Beatriz Ramos

Lipo-Chitooligosaccharides (LCOs) as Elicitors of the Enzymatic Activities Related to ROS Scavenging to Alleviate Oxidative Stress Generated in Tomato Plants under Stress by UV-B Radiation

Plants

Exposure to ultraviolet-B (UV-B) radiation can lead to oxidative damage in plants, increasing rea... more Exposure to ultraviolet-B (UV-B) radiation can lead to oxidative damage in plants, increasing reactive oxygen species (ROS) production. To overcome ROS burst, plants have antioxidant mechanisms related to ROS scavenging which can be improved by elicitation with biological agents or derived molecules (elicitors), as they can trigger a physiological alert state called “priming”. This work describes the effects of lipo-chitooligosaccharides (LCOs) treatment applied to tomato plants under UV-B stress. The LCOs used in the study are produced by three species of the genus Ensifer (formerly Sinorhizobium) (SinCEU-1, SinCEU-2, and SinCEU-3) were assayed on tomato plants under UV-B stress. LCOs were able to significantly increase most of the enzymatic activities related to ROS scavenging while non-enzymatic antioxidants were not modified. This response was associated with a lower oxidative stress, according to malondialdehyde (MDA) levels and the higher antioxidant capacity of the plants. Fu...

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Alterations in the rhizobacterial community associated with European alder growth when inoculated with PGPR strain Bacillus licheniformis

Environmental and Experimental Botany, 2003

... response ( Holl and Chanway, 1992). Soil influences colonisation in two ways, either because ... more

Functional diversity of rhizosphere microorganisms from different genotypes of Arabidopsis thaliana

Community Ecol, 2009

... 1998). Differences in exudate composition exist between plant types but also, for the same pl... more

Effects of Plant Growth Promoting Rhizobacteria (PGPRs) on the Biological Nitrogen Fixation, Nodulation, and Growth ofLupinus albus l. cv. Multolupa

Eng Life Sci, 2004

ABSTRACT The effects of five plant growth promoting rhizobacteria on the biological nitrogen fixa... more ABSTRACT The effects of five plant growth promoting rhizobacteria on the biological nitrogen fixation (BNF), nodulation, and growth promotion of plants of Lupinus albus cv. Multolupa were investigated. The plants were selected for their capacity to use 1-aminocyclopropane-1-carboxylic acid (ACC) as the sole source of nitrogen. Four strains belonged to the genus Pseudomonas (Luc 1, Luc 2, Luc 3, and Luc 4) and one (Luc 5) belonged to the genus Bacillus. Three patterns of inoculation were examined. In the first pattern, PGPRs were inoculated seven days before being inoculated with B. japonicum. In the second pattern, PGPRs and B. japonicum were co-inoculated, and in the last pattern, PGPRs were inoculated seven days after being inoculated with B. japonicum. The plants were sampled 30 and 45 days after being inoculated with B. japonicum (T1 and T2). In the first pattern of inoculation, Luc 5 significantly increased the biological nitrogen fixation compared to the control at the first sampling time, as did Luc 1 and Luc 4 at the second sampling time. In the second pattern of inoculation, Luc 5 negatively effected the biological nitrogen fixation at both sampling times. In the third pattern of inoculation, all PGPRs caused a decrease in the nitrogen content of the plants compared to the control. The results obtained according to the patterns of inoculation showed that the mechanisms of action of the effects and routes used by Gram-negative and Gram-positive strains were clearly different. Competition between PGPRs and B. japonicum, competition for the niches in the rhizoplane, production of auxins, and induction of systemic resistance (ISR) by the production of siderophores or by lipopolysaccharides present in the outer membrane (LPS) are discussed as probable reasons for the effects observed.

Effects of european alder (Alnus flutinosa (L.) Gaertn) rhizobacteria on nodular metabolism and root development

Plant Growth Regul, 1997

The effects of 3 Bacillus and 7 Pseudomonas strains on development of the root system and nodular... more The effects of 3 Bacillus and 7 Pseudomonas strains on development of the root system and nodular metabolism, evaluating CO 2 production and acetylene reduction activity (ARA) of Alnus glutinosa, were studied. All experiments were done on nodulated plants (N) with the symbiont Frankia and on non-nodulated plants (NN). An increase in root length (RL) and root surface (RS) was detected when growth culture media from three different Bacillus free of bacteria were assayed, both in N and NN plants. However, Pseudomonas growth culture media reduced RS in N plants, and a decrease in RL parallel to an increase in RS in NN plants. Bacillus growth culture media caused an increase and CO 2 production while Pseudomonas culture media caused lower ARA and a noticeable increase in nodular respiration. Results are discussed considering nutritional and/or hormonal (Bacillus) or phytotoxic factors (Pseudomonas).

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Arthrobacter oxydans BB1 as stimulant of the secondary metabolism of plants, and protection against pathogens and saline stress

Daniel García-Seco & Alfonso Bonilla & Elena Algar & Ana García-Villaraco & Javier Gutierrez Mañero & Beatriz Ramos-Solano. Enhanced blackberry production using Pseudomonas fluorescens as elicitor. Agron. Sustain. Dev. DOI 10.1007/s13593-012-0103-z Accepted: 21 June 2012

Agronomy for Sustainable Development

This report shows for the first time the ability of Pseudomonas fluorescens N21.4 to trigger the ... more This report shows for the first time the ability of Pseudomonas fluorescens N21.4 to trigger the secondary metabolism of blackberries, Rubus fruticosus, in the field. Blackberries are an excellent source of bioactive compounds as compared to other marketable berries. Biotic elicitation with plant growth-promoting rhizobacteria has been proposed to improve biomass production and to trigger secondary metabolism. However, most reports that support this statement involve controlled, in-door experiments, not real field conditions under continuous environmental changes. Furthermore, most investigations are carried out using model plants. Strain P. fluorescens N21.4 has been able to trigger secondary metabolism of plant species. Therefore we studied P. fluorescens ability to increase blackberry fitness, fruit quality, and protection against natural pests under field conditions. P. fluorescens N21.4 was delivered in the root or shoot system of blackberry plants along its entire production p...

Biotechnology of the rhizosphere

This chapter deals with the management of the rhizosphere as a living system, paying special atte... more This chapter deals with the management of the rhizosphere as a living system, paying special attention to one of the three partners that define the rhizosphere: beneficial microorganisms (termed PGPR or the plant growth-promoting rhizosphere bacteria) that inhabit it. After that, several biotechnological approaches for management of the rhizosphere will be presented. These approaches relate to environment friendly agricultural practices, the production of high-quality foods with bioactive compounds (phytonutrients), and applications in the pharmaceutical industry. The rhizosphere refers to the soil region that is subject to the influence of plant roots and their associated microorganisms. Among these microorganisms are plant growth-promoting rhizobacteria which are beneficial for plant health in many ways: by improving plant nutrition, protecting against other microorganisms, producing plant growth regulators, or enhancing plant secondary metabolic pathways that are directly related to a plant's defense. In some plant species, these secondary metabolites are useful to human health. The biotechnology of the rhizosphere covers a wide array of applications that deal with sustainable agriculture (intensive or extensive): lowering of chemical inputs due to fertilizers and pesticides; improving crop productivity in saline and non-fertile soils; improvement of plant fitness for reforestation of degraded soils; and improvement in the bioactive levels of metabolites in medicinal plant species, among others. In this connection, the identification of elicitors (molecules that stimulate any of a number of defense responses in plants) appears to be an alternative to PGPR for unraveling limiting steps of secondary metabolism pathways.

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Effect of heavy metals on soil denitrification and CO2 production after short term incubation

Microbiología (Madrid, Spain), 1996

The toxicity of three heavy metals, Cd, Zn and Cu, has been tested in a Mediterranean soil. The s... more The toxicity of three heavy metals, Cd, Zn and Cu, has been tested in a Mediterranean soil. The soil was incubated (108h) with mixed solutions of those metals before evaluating denitrification and CO2 production, both by gas chromatography. These activities were used as biological indicators of heavy metal toxicity, and compared to non-treated control soil samples. Statistical analyses showed no significant differences in CO2 production between treated and non-treated control soils. The lowest levels of respiration were observed in soils treated with the largest amounts of Zn and Cd. Denitrification increased significantly in soils treated with solutions containing 100 micrograms/ml of Cu and 1000 micrograms/ml of Cd or Zn.

Supplementing Diet with Blackberry Extract Causes a Catabolic Response with Increments in Insulin Sensitivity in Rats

Plant Foods for Human Nutrition, 2015

Blackberry (Rubus sp.) fruit has a high content of anthocyanins, but its health benefits have not... more Blackberry (Rubus sp.) fruit has a high content of anthocyanins, but its health benefits have not been sufficiently explored in healthy individuals. Thus, the aim of the study was to determine the effects of blackberry extract on lipid and glucose variables in female and male rats. Sprague Dawley rats were given a standard pellet (SD) or cafeteria (CD) diet supplemented (SD+R and CD+R) or not with Rubus extract for 80 days. Female rats given SD+R had lower body and liver weights than SD females; both sexes given SD+R showed lower plasma glucose and insulin, higher plasma NEFA, glycerol and 3-hydroxybutyrate, and higher liver concentration of triacylglycerols than SD rats. The homeostasis model of insulin resistance (HOMA) was lower in SD+R rats than in SD rats, but higher in CD rats. No effects of Rubus extract were observed in CD rats. In conclusion, Rubus extract, in rats given SD, decreased glycemia and increased insulin sensitivity. It also increased lipid breakdown in adipose tissue. The effects were greater in females than in males. No effect was seen in rats given CD, probably as a result of their high insulin resistance.

Induction of Systemic Resistance on Arabidopsis Thaliana by Three Plant Growth Promoting Rhizobacteria

Beneficial rhizobacteria from rice rhizosphere confers high protection against biotic and abiotic stress inducing systemic resistance in rice seedlings

Plant Physiology and Biochemistry, 2014

The present study reports a screening for PGPR in a highly selective environment, the rhizosphere... more The present study reports a screening for PGPR in a highly selective environment, the rhizosphere of rice plants, in southwestern of Spain. Among the 900 isolates, only 38% were positive for at least one of the biochemical activities to detect putative PGPR. The best 80 isolates were selected and identified by 16S rRNA partial sequencing. Among these, 13 strains were selected for growth promotion assays. Only one strain (BaC1-38) was able to significantly increase height, while nine strains significantly inhibited it. Five strains significantly increased dry weight, and only BaC1-21 significantly decreased it. Based on significant modifications in growth, three bacteria (BaC1-13, BaC1-21 and BaC1-38) were tested for systemic induction of resistance against stress challenge (salt and Xanthomonas campestris infection). Protection against salt stress and pathogen infection was similar; BaC1-38 protected by 80%, BaC1-13 by 50% and BaC1-21 only by 20%. Toxicity of salt stress to the plants was evaluated by photosynthetic efficiency of seedlings. Fv/Fm only decreased significantly in plants inoculated with BaC1-13. ΦPSII also decreased significantly in plants inoculated with BaC1-21, but increased significantly with BaC1-38. NPQ decreased significantly in plants inoculated with BaC1-21. The two strains able to induce systemic resistance against Xanthomonas campestris seem to work by different pathways. BaC1-13 primed enzymes related with the detoxification of reactive oxygen species (ROS). However, BaC1-38 primed pathogenesis-related proteins (PRs), and this pathway was more effective, both improved chlorophyll index confirming the priming state of the plant.

Blackberry (Rubus sp. var. Loch Ness) Extract Reduces Obesity Induced by a Cafeteria Diet and Affects the Lipophilic Metabolomic Profile in Rats

Journal of Food & Nutritional Disorders, 2014

ABSTRACT Blackberries (Rubus sp. var. Loch Ness) contain large amounts of anthocyanins and flavon... more ABSTRACT Blackberries (Rubus sp. var. Loch Ness) contain large amounts of anthocyanins and flavonols, which have several health benefits. The present study was designed to determine the effects of a methanolic blackberry extract in rats fed a cafeteria diet. Weaned female rats were assigned to one of three dietary groups: standard pellet diet (SD), cafeteria diet (CD) and cafeteria diet supplemented with Rubus extract (CRD) for 90 days. Plasma metabolites and insulin were analyzed with commercial kits and fatty acid profile was measured by gas chromatography whereas other aliquots were subjected to metabolomics fingerprinting analysis using ultra high efficiency liquid chromatography. Lipoprotein lipase (LPL) activity was determined in fat depots by a radiochemical method. In comparison to the SD group, rats of the CD and CRD groups had increased plasma myristic, palmitic and oleic acids and those of the CD group had increased liver and different adipose tissue weights; the area under the curve of glucose and insulin after oral glucose load and inguinal adipose tissue LPL activity were also increased. Any of these variables were lower in rats of the CRD group, which also showed increased plasma triacylglycerols. However, both the CD and CRD decreased the insulin sensitivity index (ISI). The metabolomic variables showed that most of the acyl-carnitines were up-regulated whereas most of the phosphatidylcholines and lysophosphatidylcholines were down-regulated when comparing rats of the CD group versus those of SD, while when comparing CRD versus CD, oleic acid and lysophosphatidylethanolamines as well as phosphatidylserine and lysophosphatidylserine were up-regulated. In conclusion, besides evidencing the obesogenic and metabolic effects of a cafeteria diet in female rats, results show that such effects are reduced when the same diet is supplemented with this Rubus extract, although it did not modify the decreased ISI values.

Phosphate-solubilizing microorganisms in the rhizosphere of Pinus pinaster and in the mycosphere of associated Lactarius deliciosus

Developments in Plant and Soil Sciences, 2007

Page 1. Phosphate-solubilizing microorganisms in the rhizosphere of Pinus pinaster and in the myc... more

Bacterial bioeffectors modify bioactive profile and increase isoflavone content in soybean sprouts (Glycine max var Osumi)

Plant foods for human nutrition (Dordrecht, Netherlands), 2013

The effect of two bacterial strains to enhance bioactive contents (total phenolic compounds, tota... more The effect of two bacterial strains to enhance bioactive contents (total phenolic compounds, total flavonoid compounds and isoflavones) and antioxidant activity on 3-day-old soybean sprouts were investigated. To identify bacterial determinants responsible for these effects, viable and UV-treated strains were delivered to wounded seeds at different concentration. Multivariate analysis performed with all the evaluated parameters indicated the different effectiveness of Stenotrophomonas maltophilia N5.18 and Pseudomonas fluorescens N21.4 based on different structural and metabolic determinants for each. N21.4 increased total phenolics and isoflavones from the genistein family, while N5.18 triggered biosynthesis of daidzein and genistein families coupled to a decrease in total phenolics, suggesting different molecular targets in the phenilpropanoid pathway. Only extracts from N5.18 treated seeds showed an improved antioxidant activity according to the β-carotene bleaching prevention met...

RNA-Seq analysis and transcriptome assembly for blackberry (Rubus sp. Var. Lochness) fruit

BMC genomics, Jan 22, 2015

There is an increasing interest in berries, especially blackberries in the diet, because of recen... more There is an increasing interest in berries, especially blackberries in the diet, because of recent reports of their health benefits due to their high content of flavonoids. A broad range of genomic tools are available for other Rosaceae species but these tools are still lacking in the Rubus genus, thus limiting gene discovery and the breeding of improved varieties. De novo RNA-seq of ripe blackberries grown under field conditions was performed using Illumina Hiseq 2000. Almost 9 billion nucleotide bases were sequenced in total. Following assembly, 42,062 consensus sequences were detected. For functional annotation, 33,040 (NR), 32,762 (NT), 21,932 (Swiss-Prot), 20,134 (KEGG), 13,676 (COG), 24,168 (GO) consensus sequences were annotated using different databases; in total 34,552 annotated sequences were identified. For protein prediction analysis, the number of coding DNA sequences (CDS) that mapped to the protein database was 32,540. Non redundant (NR), annotation showed that 25,418...

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Physiological and Molecular Mechanisms of Plant Growth Promoting Rhizobacteria (PGPR)

Plant-Bacteria Interactions, 2008

... According to González and Lluch [29], the production of these substances by Azotobacter strai... more

Bacterial bioeffectors delay postharvest fungal growth and modify total phenolics, flavonoids and anthocyanins in blackberries

LWT - Food Science and Technology, 2015

ABSTRACT Blackberries are naturally rich in functional components beneficial for human health. Th... more ABSTRACT Blackberries are naturally rich in functional components beneficial for human health. The postharvest period of these fruits is very short due to fungal development, therefore, it is of great economic interest. Flavonoids and anthocyanins are secondary metabolites, and thus, strongly inducible. The aim of this study was to evaluate the ability of 6 bacteria with biocontrol traits and demonstrated Induced Systemic Resistance capacity, to prevent fungal growth during the postharvest period; the secondary aim was to identify whether the bacterial determinant was structural or metabolic, and if the treatment would affect flavonoid and anthocyanin levels. To achieve this goal, bacterial strains were sprayed dead or alive; fungal growth and phytochemicals were recorded.

Enhanced blackberry production using Pseudomonas fluorescens as elicitor

Agronomy for Sustainable Development, 2012

This report shows for the first time the ability of Pseudomonas fluorescens N21.4 to trigger the ... more This report shows for the first time the ability of Pseudomonas fluorescens N21.4 to trigger the secondary metabolism of blackberries, Rubus fruticosus, in the field. Blackberries are an excellent source of bioactive compounds as compared to other marketable berries. Biotic elicitation with plant growth-promoting rhizobacteria has been proposed to improve biomass production and to trigger secondary metabolism. However, most reports that support this statement involve controlled, indoor experiments, not real field conditions under continuous environmental changes. Furthermore, most investigations are carried out using model plants. Strain P. fluorescens N21.4 has been able to trigger secondary metabolism of plant species. Therefore we studied P. fluorescens ability to increase blackberry fitness, fruit quality, and protection against natural pests under field conditions. P. fluorescens N21.4 was delivered in the root or shoot system of blackberry plants along its entire production period, evaluating fruit quality and yield. Our results show an average increase up to 800 g per plant in total production, directly related to the increase in flowering buds. Protection against Spodoptera littoralis in inoculated plants was similar to control plants, hence contributing to increase in yield. Fruits from inoculated plants showed significant increases of up to 3°Brix, total phenolics of up to 18 %, and flavonoids of up to 22 %. We conclude that P. fluorescens N21.4 enhances plant defense and fruit quality together with an increased productivity as compared to current management practices, already obtaining high yields with economic profit.

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Effects of european alder (Alnus flutinosa (L.) Gaertn) rhizobacteria on nodular metabolism and root development

Plant Growth Regulation, 1997

The effects of 3 Bacillus and 7 Pseudomonas strains on development of the root system and nodular... more The effects of 3 Bacillus and 7 Pseudomonas strains on development of the root system and nodular metabolism, evaluating CO2 production and acetylene reduction activity (ARA), of Alnus glutinosa, were studied. All experiments were done on nodulated plants (N) with the symbiont Frankia and on non-nodulated plants (NN).

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