THE POWER OF BACILLUS SUBTILIS: HOW THIS BACTERIUM PROMOTES PLANT GROWTH AND RESILIENCE
CHRISTIAN LÖFKE
Bacillus subtilis is a beneficial microbe that is commonly found in soil and other natural environments. This bacterium has been shown to promote plant growth, facilitate nodulation processes in roots, and enhance plant resistance to pathogens. In this article, we’ll take a closer look at how B. subtilis accomplishes these feats and why it’s an important tool for farmers and gardeners.
PLANT GROWTH PROMOTING MICROBES
One of the key ways in which B. subtilis promotes plant growth is through the production of plant growth hormones. Auxins and gibberellins are two hormones that are involved in many aspects of plant development, including cell division, elongation, and differentiation. By producing these hormones, B. subtilis can help plants grow more vigorously and produce more biomass.
In addition to producing plant growth hormones, B. subtilis can also facilitate nutrient uptake. This bacterium has been shown to produce enzymes that break down organic matter in the soil, making nutrients like nitrogen, phosphorus, and potassium more available to plants. It can also help solubilize minerals like iron, zinc, and calcium, which are essential for healthy plant growth. By making these nutrients more available, B. subtilis can help plants grow more efficiently and produce better yields.
BACILLUS SUBTILIS SUPPORTS THE NODULATION PROCESS IN THE ROOTS
Nodulation is the process by which certain plants, like legumes, form symbiotic relationships with nitrogen-fixing bacteria. These bacteria take nitrogen from the atmosphere and convert it into a form that plants can use, providing a valuable source of this essential nutrient.
Bacillus subtilis can help facilitate nodulation by promoting the growth of nitrogen-fixing bacteria in the soil.
One way to promote nodulation is by producing compounds that nitrogen-fixing bacteria need to grow and thrive. For example, some strains of B. subtilis produce a compound called lipopeptide surfactin, which has been demonstrated to stimulate the growth of rhizobia, a type of nitrogen-fixing bacteria. By providing this compound, B. subtilis can help ensure that plants have access to a steady supply of nitrogen.
Bacillus subtilis can also help promote nodulation by producing organic acids that acidify the soil. Some plants, like legumes, are better able to form symbiotic relationships with nitrogen-fixing bacteria in slightly acidic soil. By acidifying the soil, B. subtilis can create an environment that is more conducive to nodulation.
Besides promoting the growth of nitrogen-fixing bacteria, it can also help protect these bacteria from harmful microbes. For example, B. subtilis has been shown to synthesize antimicrobial compounds that are toxic to some plant pathogens. By protecting nitrogen-fixing bacteria from these pathogens, B. subtilis can help ensure that they are able to continue fixing nitrogen for the plant.
Overall, the ability of B. subtilis to promote nodulation in roots is an important aspect of its role in plant growth and health. By facilitating the formation of symbiotic relationships between plants and nitrogen-fixing bacteria, it can help ensure that plants have access to a valuable source of nitrogen. This can have a significant impact on plant growth and productivity, particularly in environments where nitrogen is limited.
MICROBE MEDIATED RESISTANCE TO PATHOGENS
Bacillus subtilis can help plants resist pathogens by producing antibiotics and other compounds that are toxic to harmful microbes. These compounds can help protect plants from a variety of diseases, including fungal and bacterial infections. Bacillus subtilis can also help prime plants’ immune systems to better defend against pathogens. This bacterium has been shown to induce systemic resistance in plants, meaning that it can activate plant defenses throughout the entire plant, not just in the area immediately surrounding the infection. This can help limit the spread of infections and reduce the overall damage caused by pathogens.
BIOCONTROL THE FORCE OF MICROBES
Biocontrol is the use of beneficial microbes to control harmful organisms like pests and pathogens. Bacillus subtilis can also be used as a biocontrol agent and has been shown to be effective against a wide range of plant pathogens, including bacteria, fungi, and viruses. This bacterium can also help control plant pests like aphids and spider mites.
One of the advantages of using B. subtilis as a biocontrol agent is that it is a naturally occurring microbe. This means that it is unlikely to have negative effects on the environment or other beneficial organisms. Additionally, B. subtilis is considered to be safe for use in organic agriculture.
ONE SPICIES CAN IMPACT THE WHOLE MICROBIOME
In recent years, scientists have begun to recognize the importance of the microbiome in plant health. The microbiome is the community of microorganisms that live in and on plants. These microbes can have a profound impact on plant growth, nutrient uptake, and resistance to pathogens. Bacillus subtilis is an important team member of this consortium covering all aspects of a plants life.
Furthermore to its role in the plant microbiome, B. subtilis has potential applications in human health as well. For example, it has been shown to produce compounds that can inhibit the growth of harmful bacteria in the human gut. This has led to research on the use of B. subtilis as a probiotic supplement, which could help to promote gut health and prevent certain diseases.
CULINARY FUN FACT:
Natto is a traditional Japanese food made from fermented soybeans. The fermentation process is facilitated by the bacterium B. subtilis var. natto, which is responsible for producing the characteristic sticky texture and strong flavor of the delicacy. During the fermentation process a number of beneficial compounds are produced, including nattokinase, which is an enzyme that has been shown to have anticoagulant and fibrinolytic properties. Natto also contains high levels of vitamin K2, which is important for bone and heart health, and is a good source of protein and fiber. Due to its unique flavor and nutritional profile, natto is a popular food in Japan and is also enjoyed by people around the world as a health supplement.
The potential of B. subtilis in both the plant and human microbiomes highlights the importance of understanding the role of microorganisms in these ecosystems. By studying the interactions between microorganisms and their hosts, we can identify potential applications in agriculture, medicine, and biotechnology. This can lead to the development of new and innovative solutions for a wide range of problems, from improving soil fertility to promoting human health.
Collectively, B. subtilis is a fascinating microorganism that has a significant impact on the plant microbiome and on human health. By continuing to study its interactions with other microorganisms and its potential applications, we can unlock new solutions for a variety of challenges in agriculture and medicine.
Promote sustainable agriculture practices: The use of nitrogen fertilizers is a major contributor to greenhouse gas emissions and other environmental problems. By promoting sustainable agriculture practices that emphasize the use of nitrogen-fixing bacteria like those facilitated by B. subtilis, we can reduce the environmental impact of agriculture.
