- Seminars - maillist.psb.ugent.be

PSB event reminder
by contact＠psb.vib-ugent.be 26 May '13

26 May '13

Calendar Name: seminars Scheduled for: Tuesday, May 28 2013, 11:00 - 12:30 Event text: Prof Ueli Grossniklaus Plant Developmental Genetics Institute of Plant Biology University of Z�rich Z�rich Switzerland Details: �Molecular control of fertilization and interspecific hybridization� ABSTRACT Lena M�ller, Heike Lindner, Sharon A. Kessler, Michael T. Raissig, Hiroko Shimosato-Asano, Ueli Grossniklaus Research in our laboratory focuses on the developmental genetics of plant reproduction, with an emphasis on cellular interactions during double fertilization. I will focus on the reception of the pollen tube by the synergid cells, where the pollen tube arrests growth and ruptures to release the sperm cells. We have isolated and characterized female gametophytic mutants that disrupt pollen tube reception. Pollen tubes that encounter such mutant female gametophytes are unable to rupture and release the sperm cells (Huck et al., Development 130:2149; Kessler et al., Science 330:968). These phenotypes suggest that the female gametophyte controls the behaviour of the male gametophyte (pollen) in this process. One of the mutants, feronia, was shown to affect a receptor-like kinase (Escobar-Restrepo et al., Science 317:656), while another, nortia, disrupts a seven-transmembrane-domain-protein similar to the powdery mildew resistance protein Mlo (Kessler et al., Science 330:968). The identification of additional components in this signal transduction cascade suggest the involvement of glycosylation in this recognition process. Furthermore, interspecific crosses between Brassicaceae can result in a similar phenotype, suggesting the cell-cell interactions during pollen tube reception may be involved in interspecific crossing barriers. Using genome-wide association studies, we have been able to identify a factor that plays a specific role in interspecific compatibility while intraspecific crosses are not affected. Thus, pollen tube reception may be involved in establishing crossing barriers essential to maintain species boundaries similar to sperm-egg interactions in animals.

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PSB event reminder
by contact＠psb.vib-ugent.be 23 May '13

23 May '13

Calendar Name: seminars Scheduled for: Thursday, May 23 2013, 11:00 - 12:30 Event text: Prof Ann Depicker VIB, Dept. of Plant Systems Biology Ghent University Gent BELGIUM Details: �Plant transgenes: integration, silencing and overexpression� ABSTRACT Plant transgene expression group I will describe the general picture of plant transgenesis by presenting the latest results obtained in the group on the integration and expression of transgenes in plants. Although Agrobacterium mediated transformation is widely used, the system is certainly not completely understood and there are still many unanswered questions. A first big unknown is how and when the variable number of T-DNA copies are integrated at random positions in the plant chromosomes. However, using the new recombination technologies, the target position and copy number of transgenes can now better be controlled. A second enigma is how a particular transgene may show up to 1000 fold different expression levels in independently obtained transformants. It became clear that the transgene expression level is not only controlled by its sequence such as the quality of the promotor and transcript maturation signals but also by the transgene insertion site, the copy number, genetic background and several expression controlling mechanisms. Studying transgenes, it was found that chromatin modifications, DNA scanning mechanisms and posttranscriptional control all modulate the expression level. Particular determinants are inverted repeats and thresholds for aberrantly processed transcripts in nucleus and cytoplasm.. We will present 2 examples of how various epigenetic mechanisms can change transgene expression levels. I will conclude by illustrating the application of plant transgene expression for molecular farming of valuable recombinant proteins. For this, we will focus on the protective ability of IgA antibodies when provided in the feed against enterotoxigenic Escherichia coli infection in weaned piglets.

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PSB event reminder
by contact＠psb.vib-ugent.be 21 May '13

21 May '13

Calendar Name: seminars Scheduled for: Thursday, May 23 2013, 11:00 - 12:30 Event text: Prof Ann Depicker VIB, Dept. of Plant Systems Biology Ghent University Gent BELGIUM Details: �Plant transgenes: integration, silencing and overexpression� ABSTRACT Plant transgene expression group I will describe the general picture of plant transgenesis by presenting the latest results obtained in the group on the integration and expression of transgenes in plants. Although Agrobacterium mediated transformation is widely used, the system is certainly not completely understood and there are still many unanswered questions. A first big unknown is how and when the variable number of T-DNA copies are integrated at random positions in the plant chromosomes. However, using the new recombination technologies, the target position and copy number of transgenes can now better be controlled. A second enigma is how a particular transgene may show up to 1000 fold different expression levels in independently obtained transformants. It became clear that the transgene expression level is not only controlled by its sequence such as the quality of the promotor and transcript maturation signals but also by the transgene insertion site, the copy number, genetic background and several expression controlling mechanisms. Studying transgenes, it was found that chromatin modifications, DNA scanning mechanisms and posttranscriptional control all modulate the expression level. Particular determinants are inverted repeats and thresholds for aberrantly processed transcripts in nucleus and cytoplasm.. We will present 2 examples of how various epigenetic mechanisms can change transgene expression levels. I will conclude by illustrating the application of plant transgene expression for molecular farming of valuable recombinant proteins. For this, we will focus on the protective ability of IgA antibodies when provided in the feed against enterotoxigenic Escherichia coli infection in weaned piglets.

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Seminar Prof Ueli Grossniklaus on Tuesday, May 28 at 11 am
by Delphine Verspeel 14 May '13

14 May '13

You are receiving this e-mail because you subscribed to our seminars announcements and reminders service at https://maillist.psb.ugent.be/mailman/listinfo/seminars . If you do not wish to receive this information anymore, please unsubscribe from future mailings at https://maillist.psb.ugent.be/mailman/options/seminars . cid:946540515@15122008-0D1CPSBcid:946540515@15122008-0D23 VIB - Department of Plant Systems Biology Technologiepark 927 B - 9052 Gent/Zwijnaarde Phone: +32 9 33 13 800 Fax: +32 9 33 13 809 Http://www.psb.vib-ugent.be

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Seminar Prof Ann Depicker on Thursday, May 23 at 11 am
by Delphine Verspeel 13 May '13

13 May '13

You are receiving this e-mail because you subscribed to our seminars announcements and reminders service at https://maillist.psb.ugent.be/mailman/listinfo/seminars . If you do not wish to receive this information anymore, please unsubscribe from future mailings at https://maillist.psb.ugent.be/mailman/options/seminars . cid:946540515@15122008-0D1CPSBcid:946540515@15122008-0D23 VIB - Department of Plant Systems Biology Technologiepark 927 B - 9052 Gent/Zwijnaarde Phone: +32 9 33 13 800 Fax: +32 9 33 13 809 Http://www.psb.vib-ugent.be

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PSB event reminder
by contact＠psb.vib-ugent.be 06 May '13

06 May '13

Calendar Name: seminars Scheduled for: Monday, May 6 2013, 11:00 - 12:30 Event text: Prof Waltraud Schulze Department of Plant Systems Biology University of Hohenheim Stuttgart GERMANY Details: �Into the unknown: Dynamic phosphoproteomics in identifying novel functions for a plant receptor kinase� ABSTRACT Growth and development of plants depends on uptake and assimilation of nutrients. Many assimilation products of macronutrients are not only essential for plant growth but also have signaling functions. Similarly to hormones they can trigger and control various metabolic, physiological and developmental processes. The nutrient and sugar induced signal transduction events upstream of transcription are less well understood. Since signaling pathways involve protein phosphorylation, modification-dependent changes in protein abundance and activity can be important features in signaling networks. Therefore, the analysis of phosphorylation events of membrane proteins under different nutrient regimes, and their dynamics was analyzed with the aim to identify proteins involved in early nutrient signaling processes. Using systems biology approaches such as clustering of time-course data and respective network reconstruction we are able to identify candidate proteins as key players in the plant signalling networks. Based on the network model, we generate new biological hypotheses on novel protein functions that we experimentally verified in tailored physiological and cell biological experiments. An example of a novel function for a plant receptor kinase in context of sucrose-induced responses will be discussed.

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PSB event reminder
by contact＠psb.vib-ugent.be 04 May '13

04 May '13

Calendar Name: seminars Scheduled for: Monday, May 6 2013, 11:00 - 12:30 Event text: Prof Waltraud Schulze Department of Plant Systems Biology University of Hohenheim Stuttgart GERMANY Details: �Into the unknown: Dynamic phosphoproteomics in identifying novel functions for a plant receptor kinase� ABSTRACT Growth and development of plants depends on uptake and assimilation of nutrients. Many assimilation products of macronutrients are not only essential for plant growth but also have signaling functions. Similarly to hormones they can trigger and control various metabolic, physiological and developmental processes. The nutrient and sugar induced signal transduction events upstream of transcription are less well understood. Since signaling pathways involve protein phosphorylation, modification-dependent changes in protein abundance and activity can be important features in signaling networks. Therefore, the analysis of phosphorylation events of membrane proteins under different nutrient regimes, and their dynamics was analyzed with the aim to identify proteins involved in early nutrient signaling processes. Using systems biology approaches such as clustering of time-course data and respective network reconstruction we are able to identify candidate proteins as key players in the plant signalling networks. Based on the network model, we generate new biological hypotheses on novel protein functions that we experimentally verified in tailored physiological and cell biological experiments. An example of a novel function for a plant receptor kinase in context of sucrose-induced responses will be discussed.

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Seminar Prof Waltraud Schulze on Monday, May 6 at 11 am
by Delphine Verspeel 26 Apr '13

26 Apr '13

You are receiving this e-mail because you subscribed to our seminars announcements and reminders service at https://maillist.psb.ugent.be/mailman/listinfo/seminars . If you do not wish to receive this information anymore, please unsubscribe from future mailings at https://maillist.psb.ugent.be/mailman/options/seminars . cid:946540515@15122008-0D1CPSBcid:946540515@15122008-0D23 VIB - Department of Plant Systems Biology Technologiepark 927 B - 9052 Gent/Zwijnaarde Phone: +32 9 33 13 800 Fax: +32 9 33 13 809 Http://www.psb.vib-ugent.be

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PSB event reminder
by contact＠psb.vib-ugent.be 18 Apr '13

18 Apr '13

Calendar Name: seminars Scheduled for: Thursday, April 18 2013, 11:00 - 12:30 Event text: Prof Dirk Inz� Scientific Director Head of Department VIB, Dept. of Plant Systems Biology Ghent University Gent BELGIUM Details: �LEAF growth: from images to molecular networks� ABSTRACT Growth of plants and plant organs is orchestrated by complex molecular networks that integrates both intrinsic development signals encoded by the genome as well as a wide variety of environmental cues such as light, availability of water and minerals, temperature, e.a. Understanding the molecular composition and topology of these networks ultimately will accelerate advanced breeding and gene engineering for higher yielding crops. We have chosen leaves as a model organ to understand growth and size control mechanisms. As leaf growth is a quantitative trait, several (semi-) automated growth analysis platforms were developed to analyze leaf growth over time. Detailed cellular and molecular analysis of numerous Arabidopsis mutants revealed the existence of at least five mechanisms that contribute to final leaf size: i) the initial size of the leaf primordium; ii) cell cycle duration; iii) the developmental timing of the transition from cell division to cell expansion; iv) the timing of meristemoid division; and v) cell expansion. For each mechanism, multiple genes have been identified that when overexpressed or mutated enhance leaf organ size. For example, cell cycle duration appears to be controlled by the ANAPHASE PROMOTING COMPLEX, a multi-protein E3 ligase that is involved in mitosis. On the other hand the transition from cell division to cell expansion during leaf development is mediated by the gibberellic acid (GA) dependent activity of a chromatin remodeling complex. GA levels in the growth zones are regulated by the activity of two stress responsive transcription factors ERF5 and ERF6 and our experimental data show that these transcription factor have a pivotal role in regulation growth in response to the environment. Furthermore, GA also was shown to have an important function in mediating leaf growth in maize and by engineering GA metabolism maize leaves that have a 40% increase in length were obtained. We will discussed our current understanding of growth regulatory networks and how we can use this information to improve crop yield.

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PSB event reminder
by contact＠psb.vib-ugent.be 16 Apr '13

16 Apr '13

Calendar Name: seminars Scheduled for: Thursday, April 18 2013, 11:00 - 12:30 Event text: Prof Dirk Inz� Scientific Director Head of Department VIB, Dept. of Plant Systems Biology Ghent University Gent BELGIUM Details: �LEAF growth: from images to molecular networks� ABSTRACT Growth of plants and plant organs is orchestrated by complex molecular networks that integrates both intrinsic development signals encoded by the genome as well as a wide variety of environmental cues such as light, availability of water and minerals, temperature, e.a. Understanding the molecular composition and topology of these networks ultimately will accelerate advanced breeding and gene engineering for higher yielding crops. We have chosen leaves as a model organ to understand growth and size control mechanisms. As leaf growth is a quantitative trait, several (semi-) automated growth analysis platforms were developed to analyze leaf growth over time. Detailed cellular and molecular analysis of numerous Arabidopsis mutants revealed the existence of at least five mechanisms that contribute to final leaf size: i) the initial size of the leaf primordium; ii) cell cycle duration; iii) the developmental timing of the transition from cell division to cell expansion; iv) the timing of meristemoid division; and v) cell expansion. For each mechanism, multiple genes have been identified that when overexpressed or mutated enhance leaf organ size. For example, cell cycle duration appears to be controlled by the ANAPHASE PROMOTING COMPLEX, a multi-protein E3 ligase that is involved in mitosis. On the other hand the transition from cell division to cell expansion during leaf development is mediated by the gibberellic acid (GA) dependent activity of a chromatin remodeling complex. GA levels in the growth zones are regulated by the activity of two stress responsive transcription factors ERF5 and ERF6 and our experimental data show that these transcription factor have a pivotal role in regulation growth in response to the environment. Furthermore, GA also was shown to have an important function in mediating leaf growth in maize and by engineering GA metabolism maize leaves that have a 40% increase in length were obtained. We will discussed our current understanding of growth regulatory networks and how we can use this information to improve crop yield.

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