Book of Abstracts - Geyseco

P10
Signalling
And Gene
Expression
P10-001: CYTOKININ AND LIGHT: THE WAYS TO RE-
GULATE DE-ETIOLATION OF BARLEY
Kravtsov, A.* - Zubo, Y. - Kulaeva, O. - Kusnetsov, V.
Timiryazev Institute of Plant Physiology, Russian Academy of
Sciences.
*Corresponding author, e-mail: KravtsovAK@rambler.ru
De-etiolation is a set of physiological, biochemical, and morphological
changes undergone by a seedling in response to transition
from the growth in the dark to the light, which result in the chlorophyll
accumulation and initiation of photosynthesis. We report
here on thecytokinin(CK) and light effects on expression of plastid
genes in the course de-etiolation of monocot plants (Hordeum
vulgare L.).The leading factor in regulation of greening is light.
However its effect on a plant is presumably determined by endogeneous
factors, the main of which are phytohormones. To
investigate hormonal regulation of greening, plant development
was studied both in the light and at a preceding growth stage in
the dark. As the time course of plant growth in the dark increased,
the expression of plastid genes gradually declined, as well as the
ability of a plant to green, and after 12 days of dark treatment
the irreversible etiolation occurred. CK in the concert with light
reduced duration of barley transition to autotrophic type of nutrition,
enhanced pigment accumulation and activated expression
of the genes the products of which participated in chloroplast
biogenesis. For more rapid rates of plant greening both light and
CK were required . Hence, our data proves CK involvement in
regulation of plastome gene expression while greening. Along
with the light-dependent regulation of gene transcription we
demonstrate(for the first time) light independent CK activation
of transcription for a number of plastid genes in etiolated barley
seedlings. Thus, this study reveals for the first time cytokinin involvement
in the de-etiolation process of monocot plants.
P10-002: THE REGULATION OF THE GENE OF PRI-
MARY RESPONSE TO CYTOKININ IN ARABIDOPSIS
BY BRASSINOSTEROIDS
Efimova, M. 1 * - Kudryakova, N. 2 - Karnachuk, R. 1 - Khripach,
V. 3 - Kuznetsov, Vl. 4
1
Tomsk State University
2
Institute of Plant Physiology RAS
3
Institute of Bioorganic Chemistry NAS of Belarus
4
Timiryazev Institute of Plant Physiology RAS
*Corresponding author, e-mail: stevia555@mail.ru
Brassinosteroids (BRs) are steroidal plant hormones known to
play an essential role in a wide spectrum of physiological processes.
It is assumed that BRs are integrated in a complex signaling
networks via a modulation of levels and sensitivity of other
phytohormones, though the precise function of BRsin these interactions
is poorly understood. In the present study plants of Arabidopsis
thaliana (L.) Heynh transformed with the PARR5::GUS
consruct were used to estimate the influence of several BRs
(brassinolide (BL), epibrassinolide (EBL) and homobrassinolide
P - Posters
(HBL) on the expression of the ARR5 gene which belongs to the
type A negative regulators of plant response to cytokinin (CK).
Exogenous application of BRs to plant seedlings as well as to
detached mature leaves in the dark but not under white light induced
elevation of the GUS activity comparable with the shift of
PARR5::GUS expression in plants treated with CK (benzyladenine).
The levels of GUS activity induction differed ranging from
the highest for BLand the lowest for HBL treatment. The activation
of cytokinin primary response gene by BRs in darkness
could be induced either by the direct effect of these hormones on
the ARR5 gene promoter or indirect action through conversion
of bound forms of CKs to free forms. The results further suggest
that interaction between CKs and BRs is regulated by light which
might alter responsibility of cells to BRs.
We are grateful to Prof. J.J. Kieber (University of North Caroline,
NC, USA) for the generous gift of transgenic Arabidopsis
seeds. This research was supported by The Federal Agency for
Education (State Contract no. P1369) and Russian Foundation
for Basic Research.
P10-003: MOLECULAR CHARACTERIZATION OF
A BIOTIC AND ABIOTIC STRESS RESISTANCE-RE-
LATED GENE RELA/SPOT HOMOLOGUE(PEPRSH)
FROM PEPPER
Kim , T. * - Tae-Ho, K.
National Academy of Agricultural Science, RDA
*Corresponding author, e-mail: thkim1961@korea.com
A gene encoding a putative guanosine 50-diphosphate (or 50-triphosphate)
30-diphosphate ((p)ppGpp)synthetase, designated
PepRSH (Pepper RelA/SpoT homologue), was isolated from
hot peppers. A genomic DNA gel blot analysis revealed that the
pepper genome has at least a single copy of PepRSH. PepRSH
transcripts were highly accumulated in non-host resistance response-induced
leaves and in leaves following induction with salicylic
acid, methyl jasmonate, wounding, hydrogen peroxide, and
ultraviolet-B. The expression of PepRSH was also influenced by
abiotic stresses, such as flooding and high salinity. The deduced
PepRSH protein has a putative chloroplast-targeting transit peptide
at its Nterminus, and immunolocalization studies verified
the translocation of PepRSH to the chloroplast. The predicted
PepRSH protein is markedly similar to known plant and bacterial
RSH proteins. Expression of a putative (p)ppGpp synthetase
domain in an Escherichia coli single mutant (RelAˇSpoT+)
complemented growth of the mutant but not of an E. coli double
mutant (RelAˇSpoTˇ), demonstrating that PepRSH has (p)ppGpp
synthetase activity only in the (p)ppGpp synthetase domain. Sitedirected
mutagenesis of the conserved histidine and aspartic acid
(HD) site in the putative HD domain of PepRSH revealed that
the histidine and aspartic acid dual sites were critical residues for
the (p)ppGpp synthetase activity of PepRSH protein. Mutation
of the HD site limited the tolerance of bacteria to both salt and
osmotic stress. Our results indicate that pepper plants have a (p)
ppGpp regulatory system that is similar to that of bacteria and
which may transduce stress-related signals through the regulation
of (p)ppGpp by PepRSH localized in chloroplasts.
P10-004: THE NOVEL METHANOL INDUCED GENES
OF N. BENTHAMIANA
Pozdyshev D 1 * - Shvarts, A. M. 2 - Komarova T. V. 3
1
Lomonosov Moscow State University
2
Vavilov Institute of General Genetics, Russian Academy of
Science
3
Belozersky Institute of Physico-Chemical Biology, Moscow State
University
*Corresponding author, e-mail: denispoz@gmail.com
It is widely accepted idea that small highly volatile organic
compounds (VOCs) released by pathogen-attacked neighbors
may activate defenses before being attacked themselves. The
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