Phosphoinositide-specific phospholipase C9 is involved in the thermotolerance of Arabidopsis.
Intracellular calcium (Ca(2+)) increases rapidly after heat shock (HS) in the Ca(2+)/calmodulin (Ca(2+)/CaM) HS signal transduction pathway: a hypothesis proposed based on our previous findings. However, evidence for the increase in Ca(2+) after HS was obtained only through physiological and pharmacological experiments; thus, direct molecular genetic evidence is needed. The role of phosphoinositide-specific phospholipase C (PI-PLC) is poorly understood in the plant response to HS. In this work, atplc9 mutant plants displayed a serious thermosensitive phenotype compared with wild-type (WT) plants after HS. Complementation of atplc9 with AtPLC9 rescued both the basal and acquired thermotolerance phenotype of the WT plants. In addition, thermotolerance was even improved in overexpressed lines. The GUS staining of AtPLC9 promoter:GUS transgenic seedlings showed that AtPLC9 expression was ubiquitous. The fluorescence distribution of the fusion protein AtPLC9 promoter:AtPLC9:GFP revealed that the subcellular localization of AtPLC9 was restricted to the plasma membrane. The results of a PLC activity assay showed a reduction in the accumulation of inositol-1,4,5-trisphosphate (IP(3)) in atplc9 during HS and improved IP(3) generation in the overexpressed lines. Furthermore, the heat-induced increase in intracellular Ca(2+) was decreased in atplc9. Accumulation of the small HS proteins HSP18.2 and HSP25.3 was downregulated in atplc9 and upregulated in the overexpressed lines after HS. Together, these results provide molecular genetic evidence showing that AtPLC9 plays a role in thermotolerance in Arabidopsis.
Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijiazhuang 050016, China.
Shu-Zhi
SZ
Zheng
Yu-Liang
YL
Liu
Bing
B
Li
Zhong-lin
ZL
Shang
Ren-Gang
RG
Zhou
Da-Ye
DY
Sun
D000064:Acclimatization / Q000502:physiology*; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000032:analysis / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D015870:Gene Expression / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D006360:Heat-Shock Proteins / Q000378:metabolism; D018869:Heat-Shock Response / Q000502:physiology*; D006358:Hot Temperature; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D016254:Mutagenesis, Insertional; D010641:Phenotype; D010716:Phosphatidylinositols / Q000378:metabolism; D010740:Phospholipases / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D015398:Signal Transduction; D016019:Survival Analysis
D029681:Arabidopsis Proteins; D006360:Heat-Shock Proteins; D010716:Phosphatidylinositols; D011993:Recombinant Fusion Proteins; D015544:Inositol 1,4,5-Trisphosphate; D010740:Phospholipases; D002118:Calcium