CEP genes regulate root and shoot development in response to environmental cues and are specific to seed plants

• Published in: Journal of experimental botany Vol. 64; no. 17; pp. 5383 - 5394
• Main Authors: Delay, Christina, Imin, Nijat, Djordjevic, Michael A
• Format: Journal Article
• Language: English
• Published: England Oxford University Press [etc.] 01.12.2013; Oxford University Press
• Subjects: abiotic stress; Amino Acid Sequence; Amino acids; Arabidopsis; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; bioactive properties; branching; carbon dioxide; Carbon Dioxide - metabolism; Computational Biology; Datasets; embryophytes; Environment; Gene Expression Regulation, Plant; Gene Knockout Techniques; gene overexpression; Genes; Genome, Plant - genetics; Magnoliopsida - genetics; Magnoliopsida - growth & development; Magnoliopsida - physiology; Molecular Sequence Data; mutants; Mutation; Nitrates; Nitrogen; Nitrogen - metabolism; Organ Specificity; peptides; Peptides - genetics; Peptides - metabolism; Phenotypes; Plant Growth Regulators - genetics; Plant Growth Regulators - metabolism; Plant roots; Plant Roots - genetics; Plant Roots - growth & development; Plant Roots - metabolism; Plant Shoots - genetics; Plant Shoots - growth & development; Plant Shoots - metabolism; Plants; Plants, Genetically Modified - genetics; Plants, Genetically Modified - metabolism; RESEARCH PAPER; Root growth; roots; Seeds - genetics; Seeds - metabolism; shoots; Signals; Stress, Physiological; lateral root formation; root development; small signalling peptide; environmental regulation; CEP
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/ert332

The manifestation of repetitive developmental programmes during plant growth can be adjusted in response to various environmental cues. During root development, this means being able to precisely control root growth and lateral root development. Small signalling peptides have been found to play roles in many aspects of root development. One member of the CEP (C-TERMINALLY ENCODED PEPTIDE) gene family has been shown to arrest root growth. Here we report that CEP genes are widespread among seed plants but are not present in land plants that lack true branching roots or root vasculature. We have identified 10 additional CEP genes in Arabidopsis. Expression analysis revealed that CEP genes are regulated by environmental cues such as nitrogen limitation, increased salt levels, increased osmotic strength, and increased CO2 levels in both roots and shoots. Analysis of synthetic CEP variants showed that both peptide sequence and modifications of key amino acids affect CEP biological activity. Analysis of several CEP over-expression lines revealed distinct roles for CEP genes in root and shoot development. A cep3 knockout mutant showed increased root and shoot growth under a range of abiotic stress, nutrient, and light conditions. We demonstrate that CEPs are negative regulators of root development, slowing primary root growth and reducing lateral root formation. We propose that CEPs are negative regulators that mediate environmental influences on plant development.