Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Global climate change can af fect agricultural production by facilitating the establishment of pests and pathogens. Banana (Musa paradisiaca) is one of the main agricultural products in Ecuador, but it is af fected by the moko disease caused by Ralstonia solanacearum. The objective of this research was to evaluate the potential ef fects of climate change on the ecological niche and potential distribution of this pathogen, and its implications for banana plantations in continental Ecuador. The ecological niche of the bacterium was described from 340 records of its presence globally and modeled with 62 records in Ecuador. Spatial variations in its potential geographic distribution under two climate change scenarios were evaluated and the banana plantations most susceptible to the spread of the pathogen were identified.The ecological niche of the pathogen showed a low centrality in Ecuador compared to the overall niche of the species, indicating that the current climatic conditions in the country are not the most typical for the pathogen, although still within the range it can support. The potential geographic distribution of the current pathogen was 5839 km2, and in future climate scenarios the areas with favorable conditions for its distribution was more than doubled. The plantations most likely to be at risk are in central-northern Ecuador, in Los Ríos, Santo Domingo de los Tsáchilas, Manabí and Esmeraldas provinces. In the future, the extent of the distribution of this pathogen will depend on the establishment and compliance of strict disease management and control protocols.

Animal organic wastes are commonly applied to soil to enhance fertility. Still, before application, they are of ten composted or vermicomposted to produce a more stabilized, nutrient-rich product with a broad beneficial bacterial diversity. This study was aimed to investigate how composting and vermicomposting influenced the physicochemical properties and bacterial community structure of various organic wastes. Cow manure, goat and rabbit feces, and pig slurry were subjected to either composting or vermicomposting using Eisenia fetida for 90 days, during which their physicochemical characteristics and bacterial communities were monitored. Both composting and vermicomposting had similar ef fects on the physicochemical properties of the animal wastes: pH and total nitrogen (N) content increased. In contrast, electrolytic conductivity and organic carbon (C) content decreased. Although both processes altered the bacterial community structure across all operational taxonomic units (OTUs), significant dif ferences remained between the bacterial communities of the dif ferent organic wastes. Vermicomposting also reduced the prevalence of bacterial genera with pathogenic potential, such as Enterobacterand and Acinetobacter. The introduction of earthworms into organic waste had a similar ef fect to composting on the structure of the bacterial community.

For the establishment of any crop, it is essential to know the properties of the soil since a lack of knowledge of the quality of the soil and its deficiencies in organic reserves and mineral nutrients becomes a limiting factor to obtain the desired yield and quality in the crop. In the present work, the physical-chemical characterization of the soil with maguey production in the municipalities of Sitio Xitlapehua and San Luis Amatlán, Miahuatlán de Porfirio Díaz, Oaxaca, was carried out to produce mezcal  under  an  artisanal  process. The  results  of the physical-chemical parameters were: pH (7.3 - 7.5), organic matter (0.26% - 3.86%), total nitrogen (0.063% - 0.463%), electrical conductivity (0.25-0.40 dS m-1), exchange capacity cationic (17.05-41.93 cmol(+) kg-1), calcium (15.67 cmol(+) kg-1 - 48.90 cmol(+) kg-1) and magnesium (1.43 cmol(+) kg-1 - 11.21 cmol(+) kg-1) exchangeable, available phosphorus (0.3 mg kg-1 - 8.0 mg kg-1) calcium carbonate (1.4% - 32.2%), bulk density (1.0 g cm-3 - 1.88 g cm-3), texture (loam, clay loam and sandy clay loam) and color (light gray, gray, black and red). Spearman correlation analysis allowed to determine the relationship between the physical-chemical variables, and the principal components analysis to identify the variables that characterize each plot. The comparison of the analyzed parameters with the NOM-021-SEMARNAT-2000 standard showed that the soils have a neutral pH, with low content of organic matter, nitrogen and phosphorus, but with high content of calcium, magnesium, calcium carbonate and capacity cation exchange. These parameters allowed us to identify the limiting factors in the nutrition of wild maguey. Based on this information, nutrition strategies will be proposed that lead to increasing the accumulation of sugars in the mature maguey and, consequently, increasing the yield in the production of mezcal.

Maize (Zea mays L.) is a crop of significant agricultural and socio-economic importance worldwide. The search for and application of plant growth-promoting bacteria (PGPB) represent a sustainable strategy to enhance agricultural productivity. This study aimed to identify and characterize rhizospheric and endophytic bacterial strains with PGPB potential associated with maize in soils from Chiapas, Mexico, using molecular techniques and in vitro assays. The nitrogen-fixing ability, phosphate solubilization, and siderophore production of each strain were evaluated. Genetic diversity was assessed using ERIC-PCR genomic fingerprinting, and strain identity was confirmed through 16S rRNA gene sequencing. A total of 46 strains were isolated and grouped  into  26  genomic  patterns. The  isolates  belonged  to  the  genera Klebsiella,Acinetobacter, and Pseudomonas, followed by Pseudacidovorax, Stenotrophomonas, and Ochrobactrum. The Klebsiella genus exhibited notable capacities for phosphate solubilization, siderophore production, and nitrogen fixation. The specific conditions of the study site played a crucial role in obtaining beneficial microorganisms. These findings highlight the potential of rhizospheric and endophytic bacteria isolated from maize as promising sources for identifying microorganisms with biotechnological applications, contributing to improved crop sustainability and productivity.

Cof fea arabica is a species of economic interest in various countries, with Mexico standing out as one of the main exporters. However, there are several pests and diseases, such as cof fee leaf rust, that reduce the production of cof fee fields, af fecting the economy of the producers. Therefore, research on genetic improvement and the propagation of this species has increased in recent years. Among the genetic improvement techniques, mutagenesis stands out. However, mutant plants may exhibit insensitivity to hormonal stimuli. For this reason, the research evaluated the ef fect of dif ferent growth regulators on the morphogenic response of mutant plants obtained through chemical mutagenesis using ethyl methanesulfonate (EMS) during in vitro propagation processes. During the propagation stage, no dif ference was observed  in the response of mutagenized and non-mutagenized plants, with thehighest shoot production (5.1) occurring with 6 mg L-1 of 6-Benzylaminopurine (BAP). In the in vitro rhizogenesis stage, dif ferences were observed in the morphological response of root formation in mutant plants, with the combination of 3 mg L-1 of naphthaleneacetic acid and 3 mg L-1 of indolebutyric acid resulting in the highest root formation (83%).

Plant growth promoting bacteria (PGPB) are a viable option for sustainable agriculture and an eco-friendly alternative to the excessive use of chemical fertilizers and pesticides. Beneficial microorganisms of this type, such as actinobacteria, have the ability to promote plant growth. The study aims to evaluate the potential of two strains of actinomycetes Streptomyces sp. (EA2 and B8), as promoters of the initial growth of tobacco (Nicotiana tabacum L.) seedlings under controlled conditions. Beneficial characteristics such as indoleacetic acid (IAA) production, biological nitrogen fixation and phosphate solubilization were evaluated in vitro. A completely randomized experimental design was applied with two PGPB treatments: T1 (Streptomyces sp. EA2 + B8); T2 (Trichoderma harzianum), and T3 (Sterile distilled water) control treatment, with three replicates per treatment. The response variables studied in vivo were stem length (TL) and root length (RL), leaf width (W) and length (LH), and fresh and dry biomass of shoot and root parts. The results obtained reveal that strains EA2 and B8 possess BPCV characteristics, such as phosphate solubilization, IAA production and biological nitrogen fixation. T1 strains (EA2 + B8) had a positive ef fect on the evaluated growth indicators, outperforming T2 (T. harzianum) and the control treatment (T3). It is confirmed that the combination of Streptomyces sp strains (EA2 + B8) is an ef fective, safe, and eco-friendly alternative, with the with potential to reduce the application of agrochemicals in tobacco cultivation (N. tabacum L.).

The incidence of citrus tristeza virus (CTV) and Huanglongbing (HLB) are associated with nutritional imbalance, the presence of symptoms in the tree canopy and low orange production. Balanced fertilization is used as an alternative to mitigate damage. The objective of our study was to assess the fertilization ef fects in nutritional status of ‘Marrs’ orange trees with symptoms associated with CTV and HLB, and the mineral composition of the fruits. The study was conducted of August 2019 to December 2020 in a commercial plantation with six-year-old trees. Before fertilization, implementing the DOP indices carried out a nutritional diagnosis. The experimental design used was random blocks in split plot arrangement, with three replications. The variables were: nutritional status of the tree, nutritional deficiencies in the leaf, and mineral composition of the fruit. The DOP method detected that Zn > Mn > Cu > B > P > Mg > Fe > K > N > S were the most required minerals; indicesfor N, S, Zn, and Mn show a tendency to decrease in trees with mild and advanced symptoms. Chemical foliar fertilization promoted the development of vegetative shoots without nutritional deficiencies during flowering and fruit set. However, an atypical drought during fruiting af fected the trees’ response to the treatments. The trees presented symptoms of Zn and Mn deficiencies, combined with asymmetric chlorotic mottling in the leaf blade associated with CTV and HLB. Overall, the mineral composition of the fruits was deficient except for P, Ca, and Cu.

Heavy metals (HM) are toxic to the microbiota of agricultural soils because they af fect the development of bacteria and fungi that promote plant growth and are agents of biological control of pathogenic organisms. In this regard, fungi of the genus Trichoderma have these functions in plants, but like other organisms, HM af fects their growth and biological activity. This article reviews the lithogenic and anthropogenic sources of generation of HM Cu, CrVI, Pb, and Cd, the tolerance mechanisms, and the antioxidant response to oxidative damage in Trichoderma caused by HM. It was identified that in some agricultural soils, the HM content increases mainly due to irrigation with wastewater and the intensive use of agrochemicals, such as pesticides and fertilizers. In Trichoderma, the tolerance mechanisms to Cu, CrVI, Pb, and Cd include  biosorption,  bioaccumulation,  and biotransformation. In contrast, studies ofthe antioxidant response of Trichoderma to oxidative stress caused by MP are scarce. In the case of Cu and Cr, a relationship between changes in antioxidant enzyme activity and a decrease in the oxidation of cell membrane lipids is reported. This represents an ​​opportunity to understand the toxic ef fect of MP on fungi of the genus Trichoderma, which is part of the biotic soil community.

Peanut (Arachis hypogaea) is a crop of great importance in human nutrition and in national and international markets, thanks to its rich nutrient profile and versatile applications in both gastronomy and the cosmetics industry. However, peanut production faces challenges such as drought and phytopathogen control. In this context, this study evaluated the impact of laser irradiation, magnetic fields, and UV-C light on agronomic variables of peanut. An experimental design of completely randomized blocks was used, with four treatments and three replicates each, measuring 41 variables, from germination to morphometric and yield characteristics. The results showed that laser irradiation increased seed biomass, while UV-C light increased the production of pods with three seeds. Surprisingly, the magnetic field resulted in the highest yield in pods, hulls, and seeds, with an 80% increase in production  per  hectare, especially under drought conditions. These  results suggestthat physical stimuli could be a valuable alternative to improve peanut yield under unfavorable climatic conditions, of fering new perspectives for both agronomic research and field practice, highlighting the importance of exploring and better understanding the role of these stimuli in enhancing crop performance and food security.

In Mexico, chili (Capsicum chinense Jacq.) is a crop of economic and nutritional importance whose production is affected by soil phytopathogens, with biological control being a beneficial tool for the ecosystem; in the case of M. anisopliae, its limitation is sensitivity to environmental factors that reduce its effectiveness, so coverage using a polymer matrix is ​​feasible to provide protection, for this reason, the characterization of encapsulated spores of M. anisopliae and its effect on the growth of chili plants inoculated with Fusarium oxysporum was carried out. The encapsulation was done by ionic gelation with sodium alginate and calcium chloride, the water retention and absorption capacity of the encapsulates was analyzed, as well as the viability of the spores and their antagonistic activity in vitro by dual confrontationon F. oxysporum. The capacity of the encapsulation and the spore suspension of M. anisopliae for the control of Fusarium in C. chinense Jacq. plants was also compared. The encapsulate CEM2 (3000 μm ∅, 1 M CaCl2) with 43.4% humidity and 48.3% swelling, showed the highest spore survival of 96% and viability of more than 90% during 75 days of storage at 37 °C. CEM2 demonstrated its antagonistic capacity in vitro by inhibiting the radial growth and sporulation spores of F. oxysporum 62.9 and 60.5% respectively. The application of the encapsulate CEM2 and the suspension spores of M. anisopliae reduced the effect of Fusarium inoculation in chili plants since the values ​​of height, stem diameter and chlorophyll were higher than diseased plants and demonstrated that it promotes growth when applied to healthy plants.