Warming intensifies soil pathogen negative feedback on a temperate tree

Abstract

 The soil pathogen-induced Janzen-Connell (JC) effect is considered as a primary mechanism regulating plant biodiversity worldwide. As predicted by the framework of the classic plant disease triangle, severity of plant diseases is often influenced by temperature, yet insufficient understanding of how increasing temperatures affect the JC effect contributes uncertainty in predictions about how global warming affects biodiversity.  We conducted a three-year field warming experiment, combining open-top chambers with pesticide treatment, to test the effect of elevated temperature on seedling mortality of a temperate tree species, Prunus padus, from a genus with known susceptibility to soil-borne pathogens.  Elevated temperature significantly increased mortality of P. padus seedlings in the immediate vicinity of parent trees, concurrent with increased relative abundance of pathogenic fungi identified to be virulent to Prunus species.  Our study offers experimental evidence suggesting that global warming significantly intensify the JC effect on a temperate tree species due to increased relative abundance of pathogenic fungi. This work advances our understanding about changes in the JC effect linked to the ongoing global warming, which has important implications for predicting tree diversity in a warmer future.

A latitudinal pattern of plant leaf-associated bacterial community assembly

“…A corollary of this finding is that global change is likely to have different effects on plant leaf-microbe associations along the latitudinal gradient, with tropical associations being more sensitive to climate warming and environmental changes and temperate associations being more sensitive to changes in host plant abundance and plant species range shifts. The direction of the global change effect could even reverse from negative to positive from low latitudes to high latitudes, as recently shown for plant soil microbes 39,40 . Host selection could result in distinct microbiome compositions that exert plant species-specific impacts on host fitness.…”

The plant microbiota signature of the Anthropocene as a challenge for microbiome research

“… [ 23 ] Cherry Warming increased the abundance of fungal plant pathogens with higher host infection rates as a consequence. [ 24 ] Bog ecosystem Microbiome shifts were observed in controlled warming experiments. A decreased diversity of bacteria and diazotrophs as well as a reduced nitrogen fixation rate was observed.…”

“…In detail, Delgado-Baquerizo et al [ 23 ] provided predictions for the introduction of new pathogens into production areas that were spared so far, especially fungal plant pathogens. Experimental evidence for the impact of global warming on pathogens was provided with Prunus padua plants, which showed a significantly increased abundance of pathogenic fungi and infections [ 24 ]. Bacterial and fungal populations often show negative co-occurrences within the plant microbiome.…”

Tree species diversity increases with conspecific negative density dependence across an elevation gradient

“…Our findings provide a potential explanation for apparent contradictions between results of two recent experimental studies. One found more positive and the other found more negative CDD–HDD in seedling survival following warming experiments (Bachelot et al, 2020; Liu & He, 2021). Our findings suggest that warming may generate more positive CDD–HDD if warming also decreases relative humidity (which is expected without an increase in air moisture).…”