BIOTIC AND ABIOTIC STRESS
The rice pathogen-related protein 10 (JIOsPR10) is induced
by abiotic and biotic stresses and exhibits ribonuclease
activity
Sun Tae Kim Æ Seok Yu Æ Young Hyun Kang Æ
Sang Gon Kim Æ Jae-Yean Kim Æ Sun-Hyung Kim Æ
Kyu Young Kang
Received: 30 July 2007 / Revised: 16 October 2007 / Accepted: 15 November 2007 / Published online: 12 December 2007
Ó Springer-Verlag 2007
Abstract We previously reported that rice blast fungus or
jasmonic acid induced the expression of rice pathogenesis-
related class 10 (JIOsPR10) proteins (Kim et al. 2003,
2004). However, no further studies have been carried out to
examine the expression, localization, and enzymatic
activity of this protein in either developmental tissues or in
tissues under abiotic stress conditions. In this study, rice
JIOsPR10 was examined by Western blot analysis,
immunolocalization, and biochemical assays. Western
blots revealed that the JIOsPR10 protein was expressed in
developmental tissues, including in flower and root. The
protein was also expressed under abiotic stresses, such as
occurs during senescence and wounding. Using immuno-
histochemical techniques, we determined that expression of
JIOsPR10 was localized to the palea of flower, in the
exodermis, and inner part of the endodermis of the root. In
senescencing tissues of leaf and coleoptiles, its expression
was localized in vascular bundles. The RNase activity
using JIOsPR10 recombinant protein was determined and
abolished after treatment with DTT in a native in-gel assay.
To test this, we created JIOsPR10 mutant proteins con-
taining serine substitutions of amino acids C81S, C83S, or
both and examined their RNase activities. The activity of
the C83S mutant was decreased in the agarose gel assay
compared to the wild type. Taken together, we hypothesize
that the JIOsPR10 protein possesses RNase activity that is
sensitive to DTT, suggesting the importance of the disul-
fide bonding between cysteine residues and that it might
play a role in constitutive self-defense mechanisms in
plants against biotic and abiotic stresses.
Keywords Abiotic stresses Á Biotic stresses Á
Pathogenesis-related (PR) proteins Á RNase activity
Introduction
Higher plants have the ability to protect themselves from
various pathological processes, such as biotic and abiotic
stresses. During these occurances, most plants synthesize
and/or accumulate a number of proteins called ‘‘defense-
related proteins’’ (PRs) (Dixon and Lamb 1990). These
inducible defense mechanisms have been identified in
many plant species. PR proteins can be classified into
several families, and are currently grouped into 17 inde-
pendent classifications, PR-1 to PR-17, based on their
amino acid sequence, serological relationship, and enzy-
matic activities (Van Loon and Van Strien 1999). Although
the biological and biochemical functions of PR proteins
have been studied for several decades, only a few proteins,
such as chitinases and glucanases, have been extensively
studied for their catalytic functions. The roles of the other
known PR proteins in plant defense remain to be
determined.
Communicated by H. Judelson.
S. T. Kim Á J.-Y. Kim Á K. Y. Kang (&)
Environmental Biotechnology National Core Research Center,
Gyeongsang National University, Jinju 660-701, Korea
e-mail: kykang@gnu.ac.kr
S. Yu Á J.-Y. Kim Á K. Y. Kang
Plant Molecular Biology and Biotechnology Research Center,
Gyeongsang National University, Jinju 660-701, Korea
Y. H. Kang Á S. G. Kim Á J.-Y. Kim Á K. Y. Kang
Division of Applied Life Science (BK21 Program),
Gyeongsang National University, Jinju 660-701, Korea
S.-H. Kim
Department of Environmental Horticulture,
University of Seoul, Seoul 130-743, Korea
123
Plant Cell Rep (2008) 27:593–603
DOI 10.1007/s00299-007-0485-6