微生物群进行进一步研究，将增进对微生物适应性的理解，并为减轻人为影响、保护独特的南极生态系统提供策略依据。
