Soil degradation resulting from intensive agricultural practices, the excessive use of agrochemicals, and climate-induced stresses has significantly impaired soil fertility, disrupted microbial diversity, and reduced crop productivity. Plant growth-promoting bacteria (PGPB) represent a sustainable biological approach to restoring degraded soils by modulating plant physiology and soil function through diverse molecular mechanisms. PGPB synthesizes indole-3-acetic acid (IAA) to stimulate root development and nutrient uptake and produce ACC deaminase, which lowers ethylene accumulation under stress, mitigating growth inhibition. They also enhance nutrient availability by releasing phosphate-solubilizing enzymes and siderophores that improve iron acquisition. In parallel, PGPB activates jasmonate and salicylate pathways, priming a systemic resistance to biotic and abiotic stress. Through quorum sensing, biofilm formation, and biosynthetic gene clusters encoding antibiotics, lipopeptides, and VOCs, PGPB strengthen rhizosphere colonization and suppress pathogens. These interactions contribute to microbial community recovery, an improved soil structure, and enhanced nutrient cycling. This review synthesizes current evidence on the molecular and physiological mechanisms by which PGPB enhance soil restoration in degraded agroecosystems, highlighting their role beyond biofertilization as key agents in ecological rehabilitation. It examines advances in nutrient mobilization, stress mitigation, and signaling pathways, based on the literature retrieved from major scientific databases, focusing on studies published in the last decade.

Modern agriculture faces critical challenges due to increasing soil degradation resulting from overcultivation and excessive chemical use. These factors have led to declining agricultural productivity, reduced soil fertility, and a significant loss of microbial biodiversity. This review examines the role of plant growth-promoting bacteria (PGPB) as symbiotic microorganisms in restoring degraded soils. Key molecular and physiological mechanisms that enhance soil structure, improve water retention, and increase the bioavailability of essential nutrients for plants are explored. Additionally, the capacity of halotolerant bacteria to mitigate salt stress—an urgent issue in soils affected by salinization due to organic matter decomposition and irrigation practices—is analyzed. The role of plant growth regulators (PGRs) in both plant adaptation to adverse conditions and the stimulation of plant growth and development is also highlighted. Finally, current limitations in understanding biotic and abiotic stress resistance mechanisms in plants treated with growth-promoting strains are discussed, emphasizing the need for further research to optimize soil restoration strategies. This work provides a comprehensive overview of microorganism-based approaches for fostering more sustainable and resilient agriculture.

Forest cover is deteriorating rapidly due to anthropogenic causes, making its restoration urgent. Plant growth-promoting bacteria (PGPB) could offer a viable solution to ensure successful reforestation efforts. This study aimed to select bacterial strains with mechanisms that promote plant growth and enhance seedling development. The bacterial strains used in this study were isolated from the rhizosphere and endophyte regions of Pinus montezumae Lamb. and Pinus patula Schl. et Cham., two Mexican conifer species commonly used for reforestation purposes. Sixteen bacterial strains were selected for their ability to produce auxins, chitinase, and siderophores, perform nitrogen fixation, and solubilize inorganic phosphates; they also harbored genes encoding antimicrobial production and ACC deaminase. The adhesion to seeds, germination rate, and seedling response of P. montezumae and P. patula were performed following inoculation with 10 bacterial strains exhibiting high plant growth-promoting potential. Some strains demonstrated the capacity to enhance seedling growth. The selected strains were taxonomically characterized and belonged to the genus Serratia, Buttiauxella, and Bacillus. These strains exhibited at least two mechanisms of action, including the production of indole-3-acetic acid, biological nitrogen fixation, and phosphate solubilization, and could serve as potential alternatives for the reforestation of affected areas.

Se realizó el aislamiento y selección según su mecanismo de acción de bacterias endofíticas y rizosféricas promotoras de crecimiento vegetal de poblaciones silvestres de Pinus patula y Pinus montezumae, grupos arbóreos de coníferas mexicanas utilizados con fines de reforestación por su crecimiento acelerado y alto rendimiento. Ochenta y siete cepas bacterianas fueron aisladas de plántulas de pino, purificadas y agrupadas por criterios morfológicos. Se evaluaron y seleccionaron cepas que producen fitoreguladores de crecimiento, solubilización de fosfato, determinación de la cantidad de fósforo solubilizado y producción de quitinasa. Treinta y siete cepas mostraron al menos una de las actividades evaluadas, con niveles de producción de fitorreguladores en parámetros que van de 54.4 a 139 µg/ml, halos alrededor de las colonias de 3.2 a 3.8 cm solubilizando fosfato en cantidades que varían de 0.1 a 2.4 mg/L y crecimiento completo con zonas claras alrededor de las colonias con halos de 1.2 a 2 cm para la producción de quitinasa. Los resultados de este trabajo representan el primer paso para desarrollar un sistema de aceleración de crecimiento para plantas de uso forestal.

Desde tiempos ancestrales, las ranas han sido utilizadas en diversas culturas como remedio para diversos males debido a las propiedades de su piel, las cuales se atribuyen a moléculas que producen sus glándulas cutáneas, conocidas como péptidos. Algunos de estos péptidos tienen la capacidad de combatir microbios y junto con las bacterias que habitan en su piel, ayudan a protegerlas de infecciones. Este sistema de defensa natural no solo resulta fascinante, sino que también abre la puerta a nuevas ideas en biotecnología y a posibles tratamientos frente a enfermedades emergentes que hoy amenazan a las poblaciones de anfibios a nivel mundial.