Transcriptional regulation of heat shock proteins and ascorbate peroxidase by CtHsfA2b from African bermudagrass conferring heat tolerance in Arabidopsis.
Heat stress transcription factor A2s (HsfA2s) are key regulators in plant response to high temperature. Our objectives were to isolate an HsfA2 gene (CtHsfA2b) from a warm-season grass species, African bermudagrass (Cynodon transvaalensis Burtt-Davy), and to determine the physiological functions and transcriptional regulation of HsfA2 for improving heat tolerance. Gene expression analysis revealed that CtHsfA2b was heat-inducible and exhibited rapid response to increasing temperature. Ectopic expression of CtHsfA2b improved heat tolerance in Arabidopsis and restored heat-sensitive defects of Arabidopsis hsfa2 mutant, which was demonstrated by higher survival rate and photosynthetic parameters, and lower electrolyte leakage in transgenic plants compared to the WT or hsfa2 mutant. CtHsfA2b transgenic plants showed elevated transcriptional regulation of several downstream genes, including those encoding ascorbate peroxidase (AtApx2) and heat shock proteins [AtHsp18.1-CI, AtHsp22.0-ER, AtHsp25.3-P and AtHsp26.5-P(r), AtHsp70b and AtHsp101-3]. CtHsfA2b was found to bind to the heat shock element (HSE) on the promoter of AtApx2 and enhanced transcriptional activity of AtApx2. These results suggested that CtHsfA2b could play positive roles in heat protection by up-regulating antioxidant defense and chaperoning mechanisms. CtHsfA2b has the potential to be used as a candidate gene to genetically modify cool-season species for improving heat tolerance.
College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, 210095, China.|Department of Plant Biology and Pathology, Rutgers, the State University of New Jersey, New Brunswick, NJ, 08901, USA.
Xiuyun
X
Wang
College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, 210095, China.
Wanlu
W
Huang
College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, 210095, China.
Zhimin
Z
Yang
College of Agro-grassland Science, Nanjing Agricultural University, Nanjing, 210095, China.
Jun
J
Liu
Department of Plant Biology and Pathology, Rutgers, the State University of New Jersey, New Brunswick, NJ, 08901, USA.
Bingru
B
Huang
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D060387:Ascorbate Peroxidases / Q000235:genetics* / Q000378:metabolism; D031744:Cynodon / Q000235:genetics*; D018744:DNA, Plant / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D000076249:Heat Shock Transcription Factors / Q000235:genetics / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D018869:Heat-Shock Response / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D011401:Promoter Regions, Genetic; D017382:Reactive Oxygen Species / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological; D000071436:Thermotolerance / Q000235:genetics*; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques
D029681:Arabidopsis Proteins; D018744:DNA, Plant; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D060387:Ascorbate Peroxidases