The Arabidopsis thaliana ortholog of a purported maize
cholinesterase gene encodes a GDSL-lipase
Katherine E. Larrimore
Nicholas A. Segerson
Tsafrir S. Mor
Received: 30 August 2012 / Accepted: 1 February 2013 / Published online: 22 February 2013
Ó Springer Science+Business Media Dordrecht 2013
Abstract Acetylcholinesterase is an enzyme that is inti-
mately associated with regulation of synaptic transmission in
the cholinergic nervous system and in neuromuscular junc-
tions of animals. However the presence of cholinesterase
activity has been described also in non-metazoan organisms
such as slime molds, fungi and plants. More recently, a gene
purportedly encoding for acetylcholinesterase was cloned
from maize. We have cloned the Arabidopsis thaliana
homolog of the Zea mays gene, At3g26430, and studied its
biochemical properties. Our results indicate that the protein
encoded by the gene exhibited lipase activity with preference
to long chain substrates but did not hydrolyze choline esters.
The At3g26430 protein belongs to the SGNH clan of serine
hydrolases, and more speciﬁcally to the GDS(L) lipase family.
Keywords Cholinesterase Á GDS(L)lipase Á
The evolutionary history of acetylcholine (ACh) as a
neurotransmitter can be traced as far back as primitive
bilaterians (e.g. ﬂatworms), but the recruitment of this
signaling molecule for other, non-neuronal, functions pre-
dates the evolution of the bilaterian lineage (Le Novere and
Changeux 1995; Walker et al. 1996; Dent 2006). ACh and
enzymes associated with its metabolism have been found
not only in cnidrians that lack cholinergic neurons (Denker
et al. 2008) and in organisms that altogether lack an
organized nervous system (e.g. sponges, Horiuchi et al.
2003) but also in organisms outside of the fungi/metazoan
group such as slime molds (Earle and Barclay 1986), cil-
iates (Delmonte Corrado et al. 2001), algae (Raineri and
Modenesi 1986; Gupta et al. 1998), archaea (Yamada et al.
2005) and bacteria (Domenech et al. 1991). In fact, it
seems that ACh metabolism is ubiquitous (reviewed in
Horiuchi et al. 2003; Kawashima et al. 2007; Wessler and
Extensive literature describes the involvement of ACh
in several processes in plants (reviewed by Hartmann
and Gupta 1989; Tretyn and Kendrick 1991; Wessler
et al. 1999; Roshchina 2001). Others and we demon-
strated the presence of ACh hydrolytic activity in many
plants, and especially in the families Leguminosae and
Solanaceae (Fluck and Jaffe 1974; Gupta and Gupta
1997; Fletcher et al. 2004; Muralidharan et al. 2005).
Research suggested that cholinesterase (ChE) activity in
plants may be involved in a myriad of physiological
processes including phytochrome signal transduction (e.g.
Jaffe 1970), regulation of the stomatal aperture (Madh-
avan et al. 1995), gravitropism (Momonoki 1997; Mo-
monoki and Bandurski 1994; Momonoki et al. 2000),
pollen tube elongation (Tezuka et al. 2007) germination
(Beri and Gupta 2007), and root development (Bamel
et al. 2007).
Despite this wealth of physiological and biochemical
studies, the identity of the proteins/enzymes involved in
Electronic supplementary material The online version of this
article (doi:10.1007/s11103-013-0021-8) contains supplementary
material, which is available to authorized users.
M. Muralidharan Á K. Buss Á K. E. Larrimore Á
N. A. Segerson Á L. Kannan Á T. S. Mor (&)
School of Life Sciences and The Biodesign Institute, Arizona
State University, P.O. Box 874501, Tempe, AZ 85287-4501,
Plant Mol Biol (2013) 81:565–576