Diversidad de Trichoderma en el agroecosistema cacao del estado de Tabasco, México

Biotechnological insights into extracellular enzyme production by thermotolerant fungi from hot springs and caves: Morphology, pellets formation, and protease production

This study investigates the thermotolerant fungal biodiversity in caves and hot springs, focusing on their potential for extracellular enzyme production, specifically proteases. Samples were collected from the Cardonal region in Hidalgo, Mexico, using three different isolation methods. The study characterizes the morphological diversity of the isolated fungi and identifies various genera, including Aspergillus, Penicillium, Trichoderma, Cladosporium, and Fusarium, based on morphology. The isolated fungi were screened for their ability to produce extracellular enzymes on solid media, with a particular emphasis on proteases due to their industrial significance. Among the 35 isolated fungi, 20 exhibited proteolytic activity, and 12 strains were identified as good protease producers based on enzymatic index values. The study also evaluated the formation of fungal pellets by proteolytic fungi and found certain strains to display significant pellet formation. Additionally, protease production was examined by fungal pellets in submerged cultures, with isolate 6 demonstrating the highest protease activity. The findings highlight the diverse thermotolerant fungal biodiversity in extreme environments, and emphasize their potential for enzymatic production. This research contributes to our understanding of fungal ecology and provides insights into the biotechnological applications of these enzymes. The study recommends further molecular investigations to enhance biodiversity studies in such extreme environments.

In vitro evaluation of the antagonistic activity of native strains of Trichoderma spp. against Fusarium spp

Five samples of agricultural soil and five samples of Aloe barbadensis (P. Mill., 1768) plants with symptoms of wilt and root necrosis were collected in five localities of the state of Tamaulipas, México. The aims of this study were the morphological identification, molecular identification and in vitro evaluation of the antagonistic activity of Trichoderma spp. on Fusarium spp. Four strains of Trichoderma asperellum, one strain of Trichoderma harzianum and five strains of Fusarium oxysporum were identified by morphological and molecular methods. The evaluation of the antagonistic activity of T. harzianum isolate (TP) showed the highest inhibition in Fusarium spp. (78.80%). The evaluation of the antagonistic activity of Trichoderma spp. extracts in Fusarium spp. did not show significant differences between treatments (P ≤ 0.05), with Trichoderma growth percentages that oscillated between 81.08 and 94.38%. The native isolate of T. harzianum (TP) showed significant competitive capability against the mycelial growth of F. oxysporum. Trichoderma species are promising agents of biological control in the central area of the State Tamaulipas, Mexico.

Implementation of pre-harvest techniques in emerging agroforestry systems to increase the yield of cocoa tree (Theobroma cacao L.)

Cocoa is one of the most important tropical fruits worldwide, its importance lies in its use in the food, cosmetic and pharmaceutical industries. Cocoa yield has been affected by different environmental, cultural and phytosanitary aspects. The emergence of new growing areas allows exploring the possibility of generating new economic and ecological systems that comply with current trends in organic farming. For them, pre-harvest practices such as pruning and soil fertilization are two necessary tools to control the productivity of cocoa agroecosystems. Therefore, the objective of this research was to analyses the implementation of pre-harvest techniques and the quality soil to increase the yield in a cocoa agroecosystem in an emerging zone in the Huasteca Potosina of Mexico. The work was carried out in an emerging zone in the cultivation of cocoa in three different zones delimited in 30 × 30 m. Thinning and pruning practices were carried out to keep the space clear and observe the influence on fruit yield. In addition, the quality of the soil was measured in terms of physical conditions and nutrient content. 25 kg/ha of nitrogen, 22 kg/ha of P2O5, 24 kg/ha of K2O and 4 kg/ha of magnesium were added following the recommendation of the fertilization laboratory. The physical properties of the pod were also analyzed, such as size, weight, number of grains and color. And some of the cocoa bean such as size, weight and hardness, all these parameters to measure the average yield of cocoa pods. The results show a clear influence of the soil quality and pre-harvest practices on the physical properties of the fruit and the total yield from 472.36 ± 52.01 to 520.06 ± 104.91 kg. However, other aspects are also modified, such as the increase in the size of the pod and the cocoa bean. Other aspects such as the color of the pod and the hardness of the grain do not present statistical difference. In conclusion, pre-harvest practices together with the application of fertilizers are factors that positively influence the yield of cocoa fruit. Some of the limitations of this research were the age of the plants and the local plant species.

Morphological and molecular characterization of a new autochthonous Trichoderma sp. isolate and its biocontrol efficacy against Alternaria sp

The development of agriculture requires the use of microorganisms in the management of phytopathogens as a way to compensate for the use of chemical pesticides, in order to produce healthy crops. The objective of this study was to characterize a new isolate of Trichoderma sp. based on morphological and molecular features, and its potential ability to control the pathogen Alternaria sp. The antagonistic isolate was isolated from soil samples of potato fields in Guasave Sinaloa, Mexico, whereas the pathogen was collected from infected apple leaves in the orchard “La Escondida” in Guerrero County, Chihuahua, Mexico. For morphological characterization both fungi were grown on solid PDA medium. DNA of Trichoderma sp. was isolated using the CTAB method and PCR analyses were done using ITS1, ITS4 primers resulting in amplified products of 600 bp. These were sequenced, submitted to Genbank (acc. no. MN950427) and used for further phylogenetic analysis through Bayesian inference approach. Five clades were identified and the polytome topography recovered from clade 4 indicates a high genetic similarity with T. asperellum. A BLAST examination of the resulting sequence in GenBank showed 98.11% similarity with T. asperellum. This result together with the morphological and the phylogenetic analyses indicates that the isolate belongs to Trichoderma asperellum Samuels, Lieckfeldt & Nirenberg. Biocontrol tests of this isolate showed inhibition of Alternaria sp. between 50% and 93%. These results are essential for biodiversity research and give some new possibilities for pest management.

Micropropagación in vitro de naranja agria (Citrus aurantium L.) a partir de segmentos nodales

La naranja agria (Citrus aurantium L.) presenta un alto valor nutricional y gastronómico en el distrito de Huacho, Lima, Perú, pero en la actualidad se considera una especie en peligro de desaparecer del distrito y alrededores por problemas fitosanitarios. Para la recuperación y repoblación de esta especie se planteó emplear técnicas biotecnológicas para la obtención de plantas libres de patógenos. Por lo tanto, el objetivo de la presente investigación fue micropropagar in vitro naranja agria a partir de segmentos nodales. Los segmentos nodales de naranja agria fueron desinfectados en diferentes concentraciones de NaClO, luego se introdijeron en medio de cultivo MS (Murashige y Skoog) adicionado con BAP, KIN y AG3 para la fase de multiplicación, posteriormente se transfirieron a medios MS adicionado con IBA y ANA para la fase de enraizamiento. La evaluación del porcentaje de contaminación se realizó a los diez días, la evaluación de formación de brotes en fase de multiplicación se realizó a los 30 días y la evaluación de enraizamiento a los 30 días. En la fase de desinfección y establecimiento in vitro se logró obtener 0% de contaminación y 0% de oxidación de los explantes. En la fase de multiplicación in vitro los mejores resultados se obtuvieron en el medio de cultivo M8 generando 4,7 brotes por explante. Y finalmente en la fase de enraizamiento el medio E4 permitió obtener 94,7% de explantes enraizados, 23,4 mm de longitud de raíz y 2,2 raíces por explante.

Assessment of the Potential of Trichoderma spp. Strains Native to Bagua (Amazonas, Peru) in the Biocontrol of Frosty Pod Rot (Moniliophthora roreri)

The use of native Trichoderma strains has been proposed as a sustainable alternative to control cocoa diseases. The aim of this study was to assess indigenous Trichoderma strains from Bagua Province, Peru, with reference to their antagonistic characteristics in vitro and their potential for in vitro biocontrol against frosty pod rot (FPR) disease. A total of 199 strains were assessed for in vitro mycoparasitism, antibiosis, and potential antagonism. The effect of four strains was evaluated in vitro using epidemiological variables, yield, and efficacy at two sites (Copallín and La Peca). Significant differences (p < 0.05) were reported for all variables evaluated in vitro and in vitro. Mycoparasitism ranged from 32% to 100%, antibiosis from 33.36% to 57.92%, and potential antagonism from 42.36% to 78.64%. All strains were found to affect the in vitro-assessed parameters in addition to enhancing the productive yield. The efficiency ranged from 38.99% to 71.9% in Copallín, and 45.88% to 51.16% in La Peca. The CP24-6 strain showed the highest potential for biocontrol under field conditions when considering its effect on both sites.

Cellulases Production by a Trichoderma sp. Using Food Manufacturing Wastes

The cost of cellulase enzymes is a main contributor to the operational cost of a biorefinery producing ethanol from lignocellulosic material. Therefore, onsite production of enzymes using low-value substrates might be an option to make a bio-based facility more economical, while improving environmental sustainability. Food manufacturing wastes (FMWs), such as olive mill solids, tomato pomace, and grape pomace, are some of the main wastes produced by the food industry in Chile. FMWs are mostly composed of lignocellulosic material, which is primarily made of cellulose. A fungal strain obtained from olive stones was identified as a Trichoderma sp. and characterized by molecular and morphological techniques. This strain was able to grow on three FMWs in both liquid and solid cultures. In liquid cultures, cellulase and β-glucosidase activities from the culture supernatants were quantified. Identification of extracellular proteins using mass spectrometry revealed the presence of endoglucanases, exoglucanases, and β-glucosidases. Cellulase production from agroindustrial residues could be an excellent opportunity to utilize FMWs as well as decrease enzyme production costs in biorefinery processes.