Domesticated vs wild plants – the microbe edition
For plants attraction of microbes is often useful. Therefore, the question was raised about how domestication and breeding influenced the attraction of microbes.
This might be a strange question. Afterall up to recently breeders did not select for crops that attract more useful microbes. Still, it is possible that unknowingly something changed in the ability of plants to attract useful microbes.
That is because when a breeder has a plant with a preferred trait that he likes to transfer to another plant, he crosses those two plants and selects for the offspring with the preferred traits. Thereby it can be that nearby the gene for the preferred trait there lays gene for another trait. This can cause those two traits to always be inherited together. In this way selection for gene A can also mean the selection of gene X.
Is there a difference
Now is the question if this resulted in that domesticated plants attract less or different microbes that their wild relatives. This was the central question in the article: “Plant domestication does not reduce diversity in rhizosphere bacterial communities”.
To answer this question the researchers dived into lots of studies comparing the bacterial communities between wild and domesticated plants. The first thing the researchers wanted to know was the general diversity. These did not differ much between wild and domesticated plants. Subsequently the researchers looked at what is influencing this diversity. This turned out to be more species specific than if a variety was or wasn’t domesticated.
The only difference in the bacterial make up between wild and domesticated plants that the researchers could find was that domesticated plants attract two species of Rhizobiaceae more often while wild plants attract two species of Burkholderiaceae more often.
How plants attract microbes
In hindsight it is maybe not that strange that there is little difference in the bacterial diversity between wild and domesticated plants. That has all to do with how plants attract microbes. For this, plants exude three kinds of molecules.
The first group consists among others out of carbohydrates and amino acids. The second group are inorganic molecules like water and CO2. These two groups are responsible for attracting the bulk of the microbes. The third group consists of specialised metabolites. Those can attract, repel, or kill specific microbes.
Changes in the first two groups of microbe attracting substances go with high likelihood hand in hand with likely negative changes in the metabolism of the plants, something that breeders do not want. What in turn results in that the attraction of the bulk of the microbes remains unchanged
Changes in the third group of microbes can result in that the microbe community changes a little. This is something we also see in this study. With two species that occur more by domesticated plants and two species that occur more by wild plants.
In order to find out if this occurs more often researchers need to look at different circumstances, like drought for example. In stress situations like that plants often ask with specialised metabolites for help. Only in those situations a difference in ability to attract microbes becomes visible.
Literature
Hernández-Terán, A., Escalante, A.E. and Rebolleda-Gómez, M. (2025), Plant domestication does not reduce diversity in rhizosphere bacterial communities. New Phytol. https://doi.org/10.1111/nph.70588
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