title: Protein sHSP26 improves chloroplast performance under heat stress by interacting with specific chloroplast proteins in maize (Zea mays).
abstract: We recently demonstrated that chloroplast small HSP26 (sHSP26) is abundant in maize leaves under heat stress and potentially involved in maize heat tolerance. However, it largely remains unclear how sHSP26 functions in maize under heat stress. Here, 2-DE-based proteomics, RNA interference (RNAi), co-immunoprecipitation (Co-IP) and yeast two-hybrid (Y2H) were used to reveal chloroplast proteins interacting with sHSP26 and how sHSP26 functions under heat stress. After the silencing of sHSP26, a total of 45 protein spots from isolated protoplasts were greatly changed in abundance, of which 33 spots are chloroplastic. Co-IP revealed that nine proteins possibly associated with sHSP26. Y2H demonstrated that six chloroplast proteins interact with sHSP26 under heat stress. In particular, four proteins, including ATP synthase subunit β, chlorophyll a-b binding protein, oxygen-evolving enhancer protein 1 and photosystem I reaction center subunit IV, strongly interacted with sHSP26 and their abundance greatly declined after RNAi of sHSP26 under heat stress. In addition, H2O2 accumulation in the chloroplasts significantly increased the expression of sHSP26, and the suppression of sHSP26 expression significantly reduced the O2 evolution rate of photosystem II under heat stress. Overall, these findings demonstrate the relevance of sHSP26 in protecting maize chloroplasts under heat stress.
  
  
  CONCLUSIONS
  Maize is one of the most important crops worldwide. Frequent heat stress reduces significantly the yield and quality of maize. Our results demonstrated that sHSP26 improved maize chloroplast performance under heat stress by interacting with specific proteins. These findings are useful for understanding the mechanism of heat stress response and heat-tolerant molecular breeding in maize.
authors.affiliation: State Key Laboratory of Wheat & Maize Crop Science, College of Life Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China.
authors.forename: Xiuli
authors.initials: X
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Wheat & Maize Crop Science, College of Life Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China.
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Wheat & Maize Crop Science, College of Life Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China.
authors.forename: Fangping
authors.initials: F
authors.lastname: Gong
authors.affiliation: Provincial Key Laboratory of Agrobiology, Jiangsu Academy of Agricultural Sciences, Institute of Biotechnology, Nanjing 210094, China.
authors.forename: Dayong
authors.initials: D
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Wheat & Maize Crop Science, College of Life Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Wheat & Maize Crop Science, College of Life Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China.
authors.forename: Liuji
authors.initials: L
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Wheat & Maize Crop Science, College of Life Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China.
authors.forename: Chaohao
authors.initials: C
authors.lastname: Li
authors.affiliation: State Key Laboratory of Wheat & Maize Crop Science, College of Life Science, College of Agronomy, Henan Agricultural University, Zhengzhou 450002, China. Electronic address: wangwei@henau.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D060365:Chloroplast Proteins / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000378:metabolism*; D018869:Heat-Shock Response / Q000502:physiology*; D010100:Oxygen / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000378:metabolism; D014867:Water / Q000378:metabolism; D003313:Zea mays / Q000378:metabolism*
chemical_list: D060365:Chloroplast Proteins; D006360:Heat-Shock Proteins; D045332:Photosystem II Protein Complex; D014867:Water; D010100:Oxygen
keywords: Chloroplast proteins; Heat shock protein; Heat stress; Maize protoplast; Protein interaction; sHSP26