Tissue distribution of cholinesterases and anticholinesterases in native and transgenic tomato plants.
Acetylcholinesterase, a major component of the central and peripheral nervous systems, is ubiquitous among multicellular animals, where its main function is to terminate synaptic transmission by hydrolyzing the neurotransmitter, acetylcholine. However, previous reports describe cholinesterase activities in several plant species and we present data for its presence in tomato plants. Ectopic expression of a recombinant form of the human enzyme and the expression pattern of the transgene and the accumulation of its product in transgenic tomato plants are described. Levels of acetylcholinesterase activity in different tissues are closely effected by and can be separated from alpha-tomatine, an anticholinesterase steroidal glycoalkaloid. The recombinant enzyme can also be separated from the endogenous cholinesterase activity by its subcellular localization and distinct biochemical properties. Our results provide evidence for the co-existence in tomato plants of both acetylcholinesterase activity and a steroidal glycoalkaloid with anticholinesterase activity and suggest spatial mutual exclusivity of these antagonistic activities. Potential functions, including roles in plant-pathogen interactions are discussed.
Fletcher
Samuel P
SP
School of Life Sciences and Arizona Biodesign Institute, Arizona State University, USA.
Geyer
Brian C
BC
Smith
Amy
A
Evron
Tama
T
Joshi
Lokesh
L
Soreq
Hermona
H
Mor
Tsafrir S
TS
D000110:Acetylcholinesterase / Q000235:genetics / Q000378:metabolism; D002384:Catalysis; D002800:Cholinesterase Inhibitors / Q000378:metabolism*; D002802:Cholinesterases / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014053:Tomatine / Q000378:metabolism; D019076:Transgenes / Q000235:genetics
D002800:Cholinesterase Inhibitors; D007527:Isoenzymes; D011994:Recombinant Proteins; D014053:Tomatine; D000110:Acetylcholinesterase; D002802:Cholinesterases