Tissue distribution of cholinesterases and anticholinesterases in native and transgenic tomato plants

Abstract

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.

Translational control of recombinant human acetylcholinesterase accumulation in plants

“…However, yields of plant-expressed AChE were modest because of limitations in the prototype expression construct and host plant [20,21]. Here we demonstrate that AChE accumulation in plants is limited at the translation stage and that the enzyme levels can be dramatically increased as compared to our previously reported results, by conforming its codon usage and GC content to that of highly expressed plant genes.…”

“…An important factor responsible for the low observed activity in crude extracts was the presence of the anticholinesterase glycoalkaloid tomatine in the transgenic host – tomato plants [21]. However, low expression/accumulation levels of foreign proteins in transgenic plants have unfortunately been the norm rather than the exception, despite an obvious, and rather natural, bias in the literature to focus on the latter (for a comprehensive case study see Diehn et al [40]).…”

“…Vertebrate genes encoding the enzyme from several sources were expressed in a wide variety of systems such as bacteria [16], yeast [17], mammalian cell cultures [18], transgenic mice [19] and more recently in plants [20,21]. The enzyme is known for its role in the termination of synaptic transmission by hydrolyzing acetylcholine, but during the past decade evidence has been gathered indicating its critical role in various processes such as development, stress responses, innate immunity, and bioscavenging [14].…”

“…This complex array of functions is enabled through the equally complex molecular biology of the ACHE gene: the intricate control of its transcription, alternative splicing and translation and the equally intricate post-translational events governing its function such as subcellular targeting, glycosylation, proteolytic processing, membrane anchoring and protein-protein interactions [14]. Interestingly, non-cholinergic functions of AChE are underscored by identification of AChE-like activity and genes potentially encoding the enzyme in several plant species [21-23]. …”

Cyperus rotundus extract inhibits acetylcholinesterase activity from animal and plants as well as inhibits germination and seedling growth in wheat and tomato

“…The presence of AChE in wheat and tomato is already reported (Tretyn et al, 1986;Fletcher et al, 2004). Our results that …”