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Translocation of phospholipase A2α to apoplasts is modulated by developmental stages and bacterial infection in Arabidopsis.

Jung J, Kumar K, Lee HY, Park YI, Cho HT, Ryu SB - Front Plant Sci (2012)

Bottom Line: The present study shows that PLA(2)α possesses unique characteristics in terms of spatiotemporal subcellular localization, as compared with the other paralogs that remain in the ER and/or Golgi apparatus during secretory processes.When Pseudomonas syringae pv.~tomato DC3000 carrying the avirulent factor avrRpm1 infects the apoplasts of host plants, PLA(2)α rapidly translocates to the apoplasts where bacteria attempt to become established.It would be interesting to investigate if PLA(2)α functions in plant defense responses at apoplasts where secreted PLA(2)α confronts with invading pathogens.

View Article: PubMed Central - PubMed

Affiliation: Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.

ABSTRACT
Phospholipase A(2) (PLA(2)) hydrolyzes phospholipids at the sn-2 position to yield lysophospholipids and free fatty acids. Of the four paralogs expressed in Arabidopsis, the cellular functions of PLA(2)α in planta are poorly understood. The present study shows that PLA(2)α possesses unique characteristics in terms of spatiotemporal subcellular localization, as compared with the other paralogs that remain in the ER and/or Golgi apparatus during secretory processes. Only PLA(2)α is secreted out to extracellular spaces, and its secretion to apoplasts is modulated according to the developmental stages of plant tissues. Observation of PLA(2)α-RFP transgenic plants suggests that PLA(2)α localizes mostly at the Golgi bodies in actively growing leaf tissues, but is gradually translocated to apoplasts as the leaves become mature. When Pseudomonas syringae pv.~tomato DC3000 carrying the avirulent factor avrRpm1 infects the apoplasts of host plants, PLA(2)α rapidly translocates to the apoplasts where bacteria attempt to become established. PLA(2)α promoter::GUS assays show that PLA(2)α gene expression is controlled in a developmental stage- and tissue-specific manner. It would be interesting to investigate if PLA(2)α functions in plant defense responses at apoplasts where secreted PLA(2)α confronts with invading pathogens.

No MeSH data available.


Spatial and temporal expression of PLA2α. Spatiotemporal expression patterns of the PLA2α gene in transgenic Arabidopsis plants harboring the PLA2α promoter fused with the GUS gene. Promoter activity was visualized by histochemical GUS staining. (A) Seven-day-old plant. (B) Fourteen-day-old plant. (C) Three-week-old plant. (D) Flower cluster, cauline leaf, and stem of a 5-week-old plant. (E–H) Carpels and developing siliques of a 5-week-old plant. (I) Pedicel of the control transgenic plants harboring the 35S promoter fused with the GUS gene. (J) Root of a 6-week-old plant. Bars = 2 mm.
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Figure 1: Spatial and temporal expression of PLA2α. Spatiotemporal expression patterns of the PLA2α gene in transgenic Arabidopsis plants harboring the PLA2α promoter fused with the GUS gene. Promoter activity was visualized by histochemical GUS staining. (A) Seven-day-old plant. (B) Fourteen-day-old plant. (C) Three-week-old plant. (D) Flower cluster, cauline leaf, and stem of a 5-week-old plant. (E–H) Carpels and developing siliques of a 5-week-old plant. (I) Pedicel of the control transgenic plants harboring the 35S promoter fused with the GUS gene. (J) Root of a 6-week-old plant. Bars = 2 mm.

Mentions: Although RT-PCR analysis shows that PLA2α transcripts are present in different parts of Arabidopsis tissues (Kim et al., 2011), there is little information regarding PLA2α gene expression at different developmental stages. To elucidate the cell type-specific expression patterns of the PLA2α gene, transgenic Arabidopsis lines were generated that expressed the beta-glucuronidase (GUS) reporter gene under the control of the PLA2α promoter (Figure 1). GUS activity was detected in the cotyledons, the shoot apex, the hypocotyl, and the vascular tissues of 7-day-old germinated seedlings (Figure 1A). Strong GUS activity was detected in the shoot apex in 14-day-old seedlings and 3-week-old plants, and was preferentially expressed in young leaves rather than old leaves (Figures 1A–C). No GUS activity was detected in the roots at this stage. In 5-week-old plants, GUS expression was found in the cauline leaves, sepals, styles, and pedicel of reproductive tissues (Figure 1D). The apical end of the pedicel is particularly dark-stained, apparently due to its thickened cell tissues based on a comparison with the GUS staining of the control transgenic plants harboring the 35S promoter fused with the GUS gene (Figure 1I). In plants transformed with ProPLA2α::GUS, GUS expression was also detected in the developing siliques (Figures 1E–H) and in the main roots of flowering plants (Figure 1J). Taken together, these data indicate that PLA2α gene expression is controlled in a unique developmental stage- and tissue-specific manner.


Translocation of phospholipase A2α to apoplasts is modulated by developmental stages and bacterial infection in Arabidopsis.

Jung J, Kumar K, Lee HY, Park YI, Cho HT, Ryu SB - Front Plant Sci (2012)

Spatial and temporal expression of PLA2α. Spatiotemporal expression patterns of the PLA2α gene in transgenic Arabidopsis plants harboring the PLA2α promoter fused with the GUS gene. Promoter activity was visualized by histochemical GUS staining. (A) Seven-day-old plant. (B) Fourteen-day-old plant. (C) Three-week-old plant. (D) Flower cluster, cauline leaf, and stem of a 5-week-old plant. (E–H) Carpels and developing siliques of a 5-week-old plant. (I) Pedicel of the control transgenic plants harboring the 35S promoter fused with the GUS gene. (J) Root of a 6-week-old plant. Bars = 2 mm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3376726&req=5

Figure 1: Spatial and temporal expression of PLA2α. Spatiotemporal expression patterns of the PLA2α gene in transgenic Arabidopsis plants harboring the PLA2α promoter fused with the GUS gene. Promoter activity was visualized by histochemical GUS staining. (A) Seven-day-old plant. (B) Fourteen-day-old plant. (C) Three-week-old plant. (D) Flower cluster, cauline leaf, and stem of a 5-week-old plant. (E–H) Carpels and developing siliques of a 5-week-old plant. (I) Pedicel of the control transgenic plants harboring the 35S promoter fused with the GUS gene. (J) Root of a 6-week-old plant. Bars = 2 mm.
Mentions: Although RT-PCR analysis shows that PLA2α transcripts are present in different parts of Arabidopsis tissues (Kim et al., 2011), there is little information regarding PLA2α gene expression at different developmental stages. To elucidate the cell type-specific expression patterns of the PLA2α gene, transgenic Arabidopsis lines were generated that expressed the beta-glucuronidase (GUS) reporter gene under the control of the PLA2α promoter (Figure 1). GUS activity was detected in the cotyledons, the shoot apex, the hypocotyl, and the vascular tissues of 7-day-old germinated seedlings (Figure 1A). Strong GUS activity was detected in the shoot apex in 14-day-old seedlings and 3-week-old plants, and was preferentially expressed in young leaves rather than old leaves (Figures 1A–C). No GUS activity was detected in the roots at this stage. In 5-week-old plants, GUS expression was found in the cauline leaves, sepals, styles, and pedicel of reproductive tissues (Figure 1D). The apical end of the pedicel is particularly dark-stained, apparently due to its thickened cell tissues based on a comparison with the GUS staining of the control transgenic plants harboring the 35S promoter fused with the GUS gene (Figure 1I). In plants transformed with ProPLA2α::GUS, GUS expression was also detected in the developing siliques (Figures 1E–H) and in the main roots of flowering plants (Figure 1J). Taken together, these data indicate that PLA2α gene expression is controlled in a unique developmental stage- and tissue-specific manner.

Bottom Line: The present study shows that PLA(2)α possesses unique characteristics in terms of spatiotemporal subcellular localization, as compared with the other paralogs that remain in the ER and/or Golgi apparatus during secretory processes.When Pseudomonas syringae pv.~tomato DC3000 carrying the avirulent factor avrRpm1 infects the apoplasts of host plants, PLA(2)α rapidly translocates to the apoplasts where bacteria attempt to become established.It would be interesting to investigate if PLA(2)α functions in plant defense responses at apoplasts where secreted PLA(2)α confronts with invading pathogens.

View Article: PubMed Central - PubMed

Affiliation: Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea.

ABSTRACT
Phospholipase A(2) (PLA(2)) hydrolyzes phospholipids at the sn-2 position to yield lysophospholipids and free fatty acids. Of the four paralogs expressed in Arabidopsis, the cellular functions of PLA(2)α in planta are poorly understood. The present study shows that PLA(2)α possesses unique characteristics in terms of spatiotemporal subcellular localization, as compared with the other paralogs that remain in the ER and/or Golgi apparatus during secretory processes. Only PLA(2)α is secreted out to extracellular spaces, and its secretion to apoplasts is modulated according to the developmental stages of plant tissues. Observation of PLA(2)α-RFP transgenic plants suggests that PLA(2)α localizes mostly at the Golgi bodies in actively growing leaf tissues, but is gradually translocated to apoplasts as the leaves become mature. When Pseudomonas syringae pv.~tomato DC3000 carrying the avirulent factor avrRpm1 infects the apoplasts of host plants, PLA(2)α rapidly translocates to the apoplasts where bacteria attempt to become established. PLA(2)α promoter::GUS assays show that PLA(2)α gene expression is controlled in a developmental stage- and tissue-specific manner. It would be interesting to investigate if PLA(2)α functions in plant defense responses at apoplasts where secreted PLA(2)α confronts with invading pathogens.

No MeSH data available.