Sequential regulation of gibberellin, brassinosteroid, and jasmonic acid biosynthesis occurs in rice coleoptiles to control the transcript levels of anti-microbial thionin genes.
Transcripts of thionin genes encoding antimicrobial peptides were present at a high level in rice coleoptiles just after germination, and decreased to an undetectable level after about 3 d, but this decline was suppressed by co-treatment with gibberellic acid (GA(3)) and brassinolide (BL). The temporal expression patterns of key enzyme genes for the biosyntheses of gibberellins (GAs) and brassinosteroids (BRs) were correlated with the fluctuation of thionin mRNAs. Jasmonic acid (JA) replaced the effect of GA3 and BL, and its change in endogenous level was parallel to that of the thionin genes. These results strongly suggest that thionin gene expression was positively regulated by JA, whose endogenous level was synergistically regulated by GAs and BRs. In contrast, thionin gene expression in etiolated seedlings remained high while the endogenous level of JA was low, suggesting the presence of another signaling pathway in the dark to maintain the thionin level.
Kitanaga
Yukihiro
Y
Department of Applied Biological Chemistry, The University of Tokyo, Japan.
Jian
Cui
C
Hasegawa
Morifumi
M
Yazaki
Junshi
J
Kishimoto
Naoki
N
Kikuchi
Shoshi
S
Nakamura
Hidemitsu
H
Ichikawa
Hiroaki
H
Asami
Tadao
T
Yoshida
Shigeo
S
Yamaguchi
Isomaro
I
Suzuki
Yoshihito
Y
D023181:Antimicrobial Cationic Peptides / Q000235:genetics*; D060406:Brassinosteroids; D002777:Cholestanols / Q000378:metabolism* / Q000494:pharmacology; D003517:Cyclopentanes / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D005875:Gibberellins / Q000096:biosynthesis* / Q000494:pharmacology; D012275:Oryza; D054883:Oxylipins; D010940:Plant Proteins / Q000235:genetics*; D012333:RNA, Messenger; D036226:Seedlings / Q000235:genetics; D013260:Steroids, Heterocyclic / Q000378:metabolism* / Q000494:pharmacology
D023181:Antimicrobial Cationic Peptides; D060406:Brassinosteroids; D002777:Cholestanols; D003517:Cyclopentanes; D005875:Gibberellins; D054883:Oxylipins; D010940:Plant Proteins; D012333:RNA, Messenger; D013260:Steroids, Heterocyclic; C011006:jasmonic acid; C007842:gibberellic acid; C023623:brassinolide