title: Extracellular ATP-induced NO production and its dependence on membrane Ca2+ flux in Salvia miltiorrhiza hairy roots.
abstract: Extracellular ATP (eATP) is a novel signalling agent, and nitric oxide (NO) is a well-established signal molecule with diverse functions in plant growth and development. This study characterizes NO production induced by exogenous ATP and examines its relationship with other important signalling agents, Ca(2+) and H(2)O(2) in Salvia miltiorrhiza hairy root culture. Exogenous ATP was applied at 10-500 microM to the hairy root cultures and stimulated NO production was detectable within 30 min. The NO level increased with ATP dose from 10-100 microM but decreased from 100-200 muM or higher. The ATP-induced NO production was mimicked by a non-hydrolysable ATP analogue ATPgammaS, but only weakly by ADP, AMP or adenosine. The ATP-induced NO production was blocked by Ca(2+) antagonists, but not affected by a protein kinase inhibitor. ATP also induced H(2)O(2) production, which was dependent on both Ca(2+) and protein kinases, and also on NO biosynthesis. On the other hand, ATP induced a rapid increase in the intracellular Ca(2+) level, which was dependent on NO but not H(2)O(2). The results suggest that NO is implicated in ATP-induced responses and signal transduction in plant cells, and ATP signalling is closely related to Ca(2+) and ROS signalling.
authors.affiliation: Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
authors.forename: Shu-Jing
authors.initials: SJ
authors.lastname: Wu
authors.forename: Jian-Yong
authors.initials: JY
authors.lastname: Wu
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D027561:Salvia miltiorrhiza / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D010940:Plant Proteins; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D011494:Protein Kinases; D002118:Calcium