TRANSPORTER OF IBA1 Links Auxin and Cytokinin to Influence Root Architecture

Michniewicz, Marta; Ho, Cheng-Hsun; Enders, Tara A.; Floro, Eric; Damodaran, Suresh; Gunther, Lauren K.; Powers, Samantha K.; Frick, Elizabeth M.; Topp, Christopher N.; Frommer, Wolf B.; Strader, Lucia C.

doi:10.1016/j.devcel.2019.06.010

Cited by 51 publications

(60 citation statements)

References 76 publications

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“…IBA homeostasis is also regulated via its transport and conjugation, but only a few regulators have been identified. The type G ABC transporters ABCG36 and ABCG37 can efflux IBA from the cells ( Strader and Bartel, 2009 ; Ruzicka et al , 2010 ), the NPF family member TRANSPORTER OF IBA1 transports IBA across the vacuolar membrane ( Michniewicz et al , 2019 ), while the generic PXA1/COMATOSE transporter is likely to import IBA into the peroxisome. Like other auxins, IBA conjugates with sugars and amino acids.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, recent works have reported the critical role of IBA to IAA conversion in the root cap as a source of auxin for the oscillatory positioning of LR founder cells ( De Rybel et al , 2012 ; Xuan et al , 2015 ). IBA to IAA conversion taking place in the LRP itself also probably participates in further LR development ( Strader and Bartel, 2011 ; Michniewicz et al , 2019 ). Despite all these reported functions in root development, the importance of IBA-derived IAA relative to other IAA sources is still poorly understood and scarcely documented, particularly in the case of changing environmental constraints.…”

Section: Introductionmentioning

confidence: 99%

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A glutathione-dependent control of the indole butyric acid pathway supports Arabidopsis root system adaptation to phosphate deprivation

Trujillo-Hernandez

Bariat

Strader

et al. 2020

Journal of Experimental Botany

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Root system architecture results from a highly plastic developmental process to adapt to environmental conditions. In particular, the development of lateral roots and root hair growth are constantly optimized to the rhizosphere properties, including biotic and abiotic constraints. The development of the root system is tightly controlled by auxin, the driving morphogenic hormone in plants. Glutathione, a major thiol redox regulator, is also critical for root development but its interplay with auxin is scarcely understood. Previous work showed that glutathione deficiency does not alter root responses to indole acetic acid (IAA), the main active auxin in plants. Because indole butyric acid (IBA), another endogenous auxinic compound, is an important source of IAA for the control of root development, we investigated the crosstalk between glutathione and IBA during root development. We show that glutathione deficiency alters lateral roots and root hair responses to exogenous IBA but not IAA. Detailed genetic analyses suggest that glutathione regulates IBA homeostasis or conversion to IAA in the root cap. Finally, we show that both glutathione and IBA are required to trigger the root hair response to phosphate deprivation, suggesting an important role for this glutathione-dependent regulation of the auxin pathway in plant developmental adaptation to its environment.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A glutathione-dependent control of the indole butyric acid pathway supports Arabidopsis root system adaptation to phosphate deprivation

Trujillo-Hernandez

Bariat

Strader

et al. 2020

Journal of Experimental Botany

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“…Interestingly, one of the Arabidopsis NPF proteins, NPF6.3, transports IAA in vivo besides its well-known function as the nitrate transporter NRT1.1/CHL1 17,39 . More recently, another NPF protein, NPF5.12 was shown to be an IBA transporter (also called TOB1) 40 . Therefore, it is possible that NPF7.3 transports IAA, IBA and/or their related compounds.…”

Section: Discussionmentioning

confidence: 99%

The Arabidopsis NRT1/PTR FAMILY Protein NPF7.3/NRT1.5 is an Indole-3-butyric Acid Transporter Involved in Root Gravitropism

Watanabe

Takahashi

Kanno

et al. 2020

Preprint

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17Active membrane transport of plant hormones and their related compounds is an essential process 18 that determines the distribution of the compounds within plant tissues and, hence, regulates various 19 physiological events. Here, we report that the Arabidopsis NITRATE TRANSPORTER 1/PEPTIDE 20 TRANSPORTER FAMILY 7.3 (NPF7.3) protein functions as a transporter of indole-3-butyric acid 21 (IBA), a precursor of the major endogenous auxin indole-3-acetic acid (IAA). When expressed in 22Auxin is the best-characterized mobile plant hormone that plays crucial roles in many 41 aspects of plant growth and development by mainly regulating cell division, cell elongation and cell 42 differentiation 1 . Indole-3-acetic acid (IAA) is the major naturally occurring auxin. Measurements of 43 IAA by mass spectrometry as well as visualization of auxin responses by reporter genes have 44 suggested that IAA is differentially distributed within plant tissues. Furthermore, appropriate IAA 45 gradients or local IAA maxima/minima are required for proper auxin functions. In fact, mutants 46 impaired in IAA transport have been isolated based on their defects in organ development and 47 (also called as CHL1 or NRT1.1) is a well-characterized dual-affinity nitrate transporter that 65 mediates nitrogen uptake from the rhizosphere, however, the same protein also transports IAA 17,18 . 66More recently, the Arabidopsis NPF5.12 protein, also named TRANSPORTER OF IBA1 (TOB1), 67 was identified as an IBA transporter that localizes to the vacuolar membrane 14 . Here, we report that 68 NPF7.3, originally identified as a low-affinity nitrate transporter (NRT1.5) and later shown to be a 69 proton/potassium antiporter in Arabidopsis 19,20 , functions as an IBA transporter. We found that 70 npf7.3 mutant roots were not able to respond properly to gravity. Our transport assays in yeast 71 demonstrated that NPF7.3 efficiently mediated IBA uptake into the cells. Asymmetric distribution of 72 auxin activities in root tips following the reorientation of roots was not observed in the npf7.3 73 mutants, and the defect was restored by IAA but not by IBA treatment. These results suggest that 74 cellular IBA uptake mediated by NPF7.3 contributes to the production of IAA required to fully 75 induce Arabidopsis root gravitropism. 76 77 78Results 79 Mutants defective in NPF7.3 exhibit altered root gravitropism 80Some of the 53 members of the Arabidopsis NPF proteins transport plant hormones such as IAA, 81 abscisic acid (ABA), gibberellin (GA) and jasmonates (jasmonoyl isoleucine; JA-Ile) 16 . Thus, we 82 compound is considered to be an IAA precursor 25,26 . Interestingly, IBA also accumulated at a much 126 higher level in the cells expressing NPF7.3 compared to the control cells (Fig. 2b). Moreover, IBA 127 was more efficiently taken into the cells expressing NPF7.3 than IAA. 128Kinetic analyses indicated that the Km values of NPF7.3 for IAA and IBA were 129 comparable (14 µM and 11 µM for IAA and IBA, respectively), however, NPF7.3 had a much higher 130Vmax va...

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“…TRANSPORTER OF IBA1 (TOB1) was identified in a forward genetics screen for suppression of abcg36 IBA hypersensitivity (Michniewicz et al, 2019). TOB1 belongs to the NTR1 PTR FAMILY (NPF), a part of the larger group of major facilitator superfamily (MFS) transporters (Leran et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…TOB1 belongs to the NTR1 PTR FAMILY (NPF), a part of the larger group of major facilitator superfamily (MFS) transporters (Leran et al, 2014). The tob1 loss-of-function mutant displays mild resistance to 2,4-DB and IBA and wild-type sensitivity to IAA and 2,4-D in root elongation assays (Michniewicz et al, 2019). Indeed, transport assays using excised Arabidopsis root tips reveal reduced accumulation of [ 3 H]-IBA and no difference in [ 3 H]-IAA accumulation in tob1 compared to wild type root tips (Michniewicz et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Indole 3-Butyric Acid Metabolism and Transport in Arabidopsis thaliana

Damodaran

Strader

2019

Front. Plant Sci.

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Auxin is a crucial phytohormone involved in multiple plant developmental processes. Spatiotemporal regulation of auxin levels is necessary to achieve development of organs in the proper place and at the proper time. These levels can be regulated by conversion of auxin [indole 3-acetic acid (IAA)] from its conjugated forms and its precursors. Indole 3-butyric acid (IBA) is an auxin precursor that is converted to IAA in a peroxisomal β-oxidation process. In Arabidopsis, altered IBA-to-IAA conversion leads to multiple plant defects, indicating that IBA contributes to auxin homeostasis in critical ways. Like IAA, IBA and its conjugates can be transported in plants, yet many IBA carriers still need to be identified. In this review, we discuss IBA transporters identified in Arabidopsis thus far, including the pleiotropic drug resistance (PDR) members of the G subfamily of ATP-binding cassette transporter (ABCG) family, the TRANSPORTER OF IBA1 (TOB1) member of the major facilitator superfamily (MFS) family and hypothesize other potential IBA carriers involved in plant development.

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TRANSPORTER OF IBA1 Links Auxin and Cytokinin to Influence Root Architecture

Abstract: Highlights d TRANSPORTER OF IBA1 (TOB1) identified as transporter of the auxin precursor IBA d TOB1 localizes to the vacuolar membrane d TOB1 regulates root system architecture (RSA) d TOB1 integrates cytokinin response and auxin homeostasis to regulate RSA

Cited by 51 publications

References 76 publications

A glutathione-dependent control of the indole butyric acid pathway supports Arabidopsis root system adaptation to phosphate deprivation

A glutathione-dependent control of the indole butyric acid pathway supports Arabidopsis root system adaptation to phosphate deprivation

The Arabidopsis NRT1/PTR FAMILY Protein NPF7.3/NRT1.5 is an Indole-3-butyric Acid Transporter Involved in Root Gravitropism

Indole 3-Butyric Acid Metabolism and Transport in Arabidopsis thaliana

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