What exactly happens around the roots after applying a microbial product? Why are Bacillus strains key to strong roots and resilient plants in many successful biostimulants? Marco Breekweg from Biomicrobes explains. The experienced microbiologist developed a whole range of products based on microbiology throughout his career of over thirty years.
Biomicrobes is the name under which the Dutch company is already well-known in the North American market. Marco and his team have visited many trade shows there and will be present at Cultivate in Ohio, USA, from July 12 to 15.
Microorganisms play a key role in the functioning of crops. Increasingly, growers are using bacterial products to support the resilience, root development, and nutrient uptake of their crops. Notably, many of these products focus on bacteria from the Bacillus genus. What makes this group so suitable? And what exactly happens underground, in the so-called rhizosphere, after applying a Bacillus product?
© Microbac
The rhizosphere: a microbial highway
The rhizosphere is the narrow area around the roots where the plant actively collaborates with soil life. Plants excrete so-called root exudates here: a mixture of sugars, amino acids, organic acids, and other carbon compounds. These compounds act as signal and nutrient sources for microorganisms.
"Because the rhizosphere is much richer in available carbon than the surrounding bulk soil, a selective ecosystem develops where certain bacteria, including Bacillus species, feel right at home. They are attracted by exudates, settle on the root surface, and interact with the plant and other microorganisms."
Why Bacillus species are so successful
Among the group of beneficial rhizosphere bacteria, Bacillus species stand out for a combination of functional properties. Marco lists them.
1. Spore formation
One of the key characteristics of Bacillus is the ability to form endospores. "In this dormant state, the bacteria can survive long periods of drought, heat, or nutrient scarcity. In spore form, they are also easy to formulate into stable end products with a long shelf life. After application, for example, via drip irrigation, the spores are activated and start dividing once they detect root exudates."
2. Rapid colonization
Once active, Bacillus bacteria grow quickly and form colonies on the root surface. "Due to their mobility and rapid division, they can effectively establish themselves in the rhizosphere, often faster than competing microorganisms."
3. Multifunctional action
Many Bacillus strains are capable of performing multiple plant-promoting functions, such as:
- Releasing bound nutrients, such as phosphate via phosphatases;
- Production of growth-promoting substances, such as indole acetic acid (IAA);
- Synthesis of antimicrobial substances such as lipopeptides (e.g., surfactin, iturin), which suppress pathogens;
- Induction of systemic resistance in plants (ISR effect).
Marco: 'Due to this versatility, Bacillus strains contribute not only to better nutrient uptake but also to increased tolerance to biotic and abiotic stress."
Balanced blend of good bacteria
Biomicrobes 08 is a product specifically developed by Microbac to keep the root environment active and healthy. "It contains eight main types of beneficial bacteria that complement each other in their action. Together they ensure better nutrient uptake, healthier roots, and a stable microbial balance around the plant."
The following bacteria are in Biomicrobes 08:
Bacillus subtilis – Helps release nutrients and stimulates root growth
Bacillus licheniformis – Ensures stable bacterial activity and makes phosphate available
Priestia megaterium – Dissolves hardly soluble phosphate through natural acids
Bacillus pumilus – Makes iron and other trace elements easier to absorb
Bacillus amyloliquefaciens – Supports root growth and aids in nutrient uptake
Bacillus laterosporus – Keeps the microbial balance in check
Bacillus mucilaginosus – Releases potassium from soil particles
Paenibacillus polymyxa – Binds nitrogen from the air and stimulates root formation with natural growth substances
Biomicrobes will be present at Cultivate in Columbus at booth 1615.
For more information:
Biomicrobes
info@biomicrobes.com
www.biomicrobes.com