Genetic regulation of vascular tissue patterning in Arabidopsis

• Published in: The Plant cell Vol. 11; no. 11; pp. 2123 - 2137
• Main Authors: Carland, F.M, Berg, B.L, FitzGerald, J.N, Jinamornphongs, S, Nelson, T, Keith, B
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Physiologists 01.11.1999; American Society of Plant Biologists
• Subjects: Arabidopsis - cytology; Arabidopsis - genetics; Arabidopsis - physiology; Arabidopsis thaliana; Auxins; Biosynthesis; cell differentiation; cell growth; Cell morphology; chromosome mapping; Cotyledon - physiology; Cotyledons; Crosses, Genetic; cvp1 gene; cvp2 gene; genes; Genes, Plant; Genetic mutation; indole acetic acid; Indoleacetic Acids - metabolism; Indoleacetic Acids - physiology; inflorescences; Leaves; Methyl Methanesulfonate; Mutagenesis; Mutants; mutation; Phenotype; Phenotypes; phloem; plant anatomy; Plant cells; Plant tissues; Plants; procambium; provascular strand; roots; Seedlings; Seeds - physiology; segregation; Spatial distribution; Stems; tiba; translocation (plant physiology); Vascular bundles; Vascular tissues; Xylem
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.11.11.2123

Plants transport water and nutrients through a complex vascular network comprised of interconnected, specialized cell types organized in discrete bundles. To identify genetic determinants of vascular tissue patterning, we conducted a screen for mutants with altered vascular bundle organization in Arabidopsis cotyledons. Mutations in two genes, CVP1 and CVP2 (for cotyledon vascular pattern), specifically disrupt the normal pattern of vascular bundles in cotyledons, mature leaves, and inflorescence stems. The spatial distribution of the procambium, the precursor to mature vascular tissue, is altered in cvp1 and cvp2 embryos, suggesting that CVP1 and CVP2 act at a very early step in vascular patterning. Similarly, in developing stems of cvp1 and leaves of cvp2, the pattern of vascular differentiation is defective, but the maturation of individual vascular cells appears to be normal. There are no discernible alterations in cell morphology in cvp2 mutants. In contrast, cvp1 mutants are defective in directional orientation of the provascular strand, resulting in a failure to establish uniformly aligned vascular cells, and they also show a reduction in vascular cell elongation. Neither cvp1 nor cvp2 mutants displayed altered auxin perception, biosynthesis, or transport, suggesting that auxin metabolism is not generally affected in these mutants.