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The genus Sinorhizobium comprises rhizobia that fix nitrogen in symbiosis with legumes. To support taxonomic studies of this genus and of rhizobia more broadly, we report complete genome sequences and annotations for the species type strains Sinorhizobium garamanticum LMG 24692 and Sinorhizobium numidicum LMG 27395 and CIP 109850.

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).

Cajanus cajan L. (guandul) is commonly cultivated in Dominican Republic where this legume is a subsistence crop. Here we identified through MALDI-TOF MS several rhizobial strains nodulating C. cajan in two Dominican locations as Bradyrhizobium yuanmingense. The phylogenetic analysis of recA and glnII housekeeping genes showed that these strains belong to a wide cluster together with the type strain of B. yuanmingense and other C. cajan nodulating strains previously isolated in Dominican Republic. The comparison of genomes from strains representative of different lineages within this cluster support the existence of several genospecies within B. yuanmingense, which is the major microsymbiont of C. cajan in Dominican Republic where it is also nodulated by Bradyrhizobium cajani and Bradyrhizobium pachyrhizi. The analysis of the symbiotic nodC gene showed that the C. cajan nodulating strains from the B. yuanmingense complex belong to two clusters with less than 90% similarity between them. The strains from these two clusters showed nodC gene similarity values lower than 90% with respect to the remaining Bradyrhizobium symbiovars and then they correspond to two new symbiovars for which we propose the names americaense and caribense. The results of the nodC gene analysis also showed that C. cajan is nodulated by the symbiovar tropici, which has been found by first time in this work within the species Bradyrhizobium pachyrhizi. These results confirmed the high promiscuity degree of C. cajan, which is also nodulated by the symbiovar cajani of Bradyrhizobium cajani in Dominican Republic.

Vicia faba L. (faba bean) is a legume cultivated worldwide which commonly establishes effective symbiosis with the symbiovar viciae of species from the Rhizobium leguminosarum phylogenetic group. However, on the basis of the rrs, recA, and atpD gene phylogenies, in this work we identified a strain named EFBRI 42 nodulating V. faba as Rhizobium azibense. This is the first report on the nodulation of Vicia by R. azibense which commonly nodulates P. vulgaris and to date encompasses strains harboring the nodC genes typical of the symbiovars gallicum and phaseoli. However, the strain EFBRI 42 carries a nodC gene typical of the symbiovar viciae for which we report here by the first time this symbiovar in R. azibense. This finding showed the existence of symbiotic genes horizontal transfer events during the coevolution of R. azibense with P. vulgaris and V. faba in their respective distribution centers of Mesoamerica and the Middle East.

Two rod-shaped Gram negative strains, SSUT16T and SSUT22, were isolated from root nodules of Spartocytisus supranubius in soils of the Teide National Park (Tenerife, Spain). The 16S rRNA gene sequences of these two novel strains classified them within genus Bosea with similarity values ranging from 97.65 % to 99.54 % with respect to the other species of this genus. The MLSA analysis from a concatenation of the two housekeeping- genes, recA and gyrB, showed that Bosea thiooxidans LMG 26210T and B. robiniae LMG 26381T are the two closest relative species with which they share similarity sequences values of 94.42 % and 94.27 %, respectively. The genome sequence analysis of strain SSUT16T showed average nucleotide identity percentages (ANIb) and digital DNA-DNA hybridization (dDDH) below 84 % and 33 %, respectively, with the type strains of all sequenced species of genus Bosea. These values are much lower than the currently accepted cut-off values for these two parameters to delineate bacterial species, confirming that the novel strains constitute a novel Bosea species. In addition, they are also distinguished from the other closest species in their fatty acid composition and in other phenotypic characteristics. Genome sequence analysis showed the absence of the common nodulation and nitrogen fixation genes in the novel strains. Therefore, based on the results of phylogenetic, genomic, chemotaxonomic and phenotypic characterization, we propose a new species named Bosea spartocytisi sp. nov., with type strain SSUT16T (=LMG 32510T = CECT 30526T = HAMBI 3759T).

The diversity of fenugreek (Trigonella foenum-graecum L.) microsymbionts has been barely studied even though it is of great interest for being a spice and a medicinal plant. Here, we analyzed 59 bacterial strains isolated from fenugreek nodules originating from different geographic and climatic areas of Iran. Most of these strains exhibit phenotypic characteristics compatible with rhizobia and they nodulate fenugreek. Analysis of the recA and atpD genes shows that representative strains of ERIC-BOX-PCR groups cluster with the type strains of Ensifer meliloti and E. kummerowiae as well as with strains capable of nodulating different Trigonella species found in other countries. The closeness of E. meliloti and E. kummerowiae suggests there is a need to revise the taxonomic status of the latter species. The nodC gene analysis shows that most Trigonella-nodulating strains belong to the symbiovar meliloti except those nodulating Trigonella arcuata in China, which belong to the symbiovar rigiduloides. This analysis shows that the type strains of E. kummerowiae, E. meliloti, and E. medicae belonged to three well-defined groups within the symbiovar meliloti, with the Iranian strains belonging to the E. kummerowiae subgroup. The small group of strains unable to nodulate fenugreek isolated in this study belong to Enterobacter cloacae, reported for the first time as being a possible endophyte of fenugreek nodules.

Phaseolus vulgaris is a legume indigenous to America which is nodulated by strains of genus Rhizobium in Croatia. Four of these strains, 13TT, 9T, 18TT and 8Z are phylogenetically close to the species from the Rhizobium leguminosarum phylogenetic complex in the 16S rRNA gene analysis. The results of both the analyses of the concatenated recA and atpD genes and whole genomes revealed that the strains 13TT and 9T clustered with Rhizobium sophoriradicis CCBAU 03470T and the strains 18TT and 8Z with Rhizobium ecuadorense CNPSO 671T. Whole genome average nucleotide identity blast (ANIb) and dDDH values between the strains 13TT and the type strain of R. sophoriradicis and between the strains 18TT and the type strain of R. ecuadorense were lower than 95% and 70%, respectively, which are the threshold values recommended for bacterial species differentiation. These results combined with those of chemotaxonomic and phenotypic analyses support the affiliation of these strains to two novel species within the genus Rhizobium for which we propose the names Rhizobium croatiense sp. nov. 13TT (=LMG 32397T, = HAMBI 3740T) as type strain and Rhizobium redzepovicii sp. nov. 18TT (=LMG 32398T, = HAMBI 3741T) as type strain.

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.

Bacteria currently included in Rhizobium leguminosarum are too diverse to be considered a single species, so we can refer to this as a species complex (the Rlc). We have found 429 publicly available genome sequences that fall within the Rlc and these show that the Rlc is a distinct entity, well separated from other species in the genus. Its sister taxon is R. anhuiense. We constructed a phylogeny based on concatenated sequences of 120 universal (core) genes, and calculated pairwise average nucleotide identity (ANI) between all genomes. From these analyses, we concluded that the Rlc includes 18 distinct genospecies, plus 7 unique strains that are not placed in these genospecies. Each genospecies is separated by a distinct gap in ANI values, usually at approximately 96% ANI, implying that it is a ‘natural’ unit. Five of the genospecies include the type strains of named species: R. laguerreae, R. sophorae, R. ruizarguesonis, “R. indicum” and R. leguminosarum itself. The 16S ribosomal RNA sequence is remarkably diverse within the Rlc, but does not distinguish the genospecies. Partial sequences of housekeeping genes, which have frequently been used to characterize isolate collections, can mostly be assigned unambiguously to a genospecies, but alleles within a genospecies do not always form a clade, so single genes are not a reliable guide to the true phylogeny of the strains. We conclude that access to a large number of genome sequences is a powerful tool for characterizing the diversity of bacteria, and that taxonomic conclusions should be based on all available genome sequences, not just those of type strains.

Bakers use pure microorganisms and/or traditional sourdoughs as the leavening agent for making bread. The performance of each starter and the substances produced by the microorganisms greatly affect the dough rheology and features of breads. Modern sourdoughs inoculated with selected lactic acid bacteria and yeasts are microbiologically stable, safer than traditional sourdoughs, and easy to use. However, the commercial repertoire of baker’s yeasts is still limited. Therefore, there is a demand for new strains of yeast species, capable of conferring distinctive traits to breads made from a variety of agri-food matrices, in the design of innovative starters. In this context, we report the first comprehensive study on yeasts isolated from a wide range of fermented doughs, cereal flours, and grains of Spain. Nine yeast species were identified from 433 isolates, which were distributed among separate clades. Moreover, phenotypic traits of potential technological relevance were identified in selected yeast strains. Mother doughs (MDs) showed the greatest yeast biodiversity, whereas commercial Saccharomyces starters or related and wild strains often dominated the bakery doughs. A metataxonomic analysis of wheat and tritordeum MDs revealed a greater richness of yeast species and percentage variations related to the consistency, flour type, and fermentation time of MDs.

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

Pseudomonas is a large and diverse genus broadly distributed in nature. Its species play relevant roles in the biology of earth and living beings. Because of its ubiquity, the number of new species is continuously increasing although its taxonomic organization remains quite difficult to unravel. Nowadays the use of genomics is routinely employed for the analysis of bacterial systematics. In this work, we aimed to investigate the classification of species of the genus Pseudomonas on the basis of the analyses of the type strains whose genomes are currently available. Based on these analyses, we propose the creation of three new genera (Denitrificimonas gen nov. comb. nov., Neopseudomonas gen nov. comb. nov. and Parapseudomonas gen nov. comb. nov) to encompass several species currently included within the genus Pseudomonas and the reclassification of several species of this genus in already described taxa

Cicer canariense is a highly promiscuous wild chickpea nodulated by Mesorhizobium strains in La Palma Island located at Canary archipelago. Four of these strains, CCANP34, CCANP35T, CCANP38 and CCANP95 belong to a group phylogenetically close to Mesorhizobium caraganae with 100% similarity values in the 16S rRNA gene. However, the genomes of the strains CCANP35T and M. caraganae LMG 24397T obtained in this work showed ANIb and dDDH values of 90.02% and 44.1%, respectively. These values are lower than those currently accepted for different bacterial species showing that the Canarian strains do not belong to the species M. caraganae. The Canarian strains also differ from M. caraganae in the amounts of several fatty acids and in several phenotypic traits. Based on the obtained results the Canarian strains belong to a novel species for which we propose the name Mesorhizobium neociceri sp. nov. and whose type strain is CCANP35T. The results of the phylogenetic analyses of nodC and nifH symbiotic genes showed that the Canarian strains represent a novel symbiovar within genus Mesorhizobium phylogenetically divergent to that encompassing M. caraganae. We propose the names canariense and caraganae for the symbiovars encompassing the strains of M. neociceri and M. caraganae, respectively.

Phaseolus vulgaris L. (common bean) is a legume indigenous to American countries currently cultivated in all continents, which is nodulated by diferent rhizobial species and symbiovars. Most of species able to nodulate this legume worldwide belong to the genus Rhizobium, followed by those belonging to the genera Ensifer (formerly Sinorhizobium) and Pararhizo bium (formerly Rhizobium) and minority by species of the genus Bradyrhizobium. All these genera belong to the phylum alpha-Proteobacteria, but the nodulation of P. vulgaris has also been reported for some species belonging to Paraburkholderia and Cupriavidus from the beta-Proteobacteria. Several species nodulating P. vulgaris were originally isolated from nodules of this legume in American countries and are linked to the symbiovars phaseoli and tropici, which are currently present in other continents probably because they were spread in their soils together with the P. vulgaris seeds. In addition, this legume can be nodulated by species and symbiovars originally isolated from nodules of other legumes due its high promiscuity, a concept currently related with the ability of a legume to be nodulated by several symbiovars rather than by several species. In this article we review the species and symbiovars able to nodulate P. vulgaris in diferent countries and continents and the challenges on the study of the P. vulgaris endosymbionts diversity in those countries where they have not been studied yet, that will allow to select highly efective rhizobial strains in order to guarantee the success of P. vulgaris inoculation

The genus Micromonospora has been found in nodules of several legumes and some new species of this genus were isolated from these plant organs. In this study we analysed the taxonomic diversity of Micromonospora strains isolated from alfalfa nodules in Spain and Australia on the basis of three phylogenetic markers, the rrs and gyrB genes and 16S-23S intergenic spacer (ITS). The genome analysis of selected strains representative of different clusters or lineages found after rrs, gyrB and ITS analyses confirmed the results obtained with these phylogenetic markers. They showed that the analysed strains belong to at least 18 Micromonospora species including previously described ones, such as Micromonospora noduli, Micromonospora ureilytica, Micromonospora taraxaci, Micromonospora zamorensis, Micromonospora aurantiaca and Micromonospora tulbaghiae. Most of these strains belong to undescribed species of Micromonospora showing the high taxonomic diversity of strains from this genus inhabiting alfalfa nodules. Although Micromonospora strains are not able to induce the formation of these nodules, and it seems that they do not contribute to fix atmospheric nitrogen, they could play a role related with the mechanisms of plant growth promotion and pathogen protection presented by Micromonospora strains isolated from legume nodules.

The genus Agrobacterium was created a century ago by Conn who included it in the family Rhizobiaceae together with the genus Rhizobium. Initially, the genus Agrobacterium contained the non-pathogenic species Agrobacterium radiobacter and the plant pathogenic species Agrobacterium tumefaciens and Agrobacterium rhizogenes. At the end of the past century two new pathogenic species, Agrobacterium rubi and Agrobacterium vitis, were added to the genus. Already in the present century these species plus Agrobacterium larrymoorei were reclassified into genus Rhizobium. This reclassification was controversial and for a time both genus names were used when new species were described. Few years ago, after a taxonomic revision based on genomic data, the old species A. rhizogenes was maintained in the genus Rhizobium, the old species A. vitis was transferred to the genus Allorhizobium and several Rhizobium species were transferred to the genus Agrobacterium, which currently contains 14 species including the old species A. radiobacter, A. tumefaciens, A. rubi and A. larrymoorei. Most of these species are able to produce tumours in different plants, nevertheless the genus Agrobacterium also encompasses non-pathogenic species, one species able to nodulate legumes and one human pathogenic species. Taking into account that the species affiliations to five Agrobacterium genomospecies have not been determined yet, an increase in the number of species within this genus is expected in the near future.

The original type strains of Agrobacterium radiobacter and Agrobacterium tumefaciens recorded in the eighth edition of Bergey’s Manual of Determinative Bacteriology published in 1974 were NCIB 9042T and ATCC 4720T, respectively. However, in the list of the valid names of bacteria compiled in 1980, both strains were changed, A. radiobacter NCIB 9042T to ATCC 19358T and A. tumefaciens ATCC 4720T to ATCC 23308T. These changes were unjustified, particularly in the case of A. tumefaciens whose type strain was replaced by another strain from the same collection, although the original type strain ATCC 4720T was never lost and it is currently available in several culture collections. Therefore, we request that the type strain of A. tumefaciens be corrected from ATCC 23308T to ATCC 4720T

Pisum sativum L. (pea) is one of the most cultivated grain legumes in European countries due to the high protein content of its seeds. Nevertheless, the rhizobial microsymbionts of this legume have been scarcely studied in these countries. In this work, we analyzed the rhizobial strains nodulating the pea in a region from Northwestern Spain, where this legume is widely cultivated. The isolated strains were genetically diverse, and the phylogenetic analysis of core and symbiotic genes showed that these strains belong to different clusters related to R. laguerreae sv. viciae. Representative strains of these clusters were able to produce cellulose and cellulases, which are two key molecules in the legume infection process. They formed biofilms and produced acyl-homoserine lactones (AHLs), which are involved in the quorum sensing regulation process. They also exhibited several plant growth promotion mechanisms, including phosphate solubilization, siderophore, and indole acetic acid production and symbiotic atmospheric nitrogen fixation. All strains showed high symbiotic efficiency on pea plants, indicating that strains of R. laguerreae sv. viciae are promising candidates for the biofertilization of this legume worldwide.

Leucaena leucocephala is a Mimosoid legume tree indigenous to America that has spread to other continents, although it is not still present in some European countries such as Portugal. Nevertheless, we found that this legume can be nodulated in this country by slow-growing rhizobial strains which were identified as Bradyrhizobium canariense trough the analysis of the core genes recA and glnII. The analysis of the symbiotic gene nodC showed that these strains belong to the symbiovar genistearum, which commonly nodulates Genistoid legumes. Although two strains nodulating L. leucocephala in China and Brazil were classified within the genus Bradyrhizobium, they belong to undescribed species and to the symbiovars glycinearum and tropici, respectively. Therefore, we report here for the first time the ability of L. leucocephala to establish symbiosis with strains of B. canariense sv genistearum confirming the high promiscuity of L. leucocephala, that allows it to establish symbiosis with rhizobia native to different continents increasing its invasiveness potential.

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 effects on human health and the environment. Plant growth-promoting bacteria may be used to reduce the need for chemical fertilizers, but efficient 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 efficient 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.

Several artisanal cheeses are elaborated in European countries, being commonly curdled with rennets of animal origin. However, in some Spanish regions some cheeses of type “Torta” are elaborated using Cynara cardunculus L. rennets. Two of these cheeses, “Torta del Casar” and “Torta de Trujillo”, are elaborated in Cáceres province with ewe’s raw milk and matured over at least 60 days without starters. In this work, we identified the lactic acid bacteria present in these cheeses using MALDI-TOF MS and pheS gene analyses, which showed they belong to the species Lactobacillus curvatus, Lactobacillus diolivorans, Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactococcus lactis and Leuconostoc mesenteroides. The pheS gene analysis also allowed the identification of the subspecies La. plantarum subsp. plantarum, La. paracasei subsp. paracasei and Le. mesenteroides subsp. jonggajibkimchii. Low similarity values were found in this gene for some currently accepted subspecies of Lc. lactis and for the two subspecies of La. plantarum, and values near to 100% for the subspecies of Le. mesenteroides and La. paracasei. These results, which were confirmed by the calculated ANIb and dDDH values of their whole genomes, showed the need to revise the taxonomic status of these species and their subspecies

Mesorhizobium contains species widely known as nitrogen-fixing bacteria with legumes, but their ability to promote the growth of non-legumes has been poorly studied. Here, we analyzed the production of indole acetic acid (IAA), siderophores and the solubilization of phosphate and potassium in a collection of 24 strains belonging to different Mesorhizobium species. All these strains produce IAA, 46% solubilized potassium, 33% solubilize phosphate and 17% produce siderophores. The highest production of IAA was found in the strains Mesorhizobium ciceri CCANP14 and Mesorhizobium tamadayense CCANP122, which were also able to solubilize potassium. Moreover, the strain CCANP14 showed the maximum phosphate solubilization index, and the strain CCANP122 was able to produce siderophores. These two strains were able to produce cellulases and cellulose and to originate biofilms in abiotic surfaces and tomato root surface. Tomato seedlings responded positively to the inoculation with these two strains, showing significantly higher plant growth traits than uninoculated seedlings. This is the first report about the potential of different Mesorhizobium species to promote the growth of a vegetable. Considering their use as safe for humans, animals and plants, they are an environmentally friendly alternative to chemical fertilizers for non-legume crops in the framework of sustainable agriculture.

A bacterial strain, designated BC09T, was isolated from a contaminated sample of condensed milk. Phylogenetic analyses based on 16S rRNA gene sequences placed strain BC09T into the genus Bacillus with its closest relatives being Bacillus safensis and Bacillus australimaris with 100 and 99.9 % similarity, respectively. Analysis of the gyrB gene confirmed the closeness of strain BC09T with respect to the species B. safensis since it presented 97.8 and 95.2 % similarity values, respectively, to the type strains of B. safensis and B. australimaris. DNA–DNA hybridization confirmed these results showing averages of 67 and 56 %, respectively, between strain BC09T and the type strains of B. safensis and B. australimaris. Average nucleotide identity blast values obtained for BC09T compared to the closest relative type strains were 95.7 and 67.6 %, respectively, and predicted DNA–DNA hybridization values were 93.1 and 51.9 %, respectively. However, strain BC09T differs from the type strains of its closest relatives in several phenotypic characteristics. MK-7 was the only menaquinone detected and iso-C15:0 and anteiso-C15:0 were the major fatty acids. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, two unidentified phospholipids, two unidentifed glycolipids, three unidentified lipids and one unidentifed phosphoglycolipid. Meso-diaminopimelic acid was detected in the peptidoglycan. The G+C content was 40.9 mol%. Phylogenetic, chemotaxonomic and phenotypic analyses showed that strain BC09T represents a new subspecies of B. safensis, for which the name Bacillus safensis subsp. osmophilus subsp. nov. is proposed. The type strain is BC09T (=LMG 30124T, =CECT 9344T).

Primary infection of legumes by rhizobia involves the controlled localized enzymatic breakdown of cell walls at root hair tips. Previous studies determined the role of rhizobial CelC2 cellulase in different steps of the symbiotic interaction Rhizobium leguminosarum-Trifolium repens. Recent findings also showed that CelC2 influences early signalling events in the Ensifer meliloti-Medicago truncatula interaction. Here, we have monitored the root hair phenotypes of two legume plants, T. repens and M. sativa, upon inoculation with strains of their cognate and non-cognate rhizobial species, R. leguminosarum bv trifolii and E. meliloti, (over)expressing the CelC2 coding gene, celC. Regardless of the host, CelC2 specifically elicited ‘hole-on-the-tip’ events (Hot phenotype) in the root hair apex, consistent with the role of this endoglucanase in eroding the noncrystalline cellulose found in polarly growing cell walls. Overproduction of CelC2 also increased root hair tip redirections (RaT phenotype) events in both cognate and non-cognate hosts. Interestingly, heterologous celC expression also induced non-canonical alterations in ROS (Reactive Oxygen Species) homeostasis at root hair tips of Trifolium and Medicago. These results suggest the concurrence of shared unspecific and host-related plant responses to CelC2 during early steps of symbiotic rhizobial infection. Our data thus identify CelC2 cellulase as an important determinant of events underlying early infection of the legume host by rhizobia.

Melinis minutiflora is an invasive species that threatens the biodiversity of the endemic vegetation of the campo rupestre biome in Brazil, displacing the native vegetation and favouring fire spread. As M. minutiflora invasion has been associated with a high nitrogen (N) demand, we assessed changes in N cycle under four treatments: two treatments with contrasting invasion levels (above and below 50%) and two un-invaded control treatments with native vegetation, in the presence or absence of the leguminous species Periandra mediterranea. This latter species was considered to be the main N source in this site due to its ability to fix N2 in association with Bradyrhizobia species. Soil proteolytic activity was high in treatments with P. mediterranea and in those severely invaded, but not in the first steps of invasion. While ammonium was the N-chemical species dominant in plots with native species, including P.mediterranea, soil nitrate prevailed only in fully invaded plots due to the stimulation of the nitrifying bacterial (AOB) and archaeal (AOA) populations carrying the amoA gene. However, in the presence of P. mediterranea, either in the beginning of the invasion or in uninvaded plots, we observed an inhibition of the nitrifying microbial populations and nitrate formation, suggesting that this is a biotic resistance strategy elicited by P. mediterranea to compete with M. minutiflora. Therefore, the inhibition of proteolytic activity and the nitrification process were the strategies elicited by P.mediterranea to constrain M.munitiflora invasion.

Antimicrobial resistance is a worldwide problem that threatens the effectiveness of treatments for microbial infection. Consequently, it is essential to study unexplored niches that can serve for the isolation of new microbial strains able to produce antimicrobial compounds to develop new drugs. Bark beetles live in phloem of host trees and establish symbioses with microorganisms that provide them with nutrients. In addition, some of their associated bacteria play a role in the beetle protection by producing substances that inhibit antagonists. In this study the capacity of several bacterial strains, isolated from the bark beetles Ips acuminatus, Pityophthorus pityographus Cryphalus piceae, and Pityogenes bidentatus, to produce antimicrobial compounds was analyzed. Several isolates exhibited the capacity to inhibit Gram-positive and Gram-negative bacteria, as well as fungi. The genome sequence analysis of three Pseudomonas isolates predicted the presence of several gene clusters implicated in the production of already described antimicrobials and moreover, the low similarity of some of these clusters with those previously described, suggests that they encode new undescribed substances, which may be useful for developing new antimicrobial agents. Moreover, these bacteria appear to have genetic machinery for producing antitumoral and antiviral substances. Finally, the strain IA19T showed to represent a new species of the genus Pseudomonas. The 16S rRNA gene sequence analysis showed that its most closely related species include Pseudomonas lutea, Pseudomonas graminis, Pseudomonas abietaniphila and Pseudomonas alkylphenolica, with 98.6, 98.5 98.4, and 98.4% identity, respectively. MLSA of the housekeeping genes gyrB, rpoB, and rpoD confirmed that strain IA19T clearly separates from its closest related species. Average nucleotide identity between strains IA19T and P. abietaniphila ATCC 700689T, P. graminis DSM 11363T, P. alkylphenolica KL28T and P. lutea DSM 17257T were

The growing interest in a healthy lifestyle and in environmental protection is changing habits regarding food consumption and agricultural practices. Good agricultural practice is indispensable, particularly for raw vegetables, and can include the use of plant probiotic bacteria for the purpose of biofertilization. In this work we analysed the probiotic potential of the rhizobial strain PEPV40, identified as Rhizobium laguerreae through the analysis of the recA and atpD genes, on the growth of spinach plants. This strain presents several in vitro plant growth promotion mechanisms, such as phosphate solubilisation and the production of indole acetic acid and siderophores. The strain PEPV40 produces cellulose and forms biofilms on abiotic surfaces. GFP labelling of this strain showed that PEPV40 colonizes the roots of spinach plants, forming microcolonies typical of biofilm initiation. Inoculation with this strain significantly increases several vegetative parameters such as leaf number, size and weight, as well as chlorophyll and nitrogen contents. Therefore, our findings indicate, for the first time, that Rhizobium laguerreae is an excellent plant probiotic, which increases the yield and quality of spinach, a vegetable that is increasingly being consumed raw worldwide.

The infection of legume plants by rhizobia is tightly regulated to ensure accurate bacterial penetration, infection, and development of functionally efficient nitrogen-fixing root nodules. Rhizobial Nod factors (NF) have key roles in the elicitation of nodulation signaling. Infection of white clover roots also involves the tightly regulated specific breakdown of the noncrystalline apex of cell walls in growing root hairs, which is mediated by Rhizobium leguminosarum bv. trifolii cellulase CelC2. Here, we have analyzed the impact of this endoglucanase on symbiotic signaling in the model legume Medicago truncatula. Ensifer meliloti constitutively expressing celC gene exhibited delayed nodulation and elicited aberrant ineffective nodules, hampering plant growth in the absence of nitrogen. Cotreatment of roots with NF and CelC2 altered Ca spiking in root hairs and induction of the early nodulin gene ENOD11. Our data suggest that CelC2 alters early signaling between partners in the rhizobia-legume interaction.

Forest fires lead to the annual disappearance of many natural formations that require the creation of firewall areas. They can be maintained by enriching their pastures with attractive plants for grazing livestock, mainly legumes, which have a high protein content and low dependence on N fertilizers due to their ability to establish nitrogen-fixing symbiosis with rhizobia. In this study, the rhizobia isolated from the nodules of six legumes from the genera Vicia, Lathyrus and Trifolium were analysed in a firewall zone established in Lanjarón (Granada) close to the Sierra Nevada National Park (Spain). The results showed a high genetic diversity of the isolated strains that had 3, 16, 14 and 13 different types of rrs, recA, atpD and glnII genes, respectively. All strains were phylogenetically close to the species from the Rhizobium leguminosarum group, although they were not identified as any of them. The isolated strains belonged to the symbiovars viciae and trifolii but high phylogenetic diversity was found within both symbiovars, since there were 16 and 14 nodC gene types, respectively. Some of these strains clustered with strains isolated in other countries and continents, but others formed atpD, recA, glnII and nodC clusters and lineages only found to date in this study.

A bacterial strain designated RA9T was isolated from a root of Cistus ladanifer in Spain. Phylogenetic analyses based on 16S rRNA gene sequences placed the isolate into the genus Bacillus with its closest relatives being Bacillus fortis R-6514T and Bacillus fordii R-7190T with 98.2 % similarity in both cases. DNA–DNA hybridization studies showed mean relatedness values of 29 and 30 %, respectively, between strain RA9T and the type strains of B. fortis and B. fordii. Cells of the isolate were Gram-stain-positive, motile, sporulating rods. Catalase and oxidase were positive. Gelatin, starch and casein were not hydrolysed. Menaquinone MK-7 was the only menaquinone detected and iso-C15 : 0 and anteiso-C15 : 0 were the major fatty acids. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminophospholipid, one unidentified phospholipid, one unidentifed glycolipid and one unidentified lipid. meso-Diaminopimelic acid was detected in the peptidoglycan. The DNA G+C content was 43.1 mol%. Phylogenetic, chemotaxonomic and phenotypic analyses showed that strain RA9T should be considered as representing a novel species of the genus Bacillus, for which the name Bacillus terrae sp. nov. is proposed. The type strain is RA9T (=LMG 29736T=CECT 9170T).

A bacterial strain designated RTAE36T was isolated from wheat roots in northern Spain. Phylogenetic analyses based on 16S rRNA gene sequence placed the isolate into the genus Paenibacillus with its closest relative being Paenibacillus borealis DSM 13188T with 97.7% sequence similarity. Cells of the isolate were facultatively anaerobic, Gram-stain-positive, motile and sporulating rods. Catalase and oxidase were positive. Gelatin, casein and starch were not hydrolysed. Growth was supported by many carbohydrates and organic acids as carbon sources. MK-7 was the only menaquinone detected, and anteiso-C15 : 0, C16 : 0, iso-C14 : 0 and iso-C16 : 0 were the major fatty acids. The polar lipids profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminolipid, two unidentified phospholipids, three unidentified phosphoaminolipids, one unidentified glycolipid and one unidentified lipid. meso-Diaminopimelic acid was detected in the cell-wall peptidoglycan. Strains RTAE36T and P. borealis DSM 13188 had an mean DNA–DNA relatedness of 39% and differed in several phenotypic and chemotaxonomic characteristics, confirming that strain RTAE36 should be considered as a representative of a novel species of the genus Paenibacillus, for which the name Paenibacillus tritici sp. nov. is proposed. The type strain is RTAE36 (=LMG 29502=CECT 9125).

Legumes consumption has been recognized as beneficial for human health, due to their content in proteins, fiber, minerals and vitamins, and their cultivation as beneficial for sustainable agriculture due to their ability to fix atmospheric nitrogen in symbiosis with soil bacteria known as rhizobia. The inoculation with these baceria induces metabolic changes in the plant, from which the more studied to date are the increases in the nitrogen and protein contents, and has been exploited in agriculture to improve the crop yield of several legumes. Nevertheless, legumes also contain several bioactive compounds such as polysaccharides, bioactive peptides, isoflavones and other phenolic compounds, carotenoids, tocopherols and fatty acids, which makes them functional foods included into the nutraceutical products. Therefore, the study of the effect of the rhizobial inoculation in the legume bioactive compounds content is gaining interest in the last decade. Several works reported that the inoculation of different genera and species of rhizobia in several grain legumes, such as soybean, cowpea, chickpea, faba bean or peanut, produced increases in the antioxidant potential and in the content of some bioactive compounds, such as phenolics, flavonoids, organic acids, proteins and fatty acids. Therefore, the rhizobial inoculation is a good tool to enhance the yield and quality of legumes and further studies on this field will allow us to have plant probiotic bacteria that promote the plant growth of legumes improving their functionality.

A bacterial strain designated AMTAE16 was isolated from a root of wheat in Spain. Phylogenetic analyses based on 16S rRNA gene sequences placed the isolate in the genus Paenibacilluswith its closest relative being Paenibacillus daejeonensis AP-20 with 99.0 % 16S rRNA gene sequence similarity. DNA–DNA hybridization studies showed a mean of 30 % DNADNA relatedness between strain AMTAE16 and the type strain of P. daejeonensis. The isolate was a Gram-stainvariable, motile and sporulating rod. Catalase and oxidase activities were positive. Gelatin and starch were hydrolysed but not casein. Growth was supported by many carbohydrates and organic acids as carbon source. MK-7 was the only menaquinone detected and anteiso-C, C and iso-C were the major fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified aminophospholipids, four unidentified phospholipids and two unidentified lipids. meso- Diaminopimelic acid was detected in the peptidoglycan. The DNA G+C content was 55.4 mol%. Phylogenetic, chemotaxonomic and phenotypic analyses showed that strain AMTAE16represents a novel species of the genus Paenibacillus, for which the name Paenibacillus hispanicus sp. nov. is proposed. The type strain is AMTAE16(=LMG 29501=CECT 9124).

A bacterial strain designated PM10T was isolated from root nodules of Periandra mediterranea in Brazil. Phylogenetic analyses based on 16S rRNA gene sequences placed the isolate in the genus Paenibacillus with its closest relatives being Paenibacillus vulneris CCUG 53270T and Paenibacillus yunnanensis YN2T with 95.6 and 95.9 % 16S rRNA gene sequence similarity, respectively. The isolate was a Gram-stain-variable, motile, sporulating rod that was catalase-negative and oxidase-positive. Caseinase was positive, amylase was weakly positive and gelatinase was negative. Growth was supported by many carbohydrates and organic acids as carbon sources. MK-7 was the only menaquinone detected and anteiso-C15 : 0 was the major fatty acid. Major polar lipids were diphosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol and two unidentified lipids. meso-Diaminopimelic acid was detected in the peptidoglycan. The DNA G+C content was 52.9 mol%. Phylogenetic, chemotaxonomic and phenotypic analyses showed that strain PM10T should be considered representative of a novel species of the genus Paenibacillus, for which the name Paenibacillus periandrae sp. nov. is proposed. The type strain is PM10T (=LMG 28691 =CECT 8827T).

Las levaduras confieren al pan gran parte de sus propiedades organolépticas y sensoriales. Las cepas comerciales de levaduras de panificación proceden de híbridos seleccionados por su alta capacidad para fermentar harinas de trigo y son muy similares genéticamente. Existe otro grupo de levaduras presentes en masas madre naturales con características fisiológicas y origen filogenético diferente que están emparentadas con levaduras vínicas. Las masas madre son mezcla de harina, agua y comunidades simbióticas de bacterias ácido lácticas (BAL) y levaduras salvajes (LEV), cuya biodiversidad final viene determinada por varios parámetros físicos y biotecnológicos. Las masas madre confieren al pan propiedades organolépticas y sensoriales más apreciadas que las de productos fabricados a gran escala con levadura industrial. La selección y caracterización de nuevas cepas BAL y LEV autóctonas de MM desarrolladas con harinas innovadoras permitirá formular nuevos starter mixtos para conseguir fermentaciones reproducibles a gran escala y productos industriales más diferenciables y con propiedades similares a los artesanales. Para satisfacer la reciente demanda de incrementar la biodiversidad y el repertorio de las levaduras de panificación disponibles, (i) se han aislado 535 LEV a partir de grano, harinas o masas madre naturales desarrolladas por expertos; (ii) se han caracterizado genética, bioquímica y fisiológicamente; (iii) se han seleccionado nuevas cepas de Saccharomyces capaces de fermentar eficazmente harinas de cereales tradicionales o innovadores (Tritordeum); y (iv), se han aislado cepas de especies no convencionales (ncLEV) con potencial interés biotecnológico. Además se han obtenido mediante “rare mating”, por primera vez, nuevas levaduras híbridas (LEVHY), entre cepas comerciales de panificación y vínicas; de algunas de éstas con cepas de laboratorio o/y con LEV aisladas de masas madre. Las LEV, ncLEV y LEVHY no están modificadas genéticamente y poseen propiedades de

In this work we analyze through a polyphasic approach several Bradyrhizobium strains isolated in Venezuela from root nodules of Centrosema species. The analysis of the 16S rRNA gene showed that the strains belong to three clusters within genus Bradyrhizobium which have 100% similarity with Bradyrhizobium daqingense CCBAU 15774TBradyrhizobium guangxiense CCBAU 53363T and Bradyrhizobium viridifuturi SEMIA 690T. The results of recA and glnII gene analysis confirmed the identification of the strains CMVU02 and CMVU30 as Bradyrhizobium viridifuturi but the nodC gene analysis showed that they belong to a new symbiovar for which we propose the name tropici. Nevertheless, the concatenated recA and glnII gene phylogenetic analysis, DNA–DNA hybridization and phenotypic characterization showed that the strains A9T, CMVU44T and CMVU04 belong to two novel Bradyrhizobium species. The analysis of the nodC gene showed that these strains also represent two new symbiovars. Based on these results we propose the classification of the strain A9T isolated from Centrosema molle into the novel species Bradyrhizobium centrosemae (sv. centrosemae) sp. nov. (type strain A9T = LMG 29515T = CECT 9095T). and the classification of the strains CMVU44T and CMVU04 isolated from C. macrocarpum into the novel species Bradyrhizobium americanum (sv. phaseolarum) sp. nov. (type strain CMVU44T = LMG 29514T = CECT 9096T).

In this study four Mesorhizobium strains isolated from Lotus corniculatus nodules in Granada (Spain) were characterized. Their 16S rRNA gene sequences were closely related to those of M. albiziae LMG 23507T and M. chacoense Pr5T showing 99.4 and 99.2% similarity values, respectively. The analysis of concatenated rpoB, recA, atpD and glnII genes showed they formed a cluster with internal similarities higher than 97%. The closest species also were M. albiziae LMG 23507T and M. chacoense Pr5T showing similarity values lower than 92% in rpoB, recA and glnII genes and lower than 96.5% in the atpD gene. These results indicated that the L. corniculatus strains belong to a new species of genus Mesorhizobium which was confirmed by DNA-DNA hybridization and phenotypic characterization. Therefore a new species with the name Mesorhizobium olivaresii sp. nov. is proposed, and the type strain is CPS13T (LMG 29295T = CECT 9099T).

En este trabajo se han aislado aproximadamente 180 levaduras tanto de ambientes naturales, (granos de cereales y harinas refinadas o integrales de trigo, cebada, centeno y Tritordeum), como de ambientes fermentativos (a partir de masas madre de panaderías artesanas de Castilla y León donde no se inocula levadura comercial, realizadas con diferentes tipos de harina). Para identificar las levaduras se emplearon técnicas de caracterización fenotípica y genotípica por técnicas moleculares. En los granos y harinas se encontraron 5 géneros: Candida, Hyphopichia, Pichia, Wickerhamomyces y Torulaspora, además de basidiomicetes, que fueron descartadas para su aplicación industrial. En las masas madre maduras se encontraron principalmente 2 especies: Meyerozyma guillermondii y Saccharomyces cerevisiae, siendo esta última especie representada en un 99% en las masas artesanas. Por técnicas moleculares se agruparon los aislados de la especie S. cerevisiae en 9 cepas diferentes. Una vez tipificados géneros y/o especies de levadura, se valoró su capacidad para fermentar harinas tradicionales y de Tritordeum, en presencia o ausencia de sacarosa (masas dulces o secas), y la producción de CO2 en fermentaciones de masas modelo sin harina. Además, se cuantificaron las actividades maltasa e invertasa asociadas a unas alta capacidad para fermentar harinas. Se determinó que las cepas de S. cerevisiae aisladas, independientemente del origen, producen igual o mayor cantidad de CO2 que levaduras comerciales y exhiben una alta variabilidad en las actividades maltasa e invertasa. Se han seleccionado finalmente 9 levaduras por sus buenas características fermentativas de masas de distintos cereales y, notablemente, 4 levaduras fermentan específicamente con alta eficacia harinas de Tritordeum.

The increasing interest in the preservation of the environment and the health of consumers is changing production methods and food consumption habits. Functional foods are increasingly demanded by consumers because they contain bioactive compounds involved in health protection. In this sense biofertilization using plant probiotics is a reliable alternative to the use of chemical fertilizers, but there are few studies about the effects of plant probiotics on the yield of functional fruits and, especially, on the content of bioactive compounds. In the present work we reported that a strain of genus Phyllobacterium able to produce biofilms and to colonize strawberry roots is able to increase the yield and quality of strawberry plants. In addition, the fruits from plants inoculated with this strain have significantly higher content in vitamin C, one of the most interesting bioactive compounds in strawberries. Therefore the use of selected plant probiotics benefits the environment and human health without agronomical losses, allowing the production of highly functional foods.

A bacterial strain designated A4STR04T was isolated from the inner root tissue of potatoes in Spain. Phylogenetic analysis based on the 16S rRNA gene sequence placed the isolate into the genus Fontibacillus, being most closely related to Fontibacillus panacisegetis KCTC 13564T with 99 % Identity. The isolate was observed to form Grampositive, motile and sporulating rods. The catalase test was found to be negative and oxidase positive. Nitrate was found to be reduced to nitrite. b-Galactosidase and caseinase were observed to be produced but the production of gelatinase, urease, arginine dehydrolase, ornithine and lysine decarboxylase was negative. Aesculin hydrolysis was found to be positive and acetoin production was negative. Growth was found to be supported by many carbohydrates and organic acids as carbon source. MK-7 was the only menaquinone detected and the major fatty acid (61.5 %) was identified as anteiso-C15:0, as occurs in the other species of genus Fontibacillus. The strain A4STR04T was found to display a complex lipid profile consisting of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, a glycolipid, two phospholipids, a lipid and two aminophospholipids. Mesodiaminopimelic acid was detected in the peptidoglycan. The G?C content was determined to be 50.5 mol% (Tm). Phylogenetic, chemotaxonomic and phenotypic analyses showed that strain A4STR04T (=LMG 28458 T = CECT 8693T) should be classified as representing a novel species of genus Fontibacillus, for hich the name Fontibacillus solani sp. nov. is proposed.

Vigna unguiculata was introduced into Europe from its distribution centre in Africa, and it is currently being cultivated in Mediterranean regions with adequate edapho-climatic conditions where the slow growing rhizobia nodulating this legume have not yet been studied. Previous studies based on rrs gene and ITS region analyses have shown that Bradyrhizobium yuanmingense and B. elkanii nodulated V. unguiculata in Africa, but these two species were not found in this study. Using the same phylogenetic markers it was shown that V. unguiculata, a legume from the tribe Phaseolae, was nodulated in Spain by two species of group I, B. cytisi and B. canariense, which are common endosymbionts of Genisteae in both Europe and Africa. These species have not been found to date in V. unguiculata nodules in its African distribution centres. All strains from Bradyrhizobium group I isolated in Spain belonged to the symbiovar genistearum, which is found at present only in Genisteae legumes in both Africa and Europe. V. unguiculata was also nodulated in Spain by a strain from Bradyrhizobium group II that belonged to a novel symbiovar (vignae). Some African V. unguiculata-nodulating strains also belonged to this proposed new symbiovar.

In this paper we analyze through a polyphasic approach several Bradyrhizobium strains isolated in Spain and Morocco from root nodules of Retama sphaerocarpa and Retama monosperma. All the strains have identical 16S rRNA genes and their closest relative species is Bradyrhizobium lablabi CCBAU 23086T, with 99.41% identity with respect to the strain Ro19T. Despite the closeness of the 16S rRNA genes, the housekeeping genes recA, atpD and glnII were divergent in Ro19T and B. lablabi CCBAU 23086T, with identity values of 95.71%, 93.75% and 93.11%, respectively. These differences were congruent with DNA-DNA hybridization analysis that revealed an average of 35% relatedness between the novel species and B. lablabi CCBAU 23086T. Also, differential phenotypic characteristics of the new species were found with respect to the already described species of Bradyrhizobium. Based on the genotypic and phenotypic data obtained in this study, we propose to classify the group of strains isolated from R. sphaerocarpa and R. monosperma as a novel species named Bradyrhizobium retamae sp. nov. (type strain Ro19T=LMG 27393T=CECT 8261T). The analysis of symbiotic genes revealed that some of these strains constitute a new symbiovar within genus Bradyrhizobium for which we propose the name >retamae>, that mainly contains nodulating strains isolated from Retama species in different continents.

La alfalfa (Medicago sativa L.) es uno de los cultivos forrajeros más importante en todo el mundo, siendo la leguminosa forrajera más importante en el sur de Europa, dada su condición de cultivo plurianial, con una duración en el campo de 3-6 años, e incluso hasta 10 años en algunos casos, y al alto contenido en proteínas y energía que la convierte en un excelente alimento para el ganado.

The biofertilization of crops with plant-growth-promoting microorganisms is currently considered as a healthy alternative to chemical fertilization. However, only microorganisms safe for humans can be used as biofertilizers, particularly in vegetables that are raw consumed, in order to avoid sanitary problems derived from the presence of pathogenic bacteria in the final products. In the present work we showed that Rhizobium strains colonize the roots of tomato and pepper plants promoting their growth in different production stages increasing yield and quality of seedlings and fruits. Our results confirmed those obtained in cereals and alimentary oil producing plants extending the number of non-legumes susceptible to be biofertilized with rhizobia to those whose fruits are raw consumed. This is a relevant conclusion since safety of rhizobia for human health has been demonstrated after several decades of legume inoculation ensuring that they are optimal bacteria for biofertilization.

Los 'rhizobia' son bacterias del suelo ampliamente conocidas por su capacidad para establecer simbiosis fijadoras de nitrógeno con las leguminosas. Sin embargo, estas bacterias también son capaces de promover el crecimiento vegetal de las plantas no leguminosas a través de diversos mecanismos entre los que cabe citar la producción de hormonas vegetales como el ácido indol acético, la solubilización del fosfato presente en el suelo, movilizando el fósoforo de la planta o la producción de compuestos que forman complejos con el hierro del suelo dneominados sideróforos y que facilitan el control de patógenos.

La producción de vino es resultado de una amplia gama de interacciones entre levaduras, hongos y bacterias, cuyo resultado de esta interacción son las cualidades de cada caldo. Actualmente, una de las prácticas más comunes es la adición de levadura seca activa o starters consiguiendo de esta manera controlar el proceso y obtener un producto con cualidades homogéneas. Sin embargo, algunos autores señalan la importancia de las poblaciones autóctonas de levaduras para aportar un sabor distintivo al producto final. Bodegas Grupo YIlera decidió realizar un nuevo producto con el fin de captar nuevos consumidores para sus productos vinícolas, para ello se elaboró un nuevo vino de baja graduación, producido mediante la fermentación espontánea del mosto de uva verdejo aprovechando la población de levaduras autóctonas presentes en la uva en el momento de la cosecha. El resultado de la labor llevada a cabo por Bodegas Grupo YIlera S.L. fue la producción de vino YIlera 5.5, un vino con 5,5° grados de alcohol y unas cualidades organolépticas características, un sabor dulce persistiendo la acidez propia del zumo de uva verdejo, con múltiples matices afrutados, conteniendo el C02 producido durante la fermentación. Estas caracterlsticas son resultado de la población de levaduras implicadas en el proceso de fermentación, de modo que se procedió a tipificar la población de levaduras autóctonas responsables. Los estudios indican que las poblaciones presentes de forma natural en la superficie de la uva son aquellas que inician los procesos de fermentación en los primeros estadios del proceso creando en algunos casos complejos ecosistemas en el mosto. La diversidad de levaduras aisladas depende en mayor medida de las condiciones ambientales y la madurez de la uva, esta diversidad suele dividirse en levaduras no pertenecientes al género Saccharomyces y levaduras pertenecientes al género Saccharomyces. Estas últimas suelen estar involucradas de forma directa con el proceso de vinificación

The threatened caesalpinioid legume Dimorphandra wilsonii, which is native to the Cerrado biome in Brazil, was examined for its nodulation and N2-fixing ability, and was compared with another, less-threatened species, D. jorgei. Nodulation and potential N2 fixation was shown on seedlings that had been inoculated singly with five bradyrhizobial isolates from mature D. wilsonii nodules. The infection of D. wilsonii by two of these strains (Dw10.1, Dw12.5) was followed in detail using light and transmission electron microscopy, and was compared with that of D. jorgei by Bradyrhizobium strain SEMIA6099. The roots of D. wilsonii were infected via small transient root hairs at 42 d after inoculation (dai), and nodules were sufficiently mature at 63 dai to express nitrogenase protein. Similar infection and nodule developmental processes were observed in D. jorgei. The bacteroids in mature Dimorphandra nodules were enclosed in plant cell wall material containing a homogalacturonan (pectic) epitope that was recognized by the monoclonal antibody JIM5. Analysis of sequences of their rrs (16S rRNA) genes and their ITS regions showed that the five D. wilsonii strains, although related to SEMIA6099, may constitute five undescribed species of genus Bradyrhizobium, whilst their nodD and nifH gene sequences showed that they formed clearly separated branches from other rhizobial strains. This is the first study to describe in full the N2-fixing symbiotic interaction between defined rhizobial strains and legumes in the sub-family Caesalpinioideae. This information will hopefully assist in the conservation of the threatened species D. wilsonii.