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Burkholderia phytofirmans PsJN induces long-term metabolic and transcriptional changes involved in Arabidopsis thaliana salt tolerance.

Pinedo I, Ledger T, Greve M, Poupin MJ - Front Plant Sci (2015)

Bottom Line: Among the general transcriptional effects of this bacterium, the expression pattern of important ion-homeostasis related genes was altered after short and long-term stress (Arabidopsis K(+) Transporter 1, High-Affinity K(+) Transporter 1, Sodium Hydrogen Exchanger 2, and Arabidopsis Salt Overly Sensitive 1).In all, the faster and stronger molecular changes induced by the inoculation suggest a PsJN-priming effect, which may explain the observed tolerance after short-term and sustained salt-stress in plants.This opens up new venues to study these relevant biological associations, as well as new approaches to a better understanding of the spatiotemporal mechanisms involved in stress tolerance in plants.

View Article: PubMed Central - PubMed

Affiliation: Laboratorio de Bioingeniería, Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez Santiago, Chile.

ABSTRACT
Salinity is one of the major limitations for food production worldwide. Improvement of plant salt-stress tolerance using plant-growth promoting rhizobacteria (PGPR) has arisen as a promising strategy to help overcome this limitation. However, the molecular and biochemical mechanisms controlling PGPR/plant interactions under salt-stress remain unclear. The main objective of this study was to obtain new insights into the mechanisms underlying salt-stress tolerance enhancement in the salt-sensitive Arabidopsis thaliana Col-0 plants, when inoculated with the well-known PGPR strain Burkholderia phytofirmans PsJN. To tackle this, different life history traits, together with the spatiotemporal accumulation patterns for key metabolites and salt-stress related transcripts, were analyzed in inoculated plants under short and long-term salt-stress. Inoculated plants displayed faster recovery and increased tolerance after sustained salt-stress. PsJN treatment accelerated the accumulation of proline and transcription of genes related to abscisic acid signaling (Relative to Dessication, RD29A and RD29B), ROS scavenging (Ascorbate Peroxidase 2), and detoxification (Glyoxalase I 7), and down-regulated the expression of Lipoxygenase 2 (related to jasmonic acid biosynthesis). Among the general transcriptional effects of this bacterium, the expression pattern of important ion-homeostasis related genes was altered after short and long-term stress (Arabidopsis K(+) Transporter 1, High-Affinity K(+) Transporter 1, Sodium Hydrogen Exchanger 2, and Arabidopsis Salt Overly Sensitive 1). In all, the faster and stronger molecular changes induced by the inoculation suggest a PsJN-priming effect, which may explain the observed tolerance after short-term and sustained salt-stress in plants. This study provides novel information about possible mechanisms involved in salt-stress tolerance induced by PGPR in plants, showing that certain changes are maintained over time. This opens up new venues to study these relevant biological associations, as well as new approaches to a better understanding of the spatiotemporal mechanisms involved in stress tolerance in plants.

No MeSH data available.


Related in: MedlinePlus

Effect of B. phytofirmans PsJN on A. thaliana recovery after salt stress. (A) Representative photographs of in vitro salt-treated A. thaliana plants transplanted to soil. Plants were sown in half strength MS media with or without inoculation of B. phytofirmans PsJN. Eleven DAS plantlets were transplanted to MS media with or without additional 150 mM NaCl/15 mM CaCl2. Seven days after saline treatment, plants where transplanted to soil. (B–E) Graphic representation of average rosette area (B), average stem length (C), average number of siliques/plant (D), and average number of senescent leaves/plant (E) of plants under the experimental conditions described before. Data are means ± 1 SE of at least 12 plants per treatment. Asterisks indicate significant differences between control treatment and the other treatments in each time (Two-way ANOVA, p < 0.05; Bonferroni test, ∗P < 0.1; ∗∗P < 0.05; ∗∗∗P < 0.01). White bar in photograph corresponds to 2 cm.
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Figure 2: Effect of B. phytofirmans PsJN on A. thaliana recovery after salt stress. (A) Representative photographs of in vitro salt-treated A. thaliana plants transplanted to soil. Plants were sown in half strength MS media with or without inoculation of B. phytofirmans PsJN. Eleven DAS plantlets were transplanted to MS media with or without additional 150 mM NaCl/15 mM CaCl2. Seven days after saline treatment, plants where transplanted to soil. (B–E) Graphic representation of average rosette area (B), average stem length (C), average number of siliques/plant (D), and average number of senescent leaves/plant (E) of plants under the experimental conditions described before. Data are means ± 1 SE of at least 12 plants per treatment. Asterisks indicate significant differences between control treatment and the other treatments in each time (Two-way ANOVA, p < 0.05; Bonferroni test, ∗P < 0.1; ∗∗P < 0.05; ∗∗∗P < 0.01). White bar in photograph corresponds to 2 cm.

Mentions: To investigate the effects of PsJN inoculation on the recovery of A. thaliana plants exposed to salt-stress, plants were inoculated and exposed to salinity as described in the “Materials and Methods” section. After 7 days in the saline media, plants were transferred to soil and watered normally. Plant growth was recorded during 2 months (Figure 2A) by the measurement of rosette area, stem length, number of siliques, and senescent leaves (Figures 2B–E, respectively). During the first month in soil, plants treated with strain PsJN and not stressed had significantly larger rosette area, compared to the other treatments. Plants inoculated with strain PsJN and exposed to stress showed no differences in comparison to the control plants (non-inoculated and non-exposed to salt), while the non-inoculated and stressed plants had significantly smaller rosettes than all the other treatments. This pattern was observed until 46 DAS, when plants in all treatments showed comparable rosette areas (Figure 2B).


Burkholderia phytofirmans PsJN induces long-term metabolic and transcriptional changes involved in Arabidopsis thaliana salt tolerance.

Pinedo I, Ledger T, Greve M, Poupin MJ - Front Plant Sci (2015)

Effect of B. phytofirmans PsJN on A. thaliana recovery after salt stress. (A) Representative photographs of in vitro salt-treated A. thaliana plants transplanted to soil. Plants were sown in half strength MS media with or without inoculation of B. phytofirmans PsJN. Eleven DAS plantlets were transplanted to MS media with or without additional 150 mM NaCl/15 mM CaCl2. Seven days after saline treatment, plants where transplanted to soil. (B–E) Graphic representation of average rosette area (B), average stem length (C), average number of siliques/plant (D), and average number of senescent leaves/plant (E) of plants under the experimental conditions described before. Data are means ± 1 SE of at least 12 plants per treatment. Asterisks indicate significant differences between control treatment and the other treatments in each time (Two-way ANOVA, p < 0.05; Bonferroni test, ∗P < 0.1; ∗∗P < 0.05; ∗∗∗P < 0.01). White bar in photograph corresponds to 2 cm.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4477060&req=5

Figure 2: Effect of B. phytofirmans PsJN on A. thaliana recovery after salt stress. (A) Representative photographs of in vitro salt-treated A. thaliana plants transplanted to soil. Plants were sown in half strength MS media with or without inoculation of B. phytofirmans PsJN. Eleven DAS plantlets were transplanted to MS media with or without additional 150 mM NaCl/15 mM CaCl2. Seven days after saline treatment, plants where transplanted to soil. (B–E) Graphic representation of average rosette area (B), average stem length (C), average number of siliques/plant (D), and average number of senescent leaves/plant (E) of plants under the experimental conditions described before. Data are means ± 1 SE of at least 12 plants per treatment. Asterisks indicate significant differences between control treatment and the other treatments in each time (Two-way ANOVA, p < 0.05; Bonferroni test, ∗P < 0.1; ∗∗P < 0.05; ∗∗∗P < 0.01). White bar in photograph corresponds to 2 cm.
Mentions: To investigate the effects of PsJN inoculation on the recovery of A. thaliana plants exposed to salt-stress, plants were inoculated and exposed to salinity as described in the “Materials and Methods” section. After 7 days in the saline media, plants were transferred to soil and watered normally. Plant growth was recorded during 2 months (Figure 2A) by the measurement of rosette area, stem length, number of siliques, and senescent leaves (Figures 2B–E, respectively). During the first month in soil, plants treated with strain PsJN and not stressed had significantly larger rosette area, compared to the other treatments. Plants inoculated with strain PsJN and exposed to stress showed no differences in comparison to the control plants (non-inoculated and non-exposed to salt), while the non-inoculated and stressed plants had significantly smaller rosettes than all the other treatments. This pattern was observed until 46 DAS, when plants in all treatments showed comparable rosette areas (Figure 2B).

Bottom Line: Among the general transcriptional effects of this bacterium, the expression pattern of important ion-homeostasis related genes was altered after short and long-term stress (Arabidopsis K(+) Transporter 1, High-Affinity K(+) Transporter 1, Sodium Hydrogen Exchanger 2, and Arabidopsis Salt Overly Sensitive 1).In all, the faster and stronger molecular changes induced by the inoculation suggest a PsJN-priming effect, which may explain the observed tolerance after short-term and sustained salt-stress in plants.This opens up new venues to study these relevant biological associations, as well as new approaches to a better understanding of the spatiotemporal mechanisms involved in stress tolerance in plants.

View Article: PubMed Central - PubMed

Affiliation: Laboratorio de Bioingeniería, Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez Santiago, Chile.

ABSTRACT
Salinity is one of the major limitations for food production worldwide. Improvement of plant salt-stress tolerance using plant-growth promoting rhizobacteria (PGPR) has arisen as a promising strategy to help overcome this limitation. However, the molecular and biochemical mechanisms controlling PGPR/plant interactions under salt-stress remain unclear. The main objective of this study was to obtain new insights into the mechanisms underlying salt-stress tolerance enhancement in the salt-sensitive Arabidopsis thaliana Col-0 plants, when inoculated with the well-known PGPR strain Burkholderia phytofirmans PsJN. To tackle this, different life history traits, together with the spatiotemporal accumulation patterns for key metabolites and salt-stress related transcripts, were analyzed in inoculated plants under short and long-term salt-stress. Inoculated plants displayed faster recovery and increased tolerance after sustained salt-stress. PsJN treatment accelerated the accumulation of proline and transcription of genes related to abscisic acid signaling (Relative to Dessication, RD29A and RD29B), ROS scavenging (Ascorbate Peroxidase 2), and detoxification (Glyoxalase I 7), and down-regulated the expression of Lipoxygenase 2 (related to jasmonic acid biosynthesis). Among the general transcriptional effects of this bacterium, the expression pattern of important ion-homeostasis related genes was altered after short and long-term stress (Arabidopsis K(+) Transporter 1, High-Affinity K(+) Transporter 1, Sodium Hydrogen Exchanger 2, and Arabidopsis Salt Overly Sensitive 1). In all, the faster and stronger molecular changes induced by the inoculation suggest a PsJN-priming effect, which may explain the observed tolerance after short-term and sustained salt-stress in plants. This study provides novel information about possible mechanisms involved in salt-stress tolerance induced by PGPR in plants, showing that certain changes are maintained over time. This opens up new venues to study these relevant biological associations, as well as new approaches to a better understanding of the spatiotemporal mechanisms involved in stress tolerance in plants.

No MeSH data available.


Related in: MedlinePlus