School of Biotechnology and Biomolecular Sciences, University of New South Wales, New South Wales, Australia.
School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia.
Environ Microbiol. 2022 Nov;24(11):5467-5482. doi: 10.1111/1462-2920.16098. Epub 2022 Jun 29.
The soil surface of drylands can typically be colonized by cyanobacteria and other microbes, forming biological soil crusts or 'biocrusts'. Biocrusts provide critical benefits to ecosystems and are a common component of the largely arid and semi-arid Australian continent. Yet, their distribution and the parameters that shape their microbial composition have not been investigated. We present here the first detailed description of Australia's biocrust microbiome assessed from 15 sites across the continent using 16S rRNA sequencing. The most abundant bacterial phyla from all sites were Cyanobacteria, Proteobacteria, Actinobacteria, Chloroflexi and Bacteroidetes. Cyanobacterial communities from northern regions were more diverse and unclassified cyanobacteria were a noticeable feature of northern biocrusts. Segregation between northern and southern regions was largely due to the differential abundance of Microcoleus spp., with M. paludosus dominating in the north and M. vaginatus dominating in the south. The geographical shifts in bacterial composition and diversity were correlated to seasonal temperatures and summer rainfall. Our findings provide an initial reference for sampling strategies to maximize access to bacterial genetic diversity. As hubs for essential ecosystem services, further investigation into biocrusts in arid and semi-arid regions may yield discoveries of genetic mechanisms that combat increases in warming due to climate change.
干旱地区的土壤表面通常可以被蓝细菌和其他微生物定植，形成生物土壤结皮或“生物结皮”。生物结皮为生态系统提供了关键的益处，是澳大利亚大陆大部分干旱和半干旱地区的常见组成部分。然而，它们的分布和塑造其微生物组成的参数尚未得到调查。我们在这里首次详细描述了澳大利亚的生物结皮微生物组，该微生物组是从澳大利亚大陆的 15 个地点使用 16S rRNA 测序评估的。所有地点最丰富的细菌门是蓝细菌、变形菌门、放线菌门、绿弯菌门和拟杆菌门。来自北部地区的蓝细菌群落更加多样化，未分类的蓝细菌是北部生物结皮的一个显著特征。北部和南部地区之间的分离主要是由于微鞘藻属的丰度差异，其中 M. paludosus 在北部占优势，M. vaginatus 在南部占优势。细菌组成和多样性的地理变化与季节性温度和夏季降雨量有关。我们的发现为采样策略提供了初步参考，以最大限度地获取细菌遗传多样性。作为重要生态系统服务的中心，对干旱和半干旱地区生物结皮的进一步研究可能会发现对抗气候变化导致变暖增加的遗传机制。
