Tropical Region Of Brazil Research Articles

Selecting Bacillus strains antagonist to Erysiphe necator (Schw.) Burr. the causal agent of grape powdery mildew

ABSTRACT Grape powdery mildew (GPM) control is based on the preventive use of sulfur and curative application of synthetic fungicides, increasing the risk for producers’ health and environmental and fruit contamination. This work aimed to select Bacillus strains isolated from the Brazilian tropical semi-arid region that are effective antagonists to GPM. In an initial screening performed by spraying bacterial suspensions in detached grape leaves, six strains of Bacillus spp. showed disease symptom reduction higher than 70.0%. Two greenhouse experiments showed that the bacterial strains LCB03, LCB28, and LCB30 showed control efficiency >80%, statistically similar to a commercial formulation with Bacillus amyloliquefaciens QST713. 16s rDNA sequencing showed that strain LCB03 showed 100.0% homology to B. velezensis, while LCB28 has high homology to B. tequillensis (99.93%), and LCB30 had 99.71% homology with B. siamensis. As an average for both greenhouse experiments, weekly application of Bacillus sp LCB03, Bacillus sp LCB28, and Bacillus sp. LCB30 reduced the average incidence by around 50% and more than 80% for GPM severity.

Contrasting Phenological Patterns and Reproductive Strategies in Closely Related Monoecious Fig Tree Species.

Understanding the ecological and evolutionary aspects of mutualistic interactions is essential for predicting species responses to environmental changes. This study aimed to investigate the phenological patterns and reproductive strategies in two closely related fig tree species, Ficus citrifolia and Ficus eximia. We monitored 99 F. citrifolia and 21 F. eximia trees weekly from January 2006 to April 2011 in an area close to the southern edge of the tropical region in Brazil. Our results revealed contrasting phenological patterns between the two species, with F. citrifolia displaying an annual flowering pattern (1.4 episodes per tree per year) and F. eximia a supra-annual pattern (0.5 episodes per tree per year). We also found significant differences in reproductive strategies, with F. eximia producing more pistillate flowers and, consequently, more seeds and pollinating wasps per fig than F. citrifolia, likely as an adaptation to overcome limitations of low population density by maximizing the gene flow. As the shorter-lived organism, the fig wasp was found to influence critical processes associated with the success and stability of mutualism, such as fig development and ripening. Our findings emphasize the importance of understanding the intricate interactions between mutualistic partners and their adaptive responses to environmental conditions in shaping fig tree populations' reproductive strategies and genetic structure.

Assessment of the adaptive capacity of Morada Nova ewes with different coat coloration.

Coat color is a factor affecting heat tolerance in tropical ruminant and a particular coat color can determine which is more resilient to environmental changes. The aim of this study was to measure the level of adaptation of Morada Nova sheep with different coat color by using an Adaptability Index (AI). Adult ewes were used, including two different coat colors of Morada Nova sheep (red and white) with mean of body weight of 28.02 ± 5.70kg and 31.47 ± 3.41kg, respectively. Physiology parameters, hematology, electrolytes, acid-base status, mineral, renal functions, metabolites, enzymes, and proteins were measured. AI was designed using a multivariate approach (principal component analysis) to "weigh" the influence of each variable in the animal responses. The variables more important for adaptive aspects of Red Morada Nova were: haematology, electrolytes and acid-base status. The hemoglobin (HG), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), sodium (Na+), oxygen pressure (PO2), glucose (GLU) and albumin (ALB) were significantly higher in Red Morada Nova sheep and hydrogen carbonate (HCO3), base excess (BE), total carbon dioxide concentration (TCO2) and URE were significantly higher in the white phenotype. The variables more important for adaptive aspects of White Morada Nova sheep were: (K+), total protein (TP), PO2, HG, cholesterol (CHO), rectal temperature (RT) and glucose (GLU). Both phenotypes showed a high adaptation level, however, a higher value was generated for the Red Morada Nova sheep (81.97). This study concludes that both phenotypes of the Morada Nova sheep breed are well adapted to the climatic condition of the Brazilian tropical region using different adaptive mechanisms.

Impact of Fermentation on Hyptolide and Phytochemical Composition of Hyptis pectinata (L.) Poit

Solid State Fermentation has been employed for the biotransformation of the herbal plant Hyptis pectinata (L.) Poit is widely distributed in tropical regions of Brazil and is also present in Indonesia. The plant has been used to treat anti-inflammatory, anti-cancer, bacterial infection, and wound healing. This study aims to investigate the effects of using a solid-state fermentation method to ferment the leaves of Hyptis pectinata (L.) Poit towards the composition of phytochemicals and hyptolides. This study was carried out in several stages, including fermentation of Aspergillus niger leaves, sample extraction with methanol, determination of total phenolic and total triterpenoid content, phytochemical screening, and analysis of hyptolide using HPLC. The research results showed the growth of Aspergillus niger on the leaves of Hyptis pectinata (L.) Poit got into the logarithmic phase at 36 hours. Triterpenes and phenolics were present in the phytochemical profile, while alkaloids, tannins, and flavonoids were absent. The total phenolic and triterpenoid content increased by 33.68% and 17.78% respectively. HPLC analysis showed a decrease in hyptolide content in the fermented product. These results indicate the potential of fermented Hyptis pectinata (L.) Poit as an additional cancer therapy.

Molecular Docking and GC/MS-Based Approach for Identification of Anxiolytic Alkaloids from Griffinia (Amaryllidaceae) Species in a Zebrafish Model.

Griffinia gardneriana Ravenna, Griffinia liboniana Morren and Griffinia nocturna Ravenna (Amarillydaceae) are bulbous plants found in tropical regions of Brazil. Our work aimed to determine the alkaloid profiles of Griffinia spp. and evaluate their anxiolytic potential through in vivo and in silico assays. The plants grown in greenhouses were dried and their ground bulbs were subjected to liquid-liquid partitions, resulting in alkaloid fractions that were analyzed by gas chromatography coupled to mass spectrometry (GC-MS). Anxiolytic activity was evaluated in zebrafish (Danio rerio) through intraperitoneal injection at doses of 40, 100 and 200 mg/kg in light-dark box test. GC-MS analyses revealed 23 alkaloids belonging to different skeleton types: lycorine, homolychorine, galanthamine, crinine, haemanthamine, montanine and narcisclasine. The chemical profiles were relatively similar, presenting 8 alkaloids common to the three species. The major component for G. gardneriana and G. liboniana was lycorine, while G. nocturna consisted mainly of anhydrolycorine. All three alkaloid fractions demonstrated anxiolytic effect. Furthermore, pre-treatment with diazepam and pizotifen drugs was able to reverse the anxiolytic action, indicating involving the GABAergic and serotonergic receptors. Molecular docking showed that the compounds vittatine, lycorine and 11,12-dehydro-2-methoxyassoanine had high affinity with both receptors, suggesting them to be responsible for the anxiolytic effect.

Envirotypes applied to evaluate the adaptability and stability of wheat genotypes in the tropical region in Brazil

Envirotypes applied to evaluate the adaptability and stability of wheat genotypes in the tropical region in Brazil

Spatiotemporal Dengue Fever Incidence Associated with Climate in a Brazilian Tropical Region

Dengue is a serious infectious disease worldwide and a climate-sensitive disease. Thus, our goals were to (i) evaluate the relationship between dengue incidence and meteorological variables (rainfall and air temperature); (ii) identify the spatiotemporal pattern of dengue incidence in the municipalities of Mato Grosso from 2001 to 2020; and (iii) verify the spatial dependence of dengue incidence in the dry and wet seasons. We used dengue data from 2001 to 2020, monthly rainfall estimates from GPM, and daily air temperature estimates from ERA-5. The municipalities of the Mato Grosso state are included in 16 healthcare territories. The seasonal rainfall pattern indicates that the peak of the dengue endemic occurred in the wet season. However, drier and/or warmer places had a lower incidence of dengue in the dry season. Furthermore, a lagged effect of meteorological variables on dengue incidence has been identified, ranging from 0 to 7 months. Hotspot areas were identified which might have the potential for an intense spreading of dengue in Mato Grosso. They were mainly concentrated in the healthcare territory of Teles Pires (ID 14) in the dry season, while they were concentrated in the healthcare territories of Garças Araguaia (ID 5), Oeste (ID 11), and Teles Pires (ID 14) in the wet season. In addition, they are located in the Am climate and in the Amazon Forest and Brazilian savanna biomes, which have higher dengue incidence values. These results help to highlight which municipalities decision-makers must intervene in the public health system to prevent and control future epidemics.

Impact of ecological stages on the soil microbiota and soil abiotic factors in tropical and subtropical Brazilian regions.

Our aim was to test if ecological stages may influence the arbuscular mycorrhizal fungi (AMF), nematodes, and the soil chemical properties in agroforestry systems (AF), unassisted forest restoration (UFR), and natural ecosystem (Ne) located in the Brazilian Tropical and Subtropical regions. We collected soil samples to determine AMF, nematodes, soil pH, P, and soil organic carbon (SOC). AMF and nematode richness in the AF and Ne were similar in the tropical region. The redundancy analysis (RDA) indicated that the abundance of AMF and soil nematodes was mainly affected by soil pH, P, and SOC. Differences were associated with (1) ecological stages, as we found differences in AMF and nematode abundance as affected by habitat simplification, and (2) changes in soil pH, SOC, and P. Our work increases the understanding of the AMF and soil nematode community in the rhizosphere of AF and Ne in tropical and subtropical regions.

Tree height, leaf thickness and seed size drive Caatinga plants' sensitivity to climate change

AbstractAimThe Anthropocene climate crisis may shift the distribution range of various species. Global Climate Models predict an increase in temperature and changes in precipitation across the Brazilian tropical semiarid region. Based on the joint analysis of functional traits and plant distribution models, we aim to identify which functional traits define the vulnerability of plants to climate change.LocationCaatinga, Brazil.TaxonTrees‐shrub plants.MethodsWe selected 36 species common to at least 25% of the floristic and phytosociological surveys made in the Brazilian semiarid region. We modelled both the current and future spatial distribution of these species and investigated whether functional traits, such as plant height, leaf area, leaf thickness, specific leaf area, stem specific density, and seed size can explain the range shifts of these species.ResultsModels indicate that 58.4% of the species are expected to expand their distribution range in the future. These species tend to be shorter and produce large seeds and thin leaves, which confer higher hydraulic safety and resistance of seeds to prolonged droughts. Meanwhile, 41.6% of the species are expected to reduce their distribution ranges in the future. Most of these are characterized as tall individuals with thick leaves and small seeds.ConclusionSpecies with traits that confer resistance to drought are likely to increase distribution towards the coast and to areas where the Caatinga borders with other domains. Also, these species with low height, thin leaves and large seeds may expand their distribution to the slopes and plateaus. The retraction of taller plants and with thicker leaves may have profound implications for the structure and functioning of Brazilian semiarid ecosystems, given their role in ecosystem processes and carbon cycle. Retractions can result in a reduction in the number of local species, which will impact regional biodiversity.

The relationship between host plant traits and biodiversity across three sympatric seed‐feeding tri‐trophic systems in a tropical region of Brazil

Abstract We describe the diverse community of insect herbivores and parasitoids associated with the seeds and fruits of three sympatric Fabaceae species in Lavras, Minas Gerais, Brazil: Inga vera, Senna multijuga and Leucaena leucocephala. A total of 5353 individual insects, representing 77 different species, were identified via morphology and DNA barcoding. The non‐native L. leucocephala had the least diverse natural enemy community (N = 17 species), while two native species, I. vera and S. multijuga, were more diverse (N = 40 and N = 24 species, respectively). Individuals from the insect order Hymenoptera, a group dominated by parasitoid wasps, were the most diverse recovered from our samples in all hosts. Additionally, individual herbivore and parasitoid species were more likely to be found on a single host, with only four out of the 77 species found in more than one plant species. This includes the generalist agricultural pest herbivore, Lasioderma serricorne, found in two species, and three parasitoids connecting native S. multijuga and non‐native L. leucocephala communities, hinting at recent host shifts. Furthermore, different host plant traits had complex effects on the herbivore and parasitoid communities, where seed number per fruit promoted a propagating effect on the abundance and richness at both higher trophic levels, whereas seed and fruit weight did not. We highlight the importance of including parasitoids in insect community studies because they are highly diverse and provide important ecosystem services. Additional study of the biology, behaviour and distributions of parasitoids would be advantageous to inform conservation and biological control.

Leishmaniases in a tropical area of Brazil: a spatio-temporal analysis.

Leishmaniases are a group of tropical and neglected diseases caused by the protozoa of the genus Leishmania which are transmitted by insect sandflies. Despite of the major efforts undertaken at global level for the control of these diseases, a recent spreading to non-endemic areas been observed. In this study we analyzed the spatio-temporal distribution of Visceral Leishmaniasis (VL) and Tegumentary Leishmaniasis (TL) cases notified in a tropical region of Brazil. A retrospective evaluation was carried out using secondary data (e.g., demographics, origin, age and area of occurrence) of human patients obtained from 2009 to 2019. Choropleth maps with levels of color intensity represented the spatial distribution of VL and TL cases. Overall, 116 (10.5 ± 8.5) cases of leishmaniases were registered in the study area during the whole period. Of those, 61 (5.5 ± 5.5) and 55 (5 ± 4.3) were diagnosed as VL and TL, respectively. VL cases were recorded in 61.9% (13/21) and TL cases in 42.8% (9/21) of the municipalities. Most of the cases were predominantly notified in men from rural areas, and specifically for TL with an age range of 30-59years old. These findings will be useful to drive strategies of control (e.g., vector control, dog surveillance and notification of suspected cases) against these neglect diseases, preventing the spreading to non-endemic areas.

Assessing of Two Planetary Boundary Layer Schemes in RegCM4 Model Over the Tropical Region of Brazil

Assessing of Two Planetary Boundary Layer Schemes in RegCM4 Model Over the Tropical Region of Brazil

Site classification for Eucalyptus sp. in a tropical region of Brazil.

The aim was to determine the productive capacity of a forest site by applying different methods of fitting, combined with geostatistical techniques, to stands of Eucalyptus sp. in a tropical region of Brazil. Data were collected from 845 plots of a continuous forest inventory over four years. The classification of local production capacity was performed using growth curves obtained by the guide curve (GC) method, algebraic difference approach (ADA) and generalized algebraic difference approach (GADA) methods and ordinary kriging through the spherical, exponential, and Gaussian models to determine the spatial dependence of the variables site, geographical boundaries of site index classes, and their respective areas for each hectare in an annual production unit (APU). The modified Chapman-Richards model, fitted by the generalized difference approach method (GADA), provided the best statistical results, an improvement of 12.23% and 39.80% on the ADA and GC methods, respectively. The exponential model selected to express the spatial distribution of dominant height showed a high degree of spatial dependence.

Two New Endemic Tetraploid Species of the Genus Isoëtes from the Brazilian Savanna

Abstract— Isoëtes cipoensis and I. longifolia, two new endemic tetraploids from the Cerrado (Brazilian savanna), are described, illustrated, and compared to their similar species. Isoëtes cipoensis can be distinguished by a set of characters such as flaccid, straight, and erect leaves, deltate labia, presence of conspicuous sclerified phyllopodia, baculate megaspores with frequent long spine-like macroelements, and distally echinate microspores. Isoëtes longifolia is characterized by having a fully submerged habitat in the river, flaccid, long leaves (70‐100 cm long), oblong labia, uniformly baculate megaspores, and densely echinate microspores. Importantly, chloroplast genomes already published for the species further support their phylogenetic distinctness in comparison to other species from the tropical region in Brazil. This study provides a key and distribution map for the species from the Brazilian savanna and scanning electron microscopy images of the mega- and microspores for the new species. These species are only known from their type location. We suggest I. cipoensis and I. longifolia should be classified as Data Deficient (DD) and Endangered (EN) species, respectively, based on the IUCN criteria.

Precrops and N-fertilizer impacts on soybean performance in tropical regions of Brazil

Precrops have different growth patterns, nitrogen (N) requirements, and production of residues varying in amounts and quality that may affect the N-clycling and the soybean (Glycine max L. Merrill) cropped in succession. This study aimed to evaluate the effect of precrops and N fertilization on soybean performance. An experiment was conducted in Londrina, Paraná State, Brazil, with six precrops treatments: fallow, ruzigrass (Urochloa ruziziensis), showy rattlebox (Crotalaria spectabilis), corn (Zea mays) without or with 80 kg ha−1 of N at topdressing as urea, and wheat (Triticum aestivum). Subplots consisted of two levels of N fertilization at soybean sowing: 0 and 30 kg ha−1 of N as ammonium nitrate at sowing. Urochloa ruziziensis as precrops increased the soybean yield (5,171 kg ha-1) when compared with corn (4,346 kg ha-1) and fallow (4,467 kg ha-1). In 2016/17, N fertilization of soybean with 30 kg ha−1 of N at sowing, although increasing the initial plant growth (745 kg ha-1 with vs. 662 kg ha-1 without), impairs nodulation (100 mg pl-1 with vs. 130 g pl-1 without) and does not increase grain yield. Oil and protein concentrations in soybean grains are not influenced by precrops and N fertilization at sowing. We found that the use Urochloa ruziziensis as cover crop in soybean precrops is a good recommendation option in tropical regions of Brazil, because increasing the yield of soybean grown in succession. N fertilization at in soybean sowing it should not be recommended even in the presence of a large amount of straw.

Forage performance and cattle production as a function of the seasonality of a Brazilian tropical region

This study aimed to evaluate forage yield, tiller population density, canopy height, nutritional value as well as cattle performance in alternate stocking from three tropical forage cultivars. The experiment followed a randomized block design, in a 3 x 3 factorial scheme with three replications. Three forage cultivars (Marandu, Massai and Xaraés) distributed in nine hectares were evaluated in three dry season periods (transition wet/dry, dry, and end of dry season), with repeated measures over time. The following variables were evaluated: canopy height, leaf: stem ratio, forage mass, leaf mass, stem mass and dead material mass. Total digestible nutrients, crude protein and in vitro dry mass digestibility were evaluated regarding forage nutrition. Animal performance, using 36 eleven-month-old animals (half-blood Nelore), was evaluated by the daily average gain and weight gain by area. During pre-grazing, canopy height presented interaction among forage cultivars and the evaluated periods. The average daily gain showed no interaction among cultivars and period of the year the similarity in animal performance among the cultivars Marandu and Massai show that the Massai grass can be used as an alternative for forage diversification under an alternate management system.

Wind mapping using the mesoscale WRF model in a tropical region of Brazil

This study details an evaluation of the onshore and offshore wind speed field in the state of Bahia, northeastern Brazil, using the WRF (Weather Research and Forecasting) mesoscale model, version 4.0. The simulations were run for a period of five years—between 2015 and 2020—with a horizontal resolution of 3 km, and were compared with data from 41 automatic surface stations for the onshore case. For the offshore case, data from a surface station located in the Abrolhos Archipelago were used. The winter period presents higher values of wind speed for the onshore region (9–14 m/s), and the northern and southwestern regions of the state stand out for the generation of wind energy. In the offshore case, spring presents the highest averages for wind speed (7–8 m/s), followed by the summer season, highlighting the maritime coast in the extreme south of the state (7–10 m/s). Furthermore, the nocturnal wind regime is more intense than the daytime one, indicating a great complementarity with solar energy. The year 2017 had the highest average values of wind speed in the region, being considered one of the warmest years without the influence of the El Nino phenomenon recorded globally since 1850. The hourly averages of onshore and offshore winds for the state of Bahia demonstrated the great wind potential of the region, with high and medium speeds at altitude, which were in accordance with the minimum attractiveness thresholds for investments in wind energy generation.

Influence of Leaf Area Index on the Heat Index of a Tropic Urban Park

In the wake of climate change, cities need to adapt to global warming. In this context, the use of afforestation to improve the microclimate may assist in raising the quality of life for population. This objective requires research that analyzes how the variations in parameters related to canopy dynamics, such as the leaf area index (LAI) and photosynthetically active radiation (PAR) can influence thermal comfort indices. To contribute to this research, this study measured the air temperature, relative air humidity, PAR, and LAI on a monthly basis from July, 2017, to June, 2018, in an urban park in a tropical region of Brazil. Kriging maps were created for the heat index (HI), and multiple polynomial regression models were adjusted to estimate the HI using PAR and LAI data. After defining the models, positive and negative variations of LAI were tested to observe if any changes in HI occurred. The simulated results showed greater sensitivity to negative variations in LAI, in which a 50% reduction in LAI decreased the HI by 28%, particularly during the dry period.

Impact of Ensemble-Variational Data Assimilation in Heavy Rain Forecast over Brazilian Northeast

The Brazilian Northeast (BNE) is located in the tropical region of Brazil. It is bounded by the Atlantic Ocean, and its climate and vegetation are strongly affected by continental plateaus. The plateaus keep the humid air masses to the east and are responsible for the rain episodes, and at the west side the northeastern hinterland and dry air masses are observed. This work is a case study that aims to evaluate the impact of updating the model initial condition using the 3DEnVar (Three-Dimensional Ensemble Variational) system in heavy rain episodes associated with Mesoscale Convective Systems (MCS). The results were compared to 3DVar (Three-Dimensional Variational) and EnSRF (Ensemble Square Root Filter) systems and with no data assimilation. The study enclosed two MCS cases occurring on 14 and 24 January 2017. For that purpose, the RMS (Regional Modeling System) version 3.0.0, maintained by the Center for Weather Forecasting and Climate Studies (CPTEC), used two components: the Weather Research and Forecasting (WRF) mesoscale model and the GSI (Gridpoint Statistical Interpolation) data assimilation system. Currently, the RMS provides the WRF initial conditions by using 3DVar data assimilation methodology. The 3DVar uses a climatological covariance matrix to minimize model errors. In this work, the 3DEnVar updates the RMS climatological covariance matrix through the forecast members based on the errors of the day. This work evaluated the improvements in the detection and estimation of 24 h accumulated precipitation in MCS events. The statistic index RMSE (Root Mean Square Error) showed that the hybrid data assimilation system (3DEnVar) performed better in reproducing the precipitation in the MCS occurred on 14 January 2017. On 24 January 2017, the EnSRF was the best system for improving the WRF forecast. In general, the BIAS showed that the WRF initialized with different initial conditions overestimated the 24 h accumulated precipitation. Therefore, the viability of using a hybrid system may depend on the hybrid algorithm that can modify the weights attributed to the EnSRF and 3DVar matrix in the GSI over the assimilation cycles.

Biochar enhances Acrisol attributes and yield of bean in Brazilian tropical dry region

ABSTRACT Biochar is a product rich in carbon, which improve the soil attributes and crop yield. In the Brazilian tropical dry region, common bean is cultivated under rainfed, in poor, acidic, and with low water retention soils. This work aims to evaluate the effect of biochar on soil physical and chemical attributes, on evapotranspiration (ET), water use efficiency (WUE), and on bean yield. The field experiment was conducted over four biochar rates (B0: no biochar; B10: biochar at 10 t ha−1; B20: 20 t ha−1 and B40: 40 t ha−1), and three replications. Our analysis revealed that different rates of biochar do not affect the soil physical attributes due to a mismatch between soil texture and the particle size of biochar. Treatments with biochar promoted an increase in soil pH, P content, cation exchange capacity, reduced the Al+H content, which caused an increase in bean yield and consequently WUE. Our findings expand our knowledge about the effect of the biochar applied to the Acrisols on decreasing the soil acidity and to increase the yield and WUE, and add important information that can be suitable for development of strategy to mitigate problems caused by instability of rains and poor fertility soils.