Mogul Rakesh, Vaishampayan Parag, Bashir Mina, McKay Chris P, Schubert Keith, Bornaccorsi Rosalba, Gomez Ernesto, Tharayil Sneha, Payton Geoffrey, Capra Juliana, Andaya Jessica, Bacon Leonard, Bargoma Emily, Black David, Boos Katie, Brant Michaela, Chabot Michael, Chau Danny, Cisneros Jessica, Chu Geoff, Curnutt Jane, DiMizio Jessica, Engelbrecht Christian, Gott Caroline, Harnoto Raechel, Hovanesian Ruben, Johnson Shane, Lavergne Britne, Martinez Gabriel, Mans Paul, Morales Ernesto, Oei Alex, Peplow Gary, Piaget Ryan, Ponce Nicole, Renteria Eduardo, Rodriguez Veronica, Rodriguez Joseph, Santander Monica, Sarmiento Khamille, Scheppelmann Allison, Schroter Gavin, Sexton Devan, Stephenson Jenin, Symer Kristin, Russo-Tait Tatiane, Weigel Bill, Wilhelm Mary B
Chemistry and Biochemistry Department, California State Polytechnic University, Pomona, Pomona, CA, United States.
Science Team, NASA/CSU Spaceward Bound, Pomona, CA, United States.
Front Microbiol. 2017 Oct 23;8:1974. doi: 10.3389/fmicb.2017.01974. eCollection 2017.
In this study, we expand upon the biogeography of biological soil crusts (BSCs) and provide molecular insights into the microbial community and biochemical dynamics along the vertical BSC column structure, and across a transect of increasing BSC surface coverage in the central Mojave Desert, CA, United States. Next generation sequencing reveals a bacterial community profile that is distinct among BSCs in the southwestern United States. Distribution of major phyla in the BSC topsoils included Cyanobacteria (33 ± 8%), Proteobacteria (26 ± 6%), and Chloroflexi (12 ± 4%), with being the numerically dominant genus. Furthermore, BSC subsurfaces contained Proteobacteria (23 ± 5%), Actinobacteria (20 ± 5%), and Chloroflexi (18 ± 3%), with an unidentified genus from Chloroflexi (AKIW781, order) being numerically dominant. Across the transect, changes in distribution at the phylum ( < 0.0439) and genus ( < 0.006) levels, including multiple biochemical and geochemical trends ( < 0.05), positively correlated with increasing BSC surface coverage. This included increases in (a) Chloroflexi abundance, (b) abundance and diversity of Cyanobacteria, (b) OTU-level diversity in the topsoil, (c) OTU-level differentiation between the topsoil and subsurface, (d) intracellular ATP abundances and catalase activities, and (e) enrichments in clay, silt, and varying elements, including S, Mn, Co, As, and Pb, in the BSC topsoils. In sum, these studies suggest that BSCs from regions of differing surface coverage represent early successional stages, which exhibit increasing bacterial diversity, metabolic activities, and capacity to restructure the soil. Further, these trends suggest that BSC successional maturation and colonization across the transect are inhibited by metals/metalloids such as B, Ca, Ti, Mn, Co, Ni, Mo, and Pb.
在本研究中，我们拓展了生物土壤结皮（BSCs）的生物地理学，并对沿垂直BSC柱结构以及美国加利福尼亚州莫哈韦沙漠中部BSC表面覆盖率增加的样带中微生物群落和生化动态进行了分子层面的深入研究。新一代测序揭示了美国西南部BSCs中独特的细菌群落概况。BSC表土中主要门类的分布包括蓝细菌（33±8%）、变形菌门（26±6%）和绿弯菌门（12±4%），其中 是数量上占主导的属。此外，BSC次表层包含变形菌门（23±5%）、放线菌门（20±5%）和绿弯菌门（18±3%），绿弯菌门中一个未鉴定的属（AKIW781，目）在数量上占主导。在整个样带中，门类（<0.0439）和属（<0. < 0.006）水平上的分布变化，包括多种生化和地球化学趋势（<0.05），与BSC表面覆盖率的增加呈正相关。这包括以下方面的增加：（a）绿弯菌门丰度，（b）蓝细菌的丰度和多样性，（b）表土中OTU水平的多样性，（c）表土和次表层之间OTU水平的差异，（d）细胞内ATP丰度和过氧化氢酶活性，以及（e）BSC表土中粘土、粉砂和各种元素（包括S、Mn、Co、As和Pb）的富集。总之，这些研究表明，来自不同表面覆盖率区域的BSCs代表了早期演替阶段，其细菌多样性、代谢活动和重构土壤的能力不断增加。此外，这些趋势表明，样带中BSC演替成熟和定殖受到硼、钙、钛、锰、钴、镍、钼和铅等金属/类金属的抑制。
