CLE-like (CLEL) peptides control the pattern of root growth and lateral root development in Arabidopsis

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 109; no. 5; pp. 1760 - 1765
• Main Authors: Meng, Ling, Buchanan, Bob B., Feldman, Lewis J., Luan, Sheng
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 31.01.2012; National Acad Sciences
• Subjects: Amino Acid Sequence; Amino acids; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - physiology; Biological Sciences; Cell division; Cells; Developmental biology; Flowers & plants; Gene expression; Molecular Sequence Data; Peptides; Peptides - chemistry; Peptides - physiology; Phenotypes; Plant roots; Plant Roots - growth & development; Plants; Protein precursors; Proteins; Root growth; Root initiation; Seedlings; Sequence Homology, Amino Acid; Signal transduction
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1119864109

CLE peptides, named for the CLVB/ESR-related peptide family, participate in intercellular-signaling pathways. Here we investigated members of the CLE-like (CLEL) gene family that encode peptide precursors recently designated as root growth factors [Matsuzaki Y et al. (2010) Science 329: 1065-1067]. CLEL precursors share a similar domain structure with CLE precursors (i.e., they contain a putative Nterminal signal peptide and a C-terminal conserved 13-amino-acid CLEL motif with a variable middle portion). Our evidence shows that, unlike root growth factor, CLEL peptides are (i) unmodified and (ii) function in the regulation of the direction of root growth and lateral root development. Overexpression of several CLEL genes in Arabidopsis resulted in either long roots or long and wavy roots that also showed altered lateral root patterning. Exogenous application of unmodified synthetic 13-amino-acid peptides derived from two CLEL motifs resulted in similar phenotypic changes in roots of wild-type plants. In CLEL peptide-induced long roots, the root apical meristem (RAM) was enlarged and consisted of an increased number of cells, compared with wild-type root apical meristems. The wavy-root phenotype appeared to be independent of other responses of the roots to the environment (e.g., gravitropism, phototropism, and thigmotropism). Results also showed that the inhibition of lateral initiation by CLEL overexpression was not overcome by the application of auxin. These findings establish CLEL as a peptide family with previously unrecognized regulatory functions controlling the pattern of root growth and lateral root development in plants.