Identification of putative MAPK kinases in Oryza minuta and O. sativa responsive to biotic stresses.
The mitogen-activated protein kinase (MAPK) signaling cascade is critical for regulating plant defense systems against various kinds of pathogen and environmental stresses. One component of this cascade, the MAP kinase kinases (MAPKK), has not yet been shown to be induced in plants following biotic attacks, such as those by insects and fungi. We describe here a gene coding for a blast (Magnaporthe grisea)- and insect (Nilaparvata lugens)-responsive putative MAPK kinase, OmMKK1 (Oryza minuta MAPKK 1), which was identified in a library of O. minuta expressed sequence tags (ESTs). Two copies of OmMKK1 are present in the O. minuta genome. They encode a predicted protein with molecular mass 39 kDa and pI of 6.2. Transcript patterns following imbibition of plant hormones such as methyl jasmonic acid (MeJA), ethephone, salicylic acid (SA) and abscisic acid (ABA), as well as exposure to methyl viologen (MV), revealed that the expression of OmMKK1 is related to defense response signaling pathways. A comparative analysis of OmMKK1 and its O. sativa ortholog OsMKK1 showed that both were induced by stress-related hormones and biotic stresses, but that the kinetics of their responses differed despite their high amino acid sequence identity (96%).
You
Min Kyoung
MK
School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
Oh
Seung-Ick
SI
Ok
Sung Han
SH
Cho
Sung Ki
SK
Shin
Hyun Young
HY
Jeung
Ji Ung
JU
Shin
Jeong Sheop
JS
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018506:Gene Expression Regulation, Plant; D007313:Insecta / Q000502:physiology*; D020082:Magnaporthe / Q000502:physiology*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology* / Q000235:genetics / Q000382:microbiology / Q000469:parasitology; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D010940:Plant Proteins; D020929:Mitogen-Activated Protein Kinase Kinases