Biocontrol has emerged as an effective strategy for managing plant pathogens and pests. The use of plant growth-promoting rhizobacteria (PGPR) as biocontrol agents offers a sustainable alternative, enhancing plant morphology, biochemistry, physiology, and secondary metabolism. This study conducts a bibliometric analysis and systematic review of PGPR-based biocontrol research from 2019 to 2023, using the Web of Science (WoS) database. A total of 2823 publications were identified, with a significant increase in scientific output since 2019. Original research articles dominated the field, with India, China, the USA, and Pakistan leading in publication volume. Key contributors included Babalola (North-West University, South Africa), Kloepper (Auburn University, USA), and Shen (Nanjing Agricultural University, China), each with at least 25 publications. Co-authorship analysis revealed four major research networks centered in India, China, Brazil, and Canada. Bacillus and Pseudomonas were the most studied PGPR genera, recognized for their roles as bioinoculants, bioremediators, and biostimulants, mitigating the negative impacts of synthetic fertilizers and pesticides. This analysis underscores the growing global focus on PGPR-based biocontrol and its potential for sustainable agriculture. Strengthening international collaboration and accelerating applied research on PGPR formulations will be critical for optimizing their efficacy and scalability in real-world agricultural systems.

Mexico is considered one of the main vegetable producing countries, however, its production is affected by several phytopathogens, whose control of these pathogens is based on the use of agrochemicals, which cause consequent environmental and health damages. In 2018, Mexico ranked 5th in the world in the consumption of fungicides and bactericides in agriculture. For this reason, new alternatives to control phytopathogens are important, with natural compounds with antifungal properties such as chitosan, a biopolymer of N-acetyl-D-glucosamine and D-glucosamine units linked by β-(1-4) bonds derived from the deacetylation of chitin with alkalysis (NaOH) or enzymatic hydrolysis. Chitosan is extracted from exoskeletons of arthropods. Research shows that it inhibits the growth of phytopathogens, due to its polycationic nature depending on molecular weight and deacetylation percentage. With other antifungal properties, they are inducer of phytoalexins, promotion of plant growth and biostimulant of beneficial microorganisms, due to its useful and economic potential agricultural application in technological innovation.

One of the phytopathogens that cause severe damage to jalapeño pepper is Leveillula taurica (Lév.) Arnaud, the causative agent of powdery mildew. Synthetic fungicides are currently employed for its control, contributing to adverse effects on human health and the environment. The main objective of this research was to identify the causal agent of powdery mildew and assess the efficacy of chitosan in powdery mildew control on jalapeño pepper. The following treatments were evaluated in laboratory and greenhouse conditions: T1 = 0.0125% chitosan, T2 = 0.0025% chitosan, T3 = 0.05% chitosan, T4 = 0.1% chitosan, T5 = 0.2% chitosan, T6 = tebuconazole 25% (1.8 mL/L water), and T7 = control (water). Symptomatology results indicated that L. taurica is indeed the causative agent of powdery mildew. Treatments T4 and T5 exhibited the lowest percentages of incidences and severity, hence achieving higher control efficacy in the laboratory (57.70 ± 3.85 and 65.39 ± 3.85) and greenhouse (56.67 ± 4.08 and 70 ± 8.16%) compared to T6 (control efficacy, 38.46 ± 0.00% in the laboratory and 50 ± 0.00% in the greenhouse). The chitosan derived from shrimp had a significant impact on the cell walls of L. taurica spores and mycelium. Consequently, chitosan emerges as a viable organic alternative to fungicides for controlling powdery mildew in jalapeño pepper.

Ante los retos por la necesidad de fertilizantes para mantener la producción agrícola, ocurre naturalmente un proceso biológico de fijación de nitrógeno atmosférico por parte de un grupo de bacterias simbióticas que forman una asociación muy estrecha con plantas del grupo de las leguminosas, entre las que se encuentran las alfalfillas o tréboles silvestres (Melilotus spp.). Desde el punto de vista ecológico esta planta tiene una función muy importante por la buena capacidad de asociarse a bacterias nativas del suelo fijadoras de nitrógeno del género Sinorhizobium. Un aspecto fundamental es que esta especie vegetal puede crecer normalmente en suelos alcalinos, lo que le convierte aún más como doble importante, ya que, por un lado, fija nitrógeno y por el otro puede incorporarse como abono verde. Con ello, se mejoran las propiedades físico-químicas del suelo y, se incrementan los niveles de materia orgánica, condición que es muy pobre en las áreas de zonas áridas. Adicionalmente, esta especie puede resistir bajas temperaturas y crecer satisfactoriamente en invierno. Este documento presenta una síntesis del género Melilotus y su simbionte Sinorhizobium meliloti, así como su importancia como posible mejorador natural del suelo.

The production of the pepper seedling (Capsicum annuum) is affected by the fungal complex that causes the ‘damping-off’, in which some species of the oomycete Pythium spp., stand out. The objective of the present study was to identify the causal agent of the death of pepper plants and evaluate its pathogenicity in pepper seeds and seedlings. A fast and aggressive growing oomycete was isolate from pepper plants, morphologically identified as P. aphanidermatum based on its sexual and asexual reproduction structures and, by molecular techniques. This isolate had a high degree of in vitro pathogenicity in pre-emergence and post-emergence in chile, showing 100% mortality. In addition, it presented a high rate of mycelial growth in different culture media (V8-Agar, Corn Agar, Corn Potato Agar, Potato Dextrose Agar, Czapek & Oat Agar), being in V8-Agar medium the only medium where it developed reproduction structures sexual and asexual. The isolation presented a mycelial growth rate of 58.3 ± 0.3 mm / day at 26 ± 2 °C in PDA medium. Due to its rapid growth and its high degree of pathogenicity in vitro, it is an unusual and aggressive isolate for pepper seedlings.

Se evaluó la efectividad de Pseudomonas donghuensis y de Bacillus spp., para el control de Fusarium oxysporum y Pythium aphanidermatum causantes del ahogamiento de plántulas de chile en invernadero. Se comprobó su patogenicidad para ocasionar la enfermedad y se realizaron pruebas de antagonismo en placas con PDA enriquecido. Mediante la confrontación in vitro de estos fitopatógenos con siete cepas Bacillus spp., se comprobó que este esporulado inhibió en mayor o menor grado (39.35- 56.24 %) el crecimiento micelial de F. oxysporum, pero no tuvo efecto alguno para P. aphanidermatum, ningún Bacillus spp., inhibió a este Oomycete, debido a su rápido crecimiento en la placa de cultivo (36 h de incubación). En contraste P. donghuensis inhibió en un 76 % el crecimiento de P. aphanidermatum, y no presentó efecto inhibitorio para F. oxysporum, por lo que la mezcla de ambos antagonistas pudiera tener potencial para el control de los problemas de ahogamiento (‘‘Damping off“) causados por estos fitopatógenos.