Strength in Diversity: Microbes Work Together to Defeat Disease

Antifungal effects of compost tea microorganisms on tomato pathogens
Biological Control 2015
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          It is becoming well documented that Compost Tea has fungicidal properties, and that those properties come by way of the microbes in the tea.  Canadian agricultural scientists wanted to see which microbes were the most effective in control of two different tomato diseases, Botrytis and Alternaria.  To do this, the research team identified  4 different bacteria known for having anti-fungal effects in a sheep manure compost tea (Advenella incenata, Aminobacter aminovorans, Bacillus subtilis, and Brevibacterium linens).  The scientists were able to isolate the microbes, and then they ran several experiments with them. 
          In one experiment, the scientists simply grew the microbes on petri-dishes, and then placed actively growing fungal pathogens on the same dishes.  They then looked to see how much the fungal hyphae were able to grow.  They saw that the bacteria Brevibacterium linens and Bacillus subtilis  were able to prevent fungal hyphae from growing at a rate three times that of the control.  In another experiment, the scientists took tomatoes, poked holes in them, and inserted either Botrytis or Alternaria spores, and then immediately following washed the wound with a solution containing B. linens and B. subtilis, individually and combined.   The results showed that the combination of B. linens and B. subtilis worked significantly better than using the two microbes individually.  They also tested spore fungal spore germination, which was also reduced better by the combination of the two beneficial bacteria.  This leads one to conclude that biological diversity in a rich compost tea is reason for the improved fungicidal effects. 

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