Primary and secondary metabolite profiles were analyzed in roots and leaves of the halophytic shr... more Primary and secondary metabolite profiles were analyzed in roots and leaves of the halophytic shrub Prosopis strombulifera in response to control plants (no salt added in the growing media) and to lowering the osmotic potential to -1.0, -1.9, and -2.6 MPa generated by NaCl, Na2SO4, and the iso-osmotic combination of them at 24 h after reaching such potential. A rapid production of metabolites in response to sodium salt was found, which was correlated with modifications in growth parameters. Analysis of polar metabolite profiles by GC-MS rendered a total of 108 significantly altered compounds including 18 amino acids, 19 secondary metabolites, 23 carbohydrates, 13 organic acids, 4 indole acids, among others. Primary metabolites showed a differential response under the salt treatments, which was dependent on salt type and concentration, organ and age of plants. Most of identified compounds showed the strongest accumulation at the highest salt concentration assayed for Na2SO4-treated plants, which was correlated with damaging effects of sulfate anion on plant growth. Roots of NaCl-treated plants showed a higher number of altered metabolites (analyzed by UPLC-ESI-QqTOF-MS) compared to other treatments, while leaves of Na2SO4-treated plants showed the highest number of altered signals. A low degree of overlapping between secondary metabolites altered in roots and leaves of NaCl and Na2SO4-treated plants was found. However, when both NaCl and Na2SO4 salts were present plants always showed a lower number of altered metabolites. Three compounds were tentatively identified: tryptophan, lysophosphatidylcoline and 13-hydroxyoctadecadienoic acid. Increasing knowledge on P. strombulifera metabolism will contribute to unravel the underlying biochemical mechanism of salt tolerance.
Tomato is one of the most economically attractive vegetable crops due to its high yields. Disease... more Tomato is one of the most economically attractive vegetable crops due to its high yields. Diseases cause significant losses in tomato production worldwide. We carried out Polymerase Chain Reaction studies to detect the presence of genes encoding antifungal compounds in the DNA of Pseudomonas putida strain PCI2. We also used liquid chromatography-electrospray tandem mass spectrometry to detect and quantify the production of compounds that increase the resistance of plants to diseases from culture supernatants of PCI2. In addition, we investigated the presence of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase in PCI2. Finally, PCI2 was used for inoculation of tomato seeds to study its potential biocontrol activity against Fusarium oxysporum MR193. The obtained results showed that no fragments for the encoding genes of hydrogen cyanide, pyoluteorin, 2,4-diacetylphloroglucinol, pyrrolnitrin, or phenazine-1-carboxylic acid were amplified from the DNA of PCI2. On the other hand, PCI2 produced salicylic acid and jasmonic acid in Luria-Bertani medium and grew in a culture medium containing ACC as the sole nitrogen source. We observed a reduction in disease incidence from 53.33 % in the pathogen control to 30 % in tomato plants pre-inoculated with PCI2 as well as increases in shoot and root dry weights in inoculated plants, as compared to the pathogenicity control. This study suggests that inoculation of tomato seeds with P. putida PCI2 increases the resistance of plants to root rot caused by F. oxysporum and that PCI2 produces compounds that may be involved at different levels in increasing such resistance. Thus, PCI2 could represent a non-contaminating management strategy potentially applicable in vegetable crops such as tomato.
Plant physiology and biochemistry : PPB / Societe francaise de physiologie vegetale, Jan 18, 2016
Plants exposed to drought stress, as usually occurs in Patagonian shrublands, have developed diff... more Plants exposed to drought stress, as usually occurs in Patagonian shrublands, have developed different strategies to avoid or tolerate the lack of water during their development. Production of phenolic compounds (or polyphenols) is one of the strategies used by some native species of adverse environments to avoid the oxidative damage caused by drought. In the present study the relationship between phenolic compounds content, water availability and oxidative damage were evaluated in two native shrubs: Larrea divaricata (evergreen) and Lycium chilense (deciduous) of Patagonian shrublands by their means and/or by multivariate analysis. Samples of both species were collected during the 4 seasons for the term of 1 year. Soil water content, relative water content, total phenols, flavonoids, flavonols, tartaric acid esters, flavan-3-ols, proanthocyanidins, antioxidant capacity and lipid peroxidation were measured. According to statistical univariate analysis, L. divaricata showed high prod...
ABSTRACT Abscisic acid (ABA) is a phytohormone that regulates several developmental processes and... more ABSTRACT Abscisic acid (ABA) is a phytohormone that regulates several developmental processes and adaptive stress responses in plants. Legumes are a group of plants that are highly important food, feed and biofuel crops. Adaptation of these plants is a key factor that could determine the future of the effects of climatic change on agriculture. Many ABA roles in legume plants have been identified, but their importance under abiotic stress remain unclear. Recently, numerous advances have led to identify ABA roles, and to understand how growth responses are controlled by ABA under abiotic stress. Different strategies are being employed to improve plant growth under abiotic conditions; one of them is the production of tolerant legume genotypes. Many attempts to enhance the tolerance to abiotic conditions have been made to overcome this object including different alternatives such as exogenous application of ABA hormone. This chapter presents a review what is known up to date on the role of ABA in legume plants under abiotic conditions.
P. strombulifera is an interesting model plant to study mechanisms involved in plant tolerance to... more P. strombulifera is an interesting model plant to study mechanisms involved in plant tolerance to extreme salinity conditions. Total aminoacids showed no quantitative but qualitative differences within treatments; proline accumulation was independent of the medium composition, showing a direct correlation between proline content and stress intensity. There was no increase in glycinbethaine levels in response to any salt. Total protein content was no modified in salt treated plants at ? o –1.0 MPa, but increased at ?o –1.9 MPa in all treatments; at ? o -2.6 MPa only NaCl caused extra total protein synthesis; SO 4 = treated plants had reduced protein content while bisaline treated plants had and intermediate value. Total soluble carbohydrates increased proportionally to salinity increase, with changes in the root/shoot partitioning; glucose and fructose accumulated mainly in SO 4 = treated plants roots with a noticeable decrease in sucrose content. Leaves of NaCl-treated plants showed...
The plant hormone abscisic acid (ABA) plays a major role in plant responses to salt stress, and i... more The plant hormone abscisic acid (ABA) plays a major role in plant responses to salt stress, and its rapid production is essential to define ABA as a stress hormone. In glicophytes, stress tolerance is increased with high ABA concentrations, whereas in halophytes ABA roles are not yet known. Thus, in this study endogenous ABA levels and growth parameters were determined in leaves and roots of the halophyte P. strombulifera cultivated under increasing NaCl and Na2SO4 concentrations, at 30% and 70% relative humidity, respectively. Results of this investigation showed that at 30% relative humidity, roots from NaCl and Na2SO4-treated plants showed the highest ABA levels at the beginning of salinization (-1 MPa), followed by a decrease, which may imply its transport to leaves. Root growth in these plants decreased concomitantly with osmotic potential. Remarkably, these responses were more notorious in roots from Na2SO4-treated plants than NaCl-treated-plants. Similarly, in leaves from Na2...
ABSTRACT In this study, the profile of plant phytohormones traditionally considered as plant grow... more ABSTRACT In this study, the profile of plant phytohormones traditionally considered as plant growth promoters (GA1, GA3, GA4, IAA and Z) was determined in roots and leaves of the halophyte Prosopis strombulifera grown hydroponically in iso-osmotic solutions of NaCl, Na2SO4 and their mixture. Hormonal levels were correlated with growth parameters and ABA levels. Different sodium salts in the medium differentially affected the synthesis of these compounds. NaCl treated plants showed the greatest accumulation of GA4 and GA1 and lower levels of their metabolites GA8 and GA34 both in root and leaves, in coincidence with the optimum growth observed at Ψo -1.9 Mpa; this response was also observed at Ψo -2.6 MPa. IAA level was unaltered in these plants while Z content was higher in roots than in leaves. In contrast, both leaves and roots from Na2SO4 treated plants showed lower GA1 and GA4 and increased GA8 and GA34 levels at high salinity. High levels of IAA were found in roots of these plants, but the ABA/IAA ratio increased with increasing salt concentrations in the culture medium. This pattern was also observed in the high ABA/GAs ratios. Z levels were very low in all salt treatments. The results of this study show that the halophytic growth under NaCl treatment is mainly regulated by GA1 and GA4 and low relative levels of ABA and IAA. The toxicity of sulfate alters this pattern reversing the ratio ABA/GAs and increasing the synthesis of IAA in conjunction with increased lateral root formation. In bisaline-treated plants intermediate values were observed in the levels of these phytohormones as compared to monosaline treatment.
Salt stress conditions lead to increased production of reactive oxygen species (ROS) in plant cel... more Salt stress conditions lead to increased production of reactive oxygen species (ROS) in plant cells. Halophytes have the ability to reduce these toxic ROS by means of a powerful antioxidant system that includes enzymatic and non-enzymatic components. In this research, we used the halophytic shrub Prosopis strombulifera to investigate whether the ability of this species to grow under increasing salt concentrations and mixtures was related to the synthesis of polyphenolic compounds and to the maintenance of leaf pigment contents for an adequate photosynthetic activity. Seedlings of P. strombulifera were grown hydroponically in Hoagland's solution, gradually adding Na2SO4 and NaCl separately or in mixtures until reaching final osmotic potentials of -1, -1.9 and -2.6 MPa. Control plants were allowed to develop in Hoagland's solution without salt. Oxidative damage in tissues was determined by H2O2 and malondialdehyde content. Leaf pigment analysis was performed by high-performanc...
Primary and secondary metabolite profiles were analyzed in roots and leaves of the halophytic shr... more Primary and secondary metabolite profiles were analyzed in roots and leaves of the halophytic shrub Prosopis strombulifera in response to control plants (no salt added in the growing media) and to lowering the osmotic potential to -1.0, -1.9, and -2.6 MPa generated by NaCl, Na2SO4, and the iso-osmotic combination of them at 24 h after reaching such potential. A rapid production of metabolites in response to sodium salt was found, which was correlated with modifications in growth parameters. Analysis of polar metabolite profiles by GC-MS rendered a total of 108 significantly altered compounds including 18 amino acids, 19 secondary metabolites, 23 carbohydrates, 13 organic acids, 4 indole acids, among others. Primary metabolites showed a differential response under the salt treatments, which was dependent on salt type and concentration, organ and age of plants. Most of identified compounds showed the strongest accumulation at the highest salt concentration assayed for Na2SO4-treated plants, which was correlated with damaging effects of sulfate anion on plant growth. Roots of NaCl-treated plants showed a higher number of altered metabolites (analyzed by UPLC-ESI-QqTOF-MS) compared to other treatments, while leaves of Na2SO4-treated plants showed the highest number of altered signals. A low degree of overlapping between secondary metabolites altered in roots and leaves of NaCl and Na2SO4-treated plants was found. However, when both NaCl and Na2SO4 salts were present plants always showed a lower number of altered metabolites. Three compounds were tentatively identified: tryptophan, lysophosphatidylcoline and 13-hydroxyoctadecadienoic acid. Increasing knowledge on P. strombulifera metabolism will contribute to unravel the underlying biochemical mechanism of salt tolerance.
Tomato is one of the most economically attractive vegetable crops due to its high yields. Disease... more Tomato is one of the most economically attractive vegetable crops due to its high yields. Diseases cause significant losses in tomato production worldwide. We carried out Polymerase Chain Reaction studies to detect the presence of genes encoding antifungal compounds in the DNA of Pseudomonas putida strain PCI2. We also used liquid chromatography-electrospray tandem mass spectrometry to detect and quantify the production of compounds that increase the resistance of plants to diseases from culture supernatants of PCI2. In addition, we investigated the presence of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase in PCI2. Finally, PCI2 was used for inoculation of tomato seeds to study its potential biocontrol activity against Fusarium oxysporum MR193. The obtained results showed that no fragments for the encoding genes of hydrogen cyanide, pyoluteorin, 2,4-diacetylphloroglucinol, pyrrolnitrin, or phenazine-1-carboxylic acid were amplified from the DNA of PCI2. On the other hand, PCI2 produced salicylic acid and jasmonic acid in Luria-Bertani medium and grew in a culture medium containing ACC as the sole nitrogen source. We observed a reduction in disease incidence from 53.33 % in the pathogen control to 30 % in tomato plants pre-inoculated with PCI2 as well as increases in shoot and root dry weights in inoculated plants, as compared to the pathogenicity control. This study suggests that inoculation of tomato seeds with P. putida PCI2 increases the resistance of plants to root rot caused by F. oxysporum and that PCI2 produces compounds that may be involved at different levels in increasing such resistance. Thus, PCI2 could represent a non-contaminating management strategy potentially applicable in vegetable crops such as tomato.
Plant physiology and biochemistry : PPB / Societe francaise de physiologie vegetale, Jan 18, 2016
Plants exposed to drought stress, as usually occurs in Patagonian shrublands, have developed diff... more Plants exposed to drought stress, as usually occurs in Patagonian shrublands, have developed different strategies to avoid or tolerate the lack of water during their development. Production of phenolic compounds (or polyphenols) is one of the strategies used by some native species of adverse environments to avoid the oxidative damage caused by drought. In the present study the relationship between phenolic compounds content, water availability and oxidative damage were evaluated in two native shrubs: Larrea divaricata (evergreen) and Lycium chilense (deciduous) of Patagonian shrublands by their means and/or by multivariate analysis. Samples of both species were collected during the 4 seasons for the term of 1 year. Soil water content, relative water content, total phenols, flavonoids, flavonols, tartaric acid esters, flavan-3-ols, proanthocyanidins, antioxidant capacity and lipid peroxidation were measured. According to statistical univariate analysis, L. divaricata showed high prod...
ABSTRACT Abscisic acid (ABA) is a phytohormone that regulates several developmental processes and... more ABSTRACT Abscisic acid (ABA) is a phytohormone that regulates several developmental processes and adaptive stress responses in plants. Legumes are a group of plants that are highly important food, feed and biofuel crops. Adaptation of these plants is a key factor that could determine the future of the effects of climatic change on agriculture. Many ABA roles in legume plants have been identified, but their importance under abiotic stress remain unclear. Recently, numerous advances have led to identify ABA roles, and to understand how growth responses are controlled by ABA under abiotic stress. Different strategies are being employed to improve plant growth under abiotic conditions; one of them is the production of tolerant legume genotypes. Many attempts to enhance the tolerance to abiotic conditions have been made to overcome this object including different alternatives such as exogenous application of ABA hormone. This chapter presents a review what is known up to date on the role of ABA in legume plants under abiotic conditions.
P. strombulifera is an interesting model plant to study mechanisms involved in plant tolerance to... more P. strombulifera is an interesting model plant to study mechanisms involved in plant tolerance to extreme salinity conditions. Total aminoacids showed no quantitative but qualitative differences within treatments; proline accumulation was independent of the medium composition, showing a direct correlation between proline content and stress intensity. There was no increase in glycinbethaine levels in response to any salt. Total protein content was no modified in salt treated plants at ? o –1.0 MPa, but increased at ?o –1.9 MPa in all treatments; at ? o -2.6 MPa only NaCl caused extra total protein synthesis; SO 4 = treated plants had reduced protein content while bisaline treated plants had and intermediate value. Total soluble carbohydrates increased proportionally to salinity increase, with changes in the root/shoot partitioning; glucose and fructose accumulated mainly in SO 4 = treated plants roots with a noticeable decrease in sucrose content. Leaves of NaCl-treated plants showed...
The plant hormone abscisic acid (ABA) plays a major role in plant responses to salt stress, and i... more The plant hormone abscisic acid (ABA) plays a major role in plant responses to salt stress, and its rapid production is essential to define ABA as a stress hormone. In glicophytes, stress tolerance is increased with high ABA concentrations, whereas in halophytes ABA roles are not yet known. Thus, in this study endogenous ABA levels and growth parameters were determined in leaves and roots of the halophyte P. strombulifera cultivated under increasing NaCl and Na2SO4 concentrations, at 30% and 70% relative humidity, respectively. Results of this investigation showed that at 30% relative humidity, roots from NaCl and Na2SO4-treated plants showed the highest ABA levels at the beginning of salinization (-1 MPa), followed by a decrease, which may imply its transport to leaves. Root growth in these plants decreased concomitantly with osmotic potential. Remarkably, these responses were more notorious in roots from Na2SO4-treated plants than NaCl-treated-plants. Similarly, in leaves from Na2...
ABSTRACT In this study, the profile of plant phytohormones traditionally considered as plant grow... more ABSTRACT In this study, the profile of plant phytohormones traditionally considered as plant growth promoters (GA1, GA3, GA4, IAA and Z) was determined in roots and leaves of the halophyte Prosopis strombulifera grown hydroponically in iso-osmotic solutions of NaCl, Na2SO4 and their mixture. Hormonal levels were correlated with growth parameters and ABA levels. Different sodium salts in the medium differentially affected the synthesis of these compounds. NaCl treated plants showed the greatest accumulation of GA4 and GA1 and lower levels of their metabolites GA8 and GA34 both in root and leaves, in coincidence with the optimum growth observed at Ψo -1.9 Mpa; this response was also observed at Ψo -2.6 MPa. IAA level was unaltered in these plants while Z content was higher in roots than in leaves. In contrast, both leaves and roots from Na2SO4 treated plants showed lower GA1 and GA4 and increased GA8 and GA34 levels at high salinity. High levels of IAA were found in roots of these plants, but the ABA/IAA ratio increased with increasing salt concentrations in the culture medium. This pattern was also observed in the high ABA/GAs ratios. Z levels were very low in all salt treatments. The results of this study show that the halophytic growth under NaCl treatment is mainly regulated by GA1 and GA4 and low relative levels of ABA and IAA. The toxicity of sulfate alters this pattern reversing the ratio ABA/GAs and increasing the synthesis of IAA in conjunction with increased lateral root formation. In bisaline-treated plants intermediate values were observed in the levels of these phytohormones as compared to monosaline treatment.
Salt stress conditions lead to increased production of reactive oxygen species (ROS) in plant cel... more Salt stress conditions lead to increased production of reactive oxygen species (ROS) in plant cells. Halophytes have the ability to reduce these toxic ROS by means of a powerful antioxidant system that includes enzymatic and non-enzymatic components. In this research, we used the halophytic shrub Prosopis strombulifera to investigate whether the ability of this species to grow under increasing salt concentrations and mixtures was related to the synthesis of polyphenolic compounds and to the maintenance of leaf pigment contents for an adequate photosynthetic activity. Seedlings of P. strombulifera were grown hydroponically in Hoagland's solution, gradually adding Na2SO4 and NaCl separately or in mixtures until reaching final osmotic potentials of -1, -1.9 and -2.6 MPa. Control plants were allowed to develop in Hoagland's solution without salt. Oxidative damage in tissues was determined by H2O2 and malondialdehyde content. Leaf pigment analysis was performed by high-performanc...
Uploads