The POLARIS gene of Arabidopsis encodes a predicted peptide required for correct root growth and leaf vascular patterning

Casson, S.A.; Chilley, P.; Topping, J.F.; Evans, I.M.; Souter, M.; Lindsey, K.

Abstract

The POLARIS (PLS) gene of Arabidopsis was identified as a promoter trap transgenic line, showing -glucuronidase fusion gene expression predominantly in the embryonic and seedling root, with low expression in aerial parts. Cloning of the PLS locus revealed that the promoter trap T-DNA had inserted into a short open reading frame (ORF). Rapid amplification of cDNA ends PCR, RNA gel blot analysis, and RNase protection assays showed that the PLS ORF is located within a short (500 nucleotides) auxin-inducible transcript and encodes a predicted polypeptide of 36 amino acid residues. pls mutants exhibit a short-root phenotype and reduced vascularization of leaves. pls roots are hyperresponsive to exogenous cytokinins and show increased expression of the cytokinin-inducible gene ARR5/IBC6 compared with the wild type. pls seedlings also are less responsive to the growth-inhibitory effects of exogenous auxin and show reduced expression of the auxin-inducible gene IAA1 compared with the wild type. The PLS peptide-encoding region of the cDNA partially complements the pls mutation and requires the PLS ORF ATG for activity, demonstrating the functionality of the peptide-encoding ORF. Ectopic expression of the PLS ORF reduces root growth inhibition by exogenous cytokinins and increases leaf vascularization. We propose that PLS is required for correct auxin-cytokinin homeostasis to modulate root growth and leaf vascular patterning.

Citation

Casson, S., Chilley, P., Topping, J., Evans, I., Souter, M., & Lindsey, K. (2002). The POLARIS gene of Arabidopsis encodes a predicted peptide required for correct root growth and leaf vascular patterning. The Plant Cell, 14(8), 1705-1721. https://doi.org/10.1105/tpc.002618

• Journal Article Type: Article
• Publication Date: Aug 1, 2002
• Deposit Date: May 17, 2007
• Journal: Plant Cell
• Print ISSN: 1040-4651
• Electronic ISSN: 1532-298X
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 14
• Issue: 8
• Pages: 1705-1721
• DOI: https://doi.org/10.1105/tpc.002618
• Public URL: https://durham-repository.worktribe.com/output/1625239
• Publisher URL: http://www.plantcell.org/cgi/content/abstract/14/8/1705