https://ri.ufs.br/jspui/handle/riufs/2452 2026-08-28T15:44:30Z 2026-08-28T15:44:30Z Matos, Ana Paula Alves https://ri.ufs.br/jspui/handle/riufs/25788 2026-08-11T19:38:00Z 2026-02-12T00:00:00Z

Título: Microrganismos da rizosfera de mangabeiras em reserva extrativista urbana: bioprospecção e aplicação Autor(es): Matos, Ana Paula Alves Abstract: The Mangabeiras Extractive Reserve Uilson de Sá, located in Aracaju, Sergipe, hosts native populations of Hancornia speciosa Gomes (mangabeira), a species threatened by urban expansion and the consequent reduction of its natural habitats. This study aims to investigate the genetic, ecological, and biotechnological potential of the mangabeira rhizosphere microbiota, with emphasis on plant growth-promoting microorganisms. The research was organized into three main axes. First, a systematic review was conducted, covering scientific literature and patent documents on species of the genus Bacillus associated with plant growth promotion, aiming to map metabolic pathways and genes involved in the synthesis and regulation of hormones and bioactive metabolites. Second, the obtained diazotrophic isolates were phenotypically characterized and evaluated for their plant growth-promoting potential in seedlings, as well as for strain compatibility. Third, rhizospheric soil samples collected in the reserve were analyzed through metagenomics, using amplicon sequencing for taxonomic and functional characterization of the microbial community. The results revealed relevant microbial diversity associated with the rhizosphere, including the presence of functional groups linked to soil fertility and isolates capable of stimulating germination and early growth of lettuce seedlings. The rhizosphere of H. speciosa constitutes a reservoir of microorganisms with potential applications in local biodiversity conservation and in the development of bioproducts aimed at species management.

2026-02-12T00:00:00Z Aragão, Nartênia Susane Costa https://ri.ufs.br/jspui/handle/riufs/25787 2026-08-11T19:16:05Z 2026-02-20T00:00:00Z

Título: Índice MGIDI na seleção de genótipos de milho com melhor eficiência no uso de nitrogênio e tolerância à salinidade Autor(es): Aragão, Nartênia Susane Costa Abstract: Maize (Zea mays L.) plays a fundamental role in the economy and society, being widely used for human consumption and animal feed. In semi-arid regions, high evapotranspiration rates favor salt accumulation in the soil, making salinity a recurrent problem and one of the main limiting factors for agricultural production. This stress negatively affects nutrient uptake and assimilation by plants, especially nitrate, the main form of nitrogen available in the soil, compromising maize growth, development, and productivity. Despite the relevance of this topic, studies aimed at identifying genotypes that combine nitrogen use efficiency and salinity tolerance, particularly under semi-arid conditions, are still scarce. In this context, the objective of this study was to select maize half-sib progenies with superior performance regarding nitrogen use efficiency and salinity tolerance using the MGIDI index (Multi-Trait Genotype-Ideotype Distance Index). The experiments were conducted during the 2024 growing season at the Experimental Farm of the Federal University of Sergipe (UFS), Sertão Campus, under two experimental conditions: irrigated environment (greenhouse) and rainfed condition (field). In the greenhouse experiment, a randomized block design was adopted in a 21 × 2 factorial scheme (genotypes × salinity levels), with three replications. In the field experiment, a randomized block design with split plots was used in a 35 × 2 factorial scheme (genotypes × nitrogen levels), also with three replications. In the greenhouse, morphological and physiological traits were evaluated, while in the field, morphophysiological and postharvest traits were analyzed. The data were subjected to analysis of variance, factor analysis, and application of the MGIDI index. The analysis of variance indicated significant differences for the interaction between genotypes and salinity levels in the greenhouse experiment, as well as for the sources of variation genotype and nitrogen levels in the field experiment. Factor analysis grouped the variables into two factors for the greenhouse experiment and three factors for the field experiment, explaining 82.80% and 80.60% of the total data variance, respectively. In the greenhouse experiment, genotype G9_C2 stood out for presenting greater physiological tolerance to salinity. In the field, genotypes G27, G4, G35, and G31 showed high productive performance and greater agronomic nitrogen use efficiency under contrasting nitrogen availability conditions. Multivariate selection using the MGIDI index proved to be efficient in identifying superior genotypes, highlighting the potential of the selected genotypes for maize breeding programs focused on nitrogen use efficiency and salinity tolerance.

2026-02-20T00:00:00Z Gois, Larissa de Souza https://ri.ufs.br/jspui/handle/riufs/25411 2026-07-09T17:05:49Z 2022-07-29T00:00:00Z

Título: Atividade antimicrobiana e antibiofilme de óleos essenciais de Lippia gracilis e seus compostos majoritários sobre fitopatógenos do gênero Xanthomonas spp. resistentes ao cobre Autor(es): Gois, Larissa de Souza Abstract: The genus Xanthomonas is formed by gram-negative phytobacteria that produce biofilms and that cause diseases in plants of economic importance. Prominent diseases include black rot of crucifers, water belly of melon, gummosis of sugar cane, bacterial leaf streak of corn, and bacterioses of cassava and plum. Due to the need for new alternatives for treatment of these diseases, essential oils (EOs) have been studied, which are plant secondary metabolites that have different biological activities, such as antibacterial activity. The objective of this study was to evaluate the antimicrobial and antibiofilm activity of EOs from seven accessions of Lippia gracilis Schauer (LGRA-106, 107, 108, 109, 110, 201, and 202) obtained through the hydrodistillation technique and their major compounds thymol and carvacrol, as well as evaluate copper resistance in five species of phytobacteria of the genus Xanthomonas: Xanthomonas campestris pv. melonis, Xanthomonas axonopodis pv. manihotis, Xanthomonas campestris pv. pruni, Xanthomonas axonopodis pv. vasculorum, and Xanthomonas campestris pv. campestris. Using spectrophotometric techniques, Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), antibiofilm activity, cell viability, plasma membrane permeabilization, and resistance to sulfate and copper oxide were evaluated; and the biofilm was morphologically examined under microscopy in vitro. scanning electronics. The in vivo study was carried out in an agricultural greenhouse. The effect of the EO from the LGRA107 accession (previously selected for its greater bacteriostatic and bactericidal activity against X. campestris pv. campestris) and the effect of copper oxide were examined on two varieties of kale plants (Georgia and Ramoso Santana) inoculated with Xanthomonas campestris pv. campestris regarding the following variables: number of leaves, biomass, and incidence and severity of disease. The in vitro experiments were performed in duplicate with three replications. For the in vivo experiment, a completely randomized design was used in a 2 × 3 factorial arrangement, constituted by two inoculation methods (injected and sprayed) and three substances (two concentrations of EO from the LGRA-107 accession – 250 and 500 µg mL-1 , and a copper oxide concentration – 2000 µg mL-1 ). A control of 1% DMSO was also used. For analysis of disease severity and incidence, a scoring scale from 0 to 5 was used, and evaluations were carried out over a period of 15 days. The concentration of 1000 µg mL-1 of EOs from LGRA accessions and the major compounds thymol and carvacrol at concentrations between 250 and 500 µg.mL-1 , respectively, demonstrated bacteriostatic and bactericidal activity and led to an increase in cell plasma membrane permeability bacterial. The EOs of all accessions, as well as the major compounds and copper oxide, showed antibiofilm activity for the five phytobacteria. However, this activity was not observed for copper sulfate. As the result of the in vivo experiment, kale, when exposed to copper oxide, obtained higher values of fresh biomass, and broccoli kale had higher leaf numbers. The results of this study showed that the essential oils of the accessions LGRA-109, LGRA-201, and LGRA-107 had greater antimicrobial activity and are promising for control of phytobacteria of the genus Xanthomonas spp.

2022-07-29T00:00:00Z Santos, Barbara Nascimento https://ri.ufs.br/jspui/handle/riufs/25369 2026-07-07T19:46:53Z 2026-01-26T00:00:00Z

Título: Fenotipagem por Vant e aprendizado de máquina para predição da produtividade de milho em ambientes contrastantes de nitrogênio em região semiárida Autor(es): Santos, Barbara Nascimento Abstract: High-throughput phenotyping has contributed substantially to advances in agriculture and plant breeding programs. By using unmanned aerial vehicles (UAVs), its application has enabled the rapid acquisition of phenotypic data with high reliability and spatial resolution, promoting its adoption across diverse agricultural contexts. Despite these advances, several methodological limitations remain insufficiently explored, particularly when this approach is applied under conditions of environmental stress and high spectral homogeneity. This study aims to evaluate the accuracy of four predictive models, using regression and machine learning approaches to estimate the grain yield of maize half-sib progenies grown under contrasting nitrogen conditions, based on multispectral images obtained by UAV. The experiments were conducted during the 2024 growing season in two experimental areas located in the municipalities of Nossa Senhora da Glória and Graccho Cardoso, Sergipe, Brazil. A randomized block design with split plots and three replications was adopted, in which nitrogen levels (high and low) were assigned to the main plots and the half-sib progenies to the subplots. Multispectral drone images were acquired during three flights at heights of 60 and 80m throughout the crop cycle, corresponding to different phenological stages. Fourteen multispectral vegetation indices associated with canopy structure, chlorophyll content, and plant nutritional status were calculated. Four predictive approaches were evaluated: a classical linear model, a penalized regression model (LASSO), and two decision tree-based algorithms, Conditional Forest (Cforest) and Gradient Boosting Machine (GBM). Model performance was evaluated using the root mean square error (RMSE) and the mean absolute error (MAE), in addition to diagnostic analyses of the linear model assumptions and assessments of variable importance and SHAP values for the GBM and Cforest models. In both experimental areas and nitrogen conditions, the Cforest and GBM models consistently showed higher predictive accuracy than the linear approaches. Overall, images acquired at 60m resulted in superior model performance, highlighting the importance of higher spatial resolution for increased sensitivity to physiological variability within the canopy. Analyses of variable importance and SHAP values indicated that predictive contributions were concentrated in a limited subset of vegetation indices, particularly those sensitive to canopy structure and chlorophyll content. Furthermore, distinct predictive responses were observed among genotypes, depending on the modeling approach and environmental conditions. These results suggest that the acquisition and processing of spectral data can be optimized by prioritizing specific vegetation indices and strategically selected phenological stages. For predicting maize grain yield, the combined use of the Cforest and GBM models with vegetation indices such as TCARI, MCARI, and MSAVI2 is recommended. To increase the robustness and generalizability of these findings, future studies should evaluate the performance of such indices across a broader range of nitrogen levels, genotypes, and edaphoclimatic conditions.

2026-01-26T00:00:00Z