Root branching toward water involves posttranslational modification of transcription factor ARF7
Orosa-Puente, Beatriz ; Leftley, Nicola ; Wangenheim, Daniel von; Banda, Jason ; Srivastava, Anjil K. ; Hill, Kristine ; Truskina, Jekaterina ; Bhosale, Rahul ; Morris, Emily ; Srivastava, Moumita ; Kümpers, Britta ; Goh, Tatsuaki ; Fukaki, Hidehiro ; Vermeer, Joop E.M. ; Vernoux, Teva ; Dinneny, José R. ; French, Andrew P. ; Bishopp, Anthony ; Sadanandom, Ari ; Bennett, Malcolm J. - \ 2018
Science 362 (2018)6421. - ISSN 0036-8075 - p. 1407 - 1410.
Plants adapt to heterogeneous soil conditions by altering their root architecture. For example, roots branch when in contact with water by using the hydropatterning response. We report that hydropatterning is dependent on auxin response factor ARF7. This transcription factor induces asymmetric expression of its target gene LBD16 in lateral root founder cells. This differential expression pattern is regulated by posttranslational modification of ARF7 with the small ubiquitin-like modifier (SUMO) protein. SUMOylation negatively regulates ARF7 DNA binding activity. ARF7 SUMOylation is required to recruit the Aux/IAA (indole-3-acetic acid) repressor protein IAA3. Blocking ARF7 SUMOylation disrupts IAA3 recruitment and hydropatterning. We conclude that SUMO-dependent regulation of auxin response controls root branching pattern in response to water availability.
Transcriptional control of tissue formation throughout root development
Moreno-Risueno, M.A. ; Sozzani, Rosangela ; Yardimci, Galip Gürkan ; Petricka, J.J. ; Vernoux, Teva ; Blilou, Ikram ; Alonso, Jose ; Winter, C.M. ; Ohler, Uwe ; Scheres, Ben ; Benfey, P.N. - \ 2015
Science 350 (2015)6259. - ISSN 0036-8075 - p. 426 - 430.
Tissue patterns are dynamically maintained. Continuous formation of plant tissues during postembryonic growth requires asymmetric divisions and the specification of cell lineages. We show that the BIRDs and SCARECROW regulate lineage identity, positional signals, patterning, and formative divisions throughout Arabidopsis root growth. These transcription factors are postembryonic determinants of the ground tissue stem cells and their lineage. Upon further activation by the positional signal SHORT-ROOT (a mobile transcription factor), they direct asymmetric cell divisions and patterning of cell types. The BIRDs and SCARECROW with SHORT-ROOT organize tissue patterns at all formative steps during growth, ensuring developmental plasticity.
Reporters for sensitive and quantitative measurement of auxin response
Liao, C.Y. ; Smet, W.M.S. ; Brunoud, G. ; Yoshida, S. ; Vernoux, T. ; Weijers, D. - \ 2015
Nature Methods : techniques for life scientists and chemists 12 (2015). - ISSN 1548-7091 - p. 207 - 210.
apical-basal axis - box protein tir1 - aux/iaa proteins - arabidopsis - transcription - expression - transport - specificity - sufficient - perception
The visualization of hormonal signaling input and output is key to understanding how multicellular development is regulated. The plant signaling molecule auxin triggers many growth and developmental responses, but current tools lack the sensitivity or precision to visualize these. We developed a set of fluorescent reporters that allow sensitive and semiquantitative readout of auxin responses at cellular resolution in Arabidopsis thaliana. These generic tools are suitable for any transformable plant species.
Halotropism is a response of plant roots to avoid a saline environment
Galvan-Ampudia, Carlos S. ; Julkowska, Magdalena M. ; Darwish, Essam ; Gandullo, Jacinto ; Korver, Ruud A. ; Brunoud, Geraldine ; Haring, Michel A. ; Munnik, Teun ; Vernoux, Teva ; Testerink, Christa - \ 2013
Current Biology 23 (2013)20. - ISSN 0960-9822 - p. 2044 - 2050.
Tropisms represent fascinating examples of how plants respond to environmental signals by adapting their growth and development. Here, a novel tropism is reported, halotropism, allowing plant seedlings to reduce their exposure to salinity by circumventing a saline environment. In response to a salt gradient, Arabidopsis, tomato, and sorghum roots were found to actively prioritize growth away from salinity above following the gravity axis. Directionality of this response is established by an active redistribution of the plant hormone auxin in the root tip, which is mediated by the PIN-FORMED 2 (PIN2) auxin efflux carrier. We show that salt-induced phospholipase D activity stimulates clathrin-mediated endocytosis of PIN2 at the side of the root facing the higher salt concentration. The intracellular relocalization of PIN2 allows for auxin redistribution and for the directional bending of the root away from the higher salt concentration. Our results thus identify a cellular pathway essential for the integration of environmental cues with auxin-regulated root growth that likely plays a key role in plant adaptative responses to salt stress.
A novel Aux/IAA28 signalling cascade activates GATA23-dependent specification of lateral root founder cell identity
Rybel, B. De; Vassileva, V. ; Parizot, B. ; Demeulenaere, M. ; Grunewald, W. ; Audenaert, D. ; Campenhout, J. Van; Overvoorde, P. ; Janssen, L. ; Vanneste, S. ; Moller, B.K. ; Wilson, M. ; Holman, T. ; Isterdaele, G. Van; Brunoud, G. ; Vuylsteke, M. ; Vernoux, T. ; Veylder, L. De; Inze, D. ; Weijers, D. ; Bennett, M. ; Beeckman, T. - \ 2010
Current Biology 20 (2010)19. - ISSN 0960-9822 - p. 1697 - 1706.
of-function mutation - arabidopsis-thaliana - auxin transport - initiation - gene - fate - differentiation - expression - pericycle - divisions
Background - Lateral roots are formed at regular intervals along the main root by recurrent specification of founder cells. To date, the mechanism by which branching of the root system is controlled and founder cells become specified remains unknown. Results - Our study reports the identification of the auxin regulatory components and their target gene, GATA23, which control lateral root founder cell specification. Initially, a meta-analysis of lateral root-related transcriptomic data identified the GATA23 transcription factor. GATA23 is expressed specifically in xylem pole pericycle cells before the first asymmetric division and is correlated with oscillating auxin signaling maxima in the basal meristem. Also, functional studies revealed that GATA23 controls lateral root founder cell identity. Finally, we show that an Aux/IAA28-dependent auxin signaling mechanism in the basal meristem controls GATA23 expression. Conclusions - We have identified the first molecular components that control lateral root founder cell identity in the Arabidopsis root. These include an IAA28-dependent auxin signaling module in the basal meristem region that regulates GATA23 expression and thereby lateral root founder cell specification and root branching patterns