School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
Extremophiles. 2011 Jan;15(1):31-8. doi: 10.1007/s00792-010-0334-3. Epub 2010 Nov 11.
Quartz stones are ubiquitous in deserts and are a substrate for hypoliths, microbial colonists of the underside of such stones. These hypoliths thrive where extreme temperature and moisture stress limit the occurrence of higher plant and animal life. Several studies have reported the occurrence of green hypolithic colonization dominated by cyanobacteria. Here, we describe a novel red hypolithic colonization from Yungay, at the hyper-arid core of the Atacama Desert in Chile. Comparative analysis of green and red hypoliths from this site revealed markedly different microbial community structure as revealed by 16S rRNA gene clone libraries. Green hypoliths were dominated by cyanobacteria (Chroococcidiopsis and Nostocales phylotypes), whilst the red hypolith was dominated by a taxonomically diverse group of chloroflexi. Heterotrophic phylotypes common to all hypoliths were affiliated largely to desiccation-tolerant taxa within the Actinobacteria and Deinococci. Alphaproteobacterial phylotypes that affiliated with nitrogen-fixing taxa were unique to green hypoliths, whilst Gemmatimonadetes phylotypes occurred only on red hypolithon. Other heterotrophic phyla recovered with very low frequency were assumed to represent functionally relatively unimportant taxa.
石英石在沙漠中无处不在，是地下生物的基质，这些地下生物是石头底面的微生物殖民者。这些地下生物在极端温度和水分压力限制高等植物和动物生命出现的地方茁壮成长。有几项研究报告了以蓝藻为主的绿色地下生物殖民的发生。在这里，我们描述了一种来自智利阿塔卡马沙漠极度干旱核心的永盖的新型红色地下生物殖民。对来自该地点的绿色和红色地下生物的比较分析表明，16S rRNA 基因克隆文库揭示了微生物群落结构的显著差异。绿色地下生物主要由蓝藻（Chroococcidiopsis 和 Nostocales 类群）组成，而红色地下生物主要由一个分类多样性的绿屈挠菌门组成。所有地下生物中常见的异养型类群主要属于放线菌和厚壁菌门中耐旱的类群。与固氮类群相关的α变形菌门的类群是绿色地下生物所特有的，而Gemmatimonadetes 类群只出现在红色地下生物上。其他恢复频率非常低的异养门被认为代表功能上相对不重要的类群。
