Plant Molecular Biology 46: 661–671, 2001.
© 2001 Kluwer Academic Publishers. Printed in the Netherlands.
Molecular cloning of a novel pathogen-inducible cDNA encoding a
putative acyl-CoA synthetase from Capsicum annuum L.
Sang Jik Lee
, Mi-Chung Suh
, Shinje Kim
, Jin-Kyung Kwon
, Minwoo Kim
, Doil Choi
and Byung-Dong Kim
School of Plant Science, College of Agriculture and Life Sciences and
Center for Plant Molecular Genetics
and Breeding Research, Seoul National University, 103 Seodoon-dong, Suwon 441-744, Korea;
Biotechnology Laboratory, Korea Research Institute of Bioscience and Biotechnology, Taejon 305-600, Korea;
Plant Molecular Biology and Genetics Laboratory, Graduate School of Biotechnology, Korea University, Seoul
Present address: Biotechnology Center, Nong Woo Bio Co., Ltd, 537-17 Jeongdan, Kanam,
Yeoju, Kyonggi 469-880, Korea (
authors for correspondence; e-mail firstname.lastname@example.org and email@example.com;
these authors contributed equally as senior authors)
Received 19 September 2000; accepted in revised form 2 May 2001
Key words: acyl-CoA synthetase, AMP-binding protein, Capsicum annuum L., mRNA differential display, salicylic
acid, subcellular localization
By means of differential display, a pool of salicylic acid (SA)-induced mRNAs were identiﬁed and subsequently
their cDNAs were isolated from a cDNA library prepared from SA-induced leaf tissues of hot pepper. One of
these cDNA clones, designated CaSIG4, was 1900 bp and contained an open reading frame encoding 523 amino
acids with a calculated molecular mass of 56.3 kDa. The predicted amino acid sequence of CaSIG4 showed high
sequence similarity to the AMP-binding protein family of both prokaryotic and eukaryotic acyl-CoA synthetases.
CaSIG4 transcripts accumulated rapidly after SA treatment and in response to both incompatible and compatible
interactions with Xanthomonas campestris pv. vesicatoria race 1. To investigate the cis-acting elements mediating
CaSIG4 expression, the CaSIG4 5
-ﬂanking region was isolated by inverse PCR. Database searches indicated that
a potential cis-regulatory element is almost identical to the consensus core sequences ACC(A/T)ACC(A/C) which
are conserved among promoters of other phenylpropanoid biosynthetic genes. The subcellular localization of the
CaSIG4 protein was studied by using a soluble modiﬁed GFP gene fusion delivered into epidermal cells of onion by
biolistic bombardment. The CaSIG4-smGFP fusion protein was localized to the plasma membrane. Taken together,
CaSIG4 encoding a putative acyl-CoA synthetase could function as a plasma membrane-bound protein with a role
in signaling in plant defense.
Plants defend themselves against invading pathogens
by activating a large array of defense mechanisms.
These include the hypersensitive response (HR) that
restricts the pathogen from spreading from the pri-
mary site of infection, the induction of genes encoding
pathogenesis-related (PR) proteins and the production
The nucleotide sequence data reported will appear in the EMBL,
GenBank and DDBJ Nucleotide Sequence Databases under the
accession number AF354454.
of enzymes involved in the generation of phytoalexins
and those related to oxidative stress protection, tis-
sue repair and cell wall ligniﬁcation (Reymond and
In plants, transcriptional regulation of genes plays
a fundamental role in response to pathogen infection
(Rushton and Somssich, 1998). Many of these PR
and defense-related genes are induced by pathogen
attack and are transcriptionally regulated via diverse
signal transduction pathways mediated by jasmonic
acid (JA; Creelman and Mullet, 1997), salicylic acid