In Colombia, tomato production under protected conditions represents an important economic contribution to the agricultural sector. Fusarium wilt diseases, caused by pathogenic formae speciales of the soil-borne fungus Fusarium oxysporum Schltdl., cause significant yield losses in tomatoes throughout the world. Investigation of the F. oxysporum–tomato pathosystem in Colombia is required to develop appropriate alternative disease management. In this study, 120 fungal isolates were obtained from four different departments in the Central Andean Region in Colombia from tomato crops with symptoms of wilt disease. A molecular characterization of the fungal isolates was performed using the SIX1, SIX3, and SIX4 effector genes of Fusarium oxysporum f. sp. lycopersici W.C. Snyder & H.N. Hansen (Fol). Additionally, we developed a new specific marker to distinguish between Fusarium oxysporum f. sp. radicis-lycopersici Jarvis & Shoemaker (Forl) and Fol isolates. Furthermore, a phylogenetic analysis using the Translation Elongation Factor 1-alpha (EF1a) gene was performed with the collected isolates. Two isolates (named Fol59 and Fol-UDC10) were identified as Fol race 2, four isolates were identified as Forl, six isolates were identified as F. solani, and most of the isolates were grouped within the F. oxysporum species complex. The phylogenetic tree of EF1a showed that most of the isolates could potentially correspond to nonpathogenic strains of F. oxysporum. Additional pathogenicity assays carried out with Fol59 and Fol-UDC10 confirmed that both isolates were highly virulent strains. This study represents a contribution to the understanding of the local interaction between tomatoes and F. oxysporum in Colombia.

The interaction between plants and pathogens is a very dynamic and complex relationship that also includes a high degree of specificity, and it is precisely this last characteristic which triggers such important responses in the survival of one or the other. The pathosystem formed by tomato (Solanum lycopersicum L.) and Fusarium oxysporum f. sp. lycopersici (Fol) has been the subject of multiple studies due to the importance of the vegetable worldwide and for the economic and ecological impact of the fungus responsible for the vascular wilt disease in tomato, causing losses that go up to 100%. One way to find alternatives for the management of any pathosystem is to know the actors involved and the mechanisms that govern the interaction through technological and scientific advances that clearly show how the interaction develops on a genetic level. This review collects the information from different scientific sources with focus on the knowledge of the fungus, tomato cultivation and plant defense applied to this pathosystem, as well as the molecular mechanisms.

Meloidogyne causes a devastating disease known as root-knot that affects tomatoes and other cash crops worldwide. Conversely, Paraburkholderia tropica has proven beneficial in mitigating the effects of various pathogens in plants. We aimed to unravel the molecular events that underlie the beneficial effects of the bacterium and the detrimental impacts of the nematode when inoculated separately or together in tomato plants. The transcriptional responses induced by P. tropica (TB group (tomato-bacteria group)), Meloidogyne spp. (TN group (tomato-nematode group)) or by the two agents (TBN group (tomato-bacteria-nematode group)) in tomato were assessed by RNA-seq. We implemented a transcript discovery pipeline which allowed the identification of 2283 putative novel transcripts. Differential expression analysis revealed that upregulated transcripts were much more numerous than downregulated ones. At the gene ontology level, the most activated term was ‘hydrolase activity acting on ester bonds’ in all groups. In addition, when both microbes were inoculated together, ‘hydrolase activity acting on O-glycosyl compounds’ was activated. This finding suggests defense responses related to lipid and carbohydrate metabolism, membrane remodeling and signal transduction. Notably, defense genes, transcription factors and protein kinases stood out. Differentially expressed transcripts suggest the activation of a multifaceted plant defense response against the nematode occurred, which was exacerbated by pre-inoculation of P. tropica.

Esta investigación tuvo como objetivo contribuir al fortalecimiento de habilidades argumentativa en estudiantes de grado sexto de la Institución Educativa Nacional Auxiliares de Enfermería de la ciudad de Manizales, a través de una estrategia de trabajo en casa diseñada con base en actividades experimentales y el uso de herramientas virtuales. Para ello, se construyeron dos guías de intervención que integraron prácticas experimentales sencillas y un simulador de laboratorio virtual de acceso libre, abordando temáticas del área de ciencias naturales, específicamente la extracción de ADN y los factores que afectan el crecimiento y la nutrición de las plantas. La estrategia se desarrolló bajo el enfoque metodológico de la Escuela Activa Urbana (EAU) y se apoyó en el modelo de argumentación de Toulmin como base para estructurar las actividades y evaluar la progresión argumentativa de las estudiantes. El proceso de intervención contempló tres momentos: diagnóstico inicial, fundamentación y trabajo experimental, y aplicación final, combinando recursos didácticos presenciales y virtuales para fomentar el aprendizaje activo. Los resultados mostraron avances significativos en el uso de elementos estructurales del argumento, como datos, justificaciones y conclusiones. En particular, se observó una mejora en los niveles de argumentación: el porcentaje de estudiantes con respuestas en el nivel más bajo disminuyó del 94,1 % al 73,5 %, mientras que aquellas con niveles más estructurados aumentaron del 39,2 % al 60,8 %. Estos hallazgos evidencian que el trabajo experimental en casa, mediado por TIC y estrategias pedagógicas adecuadas, favorece el desarrollo de competencias científicas como la argumentación, al permitir a las estudiantes vincular la experiencia práctica con contenidos teóricos de forma significativa, contextualizada y duradera.

Root-knot nematodes (Meloidogyne spp.) are the most economically important group of plant-parasitic nematodes worldwide. We tested whether foliar elicitors induce defense enzymes in leaves and reduce nematode reproduction in the roots of the same plants. Tomato cv. Santa Clara, which lacks Mi-1 resistance, received 50 mL per plant of one of six treatments: chitosan at 2.0 or 2.5 mg mL⁻¹, Paraburkholderia tropica GIBI_0183 or Bacillus infantis GIBI_0177 at 2.5 × 10⁷ cells per plant, or a commercial chitosan or Bacillus subtilis product. Each treatment was applied with and without 1000 s-stage juveniles in the soil. β-1,3-Glucanase and chitinase activities were measured in leaves 1, 2, 6 and 8 days after application (n = 10), and eggs in whole root systems at 60 days (n = 6). Leaves sampled on days 1 and 2 were sprayed; those sampled on days 6 and 8 expanded afterward. Both enzymes showed a treatment × day interaction (permutation p = 0.0001). Every treatment reduced the egg count by 63–75% (p ≤ 0.0003), with no differences detected among treatments at the sample size used. All six raised chitinase in plants without nematodes, whereas β-1,3-glucanase fell below the control under both laboratory chitosans, which reduced the egg count as much as the treatments that raised it. Enzyme induction and nematode suppression are separate outcomes.