Warming Alters Expressions of Microbial Functional Genes Important to Ecosystem Functioning

Abstract

Soil microbial communities play critical roles in ecosystem functioning and are likely altered by climate warming. However, so far, little is known about effects of warming on microbial functional gene expressions. Here, we applied functional gene array (GeoChip 3.0) to analyze cDNA reversely transcribed from total RNA to assess expressed functional genes in active soil microbial communities after nine years of experimental warming in a tallgrass prairie. Our results showed that warming significantly altered the community wide gene expressions. Specifically, expressed genes for degrading more recalcitrant carbon were stimulated by warming, likely linked to the plant community shift toward more C4 species under warming and to decrease the long-term soil carbon stability. In addition, warming changed expressed genes in labile C degradation and N cycling in different directions (increase and decrease), possibly reflecting the dynamics of labile C and available N pools during sampling. However, the average abundances of expressed genes in phosphorus and sulfur cycling were all increased by warming, implying a stable trend of accelerated P and S processes which might be a mechanism to sustain higher plant growth. Furthermore, the expressed gene composition was closely related to both dynamic (e.g., soil moisture) and stable environmental attributes (e.g., C4 leaf C or N content), indicating that RNA analyses could also capture certain stable trends in the long-term treatment. Overall, this study revealed the importance of elucidating functional gene expressions of soil microbial community in enhancing our understanding of ecosystem responses to warming.

Long‐term impacts of warming drive decomposition and accelerate the turnover of labile, not recalcitrant, carbon

“…In part, these changes in decomposition can be traced to shifts in the ability of the soil microbial community to decompose soil organic carbon (Xue et al. , Feng et al. ).…”

“…Rates of litter decomposition in this ecosystem are changing, resulting in reductions of labile organic carbon in plots experiencing warmed conditions (Xu et al 2012b). In part, these changes in decomposition can be traced to shifts in the ability of the soil microbial community to decompose soil organic carbon (Xue et al 2016, Feng et al 2017). However, even as a picture is emerging regarding the impacts of warming on carbon cycling in terrestrial systems, we still do not fully understand the mechanisms driving these changes.…”

“…, Luo , Xue et al. ). As warming alters the structure and function of soil communities, there are likely to be shifts in ecosystem processes, including litter decomposition (Treseder , Bradford , Karhu ).…”

“…These factors, even as they directly influence decomposition, also feedback and interact with one another. The microbial community plays an important role in determining ecosystem processes such as litter decomposition (Strickland et al 2009a, b, Wickings et al 2012, Allison et al 2013, and climatic warming can alter the composition of microbial communities , Luo 2014, Xue et al 2016. As warming alters the structure and function of soil communities, there are likely to be shifts in ecosystem processes, including litter decomposition (Treseder 2012, Bradford 2013, Karhu 2014.…”

Functional diversity and redundancy across fish gut, sediment and water bacterial communities

“…However, these limitations are the same whatever the DNAbased approach being used (sequencing or microarray). Additionally, profiling the expression of environmental bacterial communities through hybridization of FGA with cDNA is still challenging and was only recently realized using the same FGA (Xue et al, 2016). These authors obtained different and complementary results using RNA-and DNAbased FGA, with the latter being less influenced by shortterm expression dynamics resulting from environmental conditions at the time of sampling.…”