Non‐canonical
            <scp>AUX</scp>
            /
            <scp>IAA</scp>
            protein
            <scp>IAA</scp>
            33 competes with canonical
            <scp>AUX</scp>
            /
            <scp>IAA</scp>
            repressor
            <scp>IAA</scp>
            5 to negatively regulate auxin signaling

Lv, Bingsheng; Yu, Qianqian; Li, Jiajia; Wen, Xuejing; Yan, Zhenwei; Hu, Kongqin; Li, Hanbing; Kong, Xiangpei; Li, Cuiling; Tian, Huiyu; Smet, Ive De; Zhang, Xiansheng; Ding, Zhaojun

doi:10.15252/embj.2019101515

Cited by 80 publications

(39 citation statements)

References 61 publications

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“…The discrepancy between Aux/IAA stabilization and DR5 upregulation might be due to the modulation of auxin concentration induced by biosynthesis and by polar auxin transport; however, it might also be related to alternative auxin signaling pathways that regulate auxin-responsive genes in parallel with the canonical TIR1/Aux/IAA-dependent pathway. The alternative pathway involves the auxin-mediated C-terminal cleavage of transmembrane kinase1 (TMK1), which contributes to the regulation of auxin responsive genes in the hypocotyl, LRs, and RAM [ 77 , 78 , 79 , 80 ]. Moreover, experiments with high spatiotemporal resolution have shown that root growth inhibition was dependent on TIR1/AFB signaling and Aux/IAA stability, but independent of transcriptional regulation [ 51 ].…”

Section: Discussionmentioning

confidence: 99%

Glutathione Enhances Auxin Sensitivity in Arabidopsis Roots

2020

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Root development is regulated by the tripeptide glutathione (GSH), a strong non-enzymatic antioxidant found in plants but with a poorly understood function in roots. Here, Arabidopsis mutants deficient in GSH biosynthesis (cad2, rax1, and rml1) and plants treated with the GSH biosynthesis inhibitor buthionine sulfoximine (BSO) showed root growth inhibition, significant alterations in the root apical meristem (RAM) structure (length and cell division), and defects in lateral root formation. Investigation of the molecular mechanisms of GSH action showed that GSH deficiency modulated total ubiquitination of proteins and inhibited the auxin-related, ubiquitination-dependent degradation of Aux/IAA proteins and the transcriptional activation of early auxin-responsive genes. However, the DR5 auxin transcriptional response differed in root apical meristem (RAM) and pericycle cells. The RAM DR5 signal was increased due to the up-regulation of the auxin biosynthesis TAA1 protein and down-regulation of PIN4 and PIN2, which can act as auxin sinks in the root tip. The transcription auxin response (the DR5 signal and expression of auxin responsive genes) in isolated roots, induced by a low (0.1 µM) auxin concentration, was blocked following GSH depletion of the roots by BSO treatment. A higher auxin concentration (0.5 µM) offset this GSH deficiency effect on DR5 expression, indicating that GSH deficiency does not completely block the transcriptional auxin response, but decreases its sensitivity. The ROS regulation of GSH, the active GSH role in cell proliferation, and GSH cross-talk with auxin assume a potential role for GSH in the modulation of root architecture under stress conditions.

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Section: Discussionmentioning

confidence: 99%

Glutathione Enhances Auxin Sensitivity in Arabidopsis Roots

2020

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“…Interactions between non-canonical AUX/IAAs and ARFs may also be regulated at the level of posttranscriptional modifications, and phosphorylation driven by TRANSMEMBRANE KINASE1 (TMK1) and MITOGEN-ACTIVATED PROTEIN KINASE14 (MPK14) was found to modulate the repressor function of non-canonical AUX/IAAs. Interestingly, AUXIN BINDING PROTEIN1 (ABP1), an apoplast-localized auxin receptor, may induce activation of the TMK1/MPK14-signaling pathway [ 27 , 28 ]. Although IAA20 and IAA30 were not revealed in the embryo proper at the 8-cell stage [ 29 ], Llavata–Peris and coworkers suggested that IAA33, another non-canonical AUX/IAA, was expressed in all cells until the late globular stage [ 30 ].…”

Section: Multi-level Regulation Of Hd-zip ⅲ and Ap2-domain Transcription Factorsmentioning

confidence: 99%

Do Plasmodesmata Play a Prominent Role in Regulation of Auxin-Dependent Genes at Early Stages of Embryogenesis?

Winnicki

Polit

Żabka

et al. 2021

Cells

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Plasmodesmata form intercellular channels which ensure the transport of various molecules during embryogenesis and postembryonic growth. However, high permeability of plasmodesmata may interfere with the establishment of auxin maxima, which are required for cellular patterning and the development of distinct tissues. Therefore, diffusion through plasmodesmata is not always desirable and the symplastic continuum must be broken up to induce or accomplish some developmental processes. Many data show the role of auxin maxima in the regulation of auxin-responsive genes and the establishment of various cellular patterns. However, still little is known whether and how these maxima are formed in the embryo proper before 16-cell stage, that is, when there is still a nonpolar distribution of auxin efflux carriers. In this work, we focused on auxin-dependent regulation of plasmodesmata function, which may provide rapid and transient changes of their permeability, and thus take part in the regulation of gene expression.

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“…In Arabidopsis, auxin binds directly to AtTIR1 and initiates auxin responses by regulating the degradation of Aux/IAA proteins (Lv et al, 2020). Because MdTIR1 was predicted to interact with MdIAA14, MdIAA28, MdIAA29, MdIAA43, and MdIAA46 in the hormone-related sub-subnetwork (Figure 5A), we hypothesized that MdTIR1 mediates root growth by promoting MdIAA degradation in apple.…”

Section: Malus Domestica Transport Inhibitor Resistant 1 Promotes the Degradation Of Mdiaasmentioning

confidence: 99%

“…As the auxin concentration increases, auxin binds to TIR1 to induce the rapid degradation of Aux/IAAs. This releases transcriptional activator ARFs from repression and leads to the subsequent transcriptional activation of auxin-responsive genes that regulate plant growth and development (Lv et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Function identification of MdTIR1 in apple root growth benefited from the predicted MdPPI network

Liu

et al. 2020

JIPB

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Protein–protein interaction (PPI) network analysis is an effective method to identify key proteins during plant development, especially in species for which basic molecular research is lacking, such as apple (Malus domestica). Here, an MdPPI network containing 30 806 PPIs was inferred in apple and its quality and reliability were rigorously verified. Subsequently, a root‐growth subnetwork was extracted to screen for critical proteins in root growth. Because hormone‐related proteins occupied the largest proportion of critical proteins, a hormone‐related sub‐subnetwork was further extracted from the root‐growth subnetwork. Among these proteins, auxin‐related M. domestica TRANSPORT INHIBITOR RESISTANT 1 (MdTIR1) served as the central, high‐degree node, implying that this protein exerts essential roles in root growth. Furthermore, transgenic apple roots overexpressing an MdTIR1 transgene displayed increased primary root elongation. Expression analysis showed that MdTIR1 significantly upregulated auxin‐responsive genes in apple roots, indicating that it mediates root growth in an auxin‐dependent manner. Further experimental validation revealed that MdTIR1 interacted with and accelerated the degradation of MdIAA28, MdIAA43, and MdIAA46. Thus, MdTIR1‐mediated degradation of MdIAAs is critical in auxin signal transduction and root growth regulation in apple. Moreover, our network analysis and high‐degree node screening provide a novel research technique for more generally characterizing molecular mechanisms.

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Non‐canonical AUX / IAA protein IAA 33 competes with canonical AUX / IAA repressor IAA 5 to negatively regulate auxin signaling

Cited by 80 publications

References 61 publications

Glutathione Enhances Auxin Sensitivity in Arabidopsis Roots

Glutathione Enhances Auxin Sensitivity in Arabidopsis Roots

Do Plasmodesmata Play a Prominent Role in Regulation of Auxin-Dependent Genes at Early Stages of Embryogenesis?

Function identification of MdTIR1 in apple root growth benefited from the predicted MdPPI network

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