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Modulation of Arabidopsis and monocot root architecture by CLAVATA3/EMBRYO SURROUNDING REGION 26 peptide.

Czyzewicz N, Shi CL, Vu LD, Van De Cotte B, Hodgman C, Butenko MA, Smet ID - J. Exp. Bot. (2015)

Bottom Line: Using chemically synthesized peptide variants, it was found that CLE26 plays an important role in regulating A. thaliana root architecture and interacts with auxin signalling.In addition, through alanine scanning and in silico structural modelling, key residues in the CLE26 peptide sequence that affect its activity are pinpointed.Finally, some interesting similarities and differences regarding the role of CLE26 in regulating monocot root architecture are presented.

View Article: PubMed Central - PubMed

Affiliation: Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Leicestershire LE12 5RD, UK.

No MeSH data available.


CLE26p concentration gradient on A. thaliana. (A) Representative pictures of CLE26p-treated wild-type seedlings at 12 d after germination. (B, C) Quantification of primary root length (C) and emerged lateral root density (D) for CLE26p-treated wild-type seedlings. The graphs indicate the mean ±SE. Statistical significance (Student’s t-test) compared with no peptide treatment is indicated: ***P<0.01; *P<0.05. Scale bar=1cm. (This figure is available in colour at JXB online.)
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Figure 3: CLE26p concentration gradient on A. thaliana. (A) Representative pictures of CLE26p-treated wild-type seedlings at 12 d after germination. (B, C) Quantification of primary root length (C) and emerged lateral root density (D) for CLE26p-treated wild-type seedlings. The graphs indicate the mean ±SE. Statistical significance (Student’s t-test) compared with no peptide treatment is indicated: ***P<0.01; *P<0.05. Scale bar=1cm. (This figure is available in colour at JXB online.)

Mentions: Subsequently, it was assessed whether these chemically synthesized CLE peptides also affected root architecture at a lower, more physiologically relevant concentration (10nM). Analyses of A. thaliana seedlings grown on 10nM CLEp revealed that only those seedlings grown on CLE26p displayed a significant 83% decrease in primary root length, a 72% decrease in lateral root number, and a 94% increase in lateral root density compared with the control (Fig. 2E–G; Supplementary Fig. S5 at JXB online). However, there was no obvious effect of CLE1p, CLE4p, and CLE7p on primary root length and neither did these seedlings display a reduced lateral root density. A dose–response analysis further indicated that CLE26p is able to restrict primary root growth and increase lateral root density in A. thaliana at a minimum concentration of 1nM (Fig. 3A–C). This is a similar activity threshold to other peptides, such as, for example, RALF, which is also active in the nanomolar range (Pearce et al., 2001), and TDIF (CLE41/CLE44), which is active in the picomolar range (Sawa et al., 2006). Surprisingly, the present CLE26p application data (at higher concentrations) are not in agreement with earlier observations based on overexpression of CLE26 (Strabala et al., 2006), but correspond to another report that showed that 19 CLE peptides are able to induce a short root phenotype (Kinoshita et al., 2007). In agreement with the present results, the latter study also showed that among all CLE peptides tested, CLE26p is the most effective one in inducing the short-root phenotype in A. thaliana. Intriguingly, CLE26p resulted in a subtle, but significant, increase in primary root length at a concentration of 0.1nM and 0.01nM (Fig. 3B), and it is possible that the previously reported CLE26 overexpression lines (which could be mild overexpressors) (Strabala et al., 2006) capture this. Taken together, the results suggest that CLE26 plays a role in A. thaliana primary and lateral root growth and development.


Modulation of Arabidopsis and monocot root architecture by CLAVATA3/EMBRYO SURROUNDING REGION 26 peptide.

Czyzewicz N, Shi CL, Vu LD, Van De Cotte B, Hodgman C, Butenko MA, Smet ID - J. Exp. Bot. (2015)

CLE26p concentration gradient on A. thaliana. (A) Representative pictures of CLE26p-treated wild-type seedlings at 12 d after germination. (B, C) Quantification of primary root length (C) and emerged lateral root density (D) for CLE26p-treated wild-type seedlings. The graphs indicate the mean ±SE. Statistical significance (Student’s t-test) compared with no peptide treatment is indicated: ***P<0.01; *P<0.05. Scale bar=1cm. (This figure is available in colour at JXB online.)
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
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getmorefigures.php?uid=PMC4526925&req=5

Figure 3: CLE26p concentration gradient on A. thaliana. (A) Representative pictures of CLE26p-treated wild-type seedlings at 12 d after germination. (B, C) Quantification of primary root length (C) and emerged lateral root density (D) for CLE26p-treated wild-type seedlings. The graphs indicate the mean ±SE. Statistical significance (Student’s t-test) compared with no peptide treatment is indicated: ***P<0.01; *P<0.05. Scale bar=1cm. (This figure is available in colour at JXB online.)
Mentions: Subsequently, it was assessed whether these chemically synthesized CLE peptides also affected root architecture at a lower, more physiologically relevant concentration (10nM). Analyses of A. thaliana seedlings grown on 10nM CLEp revealed that only those seedlings grown on CLE26p displayed a significant 83% decrease in primary root length, a 72% decrease in lateral root number, and a 94% increase in lateral root density compared with the control (Fig. 2E–G; Supplementary Fig. S5 at JXB online). However, there was no obvious effect of CLE1p, CLE4p, and CLE7p on primary root length and neither did these seedlings display a reduced lateral root density. A dose–response analysis further indicated that CLE26p is able to restrict primary root growth and increase lateral root density in A. thaliana at a minimum concentration of 1nM (Fig. 3A–C). This is a similar activity threshold to other peptides, such as, for example, RALF, which is also active in the nanomolar range (Pearce et al., 2001), and TDIF (CLE41/CLE44), which is active in the picomolar range (Sawa et al., 2006). Surprisingly, the present CLE26p application data (at higher concentrations) are not in agreement with earlier observations based on overexpression of CLE26 (Strabala et al., 2006), but correspond to another report that showed that 19 CLE peptides are able to induce a short root phenotype (Kinoshita et al., 2007). In agreement with the present results, the latter study also showed that among all CLE peptides tested, CLE26p is the most effective one in inducing the short-root phenotype in A. thaliana. Intriguingly, CLE26p resulted in a subtle, but significant, increase in primary root length at a concentration of 0.1nM and 0.01nM (Fig. 3B), and it is possible that the previously reported CLE26 overexpression lines (which could be mild overexpressors) (Strabala et al., 2006) capture this. Taken together, the results suggest that CLE26 plays a role in A. thaliana primary and lateral root growth and development.

Bottom Line: Using chemically synthesized peptide variants, it was found that CLE26 plays an important role in regulating A. thaliana root architecture and interacts with auxin signalling.In addition, through alanine scanning and in silico structural modelling, key residues in the CLE26 peptide sequence that affect its activity are pinpointed.Finally, some interesting similarities and differences regarding the role of CLE26 in regulating monocot root architecture are presented.

View Article: PubMed Central - PubMed

Affiliation: Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Leicestershire LE12 5RD, UK.

No MeSH data available.