title: Ectopic expression of ZmSIMK1 leads to improved drought tolerance and activation of systematic acquired resistance in transgenic tobacco.
abstract: The mitogen-activated protein kinase (MAPK) cascades play pivotal roles in diverse signaling pathways related to plant biotic and abiotic stress responses. In this study, a group B MAPK gene in Zea mays, ZmSIMK1, was functionally analyzed. Quantitative real-time PCR (qRT-PCR) analysis indicated that ZmSIMK1 transcript could be induced by drought, salt, Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) and certain exogenous signaling molecules. Analysis of the ZmSIMK1 promoter revealed a group of putative cis-acting elements related to drought and defense responses. β-Glucuronidase (GUS) staining produced similar results as qRT-PCR. ZmSIMK1 was mainly localized in the nucleus, and further study indicated that the C-terminal domain (CD) was essential for targeting to the nucleus. Transgenic tobacco accumulated less reactive oxygen species (ROS), had higher levels of antioxidant enzyme activity and osmoregulatory substances and exhibited an increased germination rate compared with wild-type (WT) tobacco under drought stress. ROS-related and drought stress-responsive genes in transgenic tobacco were significantly upregulated compared with the same genes in WT lines under drought stress. Moreover, overexpression of ZmSIMK1 promoted the hypersensitive response (HR) and pathogen-related gene (PR) transcription in addition to triggering systemic acquired resistance (SAR) in tobacco.
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Guohua
authors.initials: G
authors.lastname: Cai
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Jiaowen
authors.initials: J
authors.lastname: Pan
authors.affiliation: State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China. Electronic address: dqli@sdau.edu.cn.
authors.forename: Dequan
authors.initials: D
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D018525:Germination; D020928:Mitogen-Activated Protein Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D044224:Pseudomonas syringae / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013312:Stress, Physiological; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism*; D003313:Zea mays / Q000201:enzymology*
chemical_list: D010940:Plant Proteins; D017382:Reactive Oxygen Species; D020928:Mitogen-Activated Protein Kinases
keywords: Drought stress; Ectopic expression; HR; SAR; ZmSIMK1