Salicylic acid and NIM1/NPR1-independent gene induction by incompatible Peronospora parasitica in arabidopsis.
To identify pathogen-induced genes distinct from those involved in systemic acquired resistance, we used cDNA-amplified fragment length polymorphism to examine RNA levels in Arabidopsis thaliana wild type, nim1-1, and salicylate hydroxylase-expressing plants after inoculation with an incompatible isolate of the downy mildew pathogen Peronospora parasitica. Fifteen genes are described, which define three response profiles on the basis of whether their induction requires salicylic acid (SA) accumulation and NIM1/NPR1 activity, SA alone, or neither. Sequence analysis shows that the genes include a calcium binding protein related to TCH3, a protein containing ankyrin repeats and potential transmembrane domains, three glutathione S-transferase gene family members, and a number of small, putatively secreted proteins. We further characterized this set of genes by assessing their expression patterns in each of the three plant lines after inoculation with a compatible P. parasitica isolate and after treatment with the SA analog 2,6-dichloroisonicotinic acid. Some of the genes within subclasses showed different requirements for SA accumulation and NIM1/NPR1 activity, depending upon which elicitor was used, indicating that those genes were not coordinately regulated and that the regulatory pathways are more complex than simple linear models would indicate.
Rairdan
G J
GJ
Cornell University, Department of Plant Pathology, Ithaca, NY 14853, USA.
Donofrio
N M
NM
Delaney
T P
TP
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005982:Glutathione Transferase / Q000378:metabolism; D007539:Isonicotinic Acids / Q000494:pharmacology; D008565:Membrane Proteins; D006899:Mixed Function Oxygenases / Q000378:metabolism; D008969:Molecular Sequence Data; D009868:Oomycetes / Q000254:growth & development* / Q000472:pathogenicity; D010935:Plant Diseases / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D012150:Polymorphism, Restriction Fragment Length; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction; D015533:Transcriptional Activation; D014774:Virulence
D029681:Arabidopsis Proteins; D002135:Calcium-Binding Proteins; D018076:DNA, Complementary; D007539:Isonicotinic Acids; D008565:Membrane Proteins; C105496:NPR1 protein, Arabidopsis; C117885:PITPNM3 protein, human; D010940:Plant Proteins; D012333:RNA, Messenger; C077261:2,6-dichloroisonicotinic acid; D006899:Mixed Function Oxygenases; C022619:salicylate 1-monooxygenase; D005982:Glutathione Transferase; D020156:Salicylic Acid; D002118:Calcium