PINOID Positively Regulates Auxin Efflux in<i>Arabidopsis</i>Root Hair Cells and Tobacco Cells

Lee, Sang Ho; Cho, Hyung-Taeg

doi:10.1105/tpc.105.035972

Cited by 148 publications

(152 citation statements)

References 45 publications

(59 reference statements)

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“…In the case of ethylene this is supported by the phenotype of eto1 mutants, which synthesize more ethylene and have longer root hairs than wild-type plants (Pitts et al, 1998). Overexpressing a PIN auxin efflux carrier or the PIN regulator PINOID (PID: At2g34650) reduces root hair growth (Lee and Cho 2006;Cho et al, 2007), consistent with the idea that intracellular auxin sustains growth. Auxin levels may be influenced by strigolactone, to alter root hair length (Kapulnik et al, 2011).…”

Section: Molecular Genetics Of Root Hair Formationsupporting

confidence: 57%

“…Growth can be prolonged by increasing the expression of the small GTPase ROP2 (Jones et al, 2002) or the transcription factor ROOT HAIR SIX-LIKE4 (RSL4/bHLH54: At1g27740; Yi et al, 2010). Growth is sustained by auxin (Lee and Cho 2006), which is supplied by neighboring non-hair cells that transport auxin through the epidermis from the root tip toward the shoot (Jones et al, 2009). As the root tip grows away from young root hair cells, they receive less and less auxin, until the auxin supply is lost and growth ceases (Jones et al, 2009).…”

Section: Cessation Of Tip Growthmentioning

confidence: 99%

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Root Hairs

Grierson

Nielsen

Ketelaarc

et al. 2014

The Arabidopsis Book

193

220

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Roots hairs are cylindrical extensions of root epidermal cells that are important for acquisition of nutrients, microbe interactions, and plant anchorage. The molecular mechanisms involved in the specification, differentiation, and physiology of root hairs in Arabidopsis are reviewed here. Root hair specification in Arabidopsis is determined by position-dependent signaling and molecular feedback loops causing differential accumulation of a WD-bHLH-Myb transcriptional complex. The initiation of root hairs is dependent on the RHD6 bHLH gene family and auxin to define the site of outgrowth. Root hair elongation relies on polarized cell expansion at the growing tip, which involves multiple integrated processes including cell secretion, endomembrane trafficking, cytoskeletal organization, and cell wall modifications. The study of root hair biology in Arabidopsis has provided a model cell type for insights into many aspects of plant development and cell biology.

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Section: Molecular Genetics Of Root Hair Formationsupporting

confidence: 57%

Section: Cessation Of Tip Growthmentioning

confidence: 99%

Root Hairs

Grierson

Nielsen

Ketelaarc

et al. 2014

The Arabidopsis Book

193

220

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“…Deviations in free (active) indole-3-acetic acid (IAA) levels or in auxin signalling induce (high levels) or repress (low levels) root hair growth 18 . As expected, the root-hair-specific expression of PILS1, PILS3 and PILS5 significantly reduced root hair length (Fig.…”

mentioning

confidence: 99%

A novel putative auxin carrier family regulates intracellular auxin homeostasis in plants

Barbez

Kubeš

Rolčı́k

et al. 2012

Nature

356

406

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The phytohormone auxin acts as a prominent signal, providing, by its local accumulation or depletion in selected cells, a spatial and temporal reference for changes in the developmental program [1][2][3][4][5][6][7] . The distribution of auxin depends on both auxin metabolism (biosynthesis, conjugation and degradation) [8][9][10] and cellular auxin transport [11][12][13][14][15] . We identified in silico a novel putative auxin transport facilitator family, called PIN-LIKES (PILS). Here we illustrate that PILS proteins are required for auxin-dependent regulation of plant growth by determining the cellular sensitivity to auxin. PILS proteins regulate intracellular auxin accumulation at the endoplasmic reticulum and thus auxin availability for nuclear auxin signalling. PILS activity affects the level of endogenous auxin indole-3-acetic acid (IAA), presumably via intracellular accumulation and metabolism. Our findings reveal that the transport machinery to compartmentalize auxin within the cell is of an unexpected molecular complexity and demonstrate this compartmentalization to be functionally important for a number of developmental processes.Prominent auxin carriers with fundamental importance during plant development are PIN-FORMED (PIN) proteins [1][2][3]6,9,15 . PIN1-type auxin carriers regulate the directional intercellular auxin transport at the plasma membrane. In contrast, atypical family member PIN5 regulates intracellular auxin compartmentalization into the lumen of the endoplasmic reticulum and its role in auxin homeostasis was recently identified 15,16 . PIN proteins have a predicted central hydrophilic loop, flanked at each side by five transmembrane domains. We screened in silico for novel PIN-like putative carrier proteins with a predicted topology similar to PIN proteins ( Fig. 1a and Supplementary Fig. 2) and identified a protein family of seven members (Fig. 1b) in Arabidopsis thaliana, which we designated as the PILS proteins. In contrast to the similarities in the predicted protein topology, PIN and PILS proteins do not show pronounced protein sequence identity (10-18%), which limits the identification of PILS proteins by conventional, reciprocal basic local alignment search tool (BLAST) approaches. However, the distinct PIN and PILS protein families contain both the InterPro auxin carrier domain which is an insilico-defined domain, aiming to predict auxin transport function (http://www.ebi.ac.uk/panda/InterPro.html). The PILS putative carrier family is conserved throughout the whole plant lineage, including unicellular algae (such as Ostreococcus tauri and Chlamydomonas reinhardtii) (Supplementary Fig. 3) where PIN proteins are absent 16 , indicating that PILS proteins are evolutionarily older.PILS genes are broadly expressed in various tissues (Fig. 1c) and PILS2-PILS7 were transcriptionally upregulated by auxin application in wild-type seedlings (Fig. 1d-f and Supplementary Fig. 4), indicating a role in auxin-dependent processes. To investigate the potential function of the putative PILS auxi...

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“…Auxin transporters also affect root hair formation and elongation by regulating intracellular auxin concentration in the epidermal cells. [15][16][17] In Arabidopsis, the polar localization of PIN1, PIN3, and PIN7 at the basal side of stele cells and PIN4 at the basal side of root stem cells mediate rootward auxin flow; similarly, PIN2 at the upper side of root epidermis and at the basal side of root cortex mediates shootward auxin flow. 14,18,19 Arabidopsis and rice PIN1-overexpressing plants showed increased numbers of lateral roots, and pin1 mutants displayed a defect in lateral root initiation.…”

mentioning

confidence: 99%