Seed treatments with Bacillus species induce a beneficial metabolic reprogramming in melon plants

Plant-beneficial microbes are known to provide multifaceted traits to the plant health. Among them, Bacillus species are commonly detected members of the plant holobiont which have been described as stimulators of seed germination, plant growth and the defense against phytopathogens. In this work we describe, with the utilization of untargeted metabolomics and bioinformatic tools as GNPS, MolNetEnhancer and MZmine, the different metabolomic patterns found according to the elderly of the leaves. In addition, we compare the metabolomic profile of plants emerged from seeds bacterized with B. subtilis and B. velezensis identifying tryptophan, a chlorophyll A analog and flavonoids as key metabolites in the specific response of each bacterium against abiotic stresses.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Implicación de la matriz extracelular de Bacillus subtilis en la interacción beneficiosa con la planta

Bacillus subtilis es una bacteria Gram-positiva comúnmente presente en los suelos. Algunos aislados de esta especie son capaces de promover el crecimiento en plantas (actividad PGPR, del inglés plant growth promoting rhizobacteria) y de contribuir al control de diferentes enfermedades microbianas mediante la producción de una amplia batería de metabolitos secundarios con actividad antimicrobiana y la inducción de los mecanismos de defensa de la planta. Todo ello ocurre en el contexto de una eficiente colonización y persistencia sobre la raíz, la cual se cree estar asociada a la formación de biofilms: comunidades bacterianas donde las células están englobadas en una matriz extracelular de producción propia y compuesta principalmente por proteínas y exopolisacáridos. Estudios previos han demostrado que la surfactina, uno de los metabolitos secundarios producidos por esta bacteria, está involucrada en la cascada de señalización que dispara la formación del biofilm así como en la comunicación con la planta. Esta observación conduce a plantear la hipótesis de que alguno de los metabolitos secundarios u otros componentes estructurales de la matriz extracelular pueden ser mediadores de la comunicación bacteria-semilla y tener relevancia en la actividad PGPR. En este trabajo se evalúa el papel que los distintos componentes estructurales y metabolitos secundarios presentes en la matriz extracelular de B. subtilis puedan tener en la promoción de la germinación de semillas. Valiéndonos de una batería de mutantes en dichos elementos, realizamos ensayos de bacterización de semillas para estudiar posteriormente los patrones de colonización y persistencia bacteriana en la rizosfera y el efecto sobre la actividad PGPR. Los resultados obtenidos hasta la fecha sugieren que la molécula fengicina y la proteína TasA pueden ser claves en esta función de B. subtilis

Fengycin and the amyloid TasA of Bacillus subtilis stimulates the growth and immunization of plants by targeting the seed storages

Beneficial microbes are known to stimulate the germination of the seeds; however, the exact mechanisms mediating these interactions are only beginning. Bacillus subtilis is a commonly detected member of the plant holobiont and provides multifaceted traits to the plant health. In this work, we demonstrated that B. subtilis triggered genetic and physiological responses in seeds that resulted in changes in the metabolic and developmental status of adult plants. A multidisciplinary approach based on microscopy, transcriptomics and metabolomics demonstrated that the chemically diverse extracellular matrix of Bacillus structurally cooperate in bacterial colonization of the seed storage tissues. The amyloid protein TasA and fengycin, two components of the extracellular matrix, differentially stimulated levels of ROS inside seeds after imbibition and targeted the oil bodies of the seed endosperm, provoking specific changes in lipid metabolism or accumulation of glutathione-related molecules that resulted in two different plant growth programs: the development of seed radicles or major growth and immunization of adult plants. Our findings prove the versatility of the bacterial ECM in establishing a mutualistic interaction with plants.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Fengycin and the amyloid TasA of Bacillus subtilis stimulates the growth and immunization of plants by targeting the seed storages

Beneficial microbes are known to stimulate the germination of the seeds; however, the exact mechanisms mediating these interactions are only beginning. Bacillus subtilis is a commonly detected member of the plant holobiont and provides multifaceted traits to the plant health. In this work, we demonstrated that B. subtilis triggered genetic and physiological responses in seeds that resulted in changes in the metabolic and developmental status of adult plants. A multidisciplinary approach based on microscopy, transcriptomics and metabolomics demonstrated that the chemically diverse extracellular matrix of Bacillus structurally cooperate in bacterial colonization of the seed storage tissues. The amyloid protein TasA and fengycin, two components of the extracellular matrix differentially stimulated levels of ROS inside seeds after imbibition and targeted the oil bodies of the seed endosperm, provoking specific changes in lipid metabolism or accumulation of glutathione-related molecules that resulted in two different plant growth programs: the development of seed radicles or major growth and immunization of adult plants. Our findings prove the versatility of the bacterial ECM in establishing a mutualistic interaction with plants.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A community resource for paired genomic and metabolomic data mining

Genomics and metabolomics are widely used to explore specialized metabolite diversity. The Paired Omics Data Platform is a community initiative to systematically document links between metabolome and (meta)genome data, aiding identification of natural product biosynthetic origins and metabolite structures.Peer reviewe

A Noninvasive Method for Time-Lapse Imaging of Microbial Interactions and Colony Dynamics.

Complex interactions between microbial populations can greatly affect the overall properties of a microbial community, sometimes leading to cooperation and mutually beneficial coexistence, or competition and the death or displacement of organisms or subpopulations. Interactions between different biofilm populations are highly relevant in diverse scientific areas, from antimicrobial resistance to microbial ecology. The utilization of modern microscopic techniques has provided a new and interesting insight into how bacteria interact at the cellular level to form and maintain microbial biofilms. However, our ability to follow complex intraspecies and interspecies interactions in vivo at the microscopic level has remained somewhat limited. Here, we detailed BacLive, a novel noninvasive method for tracking bacterial growth and biofilm dynamics using high-resolution fluorescence microscopy and an associated ImageJ processing macro (https://github.com/BacLive) for easier data handling and image analysis. Finally, we provided examples of how BacLive can be used in the analysis of complex bacterial communities. IMPORTANCE Communication and interactions between single cells are continuously defining the structure and composition of microbial communities temporally and spatially. Methods routinely used to study these communities at the cellular level rely on sample manipulation which makes microscopic time-lapse experiments impossible. BacLive was conceived as a method for the noninvasive study of the formation and development of bacterial communities, such as biofilms, and the formation dynamics of specialized subpopulations in time-lapse experiments at a colony level. In addition, we developed a tool to simplify the processing and analysis of the data generated by this method