PLANT DEVELOPMENT. INTEGRATION OF GROWTH AND PATTERNING DURING VASCULAR TISSUE FORMATION IN ARABIDOPSIS

Citation:

De Rybel, B, Adibi M, Breda AS, Wendrich JR, Smit ME, Novak O, Yamaguchi N, Yoshida S, Van Isterdael G, Palovaara J, Nijsse B, Boekschoten MV, Hooiveld G, Beeckman T, Wagner D, Ljung K, Fleck C, Weijers D.  2014.   Plant development. Integration of growth and patterning during vascular tissue formation in Arabidopsis, Aug 8. Science. 345:1255215., Number 6197

Abstract:

Coordination of cell division and pattern formation is central to tissue and organ development, particularly in plants where walls prevent cell migration. Auxin and cytokinin are both critical for division and patterning, but it is unknown how these hormones converge upon tissue development. We identify a genetic network that reinforces an early embryonic bias in auxin distribution to create a local, nonresponding cytokinin source within the root vascular tissue. Experimental and theoretical evidence shows that these cells act as a tissue organizer by positioning the domain of oriented cell divisions. We further demonstrate that the auxin-cytokinin interaction acts as a spatial incoherent feed-forward loop, which is essential to generate distinct hormonal response zones, thus establishing a stable pattern within a growing vascular tissue.

Notes:

De Rybel, BertAdibi, MiladBreda, Alice SWendrich, Jos RSmit, Margot ENovak, OndrejYamaguchi, NobutoshiYoshida, SaikoVan Isterdael, GertPalovaara, JoakimNijsse, BartBoekschoten, Mark VHooiveld, GuidoBeeckman, TomWagner, DorisLjung, KarinFleck, ChristianWeijers, DolfengResearch Support, Non-U.S. Gov’tResearch Support, U.S. Gov’t, Non-P.H.S.New York, N.Y.2014/08/12 06:00Science. 2014 Aug 8;345(6197):1255215. doi: 10.1126/science.1255215.

Related External Link

O-GLCNAC-MEDIATED INTERACTION BETWEEN VER2 AND TAGRP2 ELICITS TAVRN1 MRNA ACCUMULATION DURING VERNALIZATION IN WINTER WHEAT

Citation:

Xiao, J, Xu S, Li C, Xu Y, Xing L, Niu Y, Huan Q, Tang Y, Zhao C, Wagner D, Gao C, Chong K.  2014.  O-GlcNAc-mediated interaction between VER2 and TaGRP2 elicits TaVRN1 mRNA accumulation during vernalization in winter wheat. Nat Commun. 5:4572.

Abstract:

Vernalization, sensing of prolonged cold, is important for seasonal flowering in eudicots and monocots. While vernalization silences a repressor (FLC, MADS-box transcription factor) in eudicots, it induces an activator (TaVRN1, an AP1 clade MADS-box transcription factor) in monocots. The mechanism for TaVRN1 induction during vernalization is not well understood. Here we reveal a novel mechanism for controlling TaVRN1 mRNA accumulation in response to prolonged cold sensing in wheat. The carbohydrate-binding protein VER2, a jacalin lectin, promotes TaVRN1 upregulation by physically interacting with the RNA-binding protein TaGRP2. TaGRP2 binds to TaVRN1 pre-mRNA and inhibits TaVRN1 mRNA accumulation. The physical interaction between VER2 and TaGRP2 is controlled by TaGRP2 O-GlcNAc modification, which gradually increases during vernalization. The interaction between VER2 and O-GlcNAc-TaGRP2 reduces TaGRP2 protein accumulation in the nucleus and/or promotes TaGRP2 dissociation from TaVRN1, leading to TaVRN1 mRNA accumulation. Our data reveal a new mechanism for sensing prolonged cold in temperate cereals.

Notes:

Related External Link

GIBBERELLIN ACTS POSITIVELY THEN NEGATIVELY TO CONTROL ONSET OF FLOWER FORMATION IN ARABIDOPSIS

Citation:

Yamaguchi, N, Winter CM, Wu MF, Kanno Y, Yamaguchi A, Seo M, Wagner D.  2014.   Gibberellin acts positively then negatively to control onset of flower formation in Arabidopsis, May 9. Science. 344:638-41., Number 6184

Abstract:

The switch to reproductive development is biphasic in many plants, a feature important for optimal pollination and yield. We show that dual opposite roles of the phytohormone gibberellin underpin this phenomenon in Arabidopsis. Although gibberellin promotes termination of vegetative development, it inhibits flower formation. To overcome this effect, the transcription factor LEAFY induces expression of a gibberellin catabolism gene; consequently, increased LEAFY activity causes reduced gibberellin levels. This allows accumulation of gibberellin-sensitive DELLA proteins. The DELLA proteins are recruited by SQUAMOSA PROMOTER BINDING PROTEIN-LIKE transcription factors to regulatory regions of the floral commitment gene APETALA1 and promote APETALA1 up-regulation and floral fate synergistically with LEAFY. The two opposing functions of gibberellin may facilitate evolutionary and environmental modulation of plant inflorescence architecture.

Notes:

Yamaguchi, NobutoshiWinter, Cara MWu, Miin-FengKanno, YuriYamaguchi, AyakoSeo, MitsunoriWagner, DorisengT32-HD007516/HD/NICHD NIH HHS/Research Support, N.I.H., ExtramuralResearch Support, U.S. Gov’t, Non-P.H.S.New York, N.Y.2014/05/09 06:00Science. 2014 May 9;344(6184):638-41. doi: 10.1126/science.1250498.

Related External Link

WAGNER LAB RESEARCH FEATURED IN PENN NEWS

“Anecdotal evidence was that the hormone gibberellin promoted the switch to flower formation in short-lived plants, along with other cues such as temperature, season and photoperiod,” Wagner said. “But in the long-lived plants, like in fruit trees, people have known that if you sprayed them with the hormone it inhibited flower production. So it was a big puzzle: why would the same hormone do one thing in short-lived plants and another in long-lived plants?”

Click here to read more

LEAFY TOGETHER WITH POLAR AUXIN TRANSPORT COORDINATES ARABIDOPSIS FLOWER DEVELOPMENT.

Citation:

Yamaguchi, N, Wu MF, Winter C, Wagner D.  2014.  LEAFY together with polar auxin transport coordinates Arabidopsis flower development.. Plants. 3:251-265., Number 2

Abstract:

The plant specific transcription factor LEAFY (LFY) plays a pivotal role in the developmental switch to floral meristem identity in Arabidopsis. Our recent study revealed that LFY additionally acts downstream of AUXIN RESPONSE FACTOR5/MONOPTEROS to promote flower primordium initiation. LFY also promotes initiation of the floral organ and floral organ identity. To further investigate the interplay between LFY and auxin during flower development, we examined the phenotypic consequence of disrupting polar auxin transport in lfy mutants by genetic means. Plants with compromised LFY activity exhibit increased sensitivity to disruption of polar auxin transport. Compromised polar auxin transport activity in the lfy mutant background resulted in formation of fewer floral organs, abnormal gynoecium development, and fused sepals. In agreement with these observations, expression of the auxin response reporter DR5rev::GFP as well as of the direct LFY target CUP-SHAPED COTYLEDON2 were altered in lfy mutant flowers. We also uncovered reduced expression of ETTIN, a regulator of gynoecium development and a direct LFY target. Our results suggest that LFY and polar auxin transport coordinately modulate flower development by regulating genes required for elaboration of the floral organs.

Notes:

NA

Related External Link

PROTOCOLS: CHROMATIN IMMUNOPRECIPITATION FROM ARABIDOPSIS TISSUES

Citation:

Yamaguchi, N, Winter CM, Wu MF, Kwon CS, William DA, Wagner D.  2014.  PROTOCOLS: Chromatin Immunoprecipitation from Arabidopsis Tissues. Arabidopsis Book. 12:e0170.

Abstract:

The ability of proteins to associate with genomic DNA in the context of chromatin is critical for many nuclear processes including transcription, replication, recombination, and DNA repair. Chromatin immunoprecipication (ChIP) is a practical and useful technique for characterizing protein / DNA association in vivo. The procedure generally includes six steps: (1) crosslinking the protein to the DNA; (2) isolating the chromatin; (3) chromatin fragmentation; (4) imunoprecipitation with antibodies against the protein of interest; (5) DNA recovery; and (6) PCR identification of factor associated DNA sequences. In this protocol, we describe guidelines, experimental setup, and conditions for ChIP in intact Arabidopsis tissues. This protocol has been used to study association of histone modifications, of chromatin remodeling ATPases, as well as of sequence-specific transcription factors with the genomic DNA in various Arabidopsis thaliana tissues. The protocol described focuses on ChIP-qPCR, but can readily be adapted for use in ChIP-chip or ChIP-seq experiments. The entire procedure can be completed within 3 days.

Notes:

Yamaguchi, NobutoshiWinter, Cara MWu, Miin-FengKwon, Chang SeobWilliam, Dilusha AWagner, Doriseng2014/03/22 06:00Arabidopsis Book. 2014 Feb 17;12:e0170. doi: 10.1199/tab.0170. eCollection 2014.

Related External Link

ANGUSTIFOLIA3 BINDS TO SWI/SNF CHROMATIN REMODELING COMPLEXES TO REGULATE TRANSCRIPTION DURING ARABIDOPSIS LEAF DEVELOPMENT

Citation:

Vercruyssen, L, Verkest A, Gonzalez N, Heyndrickx KS, Eeckhout D, Han SK, Jegu T, Archacki R, Van Leene J, Andriankaja M, De Bodt S, Abeel T, Coppens F, Dhondt S, De Milde L, Vermeersch M, Maleux K, Gevaert K, Jerzmanowski A, Benhamed M, Wagner D, Vandepoele K, De Jaeger G, Inze D.  2014.  ANGUSTIFOLIA3 Binds to SWI/SNF Chromatin Remodeling Complexes to Regulate Transcription during Arabidopsis Leaf Development, Jan. The Plant cell. 26:210-29., Number 1

Abstract:

The transcriptional coactivator ANGUSTIFOLIA3 (AN3) stimulates cell proliferation during Arabidopsis thaliana leaf development, but the molecular mechanism is largely unknown. Here, we show that inducible nuclear localization of AN3 during initial leaf growth results in differential expression of important transcriptional regulators, including GROWTH REGULATING FACTORs (GRFs). Chromatin purification further revealed the presence of AN3 at the loci of GRF5, GRF6, CYTOKININ RESPONSE FACTOR2, CONSTANS-LIKE5 (COL5), HECATE1 (HEC1), and ARABIDOPSIS RESPONSE REGULATOR4 (ARR4). Tandem affinity purification of protein complexes using AN3 as bait identified plant SWITCH/SUCROSE NONFERMENTING (SWI/SNF) chromatin remodeling complexes formed around the ATPases BRAHMA (BRM) or SPLAYED. Moreover, SWI/SNF ASSOCIATED PROTEIN 73B (SWP73B) is recruited by AN3 to the promoters of GRF5, GRF3, COL5, and ARR4, and both SWP73B and BRM occupy the HEC1 promoter. Furthermore, we show that AN3 and BRM genetically interact. The data indicate that AN3 associates with chromatin remodelers to regulate transcription. In addition, modification of SWI3C expression levels increases leaf size, underlining the importance of chromatin dynamics for growth regulation. Our results place the SWI/SNF-AN3 module as a major player at the transition from cell proliferation to cell differentiation in a developing leaf.

Notes:

Vercruyssen, LiesbethVerkest, AurineGonzalez, NathalieHeyndrickx, Ken SEeckhout, DominiqueHan, Soon-KiJegu, TeddyArchacki, RafalVan Leene, JelleAndriankaja, MeganDe Bodt, StefanieAbeel, ThomasCoppens, FrederikDhondt, StijnDe Milde, LiesbethVermeersch, MattiasMaleux, KatrienGevaert, KrisJerzmanowski, AndrzejBenhamed, MoussaWagner, DorisVandepoele, KlaasDe Jaeger, GeertInze, DirkPlant Cell. 2014 Jan;26(1):210-29. doi: 10.1105/tpc.113.115907. Epub 2014 Jan 17.

Related External Link