What type of bacterium is Bacillus subtilis?

Bacillus subtilis is a beneficial bacterium known for its role in promoting plant health through colonization of developing root systems. It forms a symbiotic relationship with plants, enhancing their growth and resistance to pathogens. This bacterium is often utilized in various agricultural applications, such as biofertilizers and biopesticides, due to its ability to stimulate root development and improve nutrient uptake.

The ability of Bacillus subtilis to colonize roots is important because this colonization can help protect plants from harmful diseases, improve soil health, and promote overall plant vigor. This beneficial aspect makes it a key player in sustainable agriculture practices.

In contrast, the other options refer to different roles or characteristics: the first option suggests a pathogenic role that does not accurately describe Bacillus subtilis, which is generally beneficial. The second option regarding nitrogen-fixing bacteria inaccurately represents this species because Bacillus subtilis is not primarily recognized for nitrogen fixation. The last option incorrectly categorizes it as harmful to seeds, whereas it is actually used to protect and promote plant growth.