Root-Associated Mycobiomes of Common Temperate Plants (Calluna vulgaris and Holcus lanatus) Are Strongly Affected by Winter Climate Conditions

Abstract

Winter temperatures are projected to increase in Central Europe. Subsequently, snow cover will decrease, leading to increased soil temperature variability, with potentially different consequences for soil frost depending on e.g. altitude. Here, we experimentally evaluated the effects of increased winter soil temperature variability on the root associated mycobiome of two plant species (Calluna vulgaris and Holcus lanatus) at two sites in Germany; a colder and wetter upland site with high snow accumulation and a warmer and drier lowland site, with low snow accumulation. Mesocosm monocultures were set-up in spring 2010 at both sites (with soil and plants originating from the lowland site). In the following winter, an experimental warming pulse treatment was initiated by overhead infrared heaters and warming wires at the soil surface for half of the mesocosms at both sites. At the lowland site, the warming treatment resulted in a reduced number of days with soil frost as well as increased the average daily temperature amplitude. Contrary, the treatment caused no changes in these parameters at the upland site, which was in general a much more frost affected site. Soil and plant roots were sampled before and after the following growing season (spring and autumn 2011). High-throughput sequencing was used for profiling of the root-associated fungal (ITS marker) community (mycobiome). Site was found to have a profound effect on the composition of the mycobiome, which at the upland site was dominated by fast growing saprotrophs (Mortierellomycota), and at the lowland site by plant species-specific symbionts (e.g. Rhizoscyphus ericae and Microdochium bolleyi for C. vulgaris and H. lanatus respectively). The transplantation to the colder upland site and the temperature treatment at the warmer lowland site had comparable consequences for the mycobiome, implying that winter climate change resulting in higher temperature variability has large consequences for mycobiome structures regardless of absolute temperature of a given site.

Warmer winters result in reshaping of the European beech forest soil microbiome (bacteria, archaea and fungi)—With potential implications for ecosystem functioning

“…A similar dynamic was observed between ericoid mycorrhizal fungi and members of Mucoromycota in a recent mesocosm experiment with the shrub Calluna vulgaris where the soil was exposed to winter pulse‐freezing treatments, resulting in a strong decrease of the mycorrhizal symbiont and a high increase in Mucoromycota sp. (Borg Dahl et al, 2021). Taken together with our observations, this suggests that a similar dynamic occurs in our S− treatment; unfortunately, no quantitative measures of EcM biomass are available to confirm this hypothesis.…”

“…On the other hand, intense freeze–thawing is a lethal threat to microorganisms due to frost dehydration and cell rupture (Jefferies et al, 2010; Schimel et al, 2007; Shchepin et al, 2014). A recent mesocosm experiment found the strong response to altered winter temperature conditions in the soil microbial community composition, which was interlinked to changes in the nutrient dynamic and plant growth in the following season of two common temperate plant species ( Calluna vulgaris and Holcus lanatus ; Borg Dahl et al, 2021). Additionally, plant–soil interaction models predict a faster response to environmental changes among soil microbes than among primary producers, for example, forest trees, with the former likely undergoing a community reordering prior to the latter (Bardgett et al, 2013).…”

Agro-Based Spent Mushroom Compost Substrates Improve Soil Properties and Microbial Diversity in Greenhouse Tomatoes

“…Both Rozellomycota and Chytridiomycota fungi belong to the Zoosporic phyla with motile spores, which typically play critical ecological roles in the recycling of energy and matter in food webs [102]. As fast growing saprotrophic fungi, the Mortierellomycota phyla are potentially influenced by soil temperature [103] and have important biological functions for the protection of plants against pathogens [104]. Interestingly, Mucoromycota fungi may be utilized as a biorefinery that employs fungi for its highly versatile metabolic system, which can generate several valuable bioproducts including of pigments, polyphosphates, ethanol, organic acids, enzymes, as well as lowand high-value lipids [105,106].…”

Vitality of heather (Calluna vulgaris) along gradients of climate, structure and diversity in dry lowland heathland habitats of Northern Germany

“…Droughts can also delay or reduce the flowering period (Jentsch et al 2009;Nagy et al 2013). It has been shown that drought affects the Calluna root-associated mycobiome, with as yet unknown consequences for the plants' vitality, soil nutrient processes and heathland productivity (Dahl et al 2021;Tobermann et al 2008).…”