Fighting Microbes with Microbes

Next generation Soil Science is being pursued that will lessen the use of pesticides, fungicides, herbicides, and even synthetic fertilizers.

"While the Human Microbiome Project has discovered that some 10,000 species of microorganisms live in and on the human body, outnumbering our own cells by ten to one, plant scientists have found that any given soil sample contains more than 30,000 taxonomic varieties of microbes. Soil microflora not only provide nutrients for plants, but also suppress disease. In exchange, roots secrete fixed carbon into the soil and feed their bacterial symbionts.

Although the medical community now warns that overprescribing antibiotics kills beneficial organisms and encourages the formation of resistant strains, a similar change in opinion has not occurred in agriculture, where a kill-all approach to plant pathogens has given rise to biocides that indiscriminately wipe out the beneficial along with the pathogenic. “Biocides can nuke the soil, but they never kill everything,” says Mike Cohen, a biologist at Sonoma State University in California. “This creates a biological vacuum that becomes filled by opportunistic survivors and organisms from the surrounding soil.” Biocides create a strong selective pressure: the few pathogens that survive face little competition and proliferate, giving rise to pathogenic communities that can evade standard treatments.

Beneficial soil organisms, however, can protect plants more selectively than biocides do. They displace pathogens and produce toxins that kill pathogenic microbes, and they also trigger plants’ own defense mechanisms. “Native bacteria are the first and most powerful barrier to prevent the establishment of pathogens,” says Jousset. “A diverse community is especially important to keeping pathogens away—this is true in the human gut and in the soil.”

Given the number of known microbes found in soil, and that each plant and each potential pest have their own complex, interconnected relationships, this will take a lot of time & work to make head-way.  But it certainly beats the alternatives of flirting with dependency on dwindling resources, or altering the evolution of ecosystems in trial & error fashion on large scales.

Full article: Image/infographic:  Catherine Delphia

#soilscience   #sciencesunday   #planthealth   #microbes   #agriculture   #sustainability   #evolution  
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