Literatuuroverzicht Plantweerbaarheid: Om inzicht te verkrijgen hoe plantweerbaarheid tot stand komt en de rol van het metaboloom en microbioom daarin

Consumers, retail and governments are increasingly aware of the possible negative side effects that crop protection products can have on human and animal health and on our living environment. This results in an increasing limitation of the availability of pesticides due to European and national regulations and due to requirements set by retail and consumers. Plant resilience, the natural ability of a plant to defend itself against diseases and pests, is an important part of an integrated approach to prevent and/or control diseases and pests in a residue-free manner. In this literature review, we show the potential of activating the plant’s natural defenses based on results obtained in model crops, such as Arabidopsis and tomato, and show what has already been translated into practice. Consumers, retail and governments are increasingly aware of the possible negative side effects that crop protection products can have on human and animal health and on our living environment. This results in an increasing limitation of the availability of pesticides due to European and national regulations and due to requirements set by retail and consumers. Plant resilience, the natural ability of a plant to defend itself against diseases and pests, is an important part of an integrated approach to prevent and/or control diseases and pests in a residue-free manner. In this literature review, we show the potential of activating the plant’s natural defenses based on results obtained in model crops, such as Arabidopsis and tomato, and show what has already been translated into practice. The activation of the natural defenses is initiated by an elicitor. This is a substance that the plant recognizes and responds to by increasing plant resilience. These can be chemical substances or substances of natural origin. Two important groups are: 1. Analogues of the plant hormones jasmonic acid and salicylic acid; 2. Polysaccharides: breakdown products of chitin, pectin or cellulose. Also, some micro-organisms act as elicitors, because the plant recognizes the micro-organism itself or a substance that it secretes. The four main genera containing strains with elicitor function are: 1.Trichoderma spp.; 2.Arbuscular mycorrhizal fungi; 3 Pseudomonas spp.; 4. Bacillus spp. Examples from the literature are given of each of the mentioned elicitors and it is indicated in which commercial product they are present. Plant resilience, plant metabolites and the microbiome (the micro-organisms in and near the plant) are three factors that cannot be seen in isolation from each other. Increasing plant resistance has consequences for the composition of the plant components and the microbiome, but also vice versa: changes in the microbiome or plant components result in changes in plant resistance. Usually secondary metabolites slow down the spread of diseases and/or pests in the crop. Important groups of metabolites with regard to plant resistance are terpenoids, carotenoids, alkaloids, glucosinolates and polyphenols. Which substances within these groups are responsible for increasing plant resistance differs per crop and even per variety. Based on research to date, changes in metabolome composition in different crops appear to follow the same pattern, but more research is needed, especially in non-model crops, to understand how wide these patterns are across the plant kingdom. Microorganisms in a microbial community are in equilibrium with each other. Microorganisms with elicitor action can only settle if they become part of this equilibrium. Adding ‘good’ micro-organisms is therefore only successful under specific circumstances. Little is known about this balance and its relationship with plant resistance.