Department of Biological Sciences, Seoul National University, Gwanak-Gu, Seoul, 151-747, Republic of Korea.
Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Republic of Korea.
Microb Ecol. 2019 Jan;77(1):168-185. doi: 10.1007/s00248-018-1215-z. Epub 2018 Jun 7.
Comparing the functional gene composition of soils at opposite extremes of environmental gradients may allow testing of hypotheses about community and ecosystem function. Here, we were interested in comparing how tropical microbial ecosystems differ from those of polar climates. We sampled several sites in the equatorial rainforest of Malaysia and Brunei, and the high Arctic of Svalbard, Canada, and Greenland, comparing the composition and the functional attributes of soil biota between the two extremes of latitude, using shotgun metagenomic Illumina HiSeq2000 sequencing. Based upon "classical" views of how tropical and higher latitude ecosystems differ, we made a series of predictions as to how various gene function categories would differ in relative abundance between tropical and polar environments. Results showed that in some respects our predictions were correct: the polar samples had higher relative abundance of dormancy related genes, and lower relative abundance of genes associated with respiration, and with metabolism of aromatic compounds. The network complexity of the Arctic was also lower than the tropics. However, in various other respects, the pattern was not as predicted; there were no differences in relative abundance of stress response genes or in genes associated with secondary metabolism. Conversely, CRISPR genes, phage-related genes, and virulence disease and defense genes, were unexpectedly more abundant in the Arctic, suggesting more intense biotic interaction. Also, eukaryote diversity and bacterial diversity were higher in the Arctic of Svalbard compared to tropical Brunei, which is consistent with what may expected from amplicon studies in terms of the higher pH of the Svalbard soil. Our results in some respects confirm expectations of how tropical versus polar nature may differ, and in other respects challenge them.
比较环境梯度两端的土壤功能基因组成，可以检验有关群落和生态系统功能的假说。在这里，我们有兴趣比较热带微生物生态系统与极地气候的微生物生态系统有何不同。我们在马来西亚和文莱的赤道雨林以及加拿大和格陵兰的斯瓦尔巴群岛高纬度地区的几个地点进行了采样，使用 Illumina HiSeq2000 高通量测序对两个纬度极端之间的土壤生物群落组成和功能属性进行了比较。基于关于热带和高纬度生态系统如何不同的“经典”观点，我们对各种基因功能类别在热带和极地环境之间的相对丰度如何不同做出了一系列预测。结果表明，在某些方面，我们的预测是正确的：极地样本中与休眠相关的基因相对丰度较高，与呼吸作用以及芳香族化合物代谢相关的基因相对丰度较低。北极的网络复杂性也低于热带地区。然而，在其他方面，模式并非如预测的那样；压力反应基因或与次生代谢相关的基因的相对丰度没有差异。相反，CRISPR 基因、噬菌体相关基因和毒力疾病与防御基因在北极出乎意料地更为丰富，这表明生物相互作用更为激烈。此外，与文莱的热带地区相比，斯瓦尔巴群岛的北极地区的真核生物多样性和细菌多样性更高，这与基于 Svalbard 土壤较高 pH 值的扩增子研究中可能预期的情况一致。我们的结果在某些方面证实了热带与极地自然可能存在差异的预期，而在其他方面则对其提出了挑战。
