![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
*
University of Freiburg, Center for Applied Biosciences, D-79104 Freiburg, Germany and the
Institute for Plant Sciences, Swiss Federal Institute of Technology, CH-8092 Zurich, Switzerland
2To whom correspondence should be addressed. E-mail: beyer{at}uni-freiburg.de
To obtain a functioning provitamin A (ß-carotene) biosynthetic pathway in rice endosperm, we introduced in a single, combined transformation effort the cDNA coding for phytoene synthase (psy) and lycopene ß-cyclase (ß-lcy) both from Narcissus pseudonarcissus and both under the control of the endosperm-specific glutelin promoter together with a bacterial phytoene desaturase (crtI, from Erwinia uredovora under constitutive 35S promoter control). This combination covers the requirements for ß-carotene synthesis and, as hoped, yellow ß-carotene-bearing rice endosperm was obtained in the T0-generation. Additional experiments revealed that the presence of ß-lcy was not necessary, because psy and crtI alone were able to drive ß-carotene synthesis as well as the formation of further downstream xanthophylls. Plausible explanations for this finding are that these downstream enzymes are constitutively expressed in rice endosperm or are induced by the transformation, e.g., by enzymatically formed products. Results using N. pseudonarcissus as a model system led to the development of a hypothesis, our present working model, that trans-lycopene or a trans-lycopene derivative acts as an inductor in a kind of feedback mechanism stimulating endogenous carotenogenic genes. Various institutional arrangements for disseminating Golden Rice to research institutes in developing countries also are discussed.
KEY WORDS: • provitamin A • transformation • Golden Rice • bioavailability • humanitarian project
This article has been cited by other articles:
|
|
 |
|
  C. Ampomah-Dwamena, T. McGhie, R. Wibisono, M. Montefiori, R. P. Hellens, and A. C. Allan The kiwifruit lycopene beta-cyclase plays a significant role in carotenoid accumulation in fruit J. Exp. Bot., July 2, 2009; (2009) erp218v1. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. A. Drubin, J. C. Way, and P. A. Silver Designing biological systems Genes & Dev., February 1, 2007; 21(3): 242 - 254. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. P. Jauhar Modern Biotechnology as an Integral Supplement to Conventional Plant Breeding: The Prospects and Challenges Crop Sci., July 25, 2006; 46(5): 1841 - 1859. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I.-P. Ahn, S. Kim, and Y.-H. Lee Vitamin B1 Functions as an Activator of Plant Disease Resistance Plant Physiology, July 1, 2005; 138(3): 1505 - 1515. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Liu, S. Roof, Z. Ye, C. Barry, A. van Tuinen, J. Vrebalov, C. Bowler, and J. Giovannoni Manipulation of light signal transduction as a means of modifying fruit nutritional quality in tomato PNAS, June 29, 2004; 101(26): 9897 - 9902. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. D. Matthews, R. Luo, and E. T. Wurtzel Maize phytoene desaturase and {zeta}-carotene desaturase catalyse a poly-Z desaturation pathway: implications for genetic engineering of carotenoid content among cereal crops J. Exp. Bot., October 1, 2003; 54(391): 2215 - 2230. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. A. Underwood Scientific Research: Essential, but Is it Enough to Combat World Food Insecurities? J. Nutr., May 1, 2003; 133(5): 1434S - 1437. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Lonnerdal Genetically Modified Plants for Improved Trace Element Nutrition J. Nutr., May 1, 2003; 133(5): 1490S - 1493. [Abstract] [Full Text] [PDF]
|
|
