title: Acetylcholine suppresses shoot formation and callusing in leaf explants of in vitro raised seedlings of tomato, Lycopersicon esculentum Miller var. Pusa Ruby.
abstract: We present experimental evidence to show that acetylcholine (ACh) causes decrease in shoot formation in leaf explants of tomato (Lycopersicon esculentum Miller var Pusa Ruby) when cultured on shoot regeneration medium. The optimum response was obtained at 10(-4) M ACh-enriched medium. ACh also causes decrease in percentage of cultures forming callus and reduces the callus mass. Inhibitors of enzymatic hydrolysis of ACh, neostigmine and physostigmine, also suppresses callogenesis and caulogenesis. On the other hand, the breakdown products of Ach, choline and acetate, do not alter the morphogenic response induced on the shoot regeneration medium. Neostigmine showed optimal reduction in shoot formation at 10(-5) M. The explants cultured on neostigmine augmented medium showed decline in the activity of ACh hydrolyzing enzyme acetylcholinesterase. ACh and neostigmine added together showed marked reduction in callus mass. These results strongly support the role of ACh as a natural regulator of morphogenesis in tomato plants.
authors.affiliation: a Department of Botany , University of Delhi , Delhi , India.|b Department of Botany , Shivaji College (University of Delhi) , Raja Garden, Delhi , India.
authors.forename: Kiran
authors.initials: K
authors.lastname: Bamel
authors.affiliation: a Department of Botany , University of Delhi , Delhi , India.
authors.forename: Rajendra
authors.initials: R
authors.lastname: Gupta
authors.affiliation: a Department of Botany , University of Delhi , Delhi , India.
authors.forename: Shirish C
authors.initials: SC
authors.lastname: Gupta
mesh_terms: D000085:Acetates / Q000378:metabolism; D000109:Acetylcholine / Q000494:pharmacology*; D000110:Acetylcholinesterase / Q000378:metabolism; D002794:Choline / Q000378:metabolism; D018551:Solanum lycopersicum / Q000187:drug effects / Q000254:growth & development*; D009024:Morphogenesis / Q000187:drug effects; D009388:Neostigmine / Q000378:metabolism; D010830:Physostigmine / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development*
chemical_list: D000085:Acetates; D009388:Neostigmine; D010830:Physostigmine; D000110:Acetylcholinesterase; D002794:Choline; D000109:Acetylcholine
keywords: Acetylcholine; Lycopersicon esculentum; callogenesis; caulogenesis; cholinesterases; morphogenesis; nAChR; nicotine; tomato