The impact of climate change on the association between arbuscular mycorrhizal fungi (AMF) and winter wheat (triticum aestivum (L.) var. asory) - insight from an ecotron experiment

Abstract

Climate change is going to impact crops such as winter wheat (Triticum aestivum (L.)) with currently unknown consequences for yields and grain quality. Indeed, various environmental parameters critical to crop growth are predicted to undergo significant change, notably temperature, precipitation, and a global rise in CO2 concentration. Wheat crops are not the only ones affected by climate change; the same applies to microorganisms associated with plants, such as arbuscular mycorrhizal fungi (AMF). AMF are symbiotic root endophytes occurring in nearly 80% of vascular plants since 400 million years. Given the wide abundance of AMF and their potential to facilitate plant nutrient uptake and stress resistance, the research questions of this Master thesis focussed on the potential role of the symbiosis in agriculture and how the plant-AMF interaction may evolve with climate change.

This Master thesis was part of the European project Biofair and integrated into the framework of work package three, which consisted of an Ecotron experiment. Using the six controlled environmental chambers (CER) of the state-of-the-art Ecotron facility at Gembloux Agro-Bio Tech, winter wheat cropping systems were studied in three different climate scenarios. The selected climate scenarios represent the meteorological conditions of the years 2013, 2068, and 2085. The year 2013 is a replication of real observed weather data, while the future climate scenarios are based on predictions according to the Representative Concentration Pathway (RCP) 8.5. Wheat plants were then grown in two soil types with conventional or organic farming practice. Thus, the impact of climate change with its combined effects of various environmental factors acting on winter wheat plants and their association with arbuscular mycorrhizal fungi could be studied simultaneously and in a realistic way.

In particular, the evolution of AMF colonization of wheat roots and hyphal soil exploration were investigated for the three climate scenarios and the two different soil types. Additionally, the study determined whether greater AMF colonization could lead to increased plant phosphorus uptake. The impact of climate change on fungal spore production was also analysed, as well as the interaction between AMF and another root endophyte, namely dark septate endophytes (DSE).

Climate change, as represented by the climate scenarios, promoted the colonization of roots by AMF. However, plant phosphorus uptake was not proportionally enhanced with the percentage of root colonization by AMF. Farming practices, soil depth, and soil composition were also found to be influential factors in soil colonization by AMF hyphae, which was greater in soil of low phosphorus content. Fungal spore abundance was unaffected by the climate scenarios, but higher in organic soil. AMF and DSE commonly co-occurred, but further in-depth experiments are necessary to study their interactions.