Subcellular localization of overexpressed maize AChE gene in rice plant.

The ACh-mediated system consisting of acetylcholine (ACh), acetylcholine receptor (AChR) and acetylcholinesterase (AChE) is fundamental for nervous system function in animals and insects. Although plants lack a nervous system, both ACh and ACh-hydrolyzing activity have been widely recognized in the plant kingdom. The function of the plant ACh-mediated system is still unclear, despite more than 30 years of research. To understand ACh-mediated systems in plants, we previously purified maize AChE and cloned the corresponding gene from maize seedlings (Plant Physiology). In a recent paper in Planta, we also purified and cloned AChE from the legume plant siratro (Macroptilium atropurpureum). In comparison with electric eel AChE, both plant AChEs showed enzymatic properties of both animal AChE and animal butyrylcholinesterase. On the other hand, based on Pfam protein family analysis, both plant AChEs contain a consensus sequence of the lipase GDSL family, while the animal AChEs possess a distinct alpha/beta-hydrolase fold superfamily sequence, but no lipase GDSL sequence. Thus, neither plant AChE belongs to the well-known AChE family, which is distributed throughout the animal kingdom. To address the possible physiological roles of plant AChEs, we herein report our data from the immunological analysis of the overexpressed maize AChE gene in plants.