Limits...
Cytokinin as a positional cue regulating lateral root spacing in Arabidopsis.

Chang L, Ramireddy E, Schmülling T - J. Exp. Bot. (2015)

Bottom Line: Interestingly, mutation of CYP735A genes required for trans-zeatin biosynthesis caused strong defects in LR positioning, indicating an important role for this cytokinin metabolite in regulating LR spacing.Further it is shown that cytokinin and a known regulator of LR spacing, the receptor-like kinase ARABIDOPSIS CRINKLY4 (ACR4), operate in a non-hierarchical manner but might exert reciprocal control at the transcript level.Taken together, the results suggest that cytokinin acts as a paracrine hormonal signal in regulating root system architecture.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Albrecht-Thaer-Weg 6, D- 14195 Berlin, Germany Present address: Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, College of Life Science, Hubei University, Wuhan 430062, China.

No MeSH data available.


Effects of a lowered cytokinin status and ACR4 mutation on LR spacing are additive. (A) Percentage of immediately adjacent LRP in 11-d-old roots of wild type (WT), 35S:CKX1, acr4, and acr4 35S:CKX1 hybrids. n = 15–18. (B) Misplacement of LRP was partially supplemented by exogenous cytokinin (BA) in 35S:CKX1 plants but not in acr4. Seedlings were grown for 11 d on medium with or without 20nM BA prior to analysis. n = 15 for wild type, 32 for acr4, and 15 for 35S:CKX1. Error bars in (A, B) indicate SEM. The statistical significance of differences was calculated using two-tailed Student’s t-test (**P < 0.01; ***P < 0.001).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4507779&req=5

Figure 6: Effects of a lowered cytokinin status and ACR4 mutation on LR spacing are additive. (A) Percentage of immediately adjacent LRP in 11-d-old roots of wild type (WT), 35S:CKX1, acr4, and acr4 35S:CKX1 hybrids. n = 15–18. (B) Misplacement of LRP was partially supplemented by exogenous cytokinin (BA) in 35S:CKX1 plants but not in acr4. Seedlings were grown for 11 d on medium with or without 20nM BA prior to analysis. n = 15 for wild type, 32 for acr4, and 15 for 35S:CKX1. Error bars in (A, B) indicate SEM. The statistical significance of differences was calculated using two-tailed Student’s t-test (**P < 0.01; ***P < 0.001).

Mentions: To further investigate whether cytokinin and ACR4 control the positioning of LR through the same or separate pathways, the LR spacing phenotype of the acr4 35S:CKX1 hybrid seedlings was compared to the parental phenotypes. The hybrid acr4 35S:CKX1 plants displayed a much higher percentage of aberrantly positioned LRP (20.0±2.9%) than both parents (Fig. 6A). This largely additive effect suggests that cytokinin and ACR4 function at least partly in separate pathways in preventing neighbouring PCs from LRI. Consistently, addition of cytokinin to the growth medium had only a weak effect on the LR spacing defect in acr4 mutants, while it did lower the LR spacing defect by 67% in 35S:CKX1 seedlings (Fig. 6B).


Cytokinin as a positional cue regulating lateral root spacing in Arabidopsis.

Chang L, Ramireddy E, Schmülling T - J. Exp. Bot. (2015)

Effects of a lowered cytokinin status and ACR4 mutation on LR spacing are additive. (A) Percentage of immediately adjacent LRP in 11-d-old roots of wild type (WT), 35S:CKX1, acr4, and acr4 35S:CKX1 hybrids. n = 15–18. (B) Misplacement of LRP was partially supplemented by exogenous cytokinin (BA) in 35S:CKX1 plants but not in acr4. Seedlings were grown for 11 d on medium with or without 20nM BA prior to analysis. n = 15 for wild type, 32 for acr4, and 15 for 35S:CKX1. Error bars in (A, B) indicate SEM. The statistical significance of differences was calculated using two-tailed Student’s t-test (**P < 0.01; ***P < 0.001).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4507779&req=5

Figure 6: Effects of a lowered cytokinin status and ACR4 mutation on LR spacing are additive. (A) Percentage of immediately adjacent LRP in 11-d-old roots of wild type (WT), 35S:CKX1, acr4, and acr4 35S:CKX1 hybrids. n = 15–18. (B) Misplacement of LRP was partially supplemented by exogenous cytokinin (BA) in 35S:CKX1 plants but not in acr4. Seedlings were grown for 11 d on medium with or without 20nM BA prior to analysis. n = 15 for wild type, 32 for acr4, and 15 for 35S:CKX1. Error bars in (A, B) indicate SEM. The statistical significance of differences was calculated using two-tailed Student’s t-test (**P < 0.01; ***P < 0.001).
Mentions: To further investigate whether cytokinin and ACR4 control the positioning of LR through the same or separate pathways, the LR spacing phenotype of the acr4 35S:CKX1 hybrid seedlings was compared to the parental phenotypes. The hybrid acr4 35S:CKX1 plants displayed a much higher percentage of aberrantly positioned LRP (20.0±2.9%) than both parents (Fig. 6A). This largely additive effect suggests that cytokinin and ACR4 function at least partly in separate pathways in preventing neighbouring PCs from LRI. Consistently, addition of cytokinin to the growth medium had only a weak effect on the LR spacing defect in acr4 mutants, while it did lower the LR spacing defect by 67% in 35S:CKX1 seedlings (Fig. 6B).

Bottom Line: Interestingly, mutation of CYP735A genes required for trans-zeatin biosynthesis caused strong defects in LR positioning, indicating an important role for this cytokinin metabolite in regulating LR spacing.Further it is shown that cytokinin and a known regulator of LR spacing, the receptor-like kinase ARABIDOPSIS CRINKLY4 (ACR4), operate in a non-hierarchical manner but might exert reciprocal control at the transcript level.Taken together, the results suggest that cytokinin acts as a paracrine hormonal signal in regulating root system architecture.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biology/Applied Genetics, Dahlem Centre of Plant Sciences (DCPS), Freie Universität Berlin, Albrecht-Thaer-Weg 6, D- 14195 Berlin, Germany Present address: Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, College of Life Science, Hubei University, Wuhan 430062, China.

No MeSH data available.