Healthy soils for healthy plants for healthy humans

Heribert Hirt,  EMBO Reports (2020) 21: e51069 https://doi.org/10.15252/embr.202051069

The human gut microbiome is a complex system of gazillions of bacteria, fungi, viruses, protists and archaea that has an enormous effect on our metabolism, health and well-being. The same holds true for the plant rhizosphere, the crucial parts below ground: roots are immersed in a soil microbiome that provides plants with important nutrients, protects them from disease and pathogens and helps plants to adapt to environmental changes (Fig 1). And, similar to faecal transplants in humans, soil transplants can have a drastic effect on plant health and growth. Moreover, plant and human microbiomes are linked to each other: since the gut and the soil microbiome share similar bacteria phyla and since microbes from fruits, salads and vegetables join the human gut microbiome, the plant microbiome can affect the gut microbiome and thereby human health (Fig 2). The current and well-known concept of a healthy diet^†—one that includes a lot of fibre, minerals and vitamins from fruits and vegetables—should therefore be expanded to consider plant microbes that not only benefit plant health but via food also human health. Vice versa, as much as antibiotics can severely change the human gut microbiome and its function, the use of herbicides, fungicides and pesticides in food production has drastic effects on the plant microbiomes in the soil and on the fruits and vegetables that we eat.