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Tissue‐specific expression and developmental regulation of cytochrome b 561 genes in Arabidopsis thaliana and Raphanus sativus
Author(s) -
Verelst Wim,
Kapila Jyoti,
De Almeida Engler Janice,
Stone Julie M.,
Caubergs Roland,
Asard Han
Publication year - 2004
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.0031-9317.2004.0235.x
Subject(s) - biology , arabidopsis thaliana , meristem , raphanus , gene , epidermis (zoology) , arabidopsis , pericycle , microbiology and biotechnology , gene expression , botany , genetics , mutant , anatomy
Ascorbate (Asc) is an essential molecule in many aspects of development and stress responses in plants and animals. Cytochromes b 561 (cyts b 561) are tightly coupled to Asc homeostasis. These proteins are found in mammalian tissues, where they are involved in the regeneration of Asc, serving the synthesis of catecholamine neurotransmitters, and in intestinal iron reduction. Plant genomes encode homologous membrane‐associated, Asc‐reducible cyts b 561. The expression of these proteins in plants, however, has so far not been studied. We have now examined the expression of two Arabidopsis thaliana cyt b 561‐encoding genes— Artb561‐1 and Artb561‐2 —using relative‐quantitative RT‐PCR and in situ hybridization (ISH) techniques. The genes show overlapping and distinct tissue‐ and organ‐specific expression patterns. Transcripts of both genes are found in leaf epidermal cells, and expression seems to correlate with leaf maturation and cessation of cell elongation. Both genes are also expressed in the epidermal cell layer of stems and roots in the L1 layer of the shoot apex, in the vascular system of leaves, stems and roots, and in the root pericycle. In addition, Artb561‐1 is expressed in the root cap, whereas Artb561‐2 mRNA is found in the epidermis of lateral roots, in the root meristem, and in unfertilized ovules. These observations provide important information for the elucidation of the physiological function of cyts b 561 in plants.