NPK1, an MEKK1-like mitogen-activated protein kinase kinase kinase, regulates innate immunity and development in plants.
Mitogen-activated protein kinase (MAPK) cascades are rapidly activated upon plant recognition of invading pathogens. Here, we describe the use of virus-induced gene silencing (VIGS) to study the role of candidate plant MAP kinase kinase kinase (MAPKKK) homologs of human MEKK1 in pathogen-resistance pathways. We demonstrate that silencing expression of a tobacco MAPKKK, Nicotiana Protein Kinase 1 (NPK1), interferes with the function of the disease-resistance genes N, Bs2, and Rx, but does not affect Pto- and Cf4-mediated resistance. Further, NPK1-silenced plants also exhibit reduced cell size, defective cytokinesis, and an overall dwarf phenotype. Our results provide evidence that NPK1 functions in the regulation of N-, Bs2-, and Rx-mediated resistance responses and may play a role in one or more MAPK cascades, regulating multiple cellular processes.
Department of Plant and Microbial Biology, University of California, Berkeley, 94720, USA.
Hailing
H
Jin
Michael J
MJ
Axtell
Douglas
D
Dahlbeck
Obi
O
Ekwenna
Shuqun
S
Zhang
Brian
B
Staskawicz
Barbara
B
Baker
D048429:Cell Size / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D020868:Gene Silencing / Q000502:physiology*; D005822:Genetic Vectors / Q000235:genetics; D007107:Immune System / Q000201:enzymology*; D007113:Immunity, Innate / Q000276:immunology*; D048728:MAP Kinase Kinase Kinase 1; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D010935:Plant Diseases; D010940:Plant Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction / Q000235:genetics; D014026:Nicotiana / Q000201:enzymology* / Q000254:growth & development / Q000276:immunology; D014027:Tobacco Mosaic Virus / Q000235:genetics / Q000276:immunology
C402462:BS2 protein, Capsicum chacoense; D010940:Plant Proteins; D012333:RNA, Messenger; D017346:Protein Serine-Threonine Kinases; D048728:MAP Kinase Kinase Kinase 1; D020930:MAP Kinase Kinase Kinases; C482576:MAP3K1 protein, human; C082276:NPK1 protein, Nicotiana tabacum