Unraveling the interplay of the soil microbiome and (poly)phenol content in blueberry in response to disturbances

Abstract

Aims Disturbances exert direct and indirect effects on plants through alterations of soil properties and microbiota composition. This can induce stress, resulting in modifications of plants’ phytochemical profile. This in turn can affect the possibility for Indigenous people to engage in cultural activities depending on wild plants used as food or medicine. As a case study, we evaluated correlations between (poly)phenols in Vaccinium angustifolium fruits, disturbances from mining and hydroelectric activities, soil properties, and soil microbiome composition. Methods We collected fruit and soil samples in the territories of three Indigenous communities in eastern Canada. Fruits were analyzed for their concentrations in anthocyanins, proanthocyanidins and other (poly)phenols. Soil microbial DNA was extracted to reconstruct bacterial and fungal communities. A secondary subset of soil samples was used to measure soil properties. Relationships between soil, disturbances and (poly)phenols were investigated using multivariate analyses. Results Disturbances affected soil properties and microbiome, but not fruit (poly)phenol content. Two soil bacterial classes unaffected by disturbances, Bacilli and Desulfitobacteriia, were positively correlated with levels of proanthocyanidines and delphinidin-, cyanidin-, and petunidin-3-glucoside in fruits. Conclusion Disturbances did not affect (poly)phenol content in V. angustifolium fruits. However, mine disturbances may contaminate fruits with pollutants detrimental to human health, which should be evaluated before drawing conclusions about the effect of disturbances on plant nutritional and medicinal properties. Some soil bacterial classes seem to enhance the (poly)phenolic content of V. angustifolium fruits, suggesting that a strategy could be developed for enhancing the nutritional and medicinal properties of this culturally salient species.