title: ZmMKK1, a novel group A mitogen-activated protein kinase kinase gene in maize, conferred chilling stress tolerance and was involved in pathogen defense in transgenic tobacco.
abstract: As an important intracellular signaling module, the mitogen-activated protein kinase (MAPK) cascades have been previously implicated in signal transduction during plants responsing to various environmental stresses as well as pathogen attack. The mitogen-activated protein kinase kinase acts as the convergent point of MAPK cascades during a variety of stress signaling. In this study, a novel MAPKK gene, ZmMKK1, in maize (Zea mays L.) belonging to group A MAPKK was isolated and functionally characterized. ZmMKK1 was mainly localized in the cytoplasm and its constitutive kinase-active form ZmMKK1DD was localized in both cytoplasm and nucleus. QRT-PCR analysis uncovered that ZmMKK1 expression was triggered by abiotic and biotic stresses and exogenous signaling molecules. Moreover, hydrogen peroxide (H2O2) and Ca(2+) mediated 12°C-induced up-regulated expressing of ZmMKK1 at mRNA level. Ectopic expression of ZmMKK1 in tobacco (Nicotiana tabacum) conferred tolerance to chilling stress by higher antioxidant enzyme activities, more accumulation of osmoregulatory substances and more significantly up-expression of ROS-related and stress-responsive genes compared with empty vector control plants. Furthermore, ZmMKK1 played differential functions in biotrophic versus necrotrophic pathogen-induced responses. These results suggested ZmMKK1 played a crucial role in chilling stress and pathogen defense in plants.
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, Shandong, China.
authors.forename: Guohua
authors.initials: G
authors.lastname: Cai
authors.forename: Guodong
authors.initials: G
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Jiaowen
authors.initials: J
authors.lastname: Pan
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Dequan
authors.initials: D
authors.lastname: Li
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology; D000595:Amino Acid Sequence; D020171:Botrytis / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism; D003080:Cold Temperature; D003593:Cytoplasm / Q000378:metabolism; D060467:Disease Resistance / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D054884:Host-Pathogen Interactions; D018613:Microscopy, Confocal; D020929:Mitogen-Activated Protein Kinase Kinases / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D010940:Plant Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011549:Pseudomonas / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism / Q000502:physiology
chemical_list: D010940:Plant Proteins; D017382:Reactive Oxygen Species; D049452:Green Fluorescent Proteins; D020929:Mitogen-Activated Protein Kinase Kinases
keywords: 3,3-diaminobenzidine; ABA; APX; CAT; CaMV; Chilling stress; DAB; DMTU; ETH; GFP; H(2)O(2); MAPK; MDA; MS; MeJA; Murashige-Skoog; NBT; O(2)(−); OE; ORF; POD; Pathogen defense; REL; ROS; Reactive oxygen species; SA; SAR; SOD; Vec plant; WT; ZmMKK1; ZmMKK1-overexpressing; abscisic acid; ascorbate peroxidase; catalase; cauliflower mosaic virus; dimethylthiourea; empty vector control plant; ethephon; green fluorescent protein; hydrogen peroxide; malondialdehyde; methyl jasmonate; mitogen-activated protein kinase; nitroblue tetrazolium; open reading frame; peroxidase; qRT-PCR; quantitative real time-polymerase chain reaction; reactive oxygen species; relative electrolyte leakage; salicylic acid; superoxide anion radical; superoxide dismutase; systemic acquired resistance; wild-type