- Seminars - maillist.psb.ugent.be

PSB event reminder
by contact＠psb.vib-ugent.be 09 May '11

09 May '11

Calendar Name: seminars Scheduled for: Wednesday, May 11 2011, 14:00 - 15:30 Event text: Dr Hinanit Koltai Department Of Ornamental Horticulture Institute of Plant Sciences ARO, Volcani center Bet-Dagan ISRAEL Details: �Strigolactones are regulators of root development� ABSTRACT Strigolactones (SLs) or associated molecules were defined as a new group of plant hormones that suppress lateral shoot branching. Recently, we have demonstrated that SLs are regulators of root development: they regulate lateral root formation and root hair elongation. Moreover, the epistatic relations between SLs, auxin and ethylene were determined in the wild type and hormone-signaling mutants. In tomato SLs were shown to interfere with the activity of auxin-efflux carriers in the presence of exogenously applied auxin, thereby affecting primary root growth, cell elongation and root hair elongation in tomato. In Arabidopsis SLs and ethylene were found to regulate root hair elongation via a common regulatory pathway, in which ethylene is epistatic to SLs, whereas SLs' effect on root hair elongation requires ethylene synthesis. SL signaling was not needed for the auxin root hair-response. Auxin signaling, on the other hand, was not necessary, but enhanced the root hair response to SLs. The results suggest that the SL, ethylene and auxin hormonal pathways converge for regulation of root hair elongation. Moreover, SL regulation of root growth suggests that these hormones are mediators of plant responses to nutritional conditions and coordinators of shoot and root development. However, SLs are also signal molecules that facilitate hyphal branching of the symbiotic arbuscular mycorrhizal fungi and thus, plant-symbiotic interactions. The two roles played by SLs, in plant development and symbiotic communication, may imply their evolution as either modulators of plant development or enhancers of beneficial plant associations.

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PSB event reminder
by contact＠psb.vib-ugent.be 09 May '11

09 May '11

Calendar Name: seminars Scheduled for: Monday, May 9 2011, 11:00 - 12:30 Event text: Dr Pascal Ratet Institut des Sciences du V�g�tal CNRS Gif-sur-Yvette FRANCE Details: �Insertion mutants in Medicago truncatula as tools to study symbiotic nodule identity and bacterial recognition.� ABSTRACT The legume species Medicago truncatula establishes a symbiotic interaction with the nitrogen-fixing bacterium Sinorhizobium meliloti. A complex molecular dialogue between the two partners is necessary for microbial colonization and plant organogenesis leading to a functional nitrogen-fixing nodule. During formation of this organ, specific cellular differentiation is seen both for host cells and for the endosymbiotic bacteria, called bacteroids. This process is accompanied by novel gene expression patterns for both plant and bacteria. Our laboratory has demonstrated that insertion mutant collections can be developed in this model legume plant using the tobacco retrotransposons Tnt1 or the endogenous retroptransposon MERE1. In collaboration with the Noble Foundation (OK-USA), we characterized tagged symbiotic plant mutants that form no nodules, nonfunctional nodules or nodules with altered development during the interaction with S. meliloti. Among these mutants, we identified three alleles of a new Fix- symbiotic mutant locus. The Fix- nodules produce fluorescent compounds reminiscent of phenolic molecules normally produced during defense reactions. This observation suggests a shift from symbiosis to pathogenesis during the interaction between the two symbiotic partners. A detailed analysis indicates that bacteroid differentiation is altered in this plant mutant and that the mutated gene may be important for the plant to recognize bacteria. The tagged locus was cloned and we are studying the biological function of this gene in order to understand its role in the recognition between the two partners. We also characterized 4 alleles of an original mutant that we called noot (nodule root). This noot mutant develops nodules that appear functional for nitrogen fixation in the presence of bacteria but are altered in the pattern of development and organization. During development, a root appears in apical position of the nodules. The noot mutation is sufficient to convert a nodule into a root suggesting that root and nodule morphogenetic pathways share more common elements that previously admitted. We have cloned the gene responsible for this phenotype. This mutant unravels one element of the molecular determinants controlling the symbiotic nodule organ identity but also how during evolution nodules evolved from legume roots.

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verandering mailadres
by Antje Rohde 08 May '11

08 May '11

Wil mijn mailadres veranderen naar Antje.Rohde(a)bayer.com Hartelijk dank, Antje Rohde

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PSB event reminder
by contact＠psb.vib-ugent.be 08 May '11

08 May '11

Calendar Name: seminars Scheduled for: Tuesday, May 10 2011, 11:00 - 12:30 Event text: Dr Keiko Sugimoto RIKEN Plant Science Center Tsurumi, Yokohama JAPAN Details: �Transcriptional control of plant cell dedifferentiation by WIND1� ABSTRACT Many multicellular organisms have a remarkable capacity to regenerate new organs after wounding. As a first step of organ regeneration, adult somatic cells often dedifferentiate to reacquire cell proliferation potential but mechanisms underlying this control remain unknown in plants. We have recently shown that an AP2/ERF transcription factor WOUND-INDUCED DEDIFFERENTIATION 1 (WIND1) participates in the regulation of cell dedifferentiation in Arabidopsis (Iwase et al. 2011). WIND1 is rapidly induced at the wound site and it promotes cell dedifferentiation and subsequent formation of callus, a mass of pluripotent cells. We further demonstrate that ectopic overexpression of WIND1 is sufficient to establish and maintain the dedifferentiated status of somatic cells without exogenous auxin and cytokinin. An in vivo imaging of a synthetic cytokinin reporter reveals that wounding up-regulates the B-type ARABIDOPSIS RESPONSE REGULATOR (ARR)-mediated cytokinin response and that WIND1 acts via the ARR-dependent signaling pathway to promote cell dedifferentiation. Discovery of WIND1 provides a new molecular basis to further dissect how transcriptional regulators reprogram cellular differentiation status in plants. Iwase A et al. The AP2/ERF transcription factor WIND1 controls cell dedifferentiation in Arabidopsis. Curr Biol 21: 508-514 (2011)

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PSB event reminder
by contact＠psb.vib-ugent.be 07 May '11

07 May '11

Calendar Name: seminars Scheduled for: Monday, May 9 2011, 11:00 - 12:30 Event text: Dr Pascal Ratet Institut des Sciences du V�g�tal CNRS Gif-sur-Yvette FRANCE Details: �Insertion mutants in Medicago truncatula as tools to study symbiotic nodule identity and bacterial recognition.� ABSTRACT The legume species Medicago truncatula establishes a symbiotic interaction with the nitrogen-fixing bacterium Sinorhizobium meliloti. A complex molecular dialogue between the two partners is necessary for microbial colonization and plant organogenesis leading to a functional nitrogen-fixing nodule. During formation of this organ, specific cellular differentiation is seen both for host cells and for the endosymbiotic bacteria, called bacteroids. This process is accompanied by novel gene expression patterns for both plant and bacteria. Our laboratory has demonstrated that insertion mutant collections can be developed in this model legume plant using the tobacco retrotransposons Tnt1 or the endogenous retroptransposon MERE1. In collaboration with the Noble Foundation (OK-USA), we characterized tagged symbiotic plant mutants that form no nodules, nonfunctional nodules or nodules with altered development during the interaction with S. meliloti. Among these mutants, we identified three alleles of a new Fix- symbiotic mutant locus. The Fix- nodules produce fluorescent compounds reminiscent of phenolic molecules normally produced during defense reactions. This observation suggests a shift from symbiosis to pathogenesis during the interaction between the two symbiotic partners. A detailed analysis indicates that bacteroid differentiation is altered in this plant mutant and that the mutated gene may be important for the plant to recognize bacteria. The tagged locus was cloned and we are studying the biological function of this gene in order to understand its role in the recognition between the two partners. We also characterized 4 alleles of an original mutant that we called noot (nodule root). This noot mutant develops nodules that appear functional for nitrogen fixation in the presence of bacteria but are altered in the pattern of development and organization. During development, a root appears in apical position of the nodules. The noot mutation is sufficient to convert a nodule into a root suggesting that root and nodule morphogenetic pathways share more common elements that previously admitted. We have cloned the gene responsible for this phenotype. This mutant unravels one element of the molecular determinants controlling the symbiotic nodule organ identity but also how during evolution nodules evolved from legume roots.

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FW: Upcoming seminars May
by Delphine Verspeel 02 May '11

02 May '11

Dear All, Enclosed the updated list for May. Kind regards, Delphine From: seminars-bounces(a)psb.vib-ugent.be [mailto:seminars-bounces@psb.vib-ugent.be] On Behalf Of Delphine Verspeel Sent: maandag 2 mei 2011 16:15 To: meetings(a)psb.vib-ugent.be Subject: [Seminars] Upcoming seminars May Dear All, Enclosed you can find our upcoming seminars for May. Kind regards, Delphine ____________________________________________ Delphine Verspeel Administrative Assistant VIB, Department of Plant Systems Biology Ghent University Technologiepark 927 9052 Gent Belgium Phone: +32/9/33.13.800 Fax: +32/33.13.809 Http://www.psb.ugent.be despe(a)psb.vib-ugent.be <mailto:nahau@psb.vib-ugent.be>

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Seminar Dr Hinanit Koltai 11/05
by Delphine Verspeel 02 May '11

02 May '11

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> 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> https://maillist.psb.ugent.be/mailman/options/seminars. cid:946540515@15122008-0D1C PSB cid: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 Dr Hinanit Koltai 11/05
by Delphine Verspeel 02 May '11

02 May '11

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> 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> https://maillist.psb.ugent.be/mailman/options/seminars. cid:946540515@15122008-0D1C PSB cid: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 Dr Keiko Sugimoto 10/05
by Delphine Verspeel 02 May '11

02 May '11

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> 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> https://maillist.psb.ugent.be/mailman/options/seminars. cid:946540515@15122008-0D1C PSB cid: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 Dr Pascal Ratet 09/05
by Delphine Verspeel 02 May '11

02 May '11

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> 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> https://maillist.psb.ugent.be/mailman/options/seminars. cid:946540515@15122008-0D1C PSB cid: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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