Farmacognosia

PHYTOCHEMISTRY Phytochemistry 67 (2006) 1177–1184 www.elsevier.com/locate/phytochem

b-Carotene accumulation induced by the cauliflower Or gene is not due to an increased capacity of biosynthesis
Li Li a a,b,*

, Shan Lu a,c, Kelly M. Cosman a, Elizabeth D. Earle b, David F. Garvin d, Jennifer O’Neill a

d

USDA-ARS, Plant, Soil and Nutrition Laboratory, Cornell University, Ithaca, NY 14853, USA b Department of Plant Breeding and Genetics, Cornell University, Ithaca, NY 14853, USA c Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA USDA-ARS, Plant Science Research Unit, University of Minnesota, St. Paul, MN 55108, USA Received 1 December 2005; received in revised form 2 March 2006

Abstract The cauliflower (Brassica oleracea L. var. botrytis) Or gene is a rare carotenoid gene mutation that confers a high level of b-carotene accumulation in various tissues of the plant, turning them orange. To investigate the biochemical basis of Or-induced carotenogenesis, we examined the carotenoid biosynthesis by evaluating phytoene accumulation in the presence of norflurazon, an effective inhibitor of phytoene desaturase. Calli were generated from young seedlings of wild type and Or mutant plants. While the calli derived from wild type seedlings showed a pale green color, the calli derived from Or seedlings exhibited intense orange color, showing the Or mutant phenotype. Concomitantly, the Or calli accumulated significantly more carotenoids than the wild type controls. Upon treatment with norflurazon, both the wild type and Or calli synthesized significant amounts of phytoene. The phytoene accumulated at comparable levels and no major differences in carotenogenic gene expression were observed between the wild type and Or calli. These results suggest that Orinduced b-carotene accumulation does not result from an increased capacity of carotenoid biosynthesis. Ó 2006 Elsevier Ltd. All rights reserved.
Keywords: Brassica oleracea var. botrytis;