Beneficial bacteria have a positive impact on tomato growth, research reveals

Study carried out by scientists from Embrapa Meio Ambiente, Federal University of Lavras (Ufla) and Chr.Hansen Indústria e Comércio Ltda. revealed that bacteria Bacillus subtilis e Bacillus licheniformis, widely used to combat nematodes, have benefits that go beyond controlling these pests. These bacteria also have significant impacts on tomato growth, demonstrating the ability to increase the fresh and dry masses of the aerial part and root system, in addition to the volume and length of the roots.

The study, titled "Bacillus subtilis and Bacillus licheniformis promote tomato growth", one of the main results was the finding that the strains used were capable of producing a hormone known as indole-acetic acid after 48 hours in in vitro culture. This hormone, in addition to promoting root elongation, also confers tolerance to water, saline and thermal stress, making it a discovery of great relevance.

Another novelty brought by the research was the evaluation of the growth and survival rates of bacteria in the rhizosphere, the region of contact between plant roots and the soil. Using the real-time quantitative PCR technique, the researchers were able to conclude that the strains were able to colonize the root system of the treated plants, while no colonization occurred in the plants that did not receive the application of the bioproduct. In the aerial parts, the bacteria were able to survive and persist for up to 45 days in plants treated with B. subtilis e B.licheniformis.

According to Peterson Nunes, a researcher at the Federal University of Lavras, several strains of bacilli are used in biological control and to promote plant growth. However, the colonization efficiency and persistence of these microorganisms in the rhizosphere of plants are significant challenges for biological control, being one of the main reasons for instability in the activity of bacterial inoculants in the soil. Nunes also highlights that colonization of the rhizosphere is crucial for these beneficial interactions, since bacteria also contribute to improving soil health.

"The presence of bacilli, both in the stem and in the rhizosphere of these plants, indicates the survival of the isolates", explains Nunes. The active colonization of tomato roots by these bacteria is essential to promote plant growth and nutrition. However, the level of colonization of the strains was influenced by the number and form of application. "In fact, it seems that the concentration of the bacteria in the rhizosphere is directly related to its effectiveness in colonizing plant tissues, and tracking the population of the introduced bacteria can be proposed as a strategy to guarantee more consistent results in the field", adds the researcher .

This research highlights the potential of bacteria Bacillus subtilis e Bacillus licheniformis not only in controlling nematodes, but also in promoting tomato growth. Understanding the interaction between these beneficial microorganisms and plants is crucial for developing sustainable and efficient strategies in agriculture, which aim to reduce the use of chemicals and increase productivity in a sustainable way. The discovery paves the way for the use of these bacteria as a viable and environmentally friendly alternative to boost the cultivation of tomato plants and, potentially, other agricultural crops.