A role for salicylic acid and NPR1 in regulating cell growth in Arabidopsis.
Salicylic acid (SA) plays a key role in activating defenses and cell death during plant-pathogen interactions. In response to some pathogens, SA also limits the extent of cell death, indicating that it acts positively or negatively depending on the host-pathogen interaction. In addition, we previously showed that SA affects cell growth in the Arabidopsis defense-related mutants accelerated cell death 6-1 (acd6-1) and aberrant growth and death 2 (agd2). Using acd6-1, agd2 and two other defense-related mutants, lesion simulating disease 6 (lsd6), suppressor of SA-insensitivity (ssi1), we show here in detail that SA regulates cell growth by specifically affecting cell enlargement, endoreduplication and/or cell division. We find that SA can act either positively or negatively to regulate cell growth depending on the context in which signaling occurs. Additionally, Nonexpressor of PR 1 (NPR1), a key SA signaling protein important for regulating defenses and cell death, also acts to promote cell division and/or suppress endoreduplication during leaf development. We propose that SA interacts with multiple receptors or signaling pathways to control cellular alterations during normal development, pathogen attack and/or stress situations. We suggest that SA and NPR1 play broader roles in cell fate control than has previously been understood.
Vanacker
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Department of Molecular Genetics and Cell Biology, The University of Chicago, 1103 East 57th Street EBC410, Chicago, IL 60637, USA.
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Greenberg
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D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000254:growth & development* / Q000382:microbiology; D029681:Arabidopsis Proteins; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002455:Cell Division / Q000187:drug effects; D048429:Cell Size / Q000502:physiology; D003433:Crosses, Genetic; D009154:Mutation; D010940:Plant Proteins / Q000378:metabolism*; D011549:Pseudomonas / Q000502:physiology; D020156:Salicylic Acid / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects
D029681:Arabidopsis Proteins; C105496:NPR1 protein, Arabidopsis; D010940:Plant Proteins; D020156:Salicylic Acid