https://ri.ufs.br/jspui/handle/riufs/2452 Sun, 05 Apr 2026 23:44:14 GMT 2026-04-05T23:44:14Z http://ri.ufs.br:80/retrieve/02a47f12-005c-4b8b-a39f-0ec70f409d9c/a15346f0-3c11-45f7-997f-dac4b3269660.jfif https://ri.ufs.br/jspui/handle/riufs/2452 https://ri.ufs.br/jspui/handle/riufs/24113 Título: Diversidade fenotípica e metagenômica de Spondias tuberosa: subsídios para a bioeconomia da Caatinga Autor(es): Silva, Maria Suzana Oliveira da Abstract: Spondias tuberosa Arr. Câm., commonly known as umbuzeiro, is a species native to the Brazilian Caatinga biome and holds great potential for regional bioeconomic development. Its fruits are of notable nutritional, sociocultural, and commercial importance to communities in the semi-arid region. However, integrated studies on the phenotypic and microbiological diversity of this species remain scarce, particularly in natural populations from the state of Sergipe. This dissertation aims to investigate the phenotypic variability of fruits and natural populations of umbuzeiro, and to functionally characterize the microbiomes associated with their endocarps, with the goal of identifying relevant traits for conservation strategies, genetic improvement, and sustainable biotechnological applications. The study is structured into three scientific chapters. The first one chapter presents a systematic review of the role of endophytic microorganisms in fruits and seeds of fruit-bearing species, highlighting their functions in plant growth promotion, biological control, resistance induction, and postharvest conservation. The review includes 59 studies selected according to PRISMA criteria, revealing that bacterial genera such as Bacillus and Pseudomonas, as well as fungi like Trichoderma and Penicillium, are most frequently associated with beneficial functions. Despite significant advances in studies on fruit microbiota, substantial gaps remain in the understanding of seed-associated microbial communities, especially in tropical native species. The second chapter addresses the phenotypic characterization of fruits and natural populations of S. tuberosa in extractive areas of Sergipe. Morphological and biometric traits such as fruit weight, soluble solids content, firmness, diameter, and length were evaluated. The analyses revealed wide intra and inter-population variability, highlighting genotypes with agronomic promise and commercial potential. Chromatic attributes, particularly luminosity, proved to be the most consistent descriptors for differentiating the origin of umbuzeiro fruits and endocarps. The Gararu population exhibited a more uniform and distinct phenotype, Poço Verde showed greater internal cohesion, whereas Canindé displayed greater variability among matrices, with matrix nine standing out due to its relevant phenotypic characteristics, such as size and sweetness, which make it distinct from the others. The third chapter employs functional metagenomic approaches to explore the composition and biotechnological potential of the microbiota found in fruit endocarps. DNA extraction, sequencing, and bioinformatic analyses were conducted to identify key microbial groups. Results revealed a diverse microbial community, with bacteria harboring genes related to nitrogen fixation, phosphate solubilization, auxin production, and ACC deaminase activity. These microbial functions support the potential use of S. tuberosa as a source of natural bioinputs in low-impact agricultural systems. The findings of this dissertation contribute significantly to the recognition of umbuzeiro as a strategic resource for fostering the bioeconomy of the Caatinga biome. The integration of morphological and molecular data provides scientific and technical foundations for public policies aimed at biodiversity conservation, the development of cultivars adapted to semi-arid conditions, and the sustainable use of native microbial resources. Ultimately, the dissertation emphasizes the value of combining traditional knowledge with modern science to strengthen sustainable and inclusive agricultural practices. Thu, 03 Jul 2025 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/24113 2025-07-03T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/24112 Título: Biochar e sua influência no solo, nas plantas e na dinâmica do carbono Autor(es): Silva, Andreza Nunes Conceição da Abstract: The application of biochar to degraded or highly weathered soils has been recommended in several countries with climate regions vulnerable to environmental problems but requiring high agricultural productivity to meet population demands. This technology stimulates the circular economy through the use of various organic residues and supports both traditional and regenerative agriculture. This study evaluated the effect of different types of biochar on soil properties, microbiota, plant growth, and the distribution of carbon and nitrogen among soil particle-size physical fractions. The first experiment, conducted in a randomized block design in an agricultural greenhouse, assessed the effect of four types of biochar (pear orange bagasse – BL, sugarcane bagasse – BC, corn cob – BM, and green coconut residue – BCV) on some chemical and biological properties of a Red-Yellow Ultisol and on the growth of curly mustard (Brassica juncea L.). All biochars increased soil carbon (by 108–175%) and total phosphorus (by 22–38%) concentrations. However, the biochar type affected total nitrogen and exchangeable calcium concentrations, as well as microbiota behavior and plant biomass, confirming findings reported in the literature on the importance of evaluating the effects of different biochars. The second study, conducted in a completely randomized design in the laboratory, evaluated the effect of three types of biochar (dry coconut residue – BCS, pear orange bagasse – BL, and biosolid – BB) on the distribution of carbon and nitrogen in the particulate organic matter (POM) and mineral-associated organic matter (MAOM) fractions of a RedYellow Ultisol after a three-year incubation. The biosolid biochar had the smallest contribution to increasing soil carbon (40%) but stood out as the best nitrogen source, increasing soil N content by 145%. This effect is clearly associated with its chemical composition. In general, the biochars did not affect the proportional mass of the POM and MAOM fractions but caused significant changes in the distribution of C and N between them, with a proportional increase of C in the POM and a reduction in the MAOM. In soil without biochar, 17% and 85% of carbon were distributed in the POM and MAOM fractions, respectively. However, biochar increased C in the POM by 4.5 (BB) to 8 times (BCS and OB), causing a shift in the carbon proportion between the two fractions. These results complicate the use of particle-size physical fractionation of organic matter as a tool for assessing changes in soil quality due to management practices, as the POM fraction is no longer a reliable indicator of carbon lability in biochar-amended soils. Wed, 30 Jul 2025 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/24112 2025-07-30T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/23396 Título: Dinâmica de quorum sensing e produção de violaceína em cocultivos de Chromobacterium subtsugae e Bacillus Autor(es): Cardoso, Jackelyne Panta Abstract: Microbial communication plays a critical role in regulating collective behaviors, such as the production of secondary metabolites, including pigments with bioactive properties. In Chromobacterium subtsugae, violacein synthesis is regulated by quorum sensing (QS) mechanisms that modulate gene expression in response to bacterial population density. This communication can be influenced by interspecies interactions, such as cocultivation with other bacterial species, which may act as inducers or inhibitors of QS-related gene expression. In this context, the influence of microbial interactions on violacein synthesis was investigated, beginning with a systematic literature review followed by experimental coculture assays. The first chapter, through the systematic review, identified the key genes involved, notably cviI, cviR, and the vioABCDE operon, and showed molecules and quorum sensing interference strategies, highlighting their potential biotechnological applications. In the second chapter, experimental assays demonstrated modulation of violacein production in C. subtsugae ATCC31532 when cocultured with various Bacillus species, particularly B. thuringiensis subsp. kurstaki. Interspecies microbial competition influenced pigment biosynthesis. Scanning electron microscopy revealed morphological changes and the presence of Cry crystals in cocultures with B. thuringiensis, indicating competitive responses. Four cultivation conditions were tested: isolated C. subtsugae (CS), sequential coculture first inoculated with C. subtsugae followed by B. thuringiensis subsp. kurstaki after 24 hours (CS + BTK), inverse coculture with initial inoculation of B. thuringiensis subsp. kurstaki followed by C. subtsugae (BTK + CS), and simultaneous coculture of both species (CB). The CS + BTK treatment showed the highest increase in violacein production compared to monoculture, while the BTK + CS and CB conditions yielded levels similar to the control. These findings suggest that the temporal dynamics of bacterial interactions directly influence quorum sensing modulation and secondary metabolite biosynthesis, providing a foundation for developing strategies to optimize the production of bioactive compounds with pharmaceutical and industrial relevance. Tue, 15 Jul 2025 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/23396 2025-07-15T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/23335 Título: Prospecção de isolados microbianos de ambientes hipersalinos para redução do estresse hídrico em milho (Zea mays L.) Autor(es): Amancio, Lucas Henrique da Silva Abstract: Hypersaline environments, such as apicuns (supratidal flats) and salt flats, harbor highly specialized microbial communities adapted to growth under extreme salinity conditions. Due to the physiological similarity between high salinity and drought stress—both characterized by reduced osmotic potential—these microorganisms present biotechnological potential to enhance plant tolerance to water deficit in agricultural systems. This study aimed to isolate, identify, and evaluate the potential of microorganisms from the rhizosphere of halophytic plants inhabiting apicuns and salt flats to confer drought tolerance in maize (Zea mays L.). Bacterial and fungal isolates were obtained through culturomic approaches, using multiple culture media with varying NaCl concentrations (4 to 25%) and incubation temperatures, followed by molecular identification, characterization of their ability to promote drought tolerance in maize, and preservation. The experimental phase was conducted in a greenhouse using the maize hybrid Morgan 20A55, grown under controlled irrigation conditions in pots containing a RedYellow Argisol (Brazilian Soil Classification System). Plants were irrigated daily during the first five weeks and then subjected to a 14-day drought stress period, followed by rehydration at levels sufficient to meet the plants' full water demand. Biometric variables (plant height and shoot dry mass), physiological parameters (leaf temperature and relative chlorophyll content measured via SPAD index), and metabolic responses (leaf proline accumulation) were assessed, in addition to a visual drought index. Statistical analyses were performed using contrasts with irrigated and non-irrigated controls, along with non-metric multidimensional scaling (NMS) to evaluate treatment distribution based on the joint response of the measured variables. The results indicated that certain isolates significantly improved plant growth and physiological performance under drought stress, including higher biomass accumulation, increased chlorophyll and proline content, and reduced visual drought symptoms. Multivariate analyses confirmed these effects, revealing associations between specific treatments and axes related to thermal regulation and maintenance of leaf hydration. Mon, 30 Jun 2025 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/23335 2025-06-30T00:00:00Z