Department of Microbiology and Plant Diseases, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
PLoS One. 2013 Jul 26;8(7):e69705. doi: 10.1371/journal.pone.0069705. Print 2013.
Microbial communities in soils may change in accordance with distance, season, climate, soil texture and other environmental parameters. Microbial diversity patterns have been extensively surveyed in temperate regions, but few such studies attempted to address them with respect to spatial and temporal scales and their correlations to environmental factors, especially in arid ecosystems. In order to fill this gap on a regional scale, the molecular fingerprints and abundance of three taxonomic groups--Bacteria, α-Proteobacteria and Actinobacteria--were sampled from soils 0.5-100 km apart in arid, semi-arid, dry Mediterranean and shoreline Mediterranean regions in Israel. Additionally, on a local scale, the molecular fingerprints of three taxonomic groups--Bacteria, Archaea and Fungi--were sampled from soils 1 cm-500 m apart in the semi-arid region, in both summer and winter. Fingerprints of the Bacteria differentiated between all regions (P<0.02), while those of the α-Proteobacteria differentiated between some of the regions (0.01<P<0.09), and actinobacterial fingerprints were similar among all regions (P>0.05). Locally, fingerprints of archaea and fungi did not display distance-decay relationships (P>0.13), that is, the dissimilarity between communities did not increase with geographic distance. Neither was this phenomenon evident in bacterial samples in summer (P>0.24); in winter, however, differences between bacterial communities significantly increased as the geographic distances between them grew (P<0.01). Microbial community structures, as well as microbial abundance, were both significantly correlated to precipitation and soil characteristics: texture, organic matter and water content (R(2)>0.60, P<0.01). We conclude that on the whole, microbial biogeography in arid and semi-arid soils in Israel is determined more by specific environmental factors than geographic distances and spatial distribution patterns.
土壤中的微生物群落可能会随着距离、季节、气候、土壤质地和其他环境参数的变化而变化。在温带地区，已经广泛调查了微生物多样性模式，但很少有研究试图根据空间和时间尺度以及与环境因素的相关性来解决这些问题，特别是在干旱生态系统中。为了在区域尺度上填补这一空白，从以色列干旱、半干旱、干燥地中海和沿海地中海地区的土壤中，以 0.5-100 公里的距离采集了三个分类群的分子指纹和丰度——细菌、α-变形菌和放线菌。此外，在局部尺度上，从半干旱地区的土壤中以 1 厘米-500 米的距离采集了三个分类群的分子指纹——细菌、古菌和真菌，分别在夏季和冬季。所有地区的细菌指纹都有区别（P<0.02），而一些地区的α-变形菌指纹有区别（0.01<P<0.09），所有地区的放线菌指纹都相似（P>0.05）。在局部地区，古菌和真菌的指纹没有显示距离衰减关系（P>0.13），即群落之间的差异没有随着地理距离的增加而增加。这种现象在夏季的细菌样本中也不明显（P>0.24）；然而，在冬季，随着它们之间的地理距离增加，细菌群落之间的差异显著增加（P<0.01）。微生物群落结构以及微生物丰度都与降水和土壤特性显著相关：质地、有机质和含水量（R(2)>0.60，P<0.01）。我们得出的结论是，总的来说，以色列干旱和半干旱土壤中的微生物生物地理学更多地取决于特定的环境因素，而不是地理距离和空间分布模式。
