UPSC Cutting Edge Seminar 2014
Speaker:
Karin Schumacher
Plant Developmental Biology
Faculty of Biosciences, Ruprecht - Karls- University Heidelberg
Germany
Title:
Vacuoles - Pumping up the plant volume
Place: lilla hörsalen KB3A9
Host: Markus Grebe
UPSC Seminar Series 2014
Cutting Edge Seminar
Speaker:
Tom Beeckman
VIB, Department of Plant Systems Biology, University of Ghent, Belgiium
Title:
Root architecture steered by the root cap
Host: Stephanie Robért
Place: Lilla hörsalen, KB3A9
UPSC Cutting Edge Seminar
Title:
Jasmonates and biosynthesis of defines metabolites, can we break the multiple feedback loops?
Speaker:
Alain Goossens
VIB, Department of Plant Systems Biology, University of Ghent, Belgiium
Host: Catherine Bellini
Time and Place: Monday October 6th - 10:00-11:00.
Place: Lilla hörsalen, KB3A9
UPSC Seminars 2014 presents
Speaker:
Terkel Hansen
University of Tromsø
The Arctic University of Norway
My bioanalytic research in Tromsø
- present and future
Place: KB3A9, Lilla hörsalen, KBC
Hosts: Gunnar Wingsle / Thomas Moritz
UPSC Seminar:
Speaker:
Rossana Henriques
Career Track Fellow
Centre de Recerca en Agrigenòmica (CRAG)
Edifici CRAG, Campus UAB
Bellaterra (Cerdanyola del Vallés)
Barcelona
Title:
From genome dark matter to biological regulation: uncovering long non-coding RNA function in plants
Host
Laszlo Bako
Place Lilla hörsalen KB3A9
UPSC Seminar
Sepaker:
Claudio Stasolla
Dept. Plant Science, University of Manitoba, Winnipeg, Canada
Title:
In vitro plant embryogenesis: improving embryo yield
Place: KB3A9, Lilla hörsalen
Host: Ulrika Egertsdotter
Plant embryogenesis is an essential phase of the plant life cycle and formation of embryos can be stimulated in vitro through the careful selection of media components and environmental conditions. Work in my lab has recently been focussed on the function of plant hemoglobins (Hbs) during somatic embryogenesis in dicots and monocots. First described in animals, Hbs have now been identified in a variety of organisms including plants where their major function is to scavenge cellular nitric oxide (NO). Suppression of the Arabidopsis class 2 Hb (Hb2) enhances the formation of somatic embryos through the NO-mediated suppression of the transcription factor MYC2. Repression of MYC2 increases IAA accumulation at the sites of embryogenic tissue formation, and favors the formation of Arabidopsis somatic embryos. In maize the two Hbs: ZmHb1 and ZmHb2 regulate the cell survival/death decision that influences somatic embryogenesis through their cell-specific localization patterns. Suppression of either of the two ZmHbs is sufficient to induce PCD through a pathway initiated by elevated nitric oxide (NO) and zinc (Zn2+) levels, and mediated by production of reactive oxygen species (ROS). The effect of the death program on the fate of the developing embryos is dependent upon the localization patterns of the two ZmHbs. During somatic embryogenesis, ZmHb2 transcripts are restricted to a few cells anchoring the embryos to the subtending embryogenic tissue, while ZmHb1 transcripts extend to several embryonic domains. Suppression of ZmHb2 induces PCD in the anchoring cells allowing the embryos to develop further, while suppression of ZmHb1 results in massive PCD leading to abortion. It is concluded that regulation of the expression of these ZmHbs has the capability to determine the developmental fate of the embryogenic tissue during somatic embryogenesis through their effect on PCD. These studies place Hbs as central regulators of in vitro embryogenesis
UPSC Seminar Series 2014
Cutting Edge Seminar
Speaker:
Sabrina Sabatini
Università degli di Roma "La Sapienza"
Rome, Italy
Title: New insight in root meristem size determination and root zonation
Host: Karin Ljung
Place Lilla hörsalen KB3A9
Abstract:
Understanding the molecular mechanisms through which plant meristems are maintained is a central question in developmental biology. In the root of Arabidopsis thaliana, stem cells in the apical region of the meristem self-renew and produce daughter cells that differentiate in the distal meristem transition zone. To ensure root growth, the rate of cell differentiation must equal the rate of generation of new cells. Cell differentiation takes place in the transition zone that is localized in the distal part of the root meristem, but must be synchronized and balanced with division of the stem cells that are localized in the apical part of the meristem. We have previously shown that maintenance of the Arabidopsis root meristem size - and consequently root growth - is controlled by the interaction between two hormones at the meristem transition zone: cytokinins, which promote cell differentiation, and auxin, which promotes cell division.
New data will be presented on the molecular mechanism by which cytokinin induce cell differentiation influencing auxin distribution and, as a consequence, root zonation
UPSC Seminar Series 2014
Cutting Edge Seminar
Speaker:
Jay J. Thelen
Department of Biochemistry,
Christopher S. Bond Life Sciences Center
University of Missouri, Columbia, MO, USA
Title:
Phosphoproteomic analysis of seed maturation – from discovering phosphorylation sites to identifying kinase clients
Host: Vaughan Hurry
Place: Lilla hörsalen, KB3A9
Abstract
Although metabolic networks for storage reserve synthesis have been largely characterized in diverse plant seed we are only beginning to understand the complex regulatory processes involved in seed development. Protein phosphorylation is a major form of post-translational regulation in eukaryotes as evidenced by over 1000 protein kinases in the Arabidopsis proteome. To begin studying protein phosphorylation in developing seed we performed large-scale, mass spectrometry-based phosphoproteomic studies on seeds at five stages of development in soybean (Glycine max), rapeseed (Brassica napus), and Arabidopsis (Arabidopsis thaliana). Phosphopeptides were enriched from 0.5 mg total peptides using a combination of immobilized metal affinity and metal oxide affinity chromatography. Enriched phosphopeptides were analyzed by Orbitrap tandem mass spectrometry and spectra mined against cognate genome or cDNA databases in both forward and randomized orientations, the latter to calculate false discovery rate (FDR). We identified a total of 2001 phosphopeptides containing 1026 unambiguous phosphorylation sites from 956 proteins with an average FDR of 0.78% for the entire study (Meyer et al., 2012). The dataset was uploaded into the Plant Protein Phosphorylation Database (P3DB, www.p3db.org), including annotated spectra, for public accession. P3DB is a portal for all plant phosphorylation data and allows for homology-based querying of experimentally-determined phosphosites (Gao et al., 2009). Comparisons to other large-scale studies revealed that 652 of the phosphoproteins are novel to this study. The unique proteins fall into several Gene Ontology categories, some of which are overrepresented in our study as well as other large scale phosphoproteomic studies including metabolic process and RNA binding; while other categories are only overrepresented in our study like embryonic development. Leveraging large-scale phosphoproteomic datasets such as these, we developed a phosphorylation prediction tool called MUSite (http://musite.sourceforge.net/) that incorporates protein disorder as one of three features for prediction (Gao et al., 2010). The sensitivity and accuracy of this prediction algorithm is unmatched, and application to whole plant proteomes such as Arabidopsis TAIR10 indicates greater than 17,000 phosphorylation sites at the 99% confidence interval. Clearly, experimental and bioinformatic prediction of phosphorylation sites is rapidly becoming a facile task. However, confirmation and identification of cognate protein kinases responsible for these events remains challenging. I will also introduce a novel approach to address this problem called the Kinase Client or KiC Assay (Huang et al., 2009). Using this approach we have identified many kinase client relationships, including three different protein kinases responsible for over ten phosphorylation events on a single phosphoprotein.
Ahsan N, Huang Y, Tovar-Mendez A, Swatek KN, Zhang J, Miernyk JA, Xu D, Thelen JJ. (2013) A
Versatile Mass Spectrometry-Based Method to Both Identify Kinase Client-Relationships and Characterize Signaling Network Topology. J Proteome Res. 12:937-48
Meyer LJ, Gao J, Xu D, Thelen JJ (2012) Phosphoproteomic analysis of seed maturation in
Arabidopsis, rapeseed, and soybean. Plant Physiol. 159:517-28
Huang Y, Houston NL, Tovar-Mendez A, Stevenson SE, Miernyk JA, Randall DD, Thelen JJ (2010) A
quantitative mass spectrometry-based approach for identifying protein kinase –clients and quantifying kinase activity. Anal. Biochem. 402:69-76
Gao J, Agrawal GK, Thelen JJ, Xu D (2009) P3DB: A plant protein phosphorylation database. Nucl. Acids
Res. 37:D960-962
Gao J, Thelen JJ, Dunker AK, Xu D (2010) Musite: a tool for global prediction of general and kinase-
specific phosphorylation sites. Mol. Cell. Prot. 9:2586-25600
UPSC Seminar - postdoc seminar
Speaker:
Adeline Rigal
Title:
Unraveling transcriptional regulation of adventitious root formation with a small molecule
Host: Stéphanie Robert
Room: KB3A9, Lilla hörsalen