-type zinc-ﬁnger transcription factor gene functions
as a pathogen-induced early-defense gene in Capsicum annuum
Sang Hee Kim, Jeum Kyu Hong, Sung Chul Lee, Kee Hoon Sohn, Ho Won Jung and
Byung Kook Hwang*
Laboratory of Molecular Plant Pathology, College of Life and Environmental Sciences, Korea University,
Seoul 136-713, Korea (*author for correspondence; e-mail firstname.lastname@example.org)
Received 26 December 2003; accepted in revised form 16 August 2004
Key words: abiotic elicitors, Capsicum annuum, Cys
-type zinc-ﬁnger transcription factor, early-de-
fense gene, Xanthomonas campestris pv. vesicatoria
A pepper zinc-ﬁnger protein gene, CAZFP1, encoding the Cys
-type zinc-ﬁnger transcription factor was
isolated from pepper leaves inoculated with an avirulent strain Bv5-4a of Xanthomonas campestris pv.
vesicatoria. The CAZFP1 protein is a nuclear targeting protein, which functions as a transcriptional regu-
lator. The full-length CAZFP1 had no transcriptional activation activity, whereas the C-terminal region of
CAZFP1 had transactivation activity. The CAZFP1 transcripts were constitutively expressed in the pepper
stem, root, ﬂower and red fruit, but were not detectable in the leaf and green fruit. The CAZFP1 transcripts
accumulated earlier than the CABPR1 (PR-1) gene in the incompatible interaction of the pepper leaves with
X. campestris pv. vesicatoria. The CAZFP1 transcripts were signiﬁcantly induced in the systemic, uninocu-
lated leaf tissues early after inoculation with bacterial pathogens, but gradually declined thereafter. The
CAZFP1 transcripts were localized, and conﬁned to the phloem cells of the vascular bundle in the pepper leaf
midrib in response to Colletotrichum. coccodes infection, ethylene and abscisic acid. The CAZFP1 gene was
also induced much earlier by abiotic elicitors and environmental stresses, compared with the CABPR1 gene.
Overexpression of the CAZFP1 gene in the transgenic Arabidopsis plants enhanced not only the resistance
against infection by Pseudomonas syringae pv. tomato, but also the drought tolerance. These results suggest
that the CAZFP1 gene functions as an early-defense gene to enhance disease resistance and drought tolerance.
The timely recognition of microbial pathogen
infection and the rapid activation of the plant
defense response through a number of signal
transduction pathways is a fundamental mecha-
nism of plant disease resistance (Yang et al., 1997).
Pathogen-induced signal transduction pathways in
plants converge into the nucleus, where a large
number of defense-related genes are transcrip-
tionally activated (Rushton and Somssich, 1998).
Pathogen-induced low molecular weight mole-
cules, including salicylic acid (SA), jasmonic acid
(JA), ethylene and reactive oxygen species (ROS),
act as signals to trigger a variety of biochemical
pathways in plants (Reymond and Farmer, 1998).
These signalings result in the hypersensitive
response (HR), enhancement of preformed barri-
ers and de novo synthesis of pathogenesis-related
(PR) proteins encoded by the defense-related genes
(Somssich and Hahlbrock, 1998).
During the signal transduction cascades
involved in the defense response of plants to path-
ogen infection, various defense signals integrate in a
terminal pathway that leads to the transcriptional
activation of defense genes in the cell nucleus (Yang
Plant Molecular Biology 55: 883–904, 2004.
Ó 2004 Kluwer Academic Publishers. Printed in the Netherlands.