Department of Biology, Universidad del Turabo, Gurabo, Puerto Rico.
Mycologia. 2013 Jul-Aug;105(4):827-36. doi: 10.3852/12-288. Epub 2013 May 24.
Microbial mats are a laminated organic-sedimentary ecosystem, found in a wide range of habitats. Fluctuating diel and seasonal physicochemical gradients characterize these ecosystems, resulting in both strata and microenvironments that harbor specific microbial communities. This study was undertaken to compare two types of microbial mats across seasons to further understand the structure of fungal communities in hypersaline microbial mats and their seasonal dynamics. The structure and diversity of fungal communities was documented in young transient and mature hypersaline microbial mats from a tropical region (Puerto Rico) using one culture-dependent and three culture-independent molecular techniques based on the internal transcribed spacer (ITS) region of ribosomal DNA: terminal restriction fragment length polymorphism (TRFLP), denaturing gradient gel electrophoresis (DGGE) and clone libraries. Two microbial mats (one young and transient, one mature) were sampled in Nov 2007 (wet season), Jan 2008 (intermediate season) and Mar 2008 (dry season) in the Cabo Rojo Solar Salterns on the southwestern coast of Puerto Rico. Traditional and molecular techniques revealed strong spatial and temporal heterogeneities in both microbial mats. Higher abundance of isolates and phylotypes were observed during the wet season, and diversity decreased from the top (oxic) to the bottom (anoxic) layers in both seasons. Some of the species isolated belong to the genera Aspergillus, Cladosporium, Hortaea, Pichia and Wallemia, which often are isolated from hypersaline environments. The most abundant clones belong to Acremonium strictum and Cladosporium halotolerans, which were not isolated in pure culture. The differences observed using culture-based and molecular techniques demonstrates the need of combining methods to study the diversity of fungi in a given substrate.
微生物席是一种分层的有机-沉积生态系统，存在于广泛的生境中。这些生态系统具有波动的昼夜和季节性物理化学梯度，导致特定的微生物群落栖息在不同的地层和微环境中。本研究旨在比较两种类型的微生物席，以进一步了解高盐微生物席中真菌群落的结构及其季节性动态。使用一种依赖培养的和三种基于核糖体 DNA 内转录间隔区 (ITS) 区的非依赖培养的分子技术，对来自热带地区（波多黎各）的年轻瞬态和成熟高盐微生物席中的真菌群落的结构和多样性进行了研究：末端限制性片段长度多态性 (TRFLP)、变性梯度凝胶电泳 (DGGE) 和克隆文库。2007 年 11 月（雨季）、2008 年 1 月（中间季）和 2008 年 3 月（旱季），在波多黎各西南海岸的卡沃罗霍太阳能盐场采集了两个微生物席（一个年轻瞬态，一个成熟）。传统和分子技术揭示了两个微生物席具有强烈的时空异质性。在雨季观察到更多的分离株和系统发育型，并且在两个季节中，多样性从顶部（氧化）到底部（缺氧）层减少。分离到的一些物种属于曲霉属、枝孢属、Hortaea 属、毕赤酵母属和瓦勒米酵母属，这些属通常分离自高盐环境。最丰富的克隆属于 Acremonium strictum 和 Cladosporium halotolerans，它们未在纯培养中分离到。基于培养的和分子技术观察到的差异表明，需要结合方法来研究特定基质中真菌的多样性。
