Book of Abstracts - Geyseco

FESPB 2010 - XVII Congress of the Federation of European Societies of Plant Biology
Clubroot disease is caused by Plasmodiophora brassicae and
leads to the development of galls in infected roots of Brassicaceae.
This physiopathological process relies on the phytohormonal
modulation of plant metabolic resource allocation. High
accumulation of trehalose has been observed in clubroot infected
plants. However, despite the central importance of the trehalose
pathway in the regulation of plant primary metabolism, little
is known about the implication of trehalose in the mechanisms
of resistance / susceptibility to P. brassicae. The present work
showed that the clubroot partially resistant Arabidopsis accession
Bur-0 was tolerant to exogenous trehalose. A QTL analysis on a
Bur-0 x Col-0 (susceptible to exogenous trehalose) segregating
population led to the identification of one QTL involved in trehalose
tolerance that co-localized with a previously identified QTL
for quantitative resistance to P. brassicae. This result was confirmed
by the analysis of near-isogenic lines (HIF). Accumulation
of trehalose in tissues of trehalose treated Bur-0 was not drastically
lower than in Col-0, suggesting that this tolerance could be
related to contrasting downstream response to trehalose rather
than to trehalose degradation. Trehalose was accumulated in both
parental accessions during clubroot infection, but trehalase enzymatic
activity was induced only in the susceptible Col-0 accession.
We conclude that tolerance to trehalose in Bur-0 is likely
involved in clubroot resistance, and that this tolerance relies on a
trehalase-independent mechanism, supporting an original model
where a partial resistance would rely on contrasting primary metabolism
regulation
P17-072: PLANT HORMONES IN FUNCTIONING OF
GLYCINE MAX – BRADYRHIZOBIUM JAPONICUM
SYMBIOSIS
Volkogon, M.* – Mamenko, P. – Kots, S.
*Corresponding author e-mail: volkogon@ifrg.kiev.ua
Biological nitrogen fixation via symbiotic systems of higher
plants and nodule bacteria is the global process gaining its actuality
nowadays at introduction of high yield farming, resources saving
and environment protection means. Using of model systems
with modified symbiotic characteristics is of a great interest for
symbiosis physiology research uncovering role of biomolecules
and the regulation pathways of symbiotic interactions.
We have studied the role of indoleacetic acid (IAA), zeatin (Z)
and zeatin-riboside (ZR) in functioning of Glycine max-Bradyrhizobium
japonicumsymbiotic systems under the seeds inoculation
with strains and Tn5-mutants varying by their symbiotic
properties. The study of auxin contents in roots and nodules of
infected plants have indicated key role of host plants in IAA
biosynthesis. It was shown that changes in IAA level are independent
of inoculum strain activity – both high and nonactive
bacteria and their Tn5-mutants have promoted IAA level
increase in the nodules. This confirms unspecific role of auxins
in symbiosis formation laying in triggering of endoreduplication
and mitoses in infected root cells.
As is known auxins act in complex with other plant hormones,
cytokinins in particular, that control root nodules initiation and
growth. Thus, Z and ZR levels in nodules had indicated direct relationships
between their activity and nitrogen fixation ability. It
was shown that inoculation with active strains and Tn5-mutants
of B. japonicum had resulted in higher cytokinins biosynthesis.
The results obtained expand our knowledge on hormonal control
of symbiotic relationships and might be used as the theoretical
and practical base for elaboration and improving of sustainable
agriculture techniques.
P17-073: EXPRESSION OF SMALL GTP-BINDING PRO-
TEINS IN ROOT NODULES OF MEDICAGO TRUNCA-
TULA
Memon, A.R. - Wiebe, A. - Kliendt, C.K. - Yuzbasioglu, E. - Weisshaar,
B. - Niehaus, K.
International University of Sarajevo, Genetics and Bioengineering
programme, Bosnia & Herzegovina, Istanbul University,
Turkey and CeBiTech, Univ.
Severasl tudies have shown that membrane associated small
GTPases belonging to the Arf/Sar, Rab, and Rop/Rac families,
along with their interacting proteins, playing a vital role in the
diverse aspects of root nodule formation and development. The
protein and gene expression studies could suggest a nodulespecific
expression of small GTP binding proteins especially the
expression of several Rabs and Rops.We previously made an
attempt to retrieve the EST databases of of two model legume
plants, Medicago and Lotus and searched the nodule specific
expressed transcripts of small GTPases. As a result of this bioinformatic
analyses, two ARL like genes, a group of 10 Rab GTPases
and one or two ROP like GTPases were found to be mainly
expressed in nodules. The sequences determined as a result of
this study, we decided to commence detail expression analysis of
these GTP-binding proteins at RNA and protein levels in rhizobium
inoculated and non inoculated roots and nodules of Medicago
truncatula. Our results show three to five times more Sar1
and Arf1 protein content in rhizobium infected roots compared to
non inoculated one. qReal-time PCR experiments clearly showed
about 5 to 10 times more expression of Sar1, Arf1, Arl1, Rab1,
Rab4, Rab7, Rab11 and Rop2 and Rop4 in roots and nodules of
inoculated plants compared to the roots of non inoculated ones.
P17-074: SEED MICROFLORA OF PLANT SPECIES AF-
TER CRYOCONSERVATION IN
Arapetyan, E.* - Bilynska, I. – Usatenko, Y.
Ivan Franko National University of Lviv
*Corresponding author e-mail: emarapetyan@gmail.com
Seeds of wild plants have many different microorganisms on its
coat. Influence of ultralow temperature on viability these microorganisms
are showed. Seeds of 14 wild plant species from different
family (Caryophyllaceae, Asteraceae, Brassicaceae) kept in
the liquid nitrogen (-1960 C, experiment) and in the room conditions
(control) during 6 months. After thawing of seeds its sowed
on nutrient medium for microorganism.
Are finded out microorganisms presence on seed coat surface of
all species as in control as in experiment variants. Quality microorganism
composition were very different. Fungi dominated on
surface of seeds after cryoconservation and bacterias - in control
variant. The least contaminate are showed for seedsfrom Caryophyllaceae
family.
P17-075: PARTIAL RESISTANCE OF POTATO TU-
BERS TO PECTOBACTERIUM ATROSEPTICUM: THE
EFFECT OF PHYSIOLOGICAL AGE ON DEFENCE
Kröner, A. – Pusnel, R. – Hamelin, G. – Val, F.
UMR 1099 BiO3P (Biologie des Organismes et des Populations
appliquée à la Protection des Plantes), INRA - Agrocampus
Ouest - Université de Rennes I)
Pectobacterium atrosepticum is the causal agent of potential
damage during storage of potato tubers. The extent of damage
varies among cultivars showing different levels of resistance.
Underlying mechanisms are still not completely understood, but
could contribute to a better control of disease.
Our hypothesis is that the level of resistance could be explained
by active induction of defence by potato tubers in response to
Pectobacterium atrosepticum. It is supported by findings of (Kumar&
Knowles, 2003) who studied the wound response of tubers
during storage. They found wound healing ability to decrease in
ageing tubers and propose that it could be caused by reduced
inducible activity of phenylalanine ammonia-lyase (PAL) and
reduced synthesis of phenolic compounds. These metabolic processes
are also implicated in defence against pathogens.
The aim of the study is to show if levels of tuber resistance to
Pectobacterium atrosepticum dependon tuber age and if it is