Arabidopsis PEN3/PDR8, an ATP binding cassette transporter, contributes to nonhost resistance to inappropriate pathogens that enter by direct penetration.
Arabidopsis thaliana is a host to the powdery mildew Erysiphe cichoracearum and nonhost to Blumeria graminis f. sp hordei, the powdery mildew pathogenic on barley (Hordeum vulgare). Screening for Arabidopsis mutants deficient in resistance to barley powdery mildew identified PENETRATION3 (PEN3). pen3 plants permitted both increased invasion into epidermal cells and initiation of hyphae by B. g. hordei, suggesting that PEN3 contributes to defenses at the cell wall and intracellularly. pen3 mutants were compromised in resistance to the necrotroph Plectosphaerella cucumerina and to two additional inappropriate biotrophs, pea powdery mildew (Erysiphe pisi) and potato late blight (Phytophthora infestans). Unexpectedly, pen3 mutants were resistant to E. cichoracearum. This resistance was salicylic acid-dependent and correlated with chlorotic patches. Consistent with this observation, salicylic acid pathway genes were hyperinduced in pen3 relative to the wild type. The phenotypes conferred by pen3 result from the loss of function of PLEIOTROPIC DRUG RESISTANCE8 (PDR8), a highly expressed putative ATP binding cassette transporter. PEN3/PDR8 tagged with green fluorescent protein localized to the plasma membrane in uninfected cells. In infected leaves, the protein concentrated at infection sites. PEN3/PDR8 may be involved in exporting toxic materials to attempted invasion sites, and intracellular accumulation of these toxins in pen3 may secondarily activate the salicylic acid pathway.
Carnegie Institution, Department of Plant Biology, Stanford, California, 94305, USA.
Mónica
M
Stein
Jan
J
Dittgen
Clara
C
Sánchez-Rodríguez
Bi-Huei
BH
Hou
Antonio
A
Molina
Paul
P
Schulze-Lefert
Volker
V
Lipka
Shauna
S
Somerville
D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology*; D001203:Ascomycota / Q000472:pathogenicity; D016923:Cell Death / Q000502:physiology; D003517:Cyclopentanes / Q000378:metabolism; D020869:Gene Expression Profiling; D007113:Immunity, Innate / Q000502:physiology; D008954:Models, Biological; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D009868:Oomycetes / Q000472:pathogenicity; D054883:Oxylipins; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000033:anatomy & histology / Q000235:genetics / Q000382:microbiology; D017434:Protein Structure, Tertiary; D020156:Salicylic Acid / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction
D018528:ATP-Binding Cassette Transporters; D003517:Cyclopentanes; D054883:Oxylipins; C510424:PDR8 protein, Arabidopsis; C011006:jasmonic acid; D020156:Salicylic Acid