Periodic Reporting for period 2 - MIRA (Microbe induced Resistance to Agricultural pests)
Okres sprawozdawczy: 2019-12-01 do 2021-11-30
Plants are intimately associated with beneficial microorganisms in their root zone, which can enhance their resistance against agricultural pests. Use of microbe-induced resistance (MiR) has therefore emerged as a promising option to improve resilience and reduce pesticide use. However, MiR is often context dependent, and it is a challenge to ensure stable associations of microbes and plants under field conditions and to avoid negative effects on other biocontrol organisms used in integrated pest management. Improved understanding and skilled researchers are therefore needed.
In the training network MiRA, "Microbe-induced Resistance to Agricultural pests”, 15 early-stage researchers (ESRs) have been trained in basic and applied aspects of MiR, with focus on impacts, context dependency, mechanisms, effects on other biocontrol organisms, combinations of different beneficial microbes, and economic constraints. The ESRs have been trained and hosted by a consortium of academic and private institutions across Europe.
Despite Covid restrictions, all ESRs have finalized their MiRA projects, delivered results on their planned objectives and are preparing for their PhD defences (or have already defended). Results from their projects have been and will be disseminated in scientific journals, at meetings and conferences, and through media outlets.
In the training network MiRA, "Microbe-induced Resistance to Agricultural pests”, 15 early-stage researchers (ESRs) have been trained in basic and applied aspects of MiR, with focus on impacts, context dependency, mechanisms, effects on other biocontrol organisms, combinations of different beneficial microbes, and economic constraints. The ESRs have been trained and hosted by a consortium of academic and private institutions across Europe.
Despite Covid restrictions, all ESRs have finalized their MiRA projects, delivered results on their planned objectives and are preparing for their PhD defences (or have already defended). Results from their projects have been and will be disseminated in scientific journals, at meetings and conferences, and through media outlets.
MiRA ESRs have been trained in specialized and transferable skills at five successful MiRA events and at secondments with other MiRA hosts. They have actively interacted in discussions and activities on scientific and practical issues within and across work packages, on career development within mentor groups, and outside MiRA through internet seminars and meetings. These activities have been supported by internal ESR progress reports and feedback, both at individual and consortium level, and by efficient project administration and communication.
The ESRs research focused on (1) context-dependency of MiR, (2) mechanisms and processes, (3) impacts on other beneficial biocontrol organisms, and (4) validation and economy in agriculture.
Effects of mycorrhizal fungi and other plant-associated fungi and bacteria on plant resistance varied depending on drought severity, light conditions, phosphorous and nitrogen availability, and exposure to plant pathogens. Wild tomato species, adapted to different climatic niches, have been evaluated for genotypic differences of microbe-induced resistance. The response of caterpillar’s gut microbiome, which can confer resistance to plant defences, has been evaluated for different combinations of plants and root-associated microbes.
Root-associated microbes, including bacteria and fungi, were found to induce resistance against different insects and plant pathogens through differential regulation of plant defences. Transcriptomic, metabolomic and bioinformatic analyses revealed that such resistance induction depends on phytohormone signalling and primed accumulation of plant chemical defences. Water and nutrient availability, and interactions with other microbes, were shown to impact this differential defence regulation, partly accounting for the context-dependency of the microbially induced plant resistance. Thus, our results confirm that context-dependency of MiR is associated with changes in defence signalling and responses, and identify jasmonates and other fatty acid derivatives, together with phenolic compounds and steroidal glycoalkaloids, as key mediators of MiR in tomato.
Mycorrhizal fungi predominantly reduced survival and growth of herbivores, although the degree depended on environmental conditions (e.g. nutrients). Mycorrhiza generally did not impede parasitoid and predator performance or foraging capacities, suggesting compatibility of resistance-inducing fungi with other biocontrol agents. Mycorrhizal fungi modulated volatiles in different tomato varieties attacked by herbivores, including compounds known to attract generalist predators. The ability of tomato to enhance resistance against pests in response to mycorrhizal inoculation was stronger in a modern domesticated than in ancient varieties.
Root inoculation with beneficial microbes alone and in consortia affected insect herbivore performance negatively and some combinations protected the plants against leaf and root pathogens. Root inoculation methods were developed for beneficial bacteria, Trichoderma and plant-associated insect-pathogenic fungi, and compatibility with mycorrhizal fungi evaluated. Such combinations seem to reduce pathogen performance on tomato leaves confirming systemic effects. Predatory insect larvae were found to transfer beneficial bacteria with their mouthparts from colonized plant material or artificial diets to other plants. Methods for in-planta PCR detection of these bacteria were developed.
The surveys conducted amongst stakeholders suggest that MiR-based innovations face several challenges for future adoption, such as lack of information on ecological and economic effects. The surveys concluded that attitude, norms, and perceived usefulness of MiR innovations are significant predictors of farmers’ intentions to adopt MiR innovation.
The ESRs research focused on (1) context-dependency of MiR, (2) mechanisms and processes, (3) impacts on other beneficial biocontrol organisms, and (4) validation and economy in agriculture.
Effects of mycorrhizal fungi and other plant-associated fungi and bacteria on plant resistance varied depending on drought severity, light conditions, phosphorous and nitrogen availability, and exposure to plant pathogens. Wild tomato species, adapted to different climatic niches, have been evaluated for genotypic differences of microbe-induced resistance. The response of caterpillar’s gut microbiome, which can confer resistance to plant defences, has been evaluated for different combinations of plants and root-associated microbes.
Root-associated microbes, including bacteria and fungi, were found to induce resistance against different insects and plant pathogens through differential regulation of plant defences. Transcriptomic, metabolomic and bioinformatic analyses revealed that such resistance induction depends on phytohormone signalling and primed accumulation of plant chemical defences. Water and nutrient availability, and interactions with other microbes, were shown to impact this differential defence regulation, partly accounting for the context-dependency of the microbially induced plant resistance. Thus, our results confirm that context-dependency of MiR is associated with changes in defence signalling and responses, and identify jasmonates and other fatty acid derivatives, together with phenolic compounds and steroidal glycoalkaloids, as key mediators of MiR in tomato.
Mycorrhizal fungi predominantly reduced survival and growth of herbivores, although the degree depended on environmental conditions (e.g. nutrients). Mycorrhiza generally did not impede parasitoid and predator performance or foraging capacities, suggesting compatibility of resistance-inducing fungi with other biocontrol agents. Mycorrhizal fungi modulated volatiles in different tomato varieties attacked by herbivores, including compounds known to attract generalist predators. The ability of tomato to enhance resistance against pests in response to mycorrhizal inoculation was stronger in a modern domesticated than in ancient varieties.
Root inoculation with beneficial microbes alone and in consortia affected insect herbivore performance negatively and some combinations protected the plants against leaf and root pathogens. Root inoculation methods were developed for beneficial bacteria, Trichoderma and plant-associated insect-pathogenic fungi, and compatibility with mycorrhizal fungi evaluated. Such combinations seem to reduce pathogen performance on tomato leaves confirming systemic effects. Predatory insect larvae were found to transfer beneficial bacteria with their mouthparts from colonized plant material or artificial diets to other plants. Methods for in-planta PCR detection of these bacteria were developed.
The surveys conducted amongst stakeholders suggest that MiR-based innovations face several challenges for future adoption, such as lack of information on ecological and economic effects. The surveys concluded that attitude, norms, and perceived usefulness of MiR innovations are significant predictors of farmers’ intentions to adopt MiR innovation.
The MiRA project is, to our knowledge, the first training project focused on microbe-induced resistance, preparing a group of young researchers for a future career in academia and industry. Their higher-than-usual cross-disciplinary knowledge and skills, and ability to bridge basic, applied and innovative research and development make them highly valuable candidates to employ at research institutions and companies. These professional profiles are highly demanded by the biotech market targeting sustainable solutions in agriculture.
The intensive collaboration among ESRs and MiRA supervisors, and their common focus on tomato and potato, has created unique collections of studies on MiR. The combined results will allow further integrative analyses that will continue also after the end of the project. For example, the collaborative dataset on context dependency of MiR from across the many ESR projects is a unique resource to identify conducive environmental conditions for MiR in plant cultivation, and to identify microbes with superior potential for MiR and with less context dependency. No other similar resources exist to our knowledge.
The many datasets on microbe-induced plant defences, including genes, metabolites and pathways, are also unique and enable comparisons among different combinations of beneficial microbes and pests. Thus, our results form a solid resource for the screening of efficient resistance-inducing microbes and for development of predictive and monitoring tools for MiR in plant production.
Our results on the performance of resistance-inducing microorganisms alone and in combinations (micro-consortia) will contribute to the development of microbial inoculants for field use. Several microbes and micro-consortia have been tested in a collaborative experiment in realistic tomato production conditions, giving important and often missing support for knowledge transfer from lab to field.
Major barriers for adopting technologies based on resistance-inducing microorganism in food production have for the first time been evaluated and will be used to recommend strategies for further development and communication towards farmers, food production associations, consumers, and other stakeholders.
The intensive collaboration among ESRs and MiRA supervisors, and their common focus on tomato and potato, has created unique collections of studies on MiR. The combined results will allow further integrative analyses that will continue also after the end of the project. For example, the collaborative dataset on context dependency of MiR from across the many ESR projects is a unique resource to identify conducive environmental conditions for MiR in plant cultivation, and to identify microbes with superior potential for MiR and with less context dependency. No other similar resources exist to our knowledge.
The many datasets on microbe-induced plant defences, including genes, metabolites and pathways, are also unique and enable comparisons among different combinations of beneficial microbes and pests. Thus, our results form a solid resource for the screening of efficient resistance-inducing microbes and for development of predictive and monitoring tools for MiR in plant production.
Our results on the performance of resistance-inducing microorganisms alone and in combinations (micro-consortia) will contribute to the development of microbial inoculants for field use. Several microbes and micro-consortia have been tested in a collaborative experiment in realistic tomato production conditions, giving important and often missing support for knowledge transfer from lab to field.
Major barriers for adopting technologies based on resistance-inducing microorganism in food production have for the first time been evaluated and will be used to recommend strategies for further development and communication towards farmers, food production associations, consumers, and other stakeholders.