Available nitrogen is the key factor influencing soil microbial functional gene diversity in tropical rainforest.
BACKGROUND
Tropical rainforests cover over 50% of all known plant and animal species and provide a variety of key resources and ecosystem services to humans, largely mediated by metabolic activities of soil microbial communities. A deep analysis of soil microbial communities and their roles in ecological processes would improve our understanding on biogeochemical elemental cycles. However, soil microbial functional gene diversity in tropical rainforests and causative factors remain unclear. GeoChip, contained almost all of the key functional genes related to biogeochemical cycles, could be used as a specific and sensitive tool for studying microbial gene diversity and metabolic potential. In this study, soil microbial functional gene diversity in tropical rainforest was analyzed by using GeoChip technology.


RESULTS
Gene categories detected in the tropical rainforest soils were related to different biogeochemical processes, such as carbon (C), nitrogen (N) and phosphorus (P) cycling. The relative abundance of genes related to C and P cycling detected mostly derived from the cultured bacteria. C degradation gene categories for substrates ranging from labile C to recalcitrant C were all detected, and gene abundances involved in many recalcitrant C degradation gene categories were significantly (P < 0.05) different among three sampling sites. The relative abundance of genes related to N cycling detected was significantly (P < 0.05) different, mostly derived from the uncultured bacteria. The gene categories related to ammonification had a high relative abundance. Both canonical correspondence analysis and multivariate regression tree analysis showed that soil available N was the most correlated with soil microbial functional gene structure.


CONCLUSIONS
Overall high microbial functional gene diversity and different soil microbial metabolic potential for different biogeochemical processes were considered to exist in tropical rainforest. Soil available N could be the key factor in shaping the soil microbial functional gene structure and metabolic potential.
School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China. yqdh77@163.com.|Institute of Forestry Ecology, Environment and Protection, and the Key Laboratory of Forest Ecology and Environment of State Forestry Administration, Chinese Academy of Forestry, Beijing, 100091, China. yqdh77@163.com.
Jing
J
Cong
School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China. xueduanliu@mail.csu.edu.cn.
Xueduan
X
Liu
Institute of Forestry Ecology, Environment and Protection, and the Key Laboratory of Forest Ecology and Environment of State Forestry Administration, Chinese Academy of Forestry, Beijing, 100091, China. 258108293@qq.com.
Hui
H
Lu
Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, 510520, China. 17843611@qq.com.
Han
H
Xu
Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, 510520, China. zhangyg@caf.ac.cn.
Yide
Y
Li
Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing, 100085, China. dengye@ou.edu.
Ye
Y
Deng
Institute of Forestry Ecology, Environment and Protection, and the Key Laboratory of Forest Ecology and Environment of State Forestry Administration, Chinese Academy of Forestry, Beijing, 100091, China. lidq@caf.ac.cn.
Diqiang
D
Li
Institute of Forestry Ecology, Environment and Protection, and the Key Laboratory of Forest Ecology and Environment of State Forestry Administration, Chinese Academy of Forestry, Beijing, 100091, China. yugzhang@sina.com.cn.
Yuguang
Y
Zhang
D058448:Biota; D002244:Carbon / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000235:genetics; D054892:Metagenome; D046228:Microarray Analysis; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000032:analysis* / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D065947:Rainforest; D017422:Sequence Analysis, DNA; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology
D012987:Soil; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen