Dawson Robin A, Fantom Nicola, Martin-Pozas Tamara, Aguila Patricia, King Gary M, Hernández Marcela
School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK.
Department of Biology and Geology, University of Almería, 04120, Almería, Spain.
Environ Microbiome. 2025 Jan 26;20(1):12. doi: 10.1186/s40793-025-00672-y.
Carbon monoxide (CO) oxidising microorganisms are present in volcanic deposits throughout succession, with levels of vegetation and soil influencing the communities present. Carboxydovores are a subset of CO oxidisers that use CO as an energy source, which raises questions about the physiological and metabolic features that make them more competitive in harsh volcanic ecosystems. To address these questions, samples were taken from volcanic strata formed by eruptions from Calbuco Volcano (Chile) in 2015 (tephra) and 1917 (soil). Two carboxydovore members of the Burkholderiaceae family were isolated for further study to elucidate the benefits of carboxydovory for the survival of these strains in extreme volcanic ecosystems. The isolates were identified as Paraburkholderia terrae COX (isolated from the 2015 tephra) and Cupriavidus str. CV2 (isolated from the 1917 soil). 16S rRNA gene sequencing showed that within the family Burkholderiacea, the genus Paraburkholderia dominated the 2015 volcanic deposit with an average relative abundance of 73.81%, whereas in the 1917 volcanic deposit, Cupriavidus accounted for 33.64% (average relative abundance). Both strains oxidise CO across a broad range of concentrations (< 100 ppmv - 10,000 ppmv), and genome sequence analysis revealed a candidate form-I carbon monoxide dehydrogenase (CODH), which is likely to catalyse this process. Each strain oxidised CO specifically at stationary phase but the conditions for induction of CODH expression were distinct. Cupriavidus strain CV2 expressed CODH only when CO was added to cultures (100 ppm), while Pb. terrae COX expressed CODH regardless of supplementary CO addition. Based on comparative metabolic and phylogenetic analyses, Cupriavidus strain CV2 is proposed as a novel species within the genus Cupriavidus with the name Cupriavidus ulmosensis sp. nov. for the type strain CV2 (= NCIMB 15506, = CECT 30956). This study provides valuable insights into the physiology and metabolism of carboxydovores which colonise volcanic ecosystems.
在火山沉积物演替的各个阶段都存在一氧化碳（CO）氧化微生物，植被和土壤的水平会影响其中存在的群落。羧基营养菌是利用CO作为能源的CO氧化菌的一个子集，这引发了关于使其在恶劣火山生态系统中更具竞争力的生理和代谢特征的问题。为了解决这些问题，从2015年（火山灰）和1917年（土壤）卡尔布科火山（智利）喷发形成的火山地层中采集了样本。分离出伯克霍尔德氏菌科的两个羧基营养菌成员进行进一步研究，以阐明羧基营养对这些菌株在极端火山生态系统中生存的益处。分离株被鉴定为土生副伯克霍尔德菌COX（从2015年火山灰中分离）和贪铜菌属菌株CV2（从1917年土壤中分离）。16S rRNA基因测序表明，在伯克霍尔德氏菌科中，副伯克霍尔德菌属在2015年火山沉积物中占主导地位，平均相对丰度为73.81%，而在1917年火山沉积物中，贪铜菌属占33.64%（平均相对丰度）。两种菌株在广泛的浓度范围（<100 ppmv - 10,000 ppmv）内都能氧化CO，基因组序列分析揭示了一种可能催化该过程的候选I型一氧化碳脱氢酶（CODH）。每种菌株都在稳定期特异性地氧化CO，但CODH表达的诱导条件不同。贪铜菌菌株CV2仅在向培养物中添加CO（100 ppm）时才表达CODH，而土生副伯克霍尔德菌COX无论是否添加补充CO都表达CODH。基于比较代谢和系统发育分析，贪铜菌菌株CV2被提议作为贪铜菌属内的一个新物种，模式菌株CV2（=NCIMB 15506，=CECT 30956）的名称为乌尔莫贪铜菌（Cupriavidus ulmosensis sp. nov.）。这项研究为定殖于火山生态系统的羧基营养菌的生理学和代谢提供了有价值的见解。
