Modifying the plant microbiome to make plants more resistant to pests and diseases
Many important agricultural and horticultural plant species are susceptible to pests and diseases caused by insects, mites, nematodes, fungi, bacteria and viruses. Plant-associated microorganisms that live in, on and around the plant – known as the microbiome – could assist the plant to defend itself against these predating organisms. The objective of this project is to gain fundamental knowledge on ways microbial inoculants can modify the plant microbiome composition in order to stimulate plant defence against pest and disease causing agents.
In the world where the demand for food is continually increasing, it is important that crop plants grow unimpeded in the absence of pests and diseases. The most common way to protect plants against pests and diseases is to make use of chemical pesticides. However, the use of chemical pesticides is under dispute as these agents can be harmful to humans and the environment. Hence, the demand for organic pesticides based on living microorganisms, naturally occurring in plant ecosystems, is increasing...
Using the microbiome
A possible organic alternative for the use of chemical pesticides is to make profit of the plant microbiome. Bacteria and fungi that live in association with plants provide natural protection against pests and diseases. The microbial communities that live in, on and around plants is called the plant microbiome. Each plant species has its own distinguishable microbiome composition, and we could improve plant resistance by modification of the plant microbiome. This could be done by adding beneficial (i.e. suppressing pest or disease causing biological agents) bacteria or fungi to plants as inoculants.
To date, little is known about the impact of inoculant bacteria and fungi on on the plant microbiome composition and physiological responses of the plant. We surmise that application of microbial inoculants to plants will result in changes in plant microbiome compositions and in the host plants metabolic status. Causal relationships between plant microbiome composition and plant metabolism and forthcoming impact on plant resistance will be investigated in this project.
The aim of the project is to investigate the impact of microbial inoculation on plant microbiome composition and plant metabolic responses via an integrated approach. Using this approach it is our intention to gain more and deeper insight in plant defence mechanisms against predators. Therefore, the following questions need to be addressed to gain deeper insight on the impact of plant microbiome composition on plant defences:
- What are the locations and growth stages in plants preferred by different applied microbial inoculants?
- To what extent will plant microbiomes be changed by microbial inoculations?
- How will the plant metabolic status be affected by microbial inoculations?
- How will plant microbiome composition interact with plant metabolism?
In order to accomplish to these objectives, the following activities will take place in the project:
- Study on the colonization of microbial inoculants in three plant species (tomato, chrysanthemum and lettuce) with respect to localization in the plant and eventual preference for particular plant growth stages.
- Impact analyses of microbial inoculation on plant microbiome composition and functioning via next generation sequencing of DNA derived from plants.
- Impact analyses of microbial inoculations on the plant transcriptome, via RNAseq, and on the composition of plant secondary metabolites, via metabolomics.
- Design of an integrative model explaining increased plant defence resulting from microbial inoculations, based on collective data from the plant microbiome, transcriptome and metabolome.
The outcome of the project will lead to more fundamental understanding on the effects of microbial inoculations on plant defences against pest and disease causing microbial agents. Derived mechanisms will be useful to predict successes of microbial inoculations under differing plant growth circumstances. Data derived from the project will be published in scientific peer-reviewed international (open access) journals.