title: Extracellular ATP functions as an endogenous external metabolite regulating plant cell viability.
abstract: ATP is a vital molecule used by living organisms as a universal source of energy required to drive the cogwheels of intracellular biochemical reactions necessary for growth and development. Animal cells release ATP to the extracellular milieu, where it functions as the primary signaling cue at the epicenter of a diverse range of physiological processes. Although recent findings revealed that intact plant tissues release ATP as well, there is no clearly defined physiological function of extracellular ATP in plants. Here, we show that extracellular ATP is essential for maintaining plant cell viability. Its removal by the cell-impermeant traps glucose-hexokinase and apyrase triggered death in both cell cultures and whole plants. Competitive exclusion of extracellular ATP from its binding sites by treatment with beta,gamma-methyleneadenosine 5'-triphosphate, a nonhydrolyzable analog of ATP, also resulted in death. The death response was observed in Arabidopsis thaliana, maize (Zea mays), bean (Phaseolus vulgaris), and tobacco (Nicotiana tabacum). Significantly, we discovered that fumonisin B1 (FB1) treatment of Arabidopsis triggered the depletion of extracellular ATP that preceded cell death and that exogenous ATP rescues Arabidopsis from FB1-induced death. These observations suggest that extracellular ATP suppresses a default death pathway in plants and that some forms of pathogen-induced cell death are mediated by the depletion of extracellular ATP.
authors.affiliation: Creative Gene Technology, Integrative Cell Biology Laboratory, School of Biological and Biomedical Sciences, University of Durham, Durham DH1 3LE, United Kingdom.
authors.forename: Stephen
authors.initials: S
authors.lastname: Chivasa
authors.forename: Bongani K
authors.initials: BK
authors.lastname: Ndimba
authors.forename: William J
authors.initials: WJ
authors.lastname: Simon
authors.forename: Keith
authors.initials: K
authors.lastname: Lindsey
authors.forename: Antoni R
authors.initials: AR
authors.lastname: Slabas
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D001081:Apyrase / Q000494:pharmacology; D017360:Arabidopsis / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D045604:Extracellular Fluid / Q000378:metabolism*; D037341:Fumonisins / Q000494:pharmacology; D027805:Phaseolus / Q000378:metabolism; D010935:Plant Diseases; D010944:Plants / Q000378:metabolism*; D014026:Nicotiana / Q000378:metabolism; D003313:Zea mays / Q000378:metabolism
chemical_list: D037341:Fumonisins; C005147:5'-adenylyl (beta,gamma-methylene)diphosphonate; C056933:fumonisin B1; D000255:Adenosine Triphosphate; D001081:Apyrase