Effects of continuous versus pulsed drought on mycorrhiza-crop-aphid interactions
Final Report Abstract
Global change scenarios predict reduced water availability together with increasing temperatures, leading to more prolonged drought periods. To study the effects of such changed climatic conditions on plants, usually continuous drought stress is considered, but pulsed droughts or droughts followed by floodings may also be of major relevance. Imbalances in water supply lead to changes in resource allocation of plants and cause various physiological responses such as changes in the biosynthesis of plant metabolites. These changes can in turn impact other organisms interacting with the plant. Furthermore, most plant species associate with symbiotic arbuscular mycorrhizal fungi (AMF), forming an arbuscular mycorrhiza (AM), which has been reported to alleviate drought stress effects in plants. In this project, the effects of different drought regimes (well-irrigated versus pulsed drought stress versus continuous stress, or versus drought followed by waterlogging) on morphological, physiological and metabolic responses of the crop plant wheat, Triticum aestivum, and its main aphid pest, Sitobion avenae, were studied in presence or absence of AM. Our studies revealed that not only the volume of irrigation but also the frequency and the duration of irrigations impact various plant traits. In particular, growth and water use efficiency were modulated by drought. Moreover, the phytometabolome of the flag leaves showed pronounced responses to drought treatments, particularly in metabolites of the shikimic acid pathway. Here, metabolic features were mostly modified by pulsed drought compared to continuous drought. These metabolic changes may have important regulatory fuctions to maintain the plant physiology. Introducing AMF to the wheat-drought system led to slight changes in plant responses. Generelly, well-irrigated plants showed a higher root colonisation than drought-stressed plants. However, colonisation by AMF did not result in a higher biomass production in comparison to non-mycorrhized plants. The ratio of foliar carbon to nitrogen and the content of phosphorous were even lower in mycorrhized plants. However, AM increased the harvest index (ratio of dry ear biomass to total aboveground biomass) of drought-stressed plants. Overall, the success of AFM to colonise the roots varied pronouncedly between experiments, probably depending on the wheat cultivar and AMF species but also on abitotic factors such as light conditions. The reproduction and survival of aphids raised on wheat plants of the different treatments was strongly affected by the water status of their host plants but not by the presence of AMF. The responses of the aphids could be related to changes in the phloem sap composition. Most strikingly, the relative concentrations of proline were enhanced in drought-stressed plants which may impact the aphids. In summary, our findings highlight the complex interplay between different global change scenarios and plant-fungus-aphid interactions.
Publications
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Poster at the GFÖ (Gesellschaft für Ökologie) meeting 2018, Vienna, Austria; Coping with drought in agriculture – role of mycorrhiza in wheat-aphid-drought interactions
Pons C., Calabro A.-C., Schweiger R. & Müller C.
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2020: Invited talk, “Changes in phytometabolomes in response to endophytes and mycorrhiza” at Joint International Symposium “Microverse I – Microbial and Biomolecular Interactions”, Jena
Müller C.
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2020: Invited talk, “Plant responses to global change from a chemical ecological perspective” at CREAF, Barcelona, Spain and at Kiel Plant Center Mini-Symposium, Kiel, Germany
Müller C.
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Effects of drought and mycorrhiza on wheat and aphid infestation. Ecology and Evolution, 10(19), 10481-10491.
Pons, Caroline; Voß, Ann‐Cathrin; Schweiger, Rabea & Müller, Caroline
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Oral presentation at the DBG meeting 2019, Rostock: Effects of drought and mycorrhiza on wheat and aphid infestation.
Pons, Caroline
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Wheat growth, applied water use efficiency and flag leaf metabolome under continuous and pulsed deficit irrigation. Scientific Reports, 10(1).
Stallmann, Jana; Schweiger, Rabea; Pons, Caroline A. A. & Müller, Caroline
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Invited keynote talk at SIP17 (Symposium of Insect-Plant Relationships) in Leiden, The Netherlands; Insights from Ecometabolomics into Intraspecific Chemodiversity of Plants and Interactions with Insects
Müller C.
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Impacts of Drought Stress and Mycorrhizal Inoculation on the Performance of Two Spring Wheat Cultivars. Plants, 11(17), 2187.
Pons, Caroline & Müller, Caroline
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Time point- and plant part-specific changes in phloem exudate metabolites of leaves and ears of wheat in response to drought and effects on aphids. PLOS ONE, 17(1), e0262671.
Stallmann, Jana; Pons, Caroline A. A.; Schweiger, Rabea & Müller, Caroline
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Effects of drought, subsequent waterlogging and redrying on growth, physiology and metabolism of wheat. Physiologia Plantarum, 175(2).
Schweiger, Rabea; Maidel, Alena‐Maria; Renziehausen, Tilo; Schmidt‐Schippers, Romy & Müller, Caroline
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Poster at the DBG (Deutsche Botanische Gesellschaft) meeting 2023, Bonn; Effects of drought, subsequent soil flooding and a recovery phase on growth, physiology and metabolism of wheat
Schweiger R., Maidel A.-M., Renziehausen T., Schmidt R. & Müller C.
