Banca de DEFESA: GISELY MOREIRA VITALINO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : GISELY MOREIRA VITALINO
DATE: 31/07/2025
TIME: 14:00
LOCAL: Auditório do PPG Ciência do Solo
TITLE:

Cultivable bacterial community of a Technosols chronosequence in the tropical semi-arid region.

KEY WORDS:

Anthropogenic soils, BNF, genetic diversity, mineral solubilization.

PAGES: 64
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SPECIALTY: Microbiologia e Bioquímica do Solo
SUMMARY:

Agricultural, industrial and mining activities lead to the removal of layers or an increase in residues in the soil, which change due to various factors resulting in the formation of soil. In scheelite mining, basins are constructed to deposit tailings, which, over time, are revegetated, forming Technosols with characteristics that differ from those of natural soils. These areas have a reserve of nutrients and a progressive increase in organic carbon, the stock of which may be higher than that found in other soil classes. Therefore, they can favor agriculture, the recovery of degraded pastures and carbon fixation. Furthermore, with bioprospecting, it may be possible to obtain microorganisms that promote soil development and benefit crops, especially in the semi-arid tropical region. This research aimed to: (i) isolate bacteria in different culture media from a chronosequence of Technosols; and (ii) evaluate the genetic diversity of isolates obtained from Technosols with different formation times using the 16S rRNA gene. Soil samples were taken in June 2022 from the soil profile at times 2, 5, 10 and 40 years, three replicates were taken from each horizon that makes up the profile and three more samples of tailings, time zero. The bacteria were isolated in different selective media, to obtain potential phosphate solubilizers, cellulase producers, carbon and nitrogen fixers, and the CFU g-1 of soil and MPN were estimated, then all the strains had their DNA extracted using an extraction kit, following the manufacturer's protocol, and were genotypically characterized by BOX-PCR. The isolates that amplified BOX were selected for molecular identification by sequencing the 16S rRNA gene using the NCBI database. Each sequence analyzed was subjected to similarity analysis using the BLAST algorithm. The isolation resulted in 378 bacteria being obtained from all media and times, with high values of CFU g-1 of soil being obtained, with Organic Carbon (OC) being the attribute that most explained the variation in populations. Clustering using BOX-A1R amplification showed that 97.33% of the groups were made up of one isolate, which may demonstrate the high diversity of cultivable bacteria in these soils. Identification using the 16S rRNA gene resulted in the most abundant phyla at all times being Proteobacteria, Actinobacteria and Firmicutes, respectively. The most abundant genera were Pseudomonas, Streptomyces, Stenotrophomonas, Pantoea, Priestia and Bacillus, which are associated with nutrient cycling, decomposition of soil organic matter and mineral solubilization. These results show that cultivable bacterial communities may have contributed to the formation of these soils, as they have high genetic diversity and are associated with different functions. In addition, they may be promising sources of inputs for agriculture, being able to support crops grown in the semi-arid tropical region, as well as in biotechnology and industry, with the need for further research into this collection of isolates in order to obtain their potential for application in these sectors.

COMMITTEE MEMBERS:
Interna - GISELLE GOMES MONTEIRO FRACETTO
Interno - MARIO DE ANDRADE LIRA JUNIOR
Externo à Instituição - FELIPE MARTINS DO RÊGO BARROS - USP