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ABA inducible rice protein phosphatase 2C confers ABA insensitivity and abiotic stress tolerance in Arabidopsis.

Singh A, Jha SK, Bagri J, Pandey GK - PLoS ONE (2015)

Bottom Line: At adult stage, OsPP108 overexpression leads to high tolerance to salt, mannitol and drought stresses with far better physiological parameters such as water loss, fresh weight, chlorophyll content and photosynthetic potential (Fv/Fm) in transgenic Arabidopsis plants.Expression profile of various stress marker genes in OsPP108 overexpressing plants revealed interplay of ABA dependent and independent pathway for abiotic stress tolerance.Overall, this study has identified a potential rice group A PP2C, which regulates ABA signaling negatively and abiotic stress signaling positively.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, India.

ABSTRACT
Arabidopsis PP2C belonging to group A have been extensively worked out and known to negatively regulate ABA signaling. However, rice (Oryza sativa) orthologs of Arabidopsis group A PP2C are scarcely characterized functionally. We have identified a group A PP2C from rice (OsPP108), which is highly inducible under ABA, salt and drought stresses and localized predominantly in the nucleus. Genetic analysis revealed that Arabidopsis plants overexpressing OsPP108 are highly insensitive to ABA and tolerant to high salt and mannitol stresses during seed germination, root growth and overall seedling growth. At adult stage, OsPP108 overexpression leads to high tolerance to salt, mannitol and drought stresses with far better physiological parameters such as water loss, fresh weight, chlorophyll content and photosynthetic potential (Fv/Fm) in transgenic Arabidopsis plants. Expression profile of various stress marker genes in OsPP108 overexpressing plants revealed interplay of ABA dependent and independent pathway for abiotic stress tolerance. Overall, this study has identified a potential rice group A PP2C, which regulates ABA signaling negatively and abiotic stress signaling positively. Transgenic rice plants overexpressing this gene might provide an answer to the problem of low crop yield and productivity during adverse environmental conditions.

No MeSH data available.


Related in: MedlinePlus

Stomata movement of OsPP108 overexpression transgenic lines under ABA treatment.(A) Stomata aperture of 4 week old WT and OsPP108OX lines, L1, L2 and L4, in mock treatment (Stomata Opening Solution; SOS) (upper panel) and 100μM ABA (lower panel). 30 stomata were analyzed for each genotype and representation of those are shown in pictures (n = 3). Pictures were taken at 60x magnification in Olympus BX53 fluorescence microscope in bright field. Scale bar = 5μM. (B) Graph depicting percentage of different type of stomata (closed, partially open and open) in WT and OsPP108OX transgenic in mock and ABA treatments. Stomata were grouped based on apertures sizes, i.e., open- 2.5–5.0μM, partially open- 1.0–2.5μM and closed- < 1 μM. Percentage of stomata is calculated based on the average of three independent replicate experiments.
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pone.0125168.g011: Stomata movement of OsPP108 overexpression transgenic lines under ABA treatment.(A) Stomata aperture of 4 week old WT and OsPP108OX lines, L1, L2 and L4, in mock treatment (Stomata Opening Solution; SOS) (upper panel) and 100μM ABA (lower panel). 30 stomata were analyzed for each genotype and representation of those are shown in pictures (n = 3). Pictures were taken at 60x magnification in Olympus BX53 fluorescence microscope in bright field. Scale bar = 5μM. (B) Graph depicting percentage of different type of stomata (closed, partially open and open) in WT and OsPP108OX transgenic in mock and ABA treatments. Stomata were grouped based on apertures sizes, i.e., open- 2.5–5.0μM, partially open- 1.0–2.5μM and closed- < 1 μM. Percentage of stomata is calculated based on the average of three independent replicate experiments.

Mentions: In order to find out the causative mechanism for stress tolerance in adult plants, and its ABA dependence or independence, stomata movement assays were performed, as ABA dependent stomata closure is known to mediate drought stress tolerance. Stomata movement analysis in adult Arabidopsis plants revealed that in control condition (mock treatment with SOS buffer) all three OsPP108OX transgenic lines have stomata aperture size similar to WT. However, treatment with 100μM ABA for 2h resulted in significant difference in stomata aperture size, and most WT stomata were closed, whereas stomata in transgenic lines exhibit ABA insensitivity and most of them remained unaffected (opened) and had aperture size similar to control condition (Fig 11A). Moreover, based on the aperture size, stomata could be divided into three groups: (i) open—2.5–5.0μM, (ii) partially open- 1.0–2.5μM and (iii) closed- < 1 μM. In WT, compare to 40% in control condition, only 8% stomata were opened after ABA treatment, approximately 60% were partially opened both in control and ABA treatment, while 28% stomata were closed after ABA treatment. In contrast, all the three transgenic lines stomata had similar percentage of open and partially opened stomata, in control and ABA conditions, and almost none of the stomata were found to be closed even after ABA treatment (Fig 11B). Therefore, these results suggest that OsPP108 mediate the stomata movement, independent of ABA pathway and OsPP108 overexpression leads to ABA insensitivity at adult plant stage also.


ABA inducible rice protein phosphatase 2C confers ABA insensitivity and abiotic stress tolerance in Arabidopsis.

Singh A, Jha SK, Bagri J, Pandey GK - PLoS ONE (2015)

Stomata movement of OsPP108 overexpression transgenic lines under ABA treatment.(A) Stomata aperture of 4 week old WT and OsPP108OX lines, L1, L2 and L4, in mock treatment (Stomata Opening Solution; SOS) (upper panel) and 100μM ABA (lower panel). 30 stomata were analyzed for each genotype and representation of those are shown in pictures (n = 3). Pictures were taken at 60x magnification in Olympus BX53 fluorescence microscope in bright field. Scale bar = 5μM. (B) Graph depicting percentage of different type of stomata (closed, partially open and open) in WT and OsPP108OX transgenic in mock and ABA treatments. Stomata were grouped based on apertures sizes, i.e., open- 2.5–5.0μM, partially open- 1.0–2.5μM and closed- < 1 μM. Percentage of stomata is calculated based on the average of three independent replicate experiments.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401787&req=5

pone.0125168.g011: Stomata movement of OsPP108 overexpression transgenic lines under ABA treatment.(A) Stomata aperture of 4 week old WT and OsPP108OX lines, L1, L2 and L4, in mock treatment (Stomata Opening Solution; SOS) (upper panel) and 100μM ABA (lower panel). 30 stomata were analyzed for each genotype and representation of those are shown in pictures (n = 3). Pictures were taken at 60x magnification in Olympus BX53 fluorescence microscope in bright field. Scale bar = 5μM. (B) Graph depicting percentage of different type of stomata (closed, partially open and open) in WT and OsPP108OX transgenic in mock and ABA treatments. Stomata were grouped based on apertures sizes, i.e., open- 2.5–5.0μM, partially open- 1.0–2.5μM and closed- < 1 μM. Percentage of stomata is calculated based on the average of three independent replicate experiments.
Mentions: In order to find out the causative mechanism for stress tolerance in adult plants, and its ABA dependence or independence, stomata movement assays were performed, as ABA dependent stomata closure is known to mediate drought stress tolerance. Stomata movement analysis in adult Arabidopsis plants revealed that in control condition (mock treatment with SOS buffer) all three OsPP108OX transgenic lines have stomata aperture size similar to WT. However, treatment with 100μM ABA for 2h resulted in significant difference in stomata aperture size, and most WT stomata were closed, whereas stomata in transgenic lines exhibit ABA insensitivity and most of them remained unaffected (opened) and had aperture size similar to control condition (Fig 11A). Moreover, based on the aperture size, stomata could be divided into three groups: (i) open—2.5–5.0μM, (ii) partially open- 1.0–2.5μM and (iii) closed- < 1 μM. In WT, compare to 40% in control condition, only 8% stomata were opened after ABA treatment, approximately 60% were partially opened both in control and ABA treatment, while 28% stomata were closed after ABA treatment. In contrast, all the three transgenic lines stomata had similar percentage of open and partially opened stomata, in control and ABA conditions, and almost none of the stomata were found to be closed even after ABA treatment (Fig 11B). Therefore, these results suggest that OsPP108 mediate the stomata movement, independent of ABA pathway and OsPP108 overexpression leads to ABA insensitivity at adult plant stage also.

Bottom Line: At adult stage, OsPP108 overexpression leads to high tolerance to salt, mannitol and drought stresses with far better physiological parameters such as water loss, fresh weight, chlorophyll content and photosynthetic potential (Fv/Fm) in transgenic Arabidopsis plants.Expression profile of various stress marker genes in OsPP108 overexpressing plants revealed interplay of ABA dependent and independent pathway for abiotic stress tolerance.Overall, this study has identified a potential rice group A PP2C, which regulates ABA signaling negatively and abiotic stress signaling positively.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, India.

ABSTRACT
Arabidopsis PP2C belonging to group A have been extensively worked out and known to negatively regulate ABA signaling. However, rice (Oryza sativa) orthologs of Arabidopsis group A PP2C are scarcely characterized functionally. We have identified a group A PP2C from rice (OsPP108), which is highly inducible under ABA, salt and drought stresses and localized predominantly in the nucleus. Genetic analysis revealed that Arabidopsis plants overexpressing OsPP108 are highly insensitive to ABA and tolerant to high salt and mannitol stresses during seed germination, root growth and overall seedling growth. At adult stage, OsPP108 overexpression leads to high tolerance to salt, mannitol and drought stresses with far better physiological parameters such as water loss, fresh weight, chlorophyll content and photosynthetic potential (Fv/Fm) in transgenic Arabidopsis plants. Expression profile of various stress marker genes in OsPP108 overexpressing plants revealed interplay of ABA dependent and independent pathway for abiotic stress tolerance. Overall, this study has identified a potential rice group A PP2C, which regulates ABA signaling negatively and abiotic stress signaling positively. Transgenic rice plants overexpressing this gene might provide an answer to the problem of low crop yield and productivity during adverse environmental conditions.

No MeSH data available.


Related in: MedlinePlus