e The soil microbial community plays an important role in terrestrial carbon and nitrogen cycling. However, microbial responses to climate warming or cooling remain poorly understood, limiting our ability to predict the consequences of future climate changes. To address this issue, it is critical to identify microbes sensitive to climate change and key driving factors shifting microbial communities. In this study, alpine soil transplant experiments were conducted downward or upward along an elevation gradient between 3,200 and 3,800 m in the Qinghai-Tibet plateau to simulate climate warming or cooling. After a 2-year soil transplant experiment, soil bacterial communities were analyzed by pyrosequencing of 16S rRNA gene amplicons. The results showed that the transplanted soil bacterial communities became more similar to those in their destination sites and more different from those in their "home" sites. Warming led to increases in the relative abundances in Alphaproteobacteria, Gammaproteobacteria, and Actinobacteria and decreases in Acidobacteria, Betaproteobacteria, and Deltaproteobacteria, while cooling had opposite effects on bacterial communities (symmetric response). Soil temperature and plant biomass contributed significantly to shaping the bacterial community structure. Overall, climate warming or cooling shifted the soil bacterial community structure mainly through species sorting, and such a shift might correlate to important biogeochemical processes such as greenhouse gas emissions. This study provides new insights into our understanding of soil bacterial community responses to climate warming and cooling. G lobal climate change greatly affects terrestrial ecosystems, particularly in polar or alpine regions (1). However, due to the complexity of soil microbiome, how global warming affects their diversity, abundance, and structure is poorly understood (2, 3). To show the responses of microorganisms to climate changes, we must identify those microbes sensitive or acclimated to temperature and their relationships to biogeochemical processes, such as greenhouse gas emissions.Warming is able to directly affect soil bacterial physiology (4) and indirectly affect microbes through changing plant and soil properties (5). For example, an increase in temperature may lead to a preponderance of thermally adapted microorganisms (6). Artificial warming is widely used to study the effects of warming on soil ecosystems. Integrated metagenomic and functional analyses of a long-term warming experiment in a grassland ecosystem show that one of the outcomes of climate warming is a shift of the microbial community composition, which most likely leads to the reduced temperature sensitivity of heterotrophic soil respiration (3). Also, multifactorial warming experiments show that warming and precipitation alter the microbial community composition in a constructed natural grass prairie (7). Likewise, another long-term in situ warming experiment experiences a moderate natural drought, and warming decreases the diversity and sig...

Light quality surrounding a plant is largely determined by the density of its neighboring vegetation. Plants are able to sense shade light signals and initiate a series of adaptation responses, which is known as shade avoidance syndrome (SAS). PHYTOCHROME INTERACTING FACTORS (PIFs) are key factors in the SAS network by regulating the biosynthesis of multiple phytohormones and the expression of cell expansion genes. Although the protein levels of PIFs were found to be acumulated in shade, the transcriptional regulation of in response to such an environmental signal remains poorly understood. Here we show that TCP17 and its two closely related homologs, TCP5 and TCP13, play an important role in mediating shade-induced hypocotyl elongation by up-regulating auxin biosynthesis via a PIF-dependent and a PIF-independent pathway. In constitutive white light, a triple mutant () showed a subtle hypocotyl defective phenotype. In shade, however, showed a significantly reduced hypocotyl elongation phenotype, indicating a positive role of TCPs in regulating SAS. Our in-depth biochemical and genetic analyses indicated that TCP17 can be significantly accumulated in shade. TCP17 binds to the promoters of and to indirectly or directly up-regulate auxin levels in shade. These data provide new insights into our better understanding of the regulatory mechanisms of SAS in plants.

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