Climate change is altering associations between plants and soil microbiota, threatening ecosystem functioning and stability. Predicting these effects requires understanding how concomitant changes in temperature and precipitation influence plant-soil microbiota associations. We identify the pathways via which temperature and precipitation shape prokaryote and fungal rhizosphere and root-associated networks of the perennial grass Festuca rubra in cold-climate ecosystems. We found that joint effects of temperature and precipitation are key in shaping plant-soil microbiota associations, with the start of the growing season as a critical mediating factor. Specifically, the start of the growing season is advanced by increasing temperature but delayed by increasing precipitation. This joint pathway particularly shaped rhizosphere organic matter degrading microbiota and root-associated putative plant pathotroph-saprotrophs and beneficial microbiota. We conclude that understanding local temperature, precipitation, and seasonal changes is crucial to accurately predict how the unique plant-microbiota interactions shaping cold-climate ecosystems are evolving with the ongoing change in climate.

• Keywords
• microbial co‐occurrence networks, precipitation, rhizosphere microbiome, root microbiome, seasonality, snow cover, temperature,
• MeSH
• Acclimatization physiology   MeSH
• Rain * MeSH
• Festuca growth & development   microbiology   MeSH
• Climate Change * MeSH
• Plant Roots microbiology   MeSH
• Microbiota * MeSH
• Soil chemistry   MeSH
• Soil Microbiology * MeSH
• Rhizosphere MeSH
• Plants * microbiology   MeSH
• Temperature * MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Soil MeSH

Epigenetic regulation of gene expression is expected to be an important mechanism behind phenotypic plasticity. Whether epigenetic regulation affects species ecophysiological adaptations to changing climate remains largely unexplored. We compared ecophysiological traits between individuals treated with 5-azaC, assumed to lead to DNA demethylation, with control individuals of a clonal grass originating from and grown under different climates, simulating different directions and magnitudes of climate change. We linked the ecophysiological data to proxies of fitness. Main effects of plant origin and cultivating conditions predicted variation in plant traits, but 5-azaC did not. Effects of 5-azaC interacted with conditions of cultivation and plant origin. The direction of the 5-azaC effects suggests that DNA methylation does not reflect species long-term adaptations to climate of origin and species likely epigenetically adjusted to the conditions experienced during experiment set-up. Ecophysiology translated to proxies of fitness, but the intensity and direction of the relationships were context dependent and affected by 5-azaC. The study suggests that effects of DNA methylation depend on conditions of plant origin and current climate. Direction of 5-azaC effects suggests limited role of epigenetic modifications in long-term adaptation of plants. It rather facilitates fast adaptations to temporal fluctuations of the environment.

• MeSH
• Azacitidine pharmacology   MeSH
• Epigenesis, Genetic * MeSH
• Climate Change MeSH
• Humans MeSH
• DNA Methylation * MeSH
• Genes, Plant MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Azacitidine MeSH

BACKGROUND AND AIMS: Rhizomes are important organs allowing many clonal plants to persist and reproduce under stressful climates with longer rhizomes, indicating enhanced ability of the plants to spread vegetatively. We do not, however, know either how rhizome construction costs change with increasing length or how they vary with environmental conditions. METHODS: We analysed the rhizome length vs. mass scaling relationship, the plasticity in the scaling relationships, their genetic basis and how scaling relationships are linked to plant fitness. We used data from 275 genotypes of a clonal grass Festuca rubra originating from 11 localities and cultivated under four contrasting climates. Data were analysed using standard major axis regression, mixed-effect regression models and a structural equation model. KEY RESULTS: Rhizome construction costs increased (i.e. lower specific rhizome length) with increasing length. The trait scaling relationships were modulated by cultivation climate, and its effects also interacted with the climate of origin of the experimental plants. With increasing length, increasing moisture led to a greater increase in rhizome construction costs. Plants with lower rhizome construction costs showed significantly higher fitness. CONCLUSIONS: This study suggests that rhizome scaling relationships are plastic, but also show genetic differentiation and are linked to plant fitness. Therefore, to persist under variable environments, modulation in scaling relationships could be an important plant strategy.

• Keywords
• Allometry, climate change, clonal grass, plasticity, resource allocation,
• MeSH
• Biomass MeSH
• Festuca * MeSH
• Poaceae MeSH
• Rhizome * MeSH
• Climate MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH