Inappropriate annotation of a key defence marker in Arabidopsis: will the real PR-1 please stand up?
PR-1 has been extensively used as a marker for salicylic acid (SA)-mediated defence and systemic and local acquired resistance. The Arabidopsis Genome Project annotates At2g19990 as PR-1. This gene is also identified as PR-1 in two "full genome" Arabidopsis microarrays, and TAIR cites approximately 60 articles to describe its patterns of expression. However, most of these citations are incorrect; the probes used were not At2g19990, but a homologous gene At2g14610, which is annotated as "PR-1-like". Because of the potential for confusion, we analyzed the expression of both genes in Arabidopsis thaliana (L.) Heynh. At2g14610 (PR-1-like) showed the archetypal patterns of SA-responsive expression: mRNA levels increased following SA-treatment, inoculation with an avirulent (but not a virulent) strain of Pseudomonas syringae, and in wild-type (but not NahG) Arabidopsis infected with cauliflower mosaic virus (CaMV). In cpr5 mutants it was expressed constitutively. In contrast, expression of At2g19990 (annotated as PR-1) was detectable in neither SA-treated Col-0 nor in cpr5. Infection by virulent and avirulent isolates of P. syringae up-regulated expression, but to a similar level, and infection by CaMV induced a modest increase in expression in both the wild type and NahG. At2g19990, although pathogen responsive, does not show the SA-dependent patterns of expression expected from a member of the PR-1 regulon, and its annotation as " PR-1" is inappropriate. The annotations should identify At2g14610 as the authentic PR-1.
Plant Science Group, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
Janet
J
Laird
Patrick
P
Armengaud
Pietro
P
Giuntini
Valérie
V
Laval
Joel J
JJ
Milner
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000096:biosynthesis / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D010935:Plant Diseases; D018515:Plant Leaves / Q000378:metabolism; D044224:Pseudomonas syringae; D012333:RNA, Messenger / Q000378:metabolism; D018749:RNA, Plant / Q000378:metabolism
D029681:Arabidopsis Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; C077262:PR-1 protein, Arabidopsis