Plant–microbe interactions are highly specialized systems shaped by co‑evolution. Certain bacterial strains establish beneficial associations with healthy plants, engaging in a molecular dialogue that enhances host fitness. Apart from actively fighting off a pathogen, these bacteria can prime plant immune pathways, activate complementary defense responses, or modulate growth signals, as the microbiome is perceived as low‑risk because of their presence. Understanding which bacterial taxa can initiate these signaling networks—and which plant pathways are activated—is essential for designing agricultural applications that harness these natural protective mechanisms. Such insights can enable the development of microbiome‑based strategies to improve crop resilience and reduce dependence on chemical inputs.
During her UNU‑BIOLAC fellowship, María Florencia Sardo traveled from the Institute of Plant Pathology (Instituto de Patología Vegetal–CIAP–INTA, Córdoba, Argentina) to the Center for Genomic Sciences at UNAM in Cuernavaca, Mexico, to investigate how some strains of the bacterium Bacillus velezensis prime defense and modulate growth in plants. Guided by host mentor Dr. Mario Serrano (Programa de Genómica Funcional de Eucariotes, UNAM) and with support from Dr. Lucio Valetti (IPAVE–CIAP–INTA), she set out to characterize the molecular dialogue between plant and microbe against Botrytis cinerea. This common plant pathogen wreaks havoc in Argentinian chickpea plantations. Here, she tracked transcriptional reprogramming, hormone‑pathway activation, and microbiome‑mediated growth responses, including effects driven by volatile signals. Over the September–December 2025 fellowship period, her work wove together RNA‑seq and RT‑qPCR insights with biocontrol outcomes, building a coherent picture of how a well‑adapted Bacillus strain can pre‑empt disease while maintaining plant vigor.
We thank Dr. Serrano and CCG‑UNAM for their mentorship and hosting, and Dr. Valetti and IPAVE–CIAP–INTA for their supervision and foundational strain development. A key strength of this project is that the beneficial Bacillus strains were isolated locally by the Argentinian team, demonstrating how region‑adapted PGPR can be advanced without introducing exogenous genomes into native ecosystems—an approach that enhances biosafety, ecological compatibility, and real‑world adoption for sustainable agriculture in the region.
