title: Heat Stress Modulates Mycelium Growth, Heat Shock Protein Expression, Ganoderic Acid Biosynthesis, and Hyphal Branching of Ganoderma lucidum via Cytosolic Ca2.
abstract: Heat stress (HS) influences the growth and development of organisms. Thus, a comprehensive understanding of how organisms sense HS and respond to it is required. Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system due to the complete sequencing of its genome, transgenic systems, and reliable reverse genetic tools. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced the accumulation of ganoderic acid biosynthesis and heat shock proteins (HSPs) in G. lucidum Our data showed that HS induced a significant increase in cytosolic Ca(2+) concentration. Further evidence showed that Ca(2+) might be a factor in the HS-mediated regulation of hyphal branching, ganoderic acid (GA) biosynthesis, and the accumulation of HSPs. Our results further showed that the calcium-permeable channel gene (cch)-silenced and phosphoinositide-specific phospholipase gene (plc)-silenced strains reduced the HS-induced increase in HSP expression compared with that observed for the wild type (WT). This study demonstrates that cytosolic Ca(2+) participates in heat shock signal transduction and regulates downstream events in filamentous fungi.
  
  
  
  Ganoderma lucidum, a higher basidiomycete with bioactive secondary metabolites, has become a potential model system for evaluating how environmental factors regulate the development and secondary metabolism of basidiomycetes. Heat stress (HS) is an important environmental challenge. In this study, we found that HS inhibited mycelium growth, reduced hyphal branching, and induced HSP expression and ganoderic acid biosynthesis in G. lucidum Further evidence showed that Ca(2+) might be a factor in the HS-mediated regulation of hyphal branching, GA biosynthesis, and the accumulation of HSPs. This study demonstrates that cytosolic Ca(2+) participates in heat shock signal transduction and regulates downstream events in filamentous fungi. Our research offers a new way to understand the mechanism underlying the physiological and metabolic responses to other environmental factors in G. lucidum This research may also provide the basis for heat shock signal transduction studies of other fungi.
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, and Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China.
authors.forename: Xue
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, and Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China.
authors.forename: Ang
authors.initials: A
authors.lastname: Ren
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, and Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China.
authors.forename: Meng-Jiao
authors.initials: MJ
authors.lastname: Li
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, and Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China.
authors.forename: Peng-Fei
authors.initials: PF
authors.lastname: Cao
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, and Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China.
authors.forename: Tian-Xi
authors.initials: TX
authors.lastname: Chen
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, and Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China.
authors.forename: Guang
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, and Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China.
authors.forename: Liang
authors.initials: L
authors.lastname: Shi
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, and Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China.
authors.forename: Ai-Liang
authors.initials: AL
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, and Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China mwzhao@njau.edu.cn.
authors.forename: Ming-Wen
authors.initials: MW
authors.lastname: Zhao
mesh_terms: D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D003600:Cytosol / Q000737:chemistry; D006360:Heat-Shock Proteins / Q000096:biosynthesis*; D006358:Hot Temperature; D025282:Mycelium / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects*; D020940:Reishi / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects*; D013312:Stress, Physiological; D014315:Triterpenes / Q000378:metabolism*
chemical_list: D006360:Heat-Shock Proteins; D014315:Triterpenes; C556862:ganoderic acid; D002118:Calcium