Journal Article

The RNAi-Mediated Silencing of Xanthine Dehydrogenase Impairs Growth and Fertility and Accelerates Leaf Senescence in Transgenic Arabidopsis Plants

Ayami Nakagawa, Saori Sakamoto, Misa Takahashi, Hiromichi Morikawa and Atsushi Sakamoto

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 48, issue 10, pages 1484-1495
Published in print October 2007 | ISSN: 0032-0781
Published online October 2007 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/pcm119
The RNAi-Mediated Silencing of Xanthine Dehydrogenase Impairs Growth and Fertility and Accelerates Leaf Senescence in Transgenic Arabidopsis Plants

More Like This

Show all results sharing these subjects:

  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

Xanthine dehydrogenase (XDH) is a ubiquitous enzyme involved in purine metabolism which catalyzes the oxidation of hypoxanthine and xanthine to uric acid. Although the essential role of XDH is well documented in the nitrogen-fixing nodules of leguminous plants, the physiological importance of this enzyme remains uncertain in non-leguminous species such as Arabidopsis. To evaluate the impact of an XDH deficiency on whole-plant physiology and development in Arabidopsis, RNA interference (RNAi) was used to generate transgenic lines of this species in which AtXDH1 and AtXDH2, the two paralogous genes for XDH in this plant, were silenced simultaneously. The nearly complete reduction in the total XDH protein levels caused by this gene silencing resulted in the dramatic overaccumulation of xanthine and a retarded growth phenotype in which fruit development and seed fertility were also affected. A less severe silencing of XDH did not cause these growth abnormalities. The impaired growth phenotype was mimicked by treating wild-type plants with the XDH inhibitor allopurinol, and was reversed in the RNAi transgenic lines by exogenous supplementation of uric acid. Inactivation of XDH is also associated with precocious senescence in mature leaves displaying accelerated chlorophyll breakdown and by the early induction of senescence-related genes and enzyme markers. In contrast, the XDH protein levels increase with the aging of the wild-type leaves, supporting the physiological relevance of the function of this enzyme in leaf senescence. Our current results thus indicate that XDH functions in various aspects of plant growth and development.

Keywords: Arabidopsis (Arabidopsis thaliana); Plant growth and development; Purine metabolism; Senescence; Xanthine dehydrogenase

Journal Article.  8602 words.  Illustrated.

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.