The plant protection of the future may come from the plants themselves

Humans and animals all have chemical and biological signatures that influence their well-being in one way or another. In medicine, the use of probiotics instead of antibiotics is now high on the agenda. However, not only humans and animals have a close relationship with their microflora. Plants also have similar relationships with their environment. Just as they do in humans, microbes play a major role in plant health and plant disease resistance.

At Aarhus University in Flakkebjerg, Denmark, researchers are studying plants, plant health and plant diseases caused by plant pathogens. The ability of plants to fight pathogens such as bacteria and fungi is largely dependent on the genes of the plants that control the plant’s ability to protect itself. In a new study, researchers at AU Flakkebjerg studied how plants with different resistance mechanisms interact with their pathogens in response to pathogen attack.

The research was published in the journal Microbiology Spectrum.

“We investigated what happens to plants when they are attacked by a virus. What changes occur in the plant itself and its associated microbial communities (ie, the microbiome) during a virus attack? What What makes some plants resistant and others not? To answer these questions, we examined the interaction between plant chemical compounds and the abundance of microbial communities associated with this plant, while It is a new area of ​​research, but by using new and modern technology in this study, we have been able to gain a more detailed understanding of what is really happening, regarding the interaction between plant chemicals and microbes. -careful,” says Assistant Professor Enoch Narh Kudjordjie, one of the leading researchers at the Department of Agroecology at Aarhus University.

Plants have their own integrated defense system

Like humans, plants have their own immune system, which plays a major role in preventing disease. Plant defense is tightly regulated by plant secondary metabolites, hormones and beneficial microbes in and around the plant.

This defense system and its operation are complex, and we do not yet fully understand how these components work together to help the plant defend itself from attack. However, there is light at the end of the tunnel as scientists make progress in studying these defense mechanisms by examining different plant species, using new techniques such as next-generation sequencing. and chemistry testing platform.

“We have been working with a model plant known as Arabidopsis thaliana. Arabidopsis genotypes have different levels of resistance to Fusarium oxysporum, a fungal pathogen that attacks many types of plants. In the present work we used two genotypes of Arabidopsis; one resistant to the other. These different genotypes were chosen to help us gain a comprehensive understanding of the metabolic and biological changes that underlie resistance and and the influence of plants during the attack of pathogens,” explains Kudjordjie.

Disease transmission

First, the researchers infected two-week-old Arabidopsis genotypes growing in field soil in a greenhouse with the fungal pathogen Fusarium oxysporum. To examine changes during infection, they collected root and shoot samples at 5-day intervals, starting 5 days after infection and lasting until day 25 after infection. They confirmed infection by qPCR and by monitoring disease symptoms.

“In this way we were absolutely sure that the plants were really infected. The qPCR analysis showed a clear difference between the two genotypes, with the resistant genotype having a very low level of virus more vulnerable.”

Plant chemistry and the microbiome are unique

Kudjordjie continues, “We then went on to examine the possible differences in chemistry and microbiomes between the two genotypes, and we found a significant difference. As it was expected, the plant metabolites and hormones studied were different in healthy and diseased plants, confirming Similarly, we found that the structure of microbes, as well as the network of microbial communities, were different from healthy and disease-resistant and susceptible plants. especially enriched in the rhizosphere of infected plants, suggesting recruitment bacteria to prevent pathogen attack.”

Plant genetics, chemistry and microbial communities are key players

“From a broader perspective, the present work has deepened our understanding of how plants defend themselves against fungal infection. More importantly, we have found a strong and unique relationship between the metabolites of individual defense and specific pathogens in healthy and diseased plants of different species. Further analysis of genes responsible for plant defense against pathogens revealed several changes in different chemical and hormonal pathways in a susceptible plant compared to a resistant plant. Controlling plant defenses in a coordinated manner,” explains Kudjordjie.

“Simply put, we found that individual plant genotypes have a unique set of genes that control microbial activity including metabolic processes that coordinate the assembly of specific microbes during conditions different parts of the plant body. However, soil microbes also influence what happens in the soil. plant.”

Natural protection of plants in the future

Can we imagine a future where plants are grown with good yields and other agricultural and economic benefits without the use of synthetic chemicals? That will improve people’s health and eliminate environmental pollution from agricultural chemicals. So far, the accumulated evidence points to that possibility, and the current findings from AU researchers are important for future research efforts to develop natural products for plant protection.

“Although these findings are exciting, we need to use our knowledge and combine it with future disease control strategies. Another approach from the plant side will be to produce genotyped plants with conditions developed protective metabolites to attract certain pathogens to fight certain pathogens. This means that plant growers must include plant chemicals in the toolbox. the opportunity to plant ‘super’ crops that are able to protect themselves against pests in the future,” says Kudjordjie.