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Brassinazole resistant 1 (BZR1)-dependent brassinosteroid signalling pathway leads to ectopic activation of quiescent cell division and suppresses columella stem cell differentiation.

Lee HS, Kim Y, Pham G, Kim JW, Song JH, Lee Y, Hwang YS, Roux SJ, Kim SH - J. Exp. Bot. (2015)

Bottom Line: BR promotes intense nuclear accumulation of BZR1 in the root tip area, and the binding of BZR1 to the promoters of several root development-regulating genes, modulating their expression in the root stem cell niche area.They could also inhibit auxin-dependent distal stem cell differentiation by antagonizing the auxin/WOX5-dependent pathway.In conclusion, BZR1-/BES1-mediated BR signalling pathways show differential effects on the maintenance of root apical meristem activities: they stimulate ectopic QC division while they show opposite effects on the differentiation of distal columella stem cells in a BR concentration- and BZR1-/BES1-dependent manner.

View Article: PubMed Central - PubMed

Affiliation: Division of Biological Science and Technology, Yonsei University, Wonju, 220-710, Republic of Korea.

No MeSH data available.


Related in: MedlinePlus

BL dose-dependent and BZR1-/BES1-mediated signalling pathways have differential effects on the differentiation of distal CSCs. (A–B) Concentration-dependent effects of BL on the QC and the distal meristem differentiation in Col-0 (A) and det2 (B) plants. (C) Effects of BR-related genetic background on the QC and distal meristem differentiation. (D) Pictures of representative seedlings used for the cell layer measurements presented in (A). Note that some Col-0 plants treated with higher concentrations of BL (10−9 M) have no CSC. (E) Pictures of representative seedlings used for the cell layer measurement presented in (C). Seedlings were grown on 1/2 MS agar media for 7 DAG in the presence or absence of the indicated concentration of BL (A) or 1/2 MS agar media for 8 DAG (C) before measurement of the QC, CSC, and CC layer frequencies. mPS-PI staining was performed to reveal cell shape, the presence of starch granules. Cells with PI-stained starch granules (black dots) or cells below the starch-stained cell layers were considered columella cells. Cells between QC layers and the starch-stained CC layers were considered CSC cell layers. n>50 seedlings for each treatment. (This figure is available in colour at JXB online.)
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Figure 2: BL dose-dependent and BZR1-/BES1-mediated signalling pathways have differential effects on the differentiation of distal CSCs. (A–B) Concentration-dependent effects of BL on the QC and the distal meristem differentiation in Col-0 (A) and det2 (B) plants. (C) Effects of BR-related genetic background on the QC and distal meristem differentiation. (D) Pictures of representative seedlings used for the cell layer measurements presented in (A). Note that some Col-0 plants treated with higher concentrations of BL (10−9 M) have no CSC. (E) Pictures of representative seedlings used for the cell layer measurement presented in (C). Seedlings were grown on 1/2 MS agar media for 7 DAG in the presence or absence of the indicated concentration of BL (A) or 1/2 MS agar media for 8 DAG (C) before measurement of the QC, CSC, and CC layer frequencies. mPS-PI staining was performed to reveal cell shape, the presence of starch granules. Cells with PI-stained starch granules (black dots) or cells below the starch-stained cell layers were considered columella cells. Cells between QC layers and the starch-stained CC layers were considered CSC cell layers. n>50 seedlings for each treatment. (This figure is available in colour at JXB online.)

Mentions: mPS-PI staining was performed according to the method of Truernit et al. (2008) with some modifications to reveal cell shape, the presence of starch granules, and auxin maximum (described in Figs 2, 3 and 4). In brief, roots were fixed in fixative (50% methanol and 10% acetic acid) and then incubated in 1% periodic acid after rinsing with water. Next, the tissues were treated with modified Pseudo Schiff reagent (100mM sodium metabisulphite and 0.15N HCl, supplemented with freshly added PI to a final concentration of 100 μg/ml). The samples were transferred onto microscope slides and covered with a chloral hydrate solution (4g chloral hydrate, 1ml glycerol, and 2ml water) for 5min to observe fluorescence or reflection signals using the Zeiss Confocal microscope.


Brassinazole resistant 1 (BZR1)-dependent brassinosteroid signalling pathway leads to ectopic activation of quiescent cell division and suppresses columella stem cell differentiation.

Lee HS, Kim Y, Pham G, Kim JW, Song JH, Lee Y, Hwang YS, Roux SJ, Kim SH - J. Exp. Bot. (2015)

BL dose-dependent and BZR1-/BES1-mediated signalling pathways have differential effects on the differentiation of distal CSCs. (A–B) Concentration-dependent effects of BL on the QC and the distal meristem differentiation in Col-0 (A) and det2 (B) plants. (C) Effects of BR-related genetic background on the QC and distal meristem differentiation. (D) Pictures of representative seedlings used for the cell layer measurements presented in (A). Note that some Col-0 plants treated with higher concentrations of BL (10−9 M) have no CSC. (E) Pictures of representative seedlings used for the cell layer measurement presented in (C). Seedlings were grown on 1/2 MS agar media for 7 DAG in the presence or absence of the indicated concentration of BL (A) or 1/2 MS agar media for 8 DAG (C) before measurement of the QC, CSC, and CC layer frequencies. mPS-PI staining was performed to reveal cell shape, the presence of starch granules. Cells with PI-stained starch granules (black dots) or cells below the starch-stained cell layers were considered columella cells. Cells between QC layers and the starch-stained CC layers were considered CSC cell layers. n>50 seedlings for each treatment. (This figure is available in colour at JXB online.)
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4507784&req=5

Figure 2: BL dose-dependent and BZR1-/BES1-mediated signalling pathways have differential effects on the differentiation of distal CSCs. (A–B) Concentration-dependent effects of BL on the QC and the distal meristem differentiation in Col-0 (A) and det2 (B) plants. (C) Effects of BR-related genetic background on the QC and distal meristem differentiation. (D) Pictures of representative seedlings used for the cell layer measurements presented in (A). Note that some Col-0 plants treated with higher concentrations of BL (10−9 M) have no CSC. (E) Pictures of representative seedlings used for the cell layer measurement presented in (C). Seedlings were grown on 1/2 MS agar media for 7 DAG in the presence or absence of the indicated concentration of BL (A) or 1/2 MS agar media for 8 DAG (C) before measurement of the QC, CSC, and CC layer frequencies. mPS-PI staining was performed to reveal cell shape, the presence of starch granules. Cells with PI-stained starch granules (black dots) or cells below the starch-stained cell layers were considered columella cells. Cells between QC layers and the starch-stained CC layers were considered CSC cell layers. n>50 seedlings for each treatment. (This figure is available in colour at JXB online.)
Mentions: mPS-PI staining was performed according to the method of Truernit et al. (2008) with some modifications to reveal cell shape, the presence of starch granules, and auxin maximum (described in Figs 2, 3 and 4). In brief, roots were fixed in fixative (50% methanol and 10% acetic acid) and then incubated in 1% periodic acid after rinsing with water. Next, the tissues were treated with modified Pseudo Schiff reagent (100mM sodium metabisulphite and 0.15N HCl, supplemented with freshly added PI to a final concentration of 100 μg/ml). The samples were transferred onto microscope slides and covered with a chloral hydrate solution (4g chloral hydrate, 1ml glycerol, and 2ml water) for 5min to observe fluorescence or reflection signals using the Zeiss Confocal microscope.

Bottom Line: BR promotes intense nuclear accumulation of BZR1 in the root tip area, and the binding of BZR1 to the promoters of several root development-regulating genes, modulating their expression in the root stem cell niche area.They could also inhibit auxin-dependent distal stem cell differentiation by antagonizing the auxin/WOX5-dependent pathway.In conclusion, BZR1-/BES1-mediated BR signalling pathways show differential effects on the maintenance of root apical meristem activities: they stimulate ectopic QC division while they show opposite effects on the differentiation of distal columella stem cells in a BR concentration- and BZR1-/BES1-dependent manner.

View Article: PubMed Central - PubMed

Affiliation: Division of Biological Science and Technology, Yonsei University, Wonju, 220-710, Republic of Korea.

No MeSH data available.


Related in: MedlinePlus