Lateral root formation is blocked by a gain‐of‐function mutation in the <i>SOLITARY‐ROOT/IAA14</i> gene of <i>Arabidopsis</i>

Fukaki, Hidehiro; Tameda, Satoshi; Masuda, Haruka; Tasaka, Masao

doi:10.1046/j.0960-7412.2001.01201.x

Cited by 646 publications

(750 citation statements)

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“…This suggests a connection between auxin signaling via PtaIAA19.3 and fungus-induced LR development. Experiments with Arabidopsis slr1 (a stabilized form of AtIAA14 conferring a gain-of-function mutation), which is blocked in auxin signaling (Fukaki et al, 2002), confirmed that the classical auxin signaling pathway is required for fungus-induced LR development in plants. In poplar, PtaIAA19.3 may be a key actor in the basic auxin signaling pathway in roots during LRI.…”

Section: Polar Auxin Transport Regulates Lr Induction During the Rootmentioning

confidence: 91%

The Ectomycorrhizal FungusLaccaria bicolorStimulates Lateral Root Formation in Poplar and Arabidopsis through Auxin Transport and Signaling

et al. 2009

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The early phase of the interaction between tree roots and ectomycorrhizal fungi, prior to symbiosis establishment, is accompanied by a stimulation of lateral root (LR) development. We aimed to identify gene networks that regulate LR development during the early signal exchanges between poplar (Populus tremula 3 Populus alba) and the ectomycorrhizal fungus Laccaria bicolor with a focus on auxin transport and signaling pathways. Our data demonstrated that increased LR development in poplar and Arabidopsis (Arabidopsis thaliana) interacting with L. bicolor is not dependent on the ability of the plant to form ectomycorrhizae. LR stimulation paralleled an increase in auxin accumulation at root apices. Blocking plant polar auxin transport with 1-naphthylphthalamic acid inhibited LR development and auxin accumulation. An oligoarray-based transcript profile of poplar roots exposed to molecules released by L. bicolor revealed the differential expression of 2,945 genes, including several components of polar auxin transport (PtaPIN and PtaAUX genes), auxin conjugation (PtaGH3 genes), and auxin signaling (PtaIAA genes). Transcripts of PtaPIN9, the homolog of Arabidopsis AtPIN2, and several PtaIAAs accumulated specifically during the early interaction phase. Expression of these rapidly induced genes was repressed by 1-naphthylphthalamic acid. Accordingly, LR stimulation upon contact with L. bicolor in Arabidopsis transgenic plants defective in homologs of these genes was decreased or absent. Furthermore, in Arabidopsis pin2, the root apical auxin increase during contact with the fungus was modified. We propose a model in which fungus-induced auxin accumulation at the root apex stimulates LR formation through a mechanism involving PtaPIN9-dependent auxin redistribution together with PtaIAA-based auxin signaling.Most temperate forest trees develop a mutualistic root symbiosis with ectomycorrhizal soil fungi. During the establishment of ectomycorrhiza (ECM), fungal hyphae invade the root from root cap cells in and upwards to the epidermis (Horan et al., 1988). After attachment to epidermal cells, hyphae multiply to form a series of layers that differentiate to establish a mantle structure around the root (Horan et al., 1988). An internal network of hyphae between the epidermis and root cortex cells forms the Hartig net (Blasius et al., 1986), while extraradical hyphae prospect throughout the surrounding soil and gather nutrients. Morphological observations of forming ECMs have shown that in the vicinity of the fungus the root architecture of the host plant is profoundly modified. Interaction with hyphae stimulates lateral root (LR) formation, dichotomy of the root apical meristem in conifer species, and cytodifferentiation of root cells (radial elongation and root hair decay; Horan et al., 1988;Dexheimer and Pargney, 1991;. Even though several studies have focused on LR stimulation during ECM formation, it still remains unclear what the molecular mechanisms are that modify root development during contact with the fungus.In the ...

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Section: Polar Auxin Transport Regulates Lr Induction During the Rootmentioning

confidence: 91%

The Ectomycorrhizal FungusLaccaria bicolorStimulates Lateral Root Formation in Poplar and Arabidopsis through Auxin Transport and Signaling

et al. 2009

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“…In Arabidopsis, two mutants, Slr (Fukaki et al, 2002) and alf4 (Celenza et al, 1995), were identified that are affected in lateral root initiation but do not significantly affect primary root formation. The slr gene encodes for IAA14, a member of the Aux/IAA protein family (Fukaki et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

“…The slr gene encodes for IAA14, a member of the Aux/IAA protein family (Fukaki et al, 2002). The alf4 gene encodes for a plant-specific protein with no structural similarity to proteins of known function (DiDonato et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

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Isolation, Characterization, and Pericycle-Specific Transcriptome Analyses of the Novel Maize Lateral and Seminal Root Initiation Mutant rum1

Woll

Borsuk²,

Stransky³

et al. 2005

Plant Physiology

179

190

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The monogenic recessive maize (Zea mays) mutant rootless with undetectable meristems 1 (rum1) is deficient in the initiation of the embryonic seminal roots and the postembryonic lateral roots at the primary root. Lateral root initiation at the shoot-borne roots and development of the aerial parts of the mutant rum1 are not affected. The mutant rum1 displays severely reduced auxin transport in the primary root and a delayed gravitropic response. Exogenously applied auxin does not induce lateral roots in the primary root of rum1. Lateral roots are initiated in a specific cell type, the pericycle. Cell-type-specific transcriptome profiling of the primary root pericycle 64 h after germination, thus before lateral root initiation, via a combination of laser capture microdissection and subsequent microarray analyses of 12k maize microarray chips revealed 90 genes preferentially expressed in the wild-type pericycle and 73 genes preferentially expressed in the rum1 pericycle (fold change .2; P-value ,0.01; estimated false discovery rate of 13.8%). Among the 51 annotated genes predominately expressed in the wild-type pericycle, 19 genes are involved in signal transduction, transcription, and the cell cycle. This analysis defines an array of genes that is active before lateral root initiation and will contribute to the identification of checkpoints involved in lateral root formation downstream of rum1.

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“…The degradation of the AUX/IAA proteins is mediated by the proteasomal pathway, which typically involves ubiquitination by E3-ubiquitin ligases (19). We investigated whether the changes in auxin responsiveness during the activity-dormancy transition involve alterations in the proteasomal degradation of AUX/IAA proteins as shown for Arabidopsis AUX/IAA proteins (20)(21)(22)(23)(24). For this, we analyzed the ubiquitination of a GST fusion of PttIAA3, a poplar AUX/IAA gene expressed in the cambial meristem in hybrid aspen (25).…”

Section: Establishment Of Endodormancy Is Correlated With the Loss Ofmentioning

confidence: 99%

Activity–dormancy transition in the cambial meristem involves stage-specific modulation of auxin response in hybrid aspen

Baba

Karlberg²,

Schmidt³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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The molecular basis of short-day-induced growth cessation and dormancy in the meristems of perennial plants (e.g., forest trees growing in temperate and high-latitude regions) is poorly understood. Using global transcript profiling, we show distinct stagespecific alterations in auxin responsiveness of the transcriptome in the stem tissues during short-day-induced growth cessation and both the transition to and establishment of dormancy in the cambial meristem of hybrid aspen trees. This stage-specific modulation of auxin signaling appears to be controlled via distinct mechanisms. Whereas the induction of growth cessation in the cambium could involve induction of repressor auxin response factors (ARFs) and down-regulation of activator ARFs, dormancy is associated with perturbation of the activity of the SKP-Cullin-F-box TIR (SCF TIR ) complex, leading to potential stabilization of repressor auxin (AUX)/indole-3-acetic acid (IAA) proteins. Although the role of hormones, such as abscisic acid (ABA) and gibberellic acid (GA), in growth cessation and dormancy is well established, our data now implicate auxin in this process. Importantly, in contrast to most developmental processes in which regulation by auxin involves changes in cellular auxin contents, day-length-regulated induction of cambial growth cessation and dormancy involves changes in auxin responses rather than auxin content.short days | meristem identity P erennial plants growing in temperate and high-latitude regions anticipate the approach of winter by sensing the associated reduction in day length (1), and when the day length becomes shorter than the critical length permitting growth [short-day signal (SD)], cell division terminates in the meristems (1). Immediately following cessation of cell division, exposure of plants to permissive conditions (e.g., long days) leads to the reversal of growth arrest (2), and this stage of growth arrest is referred to as ecodormancy. Continued exposure of ecodormant plants to short days brings about the transition from ecodormancy to endodormancy (2). The endodormant state is characterized by the inability of the meristems to respond to growth-promotive signals in contrast to the ecodormant state. Exposure to chilling temperatures is required to restore the ability of endodormant meristems to respond to growth-promotive signals and to reinitiate growth subsequently (3).Recently, the photoreceptor PHYA (4) and homologs of the flowering time genes CONSTANS and FT (5, 6) have been shown to be early-acting components in SD-induced growth cessation in trees. The targets and signaling intermediates of the SD pathway downstream of these early-acting components in growth cessation and dormancy remain largely unexplored (7). Although ecodormant and endodormant states can be distinguished physiologically, the molecular mechanisms underlying the establishment of endodormancy and the inability of endodormant meristems to respond to growth-promotive signals have remained elusive.We investigated whether the SD-regulated induction o...

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Lateral root formation is blocked by a gain‐of‐function mutation in the SOLITARY‐ROOT/IAA14 gene of Arabidopsis

Cited by 646 publications

References 75 publications

The Ectomycorrhizal FungusLaccaria bicolorStimulates Lateral Root Formation in Poplar and Arabidopsis through Auxin Transport and Signaling

The Ectomycorrhizal FungusLaccaria bicolorStimulates Lateral Root Formation in Poplar and Arabidopsis through Auxin Transport and Signaling

Isolation, Characterization, and Pericycle-Specific Transcriptome Analyses of the Novel Maize Lateral and Seminal Root Initiation Mutant rum1

Activity–dormancy transition in the cambial meristem involves stage-specific modulation of auxin response in hybrid aspen

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