http://hdl.handle.net/10366/154132 2026-05-05T17:59:18Z 2026-05-05T17:59:18Z García Martín, Elsa Martín-Diana, Ana Belén Jiménez-Pulido, Iván Jesús Rico, Daniel de la Cruz-Sánchez, Rebeca Monte Vázquez, Enrique Martin Quijada, Narciso Requena Rolania, Teresa Olmo López, Rocío http://hdl.handle.net/10366/171213 2026-05-01T00:02:04Z 2026-07-02T00:00:00Z

[EN]Donkey milk (DM) is a nutritionally rich source of bioactive compounds, essential vitamins and minerals. However, its potential for developing functional fermented products remains unexplored. To address this gap, we investigated microbial dynamics during spontaneous fermentation of raw Zamorano-Leonese DM to isolate lactic acid bacteria (LAB) suitable for dairy applications. Raw milk from Zamorano-Leonese breed donkeys, raised on an organic farm in Salamanca (Spain), was spontaneously fermented at 37 °C until reaching pH 4.6. Metataxonomic analysis revealed a clear shift from environmental bacteria dominating the raw milk to an increased prevalence of LAB at the end of the fermentation process. Through culturomics, 34 bacterial strains were isolated and identified by 16S rRNA gene sequencing, including ten potential LAB candidates. Among these, five Lactococcus lactis isolates were selected to ferment pasteurized DM, which showed promising technological features and were subsequently subjected to whole-genome sequencing. L. lactis subsp. lactis CECT 31096 was selected due to its broad enzymatic repertoire linked to fermentation and the absence of antibiotic resistance or virulence-related genes. When used to ferment pasteurized DM, this strain improved both the physicochemical and nutritional profile of the resulting product. Fermentation significantly enhanced the bioaccesibility of bioactive compounds, as demonstrated by a higher inhibition of angiotensin-converting enzyme (the fermented sample showed IC50 values of 3.17 g/L compared with IC50 7.23 g/L from pasteurized milk), doubling after digestion (IC50 1.25 g/L). Additionally, fermentation with L. lactis subsp. lactis CECT 31096 significantly increased soluble free phenols and peptides, boosting the reducing power and antioxidant capacity, and thereby enhancing the functionality of the final product.

2026-07-02T00:00:00Z Martínez Hidalgo, Pilar Flores Félix, José David Sánchez Juanes, Fernando Rivas González, Raúl Mateos González, Pedro Francisco Santa Regina, Ignacio Peix, Álvaro Martínez Molina, Eustoquio Igual, José M. Velázquez Pérez, María Encarnación http://hdl.handle.net/10366/154430 2025-04-30T19:41:30Z 2021-01-01T00:00:00Z

[ES] Canola (Brassica napus L. var. oleracea) is the third most common oil-producing crop worldwide after palm and soybean. Canola cultivation requires the use of chemical fertilizers, but the amount required can be reduced by applying plant growth-promoting bacteria (PGPB). Among PGPB, endophytic bacteria have certain advantages as biofertilizers, but canola endophytic bacteria have rarely been studied. In this work, we identified a collection of bacterial endophytes isolated from canola roots using MALDI-TOF MS, a technique that is still rarely used for the identification of such bacteria, and rrs gene sequencing, a methodology that is commonly used to identify canola endophytes. The results demonstrated that some bacterial isolates from canola roots belonged to the genera Bacillus, Neobacillus, Peribacillus (Pe.), and Terribacillus, but most isolates belonged to the genera Paenibacillus (P.) and Pseudomonas (Ps.). Inoculation of these isolates indicated that several of them could efficiently promote canola seedling growth in hydroponic conditions. These results were then confirmed in a microcosm experiment using agricultural soil, which demonstrated that several isolates of Pseudomonas thivervalensis, Paenibacillus amylolyticus, Paenibacillus polymyxa, Paenibacillus sp. (Paenibacillus glucanolyticus/Paenibacillus lautus group), and Peribacillus simplex (previously Bacillus simplex) could efficiently promote canola shoot growth under greenhouse conditions. Among them, the isolates of Paenibacillus and Peribacillus were the most promising biofertilizers for canola crops as they are sporulated rods, which is an advantageous trait when formulating biofertilizers.

2021-01-01T00:00:00Z Martínez, Oscar A. Encina, Carolina Tomckowiack, Camilo Droppelmann, Fernando Jara, Ronald Maldonado, Constanza Muñoz, Ociel García Fraile, Paula Rivas González, Raúl http://hdl.handle.net/10366/154392 2025-04-30T19:41:30Z 2018-01-01T00:00:00Z

[EN] Raulí is one of the most emblematic tree species of the Chilean temperate forests. Due to the high quality wood, this tree has been used for furniture and handicrafts manufacturing, which has positioned raulí as one of the most important commercial timber species in Chile. Currently, the international market demands sustainable production system for forest production, more specifically in plantlets production. In this regard, plant growthpromoting rhizobacteria (PGPR) inoculants may enhance the growth and survival of plantlets in nurseries, which means an increase in the effectiveness of replanting operations. Therefore, the aim of the present study was to isolate, characterize and screen rhizosphere-associated bacteria with PGPR potential, isolated from raulí that growth in volcanic soils in southern Chile. A total of 1,261 bacterial strains were isolated from different volcanic soils. Out of 1,261 isolates, 100 were selected based on their high levels of indole acetic acid (IAA) production. These isolates were then subjected to screening for 1-aminocyclopropane-1-carboxylic acid deaminase activity, and their ability to fix nitrogen was determined. From the 100 selected isolates, 7 were chosen for producing the highest amount of IAA to continue with genetic characterization based on their 16S rRNA gene sequences. These 7 isolates were characterized as members of the Serratia genus and were used to develop multi-strain inoculant mixtures. Later, a nursery study followed to determine the effect of inoculation with the Serratia strains on the growth of RA88 raulí clone plantlets. The nursery experiment demonstrated that Serratia strains have the potential to increase the root collar diameter, height, relative chlorophyll content, biomass and nitrogen content of raulí plantlets. The study concluded, that Serratia strains have the potential to be used as biofertilizers to increase plant growth in nursery conditions.

2018-01-01T00:00:00Z Roca-Couso, Rocío Flores Félix, José David Igual, José M. García Fraile, Paula Velázquez Pérez, María Encarnación Rivas González, Raúl http://hdl.handle.net/10366/154343 2025-04-30T19:41:48Z 2023-01-01T00:00:00Z

[EN]Strain CRRU44T was isolated from the stems of Rubus ulmifolius plants growing in Salamanca (Spain). The phylogenetic analysis of the 16S rRNA gene sequence places this strain within the family Rhizobiaceae showing that it is equidistant to the type species of several genera from this family with similarity values ranging from 91.0 to 96.3 %. Strain CRRU44T formed a divergent lineage which clustered with Endobacterium cereale RZME27T, Neorhizobium galegae HAMBI540T and Pseudorhizobium pelagicum R1-200B4T. The phylogenomic analysis showed that strain CRRU44T was equal to or more distant from the remaining genera of the family Rhizobiaceae than other genera among them. The calculated average nucleotide identity based on blast and average amino acid identity values with respect to the type species of all genera from the family Rhizobiaceae were lower than 78.5 and 76.5 %, respectively, which are the currently cut-off values proposed to differentiate genera within this family. All these results together with those from phenotypic and chemotaxonomic analyses support that strain CRRU44T represents a novel species of a novel genus within the family Rhizobiaceae, for which the name Ferranicluibacter rubi gen. nov., sp. nov. is proposed (type strain CRRU44T=CECT 30117T=LMG 31822T).

2023-01-01T00:00:00Z Peral Aranega, Ezequiel Saati Santamaría, Zaki Ayuso Calles, Miguel Kostovčik, Martin Veselská, Tereza Švec, Karel Rivas González, Raúl Kolařik, Miroslav García Fraile, Paula http://hdl.handle.net/10366/154313 2025-04-30T19:41:50Z 2023-01-01T00:00:00Z

[EN]Ips typographus (European spruce bark beetle) is the most destructive pest of spruce forests in Europe. As for other animals, it has been proposed that the microbiome plays important roles in the biology of bark beetles. About the bacteriome, there still are many uncertainties regarding the taxonomical composition, insect-bacteriome interactions, and their potential roles in the beetle ecology. Here, we aim to deep into the ecological functions and taxonomical composition of I. typographus associated bacteria.

2023-01-01T00:00:00Z Gonçalves, Ana C. Nunes, Ana R. Meirinho, Sara Ayuso Calles, Miguel Roca-Couso, Rocío Rivas González, Raúl Falcão, Amílcar Alves, Gilberto Silva, Luís R. Flores Félix, José David http://hdl.handle.net/10366/154282 2025-04-30T19:41:49Z 2023-01-01T00:00:00Z

[EN]Nowadays, special attention has been paid to red and purple fruits, including blueberries and sweet cherries, since they are highly attractive to consumers due to their organoleptic properties, standing out due to their vibrant red and purple colours and sweet flavour, and nutritional value. (2) Methods: The present study evaluated the phenolic profile of phenolic-enriched extracts from blueberries and sweet cherries and explored their antioxidant potential against DPPH, superoxide and nitric oxide radicals, and ferric species, and their potential to inhibit the a-glucosidase enzyme. Furthermore, their antimicrobial activity was also determined by microdilution method against four Gram-positive strains (Enterococcus faecalis ATCC 29212, Bacillus cereus ATCC 11778, Listeria monocytogenes LMG 16779, and Staphylococcus aureus ATCC 25923) and five Gram-negative strains (Salmonella enterica subsp. enterica ATCC 13311 serovar Typhimurium, Klebsiella pneumoniae ATCC 13883, Proteus mirabilis CECT 170, Serratia marcescens CECT 159, and Acinetobacter baumannii LMG 1025). (3) Results: By chromatographic techniques, eight anthocyanins were detected in blueberry coloured fraction and total extract, and five anthocyanins were detected in sweet cherry total extract and coloured fraction, while quercetin aglycone and chlorogenic acids were the dominant non-coloured compounds in blueberries and sweet cherries, respectively. All extracts demonstrated significant antioxidant properties, as well as the ability to inhibit the activity of a-glucosidase enzyme and the development of various microorganisms. (4) Conclusion: The obtained data evidence the promising biological potential of blueberries and sweet cherries, being highly correlated with the presence of phenolic compounds.

2023-01-01T00:00:00Z Saati Santamaría, Zaki Vicentefranqueira, Rocío Kolařik, Miroslav Rivas González, Raúl García Fraile, Paula http://hdl.handle.net/10366/154277 2025-04-30T19:41:49Z 2023-01-01T00:00:00Z

[EN]Plant-associated microbial communities play important roles in host nutrition, development and defence. In particular, the microbes living within internal plant tissues can affect plant metabolism in a more intimate way. Understanding the factors that shape plant microbial composition and discovering enriched microbes within endophytic compartments would thus be valuable to gain knowledge on potential plant–microbial coevolutions. However, these interactions are usually studied through reductionist approaches (in vitro models or crop controlled systems). Here, we investigate these ecological factors in wild forest niches using proximally located plants from two distant taxa (blueberry and blackberry) as a model.

2023-01-01T00:00:00Z Jiménez Gómez, Alejandro García Estévez, Ignacio García Fraile, Paula Escribano Bailón, María Teresa Rivas González, Raúl http://hdl.handle.net/10366/154270 2024-01-17T01:00:43Z 2020-01-01T00:00:00Z

[EN] There is an urgent need for a new sustainable way of satisfying the increasing demand for food worldwide. One of the main challenges is replacing chemical fertilizers with biofertilizers, which include plant root-associated beneficial microorganisms. The present study reports, for the first time, the effects of SCCPVE07 bacterial strain with respect to improving not only plant development, but also the nutritional content and bioactive compounds content of Coriandrum sativum L., one of the most economically important crops, even for plant growth under salinity stress.

2020-01-01T00:00:00Z Saati Santamaría, Zaki Selem-Mojica, Nelly Peral Aranega, Ezequiel Rivas González, Raúl García Fraile, Paula http://hdl.handle.net/10366/154259 2025-04-30T19:41:48Z 2022-02-23T00:00:00Z

[EN]Microbes host a huge variety of biosynthetic gene clusters that produce an immeasurable array of secondary metabolites with many different biological activities such as antimicrobial, anticarcinogenic and antiviral. Despite the complex task of isolating and characterizing novel natural products, microbial genomic strategies can be useful for carrying out these types of studies. However, although genomic-based research on secondary metabolism is on the increase, there is still a lack of reports focusing specifically on the genus Pseudomonas. In this work, we aimed (i) to unveil the main biosynthetic systems related to secondary metabolism in Pseudomonas type strains, (ii) to study the evolutionary processes that drive the diversification of their coding regions and (iii) to select Pseudomonas strains showing promising results in the search for useful natural products. We performed a comparative genomic study on 194 Pseudomonas species, paying special attention to the evolution and distribution of different classes of biosynthetic gene clusters and the coding features of antimicrobial peptides. Using EvoMining, a bioinformatic approach for studying evolutionary processes related to secondary metabolism, we sought to decipher the protein expansion of enzymes related to the lipid metabolism, which may have evolved toward the biosynthesis of novel secondary metabolites in Pseudomonas. The types of metabolites encoded in Pseudomonas type strains were predominantly non-ribosomal peptide synthetases, bacteriocins, N-acetylglutaminylglutamine amides and ß-lactones. Also, the evolution of genes related to secondary metabolites was found to coincide with Pseudomonas species diversification. Interestingly, only a few Pseudomonas species encode polyketide synthases, which are related to the lipid metabolism broadly distributed among bacteria. Thus, our EvoMining-based search may help to discover new types of secondary metabolite gene clusters in which lipid-related enzymes are involved. This work provides information about uncharacterized metabolites produced by Pseudomonas type strains, whose gene clusters have evolved in a species-specific way. Our results provide novel insight into the secondary metabolism of Pseudomonas and will serve as a basis for the prioritization of the isolated strains. This article contains data hosted by Microreact.

2022-02-23T00:00:00Z Saati Santamaría, Zaki Baroncelli, Riccardo Rivas González, Raúl García Fraile, Paula http://hdl.handle.net/10366/154258 2024-02-17T20:42:07Z 2022-01-01T00:00:00Z

[EN]Each Earth ecosystem has unique microbial communities. Pseudomonas bacteria have evolved to occupy a plethora of different ecological niches, including living hosts, such as animals and plants. Many genes necessary for the Pseudomonas-niche interaction and their encoded functions remain unknown. Here, we describe a comparative genomic study of 3,274 genomes with 19,056,667 protein-coding sequences from Pseudomonas strains isolated from diverse environments. We detected functional divergence of Pseudomonas that depends on the niche. Each group of strains from a certain environment harbored a distinctive set of metabolic pathways or functions. The horizontal transfer of genes, which mainly proceeded between closely related taxa, was dependent on the isolation source. Finally, we detected thousands of undescribed proteins and functions associated with each Pseudomonas lifestyle. This research represents an effort to reveal the mechanisms underlying the ecology, pathogenicity, and evolution of Pseudomonas, and it will enable clinical, ecological, and biotechnological advances.

2022-01-01T00:00:00Z Roca-Couso, Rocío Flores Félix, José David Rivas González, Raúl http://hdl.handle.net/10366/154257 2025-04-30T19:41:48Z 2021-01-01T00:00:00Z

[EN]Botrytis cinerea is a phytopathogenic fungus responsible for economic losses from USD 10 to 100 billion worldwide. It affects more than 1400 plant species, thus becoming one of the main threats to the agriculture systems. The application of fungicides has for years been an efficient way to control this disease. However, fungicides have negative environmental consequences that have changed popular opinion and clarified the need for more sustainable solutions. Biopesticides are products formulated based on microorganisms (bacteria or fungi) with antifungal activity through various mechanisms. This review gathers the most important mechanisms of antifungal activities and the microorganisms that possess them. Among the different modes of action, there are included the production of diffusible molecules, both antimicrobial molecules and siderophores; production of volatile organic compounds; production of hydrolytic enzymes; and other mechanisms, such as the competition and induction of systemic resistance, triggering an interaction at different levels and inhibition based on complex systems for the production of molecules and regulation of crop biology. Such a variety of mechanisms results in a powerful weapon against B. cinerea; some of them have been tested and are already used in the agricultural production with satisfactory results.

2021-01-01T00:00:00Z Ayuso Calles, Miguel Flores Félix, José David Amaro, Filipa García Estévez, Ignacio Jiménez Gómez, Alejandro de Pinho, Paula Guedes Escribano Bailón, María Teresa Rivas González, Raúl http://hdl.handle.net/10366/154256 2025-04-30T19:41:47Z 2023-09-12T00:00:00Z

[EN]Soils affected by salinity are a recurring problem that is continually increasing due to the impact of climate change on weather conditions and ineffective agricultural management practices. The use of plant growth promoting (PGP) Bacteria can alleviate its effects. In this regard, the genus Rhizobium has demonstrated excellent PGP capabilities through various plant growth promotion mechanisms and may therefore be a promising biofortifier under saline conditions. However, little is known about the production of volatile organic compounds (VOCs) by bacteria of this genus and their effects on plant development. Here, we aim to characterize the volatilome (the set of volatile metabolites synthesized by an organism) of Rhizobium for the first time and to further investigate the direct and VOC-mediated interaction between a strain of this genus and lettuce, a crop severely affected by salinity, both under saline and non-saline conditions.

2023-09-12T00:00:00Z Ayuso Calles, Miguel Flores Félix, José David Rivas González, Raúl http://hdl.handle.net/10366/154255 2024-01-24T20:57:12Z 2021-01-01T00:00:00Z

[EN]Salinity is one of the main causes of abiotic stress in plants, resulting in negative effects on crop growth and yield, especially in arid and semi-arid regions. The effects of salinity on plant growth mainly generate osmotic stress, ion toxicity, nutrient deficiency, and oxidative stress. Traditional approaches for the development of salt-tolerant crops are expensive and time-consuming, as well as not always being easy to implement. Thus, the use of plant growth-promoting bacteria (PGPB) has been reported as a sustainable and cost-effective alternative to enhance plant tolerance to salt stress. In this sense, this review aims to understand the mechanisms by which PGPB help plants to alleviate saline stress, including: (i) changes in the plant hormonal balance; (ii) release of extracellular compounds acting as chemical signals for the plant or enhancing soil conditions for plant development; (iii) regulation of the internal ionic content of the plant; or iv) aiding in the synthesis of osmoprotectant compounds (which reduce osmotic stress). The potential provided by PGPB is therefore an invaluable resource for improving plant tolerance to salinity, thereby facilitating an increase in global food production and unravelling prospects for sustainable agricultural productivity.

2021-01-01T00:00:00Z Flores Félix, José David Velázquez Pérez, María Encarnación Martínez Molina, Eustoquio González Andrés, Fernando Squartini, Andrea Rivas González, Raúl http://hdl.handle.net/10366/154253 2025-04-30T19:41:47Z 2021-01-01T00:00:00Z

[EN]The legume nodules are a rich source not only of rhizobia but also of endophytic bacteria exhibiting plant growth-promoting mechanisms with potential as plant biostimulants. In this work we analyzed the genomes of Phyllobacterium endophyticum PEPV15 and Rhizobium laguerreae PEPV16 strains, both isolated from Phaseolus vulgaris nodules. In silico analysis showed that the genomes of these two strains contain genes related to N-acyl-homoserine lactone (AHL) and cellulose biosynthesis, involved in quorum sensing and biofilm formation, which are essential for plant colonization. Several genes involved in plant growth promotion such as those related to phosphate solubilization, indole acetic acid production, siderophore biosynthesis and nitrogen fixation were also located in both genomes. When strains PEPV15 and PEPV16 were inoculated in lettuce and carrot in field assays, we found that both significantly increased the yield of lettuce shoots and carrot roots by more than 20% and 10%, respectively. The results of this work confirmed that the genome mining of genes involved in plant colonization and growth promotion is a good strategy for predicting the potential of bacterial strains as crops inoculants, opening new horizons for the selection of bacterial strains with which to design new, effective bacteria-based plant biostimulants.

2021-01-01T00:00:00Z Jiménez Gómez, Alejandro Saati Santamaría, Zaki Igual, José M. Rivas González, Raúl Mateos González, Pedro Francisco García Fraile, Paula http://hdl.handle.net/10366/154252 2025-04-30T19:41:46Z 2019-01-01T00:00:00Z

[EN]Plants harbor a diversity of microorganisms constituting the plant microbiome. Many bioinoculants for agricultural crops have been isolated from plants. Nevertheless, plants are an underexplored niche for the isolation of microorganisms with other biotechnological applications. As a part of a collection of canola endophytes, we isolated strain CDVBN77T. Its genome sequence shows not only plant growth-promoting (PGP) mechanisms, but also genetic machinery to produce secondary metabolites, with potential applications in the pharmaceutical industry, and to synthesize hydrolytic enzymes, with potential applications in biomass degradation industries. Phylogenetic analysis of the 16S rRNA gene of strain CDVBN77T shows that it belongs to the genus Microvirga, its closest related species being M. aerophila DSM 21344T (97.64% similarity) and M. flavescens c27j1T (97.50% similarity). It contains ubiquinone 10 as the predominant quinone, C19:0 cyclo!8c and summed feature 8 as the major fatty acids, and phosphatidylcholine and phosphatidylethanolamine as the most abundant polar lipids. Its genomic DNA G+C content is 62.3 (mol %). Based on phylogenetic, chemotaxonomic, and phenotypic analyses, we suggest the classification of strain CDVBN77T within a new species of the genus Microvirga and propose the name Microvirga brassicacearum sp. nov. (type strain CDVBN77T = CECT 9905T = LMG 31419T).

2019-01-01T00:00:00Z Jiménez Gómez, Alejandro Saati Santamaría, Zaki Kostovčik, Martin Rivas González, Raúl Velázquez Pérez, María Encarnación Mateos González, Pedro Francisco Menéndez Gutiérrez, Esther García Fraile, Paula http://hdl.handle.net/10366/154251 2025-04-30T19:41:46Z 2020-01-01T00:00:00Z

[EN]Rapeseed (Brassica napus L.) is an important crop worldwide, due to its multiple uses, such as a human food, animal feed and a bioenergetic crop. Traditionally, its cultivation is based on the use of chemical fertilizers, known to lead to several negative e ects on human health and the environment. Plant growth-promoting bacteria may be used to reduce the need for chemical fertilizers, but e cient bacteria in controlled conditions frequently fail when applied to the fields. Bacterial endophytes, protected from the rhizospheric competitors and extreme environmental conditions, could overcome those problems and successfully promote the crops under field conditions. Here, we present a screening process among rapeseed bacterial endophytes to search for an e cient bacterial strain, which could be developed as an inoculant to biofertilize rapeseed crops. Based on in vitro, in planta, and in silico tests, we selected the strain Pseudomonas brassicacearum CDVBN10 as a promising candidate; this strain produces siderophores, solubilizes P, synthesizes cellulose and promotes plant height in 5 and 15 days-post-inoculation seedlings. The inoculation of strain CDVBN10 in a field trial with no addition of fertilizers showed significant improvements in pod numbers, pod dry weight and shoot dry weight. In addition, metagenome analysis of root endophytic bacterial communities of plants from this field trial indicated no alteration of the plant root bacterial microbiome; considering that the root microbiome plays an important role in plant fitness and development, we suggest this maintenance of the plant and its bacterial microbiome homeostasis as a positive result. Thus, Pseudomonas brassicacearum CDVBN10 seems to be a good biofertilizer to improve canola crops with no addition of chemical fertilizers; this the first study in which a plant growth-promoting (PGP) inoculant specifically designed for rapeseed crops significantly improves this crop’s yields in field conditions.

2020-01-01T00:00:00Z