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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.


Co-localization of PLA2α-RFP with ST-GFP, a Golgi body marker. Close-to-mature leaves of transgenic Arabidopsis plants expressing both PLA2α-RFP and ST-GFP were observed with a laser scanning confocal microscope. PLA2α-RFP signals are mostly overlapped with ST-GFP, a Golgi body marker. ST-GFP (A), PLA2α-RFP (B), bright field (C), and merged image (D) are presented. Bar = 20 μm.
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Figure 3: Co-localization of PLA2α-RFP with ST-GFP, a Golgi body marker. Close-to-mature leaves of transgenic Arabidopsis plants expressing both PLA2α-RFP and ST-GFP were observed with a laser scanning confocal microscope. PLA2α-RFP signals are mostly overlapped with ST-GFP, a Golgi body marker. ST-GFP (A), PLA2α-RFP (B), bright field (C), and merged image (D) are presented. Bar = 20 μm.

Mentions: As secretion of proteins to apoplasts is known to occur through ER and Golgi bodies, PLA2α-RFP signals were mostly detected at the Golgi bodies in pre-mature young leaves (Figure 2A). However, the fluorescent spots become gradually bigger as the leaves become mature, leading us to suspect that they may be other cellular organelles. To investigate if the big PLA2α fluorescent spots are real Golgi bodies, we performed co-localization assay of PLA2α with a Golgi body marker, sialyltransferase (ST). Close-to-mature leaves of transgenic Arabidopsis plants expressing both PLA2α-RFP and ST-GFP were observed with a laser scanning confocal microscope. As shown in Figure 3, big spots of PLA2α-RFP signals are mostly overlapped with the spots of a Golgi body marker (ST-GFP), confirming that PLA2α is localized in Golgi apparatus before secretion to the apoplasts. We found that the apparent big size spots result from aggregation of several Golgi bodies and strong brightness of RFP-fluorescence. Aggregation of Golgi bodies appears to be gradually enhanced as the leaves become mature.


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)

Co-localization of PLA2α-RFP with ST-GFP, a Golgi body marker. Close-to-mature leaves of transgenic Arabidopsis plants expressing both PLA2α-RFP and ST-GFP were observed with a laser scanning confocal microscope. PLA2α-RFP signals are mostly overlapped with ST-GFP, a Golgi body marker. ST-GFP (A), PLA2α-RFP (B), bright field (C), and merged image (D) are presented. Bar = 20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Co-localization of PLA2α-RFP with ST-GFP, a Golgi body marker. Close-to-mature leaves of transgenic Arabidopsis plants expressing both PLA2α-RFP and ST-GFP were observed with a laser scanning confocal microscope. PLA2α-RFP signals are mostly overlapped with ST-GFP, a Golgi body marker. ST-GFP (A), PLA2α-RFP (B), bright field (C), and merged image (D) are presented. Bar = 20 μm.
Mentions: As secretion of proteins to apoplasts is known to occur through ER and Golgi bodies, PLA2α-RFP signals were mostly detected at the Golgi bodies in pre-mature young leaves (Figure 2A). However, the fluorescent spots become gradually bigger as the leaves become mature, leading us to suspect that they may be other cellular organelles. To investigate if the big PLA2α fluorescent spots are real Golgi bodies, we performed co-localization assay of PLA2α with a Golgi body marker, sialyltransferase (ST). Close-to-mature leaves of transgenic Arabidopsis plants expressing both PLA2α-RFP and ST-GFP were observed with a laser scanning confocal microscope. As shown in Figure 3, big spots of PLA2α-RFP signals are mostly overlapped with the spots of a Golgi body marker (ST-GFP), confirming that PLA2α is localized in Golgi apparatus before secretion to the apoplasts. We found that the apparent big size spots result from aggregation of several Golgi bodies and strong brightness of RFP-fluorescence. Aggregation of Golgi bodies appears to be gradually enhanced as the leaves become mature.

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.