AUTHOR=Jung Jihye , Kumar Krishna , Lee Hyoung Yool , Park Youn-Il , Cho Hyung-Taeg , Ryu Stephen B.

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

JOURNAL=Frontiers in Plant Science

VOLUME=3

YEAR=2012

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2012.00126

DOI=10.3389/fpls.2012.00126

ISSN=1664-462X

ABSTRACT=<p>Phospholipase A<sub>2</sub> (PLA<sub>2</sub>) hydrolyzes phospholipids at the <italic>sn</italic>-2 position to yield lysophospholipids and free fatty acids. Of the four paralogs expressed in <italic>Arabidopsis</italic>, the cellular functions of PLA<sub>2</sub>α <italic>in planta</italic> are poorly understood. The present study shows that PLA<sub>2</sub>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<sub>2</sub>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<sub>2</sub>α-RFP transgenic plants suggests that PLA<sub>2</sub>α localizes mostly at the Golgi bodies in actively growing leaf tissues, but is gradually translocated to apoplasts as the leaves become mature. When <italic>Pseudomonas syringae</italic> pv.~<italic>tomato</italic> DC3000 carrying the avirulent factor <italic>avrRpm1</italic> infects the apoplasts of host plants, PLA<sub>2</sub>α rapidly translocates to the apoplasts where bacteria attempt to become established. <italic>PLA</italic><sub>2</sub>α promoter::GUS assays show that PLA<sub>2</sub>α gene expression is controlled in a developmental stage- and tissue-specific manner. It would be interesting to investigate if PLA<sub>2</sub>α functions in plant defense responses at apoplasts where secreted PLA<sub>2</sub>α confronts with invading pathogens.</p>