Journal Article

Over-expression of a zeatin <i>O</i>-glucosylation gene in maize leads to growth retardation and tasselseed formation

Albert Pineda Rodó, Norbert Brugière, Radomira Vankova, Jiri Malbeck, Jaleh M. Olson, Sara C. Haines, Ruth C. Martin, Jeffrey E. Habben, David W. S. Mok and Machteld C. Mok

in Journal of Experimental Botany

Published on behalf of Society for Experimental Biology

Volume 59, issue 10, pages 2673-2686
Published in print July 2008 | ISSN: 0022-0957
Published online May 2008 | e-ISSN: 1460-2431 | DOI: http://dx.doi.org/10.1093/jxb/ern137

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To study the effects of cytokinin O-glucosylation in monocots, maize (Zea mays L.) transformants harbouring the ZOG1 gene (encoding a zeatin O-glucosyltransferase from Phaseolus lunatus L.) under the control of the constitutive ubiquitin (Ubi) promoter were generated. The roots and leaves of the transformants had greatly increased levels of zeatin-O-glucoside. The vegetative characteristics of hemizygous and homozygous Ubi:ZOG1 plants resembled those of cytokinin-deficient plants, including shorter stature, thinner stems, narrower leaves, smaller meristems, and increased root mass and branching. Transformant leaves had a higher chlorophyll content and increased levels of active cytokinins compared with those of non-transformed sibs. The Ubi:ZOG1 plants exhibited delayed senescence when grown in the spring/summer. While hemizygous transformants had reduced tassels with fewer spikelets and normal viable pollen, homozygotes had very small tassels and feminized tassel florets, resembling tasselseed phenotypes. Such modifications of the reproductive phase were unexpected and demonstrate a link between cytokinins and sex-specific floral development in monocots.

Keywords: Corn; cytokinin; plant development; tasselseed; Zea mays; zeatin O-glucosyltransferase

Journal Article.  7431 words.  Illustrated.

Subjects: Plant Sciences and Forestry

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