The Brachypodium distachyon BdWRKY36 gene confers tolerance to drought stress in transgenic tobacco plants

Plant Cell Rep. 2015 Jan;34(1):23-35. doi: 10.1007/s00299-014-1684-6. Epub 2014 Sep 16.

Abstract

The expression of BdWRKY36 was upregulated by drought treatment. BdWRKY36 -overexpressing transgenic tobacco increased drought tolerance by controlling ROS homeostasis and regulating transcription of stress related genes. WRKY transcription factor plays important roles in plant growth, development and stress response. However, the function of group IIe WRKYs is less known. In this study, we cloned and characterized a gene of group IIe WRKY, designated as BdWRKY36, from Brachypodium distachyon. Transient expression of BdWRKY36 in onion epidermal cell suggested its localization in the nucleus. Transactivation assay revealed that the C-terminal region, instead of full length BdWRKY36, had transcriptional activity. BdWRKY36 expression was upregulated by drought. Overexpression of BdWRKY36 in transgenic tobacco plants resulted in enhanced tolerance to drought stress. Physiological-biochemical indices analyses showed that BdWRKY36-overexpressing tobacco lines had lesser ion leakage (IL) and reactive oxygen species (ROS) accumulation, but higher contents of chlorophyll, relative water content (RWC) and activities of antioxidant enzyme than that in control plants under drought condition. Meanwhile expression levels of some ROS-scavenging and stress-responsive genes were upregulated in BdWRKY36-overexpressing tobacco lines under drought stress. These results demonstrate that BdWRKY36 functions as a positive regulator of drought stress response by controlling ROS homeostasis and regulating transcription of stress related genes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological / genetics
  • Brachypodium / genetics*
  • Brachypodium / metabolism
  • Catalase / metabolism
  • Cell Nucleus / metabolism
  • Chlorophyll / metabolism
  • Droughts*
  • Gene Expression Regulation, Plant
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Homeostasis / genetics
  • Microscopy, Fluorescence
  • Nicotiana / genetics*
  • Nicotiana / metabolism
  • Onions / cytology
  • Onions / metabolism
  • Peroxidase / metabolism
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Plants, Genetically Modified
  • Reactive Oxygen Species / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Stress, Physiological / genetics
  • Superoxide Dismutase / metabolism
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism
  • Water / metabolism

Substances

  • Plant Proteins
  • Reactive Oxygen Species
  • Transcription Factors
  • Water
  • Chlorophyll
  • Green Fluorescent Proteins
  • Catalase
  • Peroxidase
  • Superoxide Dismutase