Molecular cloning and mRNA expression analysis of a novel rice (Oryzasativa L.) MAPK kinase kinase, OsEDR1, an ortholog of Arabidopsis AtEDR1, reveal its role in defense/stress signalling pathways and development.
Mitogen-activated protein kinase (MAPK) cascade(s) is important for plant defense/stress responses. Though MAPKs have been identified and characterized in rice (Oryza sativa L.), a monocot cereal crop research model, the first upstream component of the kinase cascade, namely MAPK kinase kinase (MAPKKK) has not yet been identified. Here we report the cloning of a novel rice gene encoding a MAPKKK, OsEDR1, designated based on its homology with the Arabidopsis MAPKKK, AtEDR1. OsEDR1, a single copy gene in the genome of rice, encodes a predicted protein with molecular mass of 113046.13 and a pI of 9.03. Using our established two-week-old rice seedling in vitro model system, we show that OsEDR1 has a constitutive expression in seedling leaves and is further up-regulated within 15 min upon wounding by cut, treatment with the global signals jasmonic acid (JA), salicylic acid (SA), ethylene (ethephon, ET), abscisic acid, and hydrogen peroxide. In addition, protein phosphatase inhibitors, fungal elicitor chitosan, drought, high salt and sugar, and heavy metals also dramatically induce its expression. Moreover, OsEDR1 expression was altered by co-application of JA, SA, and ET, and required de novo synthesized protein factor(s) in its transient regulation. Furthermore, using an in vivo system we also show that OsEDR1 responds to changes in temperature and environmental pollutants-ozone and sulfur dioxide. Finally, OsEDR1 expression varied significantly in vegetative and reproductive tissues. These results suggest a role for OsEDR1 in defense/stress signalling pathways and development.
Kim
Jung-A
JA
Department of Molecular Biology, College of Natural Science, Sejong University, Seoul 143-747, Republic of Korea.
Agrawal
Ganesh K
GK
Rakwal
Randeep
R
Han
Keon Seon
KS
Kim
Kyung-Nam
KN
Yun
Choong-Hyo
CH
Heu
Sunggi
S
Park
Sook-Young
SY
Lee
Yong-Hwan
YH
Jwa
Nam-Soo
NS
D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D020930:MAP Kinase Kinase Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology* / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D018515:Plant Leaves / Q000502:physiology / Q000528:radiation effects; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D036226:Seedlings / Q000502:physiology / Q000528:radiation effects; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000502:physiology*; D014466:Ultraviolet Rays
D029681:Arabidopsis Proteins; C423568:EDR1 protein, Arabidopsis; D010940:Plant Proteins; D012333:RNA, Messenger; D020930:MAP Kinase Kinase Kinases