Book of Abstracts - Geyseco

P - Posters
revealed defects in exine shape and micropatterning and a reduced
endomembrane system. Several lines of evidence including
the AtbZIP34 expression pattern and the phenotypic defects
observed, suggest a complex role in male reproductive development
that involves a sporophytic role in exine patterning, and
a sporophytic and/or gametophytic mode of action of AtbZIP34
in several metabolic pathwatys, namely regulation of lipid ,etabolism
and/or cellular transport. Acknowledgment: Authors gratefully
acknowledge the financial support from the Grant Agency
of the Czech Republic (grant 522/09/0858) and Ministry of Education
of the Czech Republic (grant LC06004 and OC10054).
P04-009: IDENTIFICATION AND CHARACTERIZATION
OF PECTINASE ENZYMES IN THE OLIVE POLLEN
GRAIN
Rejón, J.* - Rodríguez-García, M.I. - Castro, A.J.
Consejo Superior de Investigaciones Científicas (CSIC)
*Corresponding author e-mail: jdavid.rejon@eez.csic.es
Pectinases might play a key function in pollen tube entry through
the papilla cells and pollen tube growth regulation [1, 2]. In the
olive, the composition and distribution of pectins in the pollen
tube wall have been studied [3]. With the aim of determining the
existence of pectinolytic activity in this species, we carried out in
vitro enzyme assays using esterified pectin as substrate. We confirmed
the existence of active pectinases in the mature pollen
grain. The pectinolytic activity remained unchanged during the
hydration and the early steps of pollen tube growth, but abruptly
decreased after 6 h of germination. We also detected the presence
of pectinase activity in the germination medium, suggesting that
pectinolytic enzymes might be released from pollen during the
process. The pectinase enzymes pattern was also determined in
polyacrylamide gels using β-naphtyl acetate as substrate. Thus,
two pectinolytic bands of 24 and 27.5 kDa, respectively, were
detected in the mature pollen grain and during germination. The
intensity of these two bands correlated well with the pectinase
activity levels reported in vitro. These proteins were excised from
gels and analyzed by mass spectrometry. They showed homology
with a partial sequence of a putative pectin methylesterase
from olive (accession no. ABS72005). At ultrastructural level,
the pectinase activity was visualized as electron-dense precipitates,
and it was mainly located in the vicinity of the plasmalemma
and the intine wall layer. [1] Bosch et al. (2005) Plant Physiol.
138: 1334 [2] Chen & Ye (2007) J. Integ. Plant Biol. 49: 94 [3]
Majewska-Sawka et al. (2002) Sex. Plant Reprod. 15: 21 This
work was supported by the MICINN (project AGL2008-00517/
AGR) and the Junta de Andalucía (project P06-AGR-01791)
P04-010: DEVELOPMENTAL CHANGES IN THE PRE-
SENCE OF ROS (REACTIVE OXYGEN SPECIES) IN THE
STIGMA AND THEIR RELATIONSHIPS WITH STIGMA
FUNCTIONALITY.
Alché, J.* - Rejón, JD. - Jiménez-Quesada, M.J. - Rodríguez-
García, M.I. – Zafra, A.
Estación experimental del Zaidín.csic.
*Corresponding author e-mail: juandedios.alche@eez.csic.es
The presence of reactive oxygen species (ROS) and NO in the
reproductive tissues of several Angiosperms has been investigated.
Early studies have shown that these molecules play putative
roles as signaling molecules during the interaction pollen-pistil.
However, their occurrence in other reproductive phases has not
been investigated. We have analyzed the presence of ROS and
NO in floral tissues over different developmental stages (unopened
flower buds, recently opened flowers, dehiscent anthers and
flowers after fertilization) by using different fluorophores and
confocal laser scanning microscopy. The study was carried out
in species with different types of stigmas and systems of compatibility
(olive tree, orange, tomato, pepper, pea and A. thaliana).
Although the presence of ROS in the stigmas was detected at
higher levels during those developmental phases considered
“receptive” to pollen interaction, these molecules
were also present at early (unopened flower) or later (post-fertilization)
stages. The biological significance of the presence of
these products may differ between these stages, including defence
functions, signaling and senescence. The study confirms the
enhanced production of NO by pollen grains and tubes during the
receptive phase, and the decrease in the presence of ROS when
NO is actively produced [1].
[1] Zafra et al. BMC Plant Biology 2010, 10:36
Acknowledgments. This work was supported by MICINN (project
BFU2008-00629/BFI), and by JA (project P06-AGR-01791).
The authors want to thank S. Hiscock (U. Bristol U.K.) for helpful
comments.
P04-011: CELLULAR STUDY OF TEOSINTE ZEA MAYS
SUBSP. PARVIGLUMIS CARYOPSIS DEVELOPMENT
SHOWING SEVERAL PROCESSES CONSERVED IN
MAIZE
Kladnik, A.¹* - Dermastia, M.² - Dolenc Koce, J.¹ – Chourey, PS.³
¹University of Ljubljana, Biotechnical Faculty, Department of
Biology
²National Institute of Biology, Slovenia
³U.S. Department of Agriculture–Agricultural Research Service,
and University of Florida, USA
*Corresponding author e-mail: ales.kladnik@bf.uni-lj.si
The evolutionary history of maize (Zea mays subsp. mays) is of
general interest because of its economic and scientific importance.
Here we show that many cellular traits described previously
in developing caryopses of maize are also seen in its wild progenitor
teosinte (Zea mays subsp. parviglumis). These features,
each with a possible role in development, include: (1) an early
programmed cell death in the maternal placento-chalazal (P-C)
layer that may lead to increased hydrolytic conductance to the
developing seed; (2) accumulation of phenolics and flavonoids
in the P-C layer that may be related to antimicrobial activity;
(3) formation of wall ingrowths in the basal endosperm transfer
layer (BETL); (4) localization of cell wall invertase in the BETL,
which is attributed to the increased transport capacity of photosynthates
to the sink; and (5) endoreduplication in endosperm
nuclei suggested to contribute to increased gene expression and
greater sink capacity of the developing seed. In maize caryopsis,
these cellular traits have been previously attributed to domestication
and selection for larger seed size and vigor. Given the
conservation of the entire cellular program in developing teosinte
caryopses described here, we suggest that these traits evolved
independently of domestication and before human selection pressure.
P04-012: HOW TO IDENTIFY NEW & IMPORTANT
CIS-ELEMENTS? BIOINFORMATIC APPROACH AND
FUNCTIONAL ANALYSIS OF REGULATORY ELE-
MENTS IN PROMOTERS OF POLLEN EXPRESSED GE-
NES.
Šolcová, K.¹* - Gibalová, A.² - Honys, D.¹
¹Institute of Experimental Botany of the AS CR
²Faculty of Science, Charles University in Prague
*Corresponding author e-mail: matczuk@ueb.cas.cz
For understanding of regulatory mechanisms specifying and
controlling male gametophytic developmental program, it is necessary
to identify regulatory sequence motifs (cis-elements) in
promoters of pollen-expressed genes and to isolate interacting
protein partners responsible for their transcriptional activation or
repression. Regulatory elements present in gene promoters include
several classes of functional DNA sequence motifs recognized
by appropriate proteins (trans-elements), components of the
RNA polymerase transcription machinery and complementary
transcription factors. Here we demonstrate identification and
P