Microbes work as natural fertilizer in poor soil

Study supported by FAPESP, published in ISME Journal yesterday (19/12), identified 522 genomes (including archaea and bacteria) associated with the roots and soil of two plant species native to Campos Rupestres. Hundreds of microorganisms that were previously unknown to science were identified, showing that Brazilian biodiversity still houses a huge number of new organisms.

The discovery paves the way for the development of biological substitutes for chemical fertilizers used in agriculture, especially those containing phosphorus.

“Phosphorus is normally present in the soil, but not always in the form that can be used by plants. What most of the microorganisms we find do is make this element soluble so that plants can absorb it”, explains Antônio Camargo, first author of the article, carried out during his doctorate at the Institute of Biology at the State University of Campinas (IB-Unicamp). with a scholarship from FAPESP.

The study took place within the scope of the Center for Research in Genomics Applied to Climate Change (GCCRC), an Engineering Research Center (CPE) constituted by FAPESP and the Brazilian Agricultural Research Corporation (Embrapa) at Unicamp.

One of the plants, Vellozia epidendroides, lives in shallow soils, while Barbacenia macranta was found living on exposed rocks. Both are part of the Velloziacea family and were collected in a private area adjacent to the Serra do Cipó National Park, in Minas Gerais.

When comparing the microorganisms of plants that grow in soil and rock, the researchers found that they are different communities, however, with many shared species. In general, microorganisms were found that were very specialized in transporting phosphorus and converting the non-soluble to the soluble version of the mineral, which is absorbed by plants.

“Microbial communities also showed an important role in making nitrogen available, another essential nutrient for plants,” says Camargo, currently a researcher at the Joint Genome Insitute, of the United States Department of Energy, where the genome sequencing was carried out.

new solutions

“Studies carried out so far have typically focused on the mechanisms of plant adaptation to the harsh conditions of Campos Rupestres, sometimes ignoring microorganisms. We show that microorganisms have an essential functional potential in plant adaptation to the extreme conditions of this environment. In particular, by providing phosphorus for plant growth,” says Rafael Soares Correa de Souza, a researcher associated with the GCCRC who was supported by FAPESP and is one of the study’s co-authors.

The researchers' expectation is that the discoveries can contribute to the creation of products that replace chemical fertilizers based on phosphorus, one of the nutrients most used in fertilizing crops in Brazil. Today, more than half of the phosphate fertilizer used in the country is imported, mainly from Morocco, but also from Russia, Egypt, China and the United States.

The next step in the research is to carry out studies to test the benefits of some of the microorganisms found in an agricultural crop. The experiments are being carried out at the GCCRC headquarters in Campinas.

The article Plant microbiomes harbor potential to promote nutrient turnover in impoverished substrates of a Brazilian biodiversity hotspot can be read here.