Contrasting phenotypes of alpine cushion species have been recurrently described in several mountain ranges along small‐scale topography gradients, with tight competitive phenotypes in stressful convex topography and loose facilitative phenotypes in sheltered concave topography. The consistency of phenotypic effects along large‐scale climate stress gradients have been proposed as a test of the likely genetic bases of the differences observed at small‐scale. Inversely, plastic phenotypic effects are more likely to vanish at some points along climate stress gradients. We tested this hypothesis for two phenotypes of the alpine cushion species Thylacospermum caespitosum at four points along regional gradients of cold and drought stress in northwest China. We measured the traits of the two cushion phenotypes and quantified their associated plant communities and environmental variables along the regional temperature and aridity gradients. Cushion height, convexity and stem density overall showed significant effect of phenotypes. Difference in tightness of cushions between phenotypes was consistent across climate conditions, whereas differences in cushion convexity and height between phenotypes increased with increasing cold stress. Phenotypic effects on species richness and abundance were consistent along both climate gradients but not effects on species composition, while there were no phenotypic effects on environmental variables. Additionally, RII (relative interaction index) curves were linear along the drought gradient but unimodal along the temperature gradient, likely due to the occurrence of contrasting species pools at the different sites. We conclude that the consistency of phenotypic effects of T. caespitosum was high for species richness and abundance and mainly explained by differences in interference mediated by likely heritable differences in cushion tightness. Additionally, our study shows that the shapes of the relationship between plant responses to neighbours and environmental stresses are not necessarily driven by niche‐based deterministic factors.

Microorganisms play a crucial role in biogeochemical cycles and ecosystem processes, but the key factors driving microbial community structure are poorly understood, particularly in alpine environments. In this study, we aim to disentangle the relative contribution of abiotic and biotic factors shaping bacterial and fungal community structure at large and small spatial and integration scales in an alpine system dominated by a stress-tolerant cushion species Thylacospermum ceaspitosum. These effects were assessed in two mountain ranges of northwest China and for two contrasting phenotypes of the cushion species inhabiting two different microtopographic positions. The large-and small-scale abiotic effects include the site and microhabitat effects, respectively, while the large-and small-scale biotic effects include the effects of cushion presence and cushion phenotype, respectively. Soil microbial communities were characterized by Illumina Miseq sequencing. Uni-and multivariate statistics were used to test the effects of abiotic and biotic factors at both scales. Results indicated that the site effect representing the soil pH and abiotic hydrothermal conditions mainly affected bacterial community structure, whereas fungal community structure was mainly affected by biotic factors with an equal contribution of cushion presence and cushion phenotype effects. Future studies should analyze the direct factors contributing to shaping microbial community structure in particular of the cushion phenotypes.

This study is performed to figure out the role of long‐chain noncoding RNA growth‐arrest specific transcript 5 (GAS5) in homocysteine (HCY)‐induced cardiac microvascular endothelial cells (CMECs) injury. CMECs were cultured and the model of CMECs injury was established by coincubation with HCY. To construct stable overexpression of GAS5 cells, the expression of GAS5, microRNA‐33a‐5p (miR‐33a‐5p) and ATP‐binding cassette transporter A1 (ABCA1), and biological characteristics of cells were determined. The messenger RNA (mRNA) level and secretion of vascular endothelial growth factor (VEGF), activity of reactive oxygen species (ROS) and superoxide dismutase (SOD), and the content of malondialdehyde (MDA) were measured. The binding site between GAS5 and miR‐33a‐5p and between miR‐33a‐5p and ABCA1 was verified. CMECs were successfully cultured. Reduction of GAS5 expression and ABCA1 expression together with increased expression of miR‐33a‐5p was found in CMECs induced by HCY. After overexpression of GAS5, there showed increased proliferative activity, decreased cell apoptosis rate and apoptosis index, enhanced cell migration ability, increased number of lumen formation, increased mRNA expression of VEGF in cells and the secretion in the supernatant, decreased activity of ROS and SOD in cells, and decreased content of ROS in cells. miR‐33a‐5p could promote the enrichment of GAS5 and ABCA1 was the direct target gene of miR‐33a‐5p. Our study suggests that the low expression of GAS5 was observed in HCY‐induced CMECs injury, and the upregulation of GAS5 could attenuate HCY‐induced CMECs injury by mediating oxidative stress, and its mechanism is related to the upregulation of ABCA1 expression by competitively binding with miR‐33a‐5p.

Questions Contrasting understorey species responses to the effects of dominant species might occur within a single community even with neutral community‐level interactions. However, no studies have assessed the contribution of below‐ and above‐ground effects for all species of a community and their consequences for community composition. We tested the following hypotheses: (i) there are contrasting responses of understorey species to the canopy and root effects of a dominant shrub; (ii) the contrasting understorey responses to the canopy and root effects of the shrub are related to community composition. Location Species‐rich sub‐alpine community, eastern Tibet Plateau, China, dominated by Dasiphora fruticosa. Methods We used a removal procedure and shade cloth treatment to separate root from canopy effects and quantified the biomass responses of 41 species of the understorey community. Species‐level responses to the root and canopy effects were quantified with the relative interaction index. We conducted multivariate analyses to assess the relative contribution of root and canopy effects to community composition. Results We found contrasting species‐level responses to the canopy and root effects of D. fruticosa that could be grouped into six cluster groups. Dominant effects were positive for the roots and negative for the canopy, with a tendency for a trade‐off between the two. Community‐level effects were less strong and weakly significant, in particular for species richness. Root and canopy effects strongly explained understorey species composition but net shrub effects did not. Conclusions This study highlights that communities include species having contrasting responses to both the canopy and root effects of dominant species that importantly explain species composition.

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