The effect of root‐associated microbes on plant growth and chemical defence traits across two contrasted elevations

Abstract

Ecotypic differences in plant growth and anti‐herbivore defence phenotypes are determined by the complex interactions between the abiotic and the biotic environment. Root‐associated microbes (RAMs) are pervasive in nature, vary over climatic gradients and have been shown to influence the expression of multiple plant functional traits related to biomass accumulation and biotic interactions. We addressed how variation in climatic conditions between lowland and subalpine habitats in the Alps and RAMs can independently or interactively affect plant growth and anti‐herbivore defence trait expression. To address the contribution of climate and RAMs on growth and chemical defences of high‐ and low‐elevation Plantago major ecotypes, we performed a full‐factorial reciprocal transplant field experiment at two elevations. We coupled it with plant functional trait measurements and metabolomics analyses. We found that local growing climatic conditions mostly influenced how the ecotypes grew, but we also found that the high‐ and low‐elevation ecotypes improved biomass accumulation if in the presence of their own‐elevation RAMs. We also found that while chemical defence expression was affected by climate, they were also more highly expressed when plants were inoculated with low‐elevation RAMs. Synthesis. Our research demonstrated that root‐associated microbes (RAMs) from contrasted elevations impact how plants grow or synthesize toxic secondary metabolites. At low elevation, where biotic interactions are stronger, RAMs enhance plant biomass accumulation and the production of toxic secondary metabolites.

Intra‐specific kin recognition contributes to inter‐specific allelopathy: A case study of allelopathic rice interference with paddy weeds

“…Kin effects mainly occur in the preferred soil where competitor relatedness alters local soil conditions, causing indirect soil effects on plant coexistence (Ehlers et al, 2016). In particular, root exudates drive plant–soil feedbacks by shaping the rhizosphere microbiota (Hu et al, 2018), impacting plant growth and chemical defenses (Formenti et al, 2021). In the presence of competing barnyard grass, allelopathic rice generated cultivar‐specific soil microbial communities that can induce positive feedbacks on growth and reproduction (Sun et al, 2014).…”

Intraspecific kin recognition contributes to interspecific allelopathy：A case study of allelopathic rice interference with paddy weeds

“…Soil microbial composition is closely associated with plant species and their root exudate metabolites (Hu et al, 2018;Schnitzer et al, 2011). In particular, root exudate metabolites drive plant-soil feedbacks by shaping the rhizosphere microbiota (Hu et al, 2018), impacting plant growth and chemical defense traits (Formenti et al, 2021). In the presence of competing barnyardgrass, allelopathic rice generated cultivar-specific soil microbial communities that can induce positive feedbacks on growth and reproduction (Sun, Wang, & Kong, 2014).…”

Ecology and potential functions of plant-associated microbial communities in cold environments

“…Root-associated microorganisms positively influenced Plantago major growth in a plant ecotype-dependent manner: plant ecotypes growing with their local root-associated microorganisms performed better than when growing with foreign microorganisms (Formenti et al . 2020 ). Thus, the development of microbial biostimulants based on indigenous cold-adapted microorganisms could be a promising approach to protect crop plants from cold stress, but further functional studies are required to better characterize the modes of action and possible limitations due to host specificity of psychrotolerant plant-growth promoting bacteria.…”