Identification of natural diterpenes that inhibit bacterial wilt disease in tobacco, tomato and Arabidopsis.
The soil-borne bacterial pathogen Ralstonia solanacearum invades a broad range of plants through their roots, resulting in wilting of the plant, but no effective protection against this disease has been developed. Two bacterial wilt disease-inhibiting compounds were biochemically isolated from tobacco and identified as sclareol and cis-abienol, labdane-type diterpenes. When exogenously applied to their roots, sclareol and cis-abienol inhibited wilt disease in tobacco, tomato and Arabidopsis plants without exhibiting any antibacterial activity. Microarray analysis identified many sclareol-responsive genes in Arabidopsis roots, including genes encoding or with a role in ATP-binding cassette (ABC) transporters, and biosynthesis and signaling of defense-related molecules and mitogen-activated protein kinase (MAPK) cascade components. Inhibition of wilt disease by sclareol was attenuated in Arabidopsis mutants defective in the ABC transporter AtPDR12, the MAPK MPK3, and ethylene and abscisic acid signaling pathways, and also in transgenic tobacco plants with reduced expression of NtPDR1, a tobacco homolog of AtPDR12. These results suggest that multiple host factors are involved in the inhibition of bacterial wilt disease by sclareol-related compounds.
Plant-Microbe Interactions Research Unit, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, 305-8602 Japan. sseo71@affrc.go.jp
Shigemi
S
Seo
Kenji
K
Gomi
Hisatoshi
H
Kaku
Hiroshi
H
Abe
Hideharu
H
Seto
Shingo
S
Nakatsu
Masahiro
M
Neya
Michie
M
Kobayashi
Kazuhiro
K
Nakaho
Yuki
Y
Ichinose
Ichiro
I
Mitsuhara
Yuko
Y
Ohashi
D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D000040:Abscisic Acid / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D005030:Ethylenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018551:Solanum lycopersicum / Q000187:drug effects / Q000382:microbiology*; D046228:Microarray Analysis; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009284:Naphthols / Q000302:isolation & purification / Q000494:pharmacology*; D010935:Plant Diseases / Q000382:microbiology*; D018517:Plant Roots / Q000187:drug effects / Q000382:microbiology; D043368:Ralstonia solanacearum / Q000472:pathogenicity*; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics / Q000382:microbiology*
D018528:ATP-Binding Cassette Transporters; D000900:Anti-Bacterial Agents; D029681:Arabidopsis Proteins; D004224:Diterpenes; D005030:Ethylenes; D009284:Naphthols; C482841:PDR12 protein, Arabidopsis; C085761:abienol; D000040:Abscisic Acid; C036216:ethylene; C070760:sclareol; D020928:Mitogen-Activated Protein Kinases