Os04g0578400

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Annotated Information

Function

• Carotenoids are a group of approximately 600 known organic pigments naturally found in plants; around 50 of these, including β-carotene, exhibit provitamin A activity.β-carotene is the most abundant source of provitamin A in the human diet.
• As a provitamin A compound, β-carotene has been the focus of many scientific studies and public health interventions. For example, many past and ongoing public health interventions have aimed to use β-carotene supplementation as a way of addressing vitamin A deficiency that causes symptoms ranging from night blindness to those of xerophthalmia and keratomalacia, leading to total blindness. In addition, due to β-carotene’s character as a highly active antioxidant, numerous scientific trials have focused on the potential for utilizing β-carotene in the prevention of cancer and other chronic diseases.
• Rice (Oryza sativa), a major staple food, is usually milled to remove the oil-rich aleurone layer that turns rancid upon storage, especially in tropical areas. The remaining edible part of rice grains, the endosperm, lacks several essential nutrients, such as β-carotene (provitamin A).

Expression

• Rice is a staple food and no rice cultivar has the capacity to produce β-carotene （provitamin A） in the endosperm tissue. Histochemical reactions clearly revealed the accumulation of β-carotene in the endosperm of transgenic seeds of indica rice (Oryza sativaL.) in comparison with non-transgenic control where no β-carotene could be detected(Figure 1).

• • Xudong Ye et al. used Agrobacterium-mediated transformation to introduce the entire β-carotene biosynthetic pathway into rice endosperm in a single transformation effort with three vectors(Figure. 2). The vector pB19hpc combines the sequences for a plant phytoene synthase (psy)originating from daffodil (Narcissus pseudonarcissus; GenBank accession number X78814) with the sequence coding for a bacterial phytoene desaturase (crtI) originating from Erwinia uredovora(GenBank accession number D90087) placed under control of the endosperm-specific glutelin (Gt1) and the constitutive CaMV (cauliflower mosaic virus) 35S promoter, respectively. The phytoene synthase cDNA contained a 59-sequence coding for a functional transit peptide , and the crtI gene contained the transit peptide (tp) sequence of the pea Rubisco small subunit.

• • To complete theb-carotene biosynthetic pathway, they also co-transformed with vectors pZPsC and pZLcyH. Vector pZPsC carriespsy and crtI, as in plasmid pB19hpc, but lacks the selectable marker aphIVexpression cassette. Vector pZLcyH provides lycopeneb-cyclase from Narcissus pseudonarcissus(GenBank accession number X98796) controlled by rice glutelin promoter and the aphIVgene controlled by the CaMV 35Spromoter as a selectable marker. Lycopene b-cyclase carried a functional transit peptide allowing plastid import.

• In most cases, the transformed endosperms were yellow, indicating carotenoid formation. The pB19hpcsingle transformants (Fig. 3A) showed a 3 :1 (colored/

noncolored) segregation pattern,whereas the pZPsC/pZLcyH co-transformants (Fig. 3B)showed variable segregation. The pB19hpcsingle transformants, engineered to synthesize only lycopene (red), were similar in colorto the pZPsC/pZLcyH co-transformants engineered forb-carotene (yellow) synthesis.

• The carotenoids found in the pB19hpc single transformants accounted for the color; none of theselines accumulated detectable amounts of lycopene. Instead,b-carotene, and to some extent lutein and zeaxanthin, were formed (Fig. 4). Thus, the lycopenea(ε)- andb-cyclases and the hydroxylase are either constitutively expressed in normal rice endosperm or induced upon lycopene formation.

Evolution

• Conservation of amino-acid sequences as well as their similar mechanisms of catalyses(one of the three enzymes which is necessary to β-carotene's synthesis) suggest that all plant cyclases, including CCS and perhaps also neoxanthin synthase, have evolved from a common ancestor, most probably the cyanobacterial CrtL (figure 5).

Labs working on this gene

• University of Freiburg, Center for Applied Biosciences, D-79104 Freiburg, Germany
• The Institute for Plant Sciences, Swiss Federal Institute of Technology, CH-8092 Zurich, Switzerland
• Columbia College, Columbia University, New York, NY, USA
• Institute for Plant Sciences, Swiss Federal Institute of Technology, CH-8092 Zurich, Switzerland.
• University of Freiburg, Center for Applied Biosciences, D-79104 Freiburg, Germany.

References

• 1. Vitamin Basics: β-carotene. [cited 2012 July 9]; Available from: http://www.vitamin-basics.com/index.php?id=35
• 2. Antioxidants and Cancer Prevention: Fact Sheet. [cited 2012 July 9]; Available from: http://www.cancer.gov/cancertopics/factsheet/prevention/antioxidants.
• 3. Tan, J., Baisakh, N., Oliva, N., Datta, K. and Datta, S. K., Screening for β-carotene in the Seeds of Rice Cultivars(Manuscript in preparation); Available from:http://tejas.serc.iisc.ernet.in/currsci/may102003/1232.pdf
• 4. Xudong Ye et al., Science J.287,303-305(2000); Available from:http://www.sciencemag.org/content/287/5451/303.short
• 5. M. Schledzet al., Plant J.10, 781 (1996).
• 6. M. Bonket al., Eur. J. Biochem.247, 942 (1997).
• 7. N. Misawaet al., Plant J.4, 833 (1993).
• 8. Joseph Hischberg. Carotenoid biosynthesis in flowering plants. Current Opinion in Plant Biology[J]. 4(3):210–218,2001.Available from: http://www.sciencedirect.com/science/article/pii/S1369526600001631

Structured Information

Gene Name	Os04g0578400
Description	Similar to Beta-ring hydroxylase (Fragment)
Version	NM_001060175.1 GI:115460079 GeneID:4336753
Length	2048 bp
Definition	Oryza sativa Japonica Group Os04g0578400, complete gene.
Source	Oryza sativa Japonica Group ORGANISM Oryza sativa Japonica Group Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta; Spermatophyta; Magnoliophyta; Liliopsida; Poales; Poaceae; BEP clade; Ehrhartoideae; Oryzeae; Oryza.
Chromosome	Chromosome 4
Location	Chromosome 4:29555718..29557765
Sequence Coding Region	29555820..29556230,29556369..29556428,29556529..29556735,29556846..29556971,29557093..29557149 ,29557272..29557340
Expression	GEO Profiles:Os04g0578400
Genome Context	<gbrowseImage1> name=NC_008397:29555718..29557765 source=RiceChromosome04 preset=GeneLocation </gbrowseImage1>
Gene Structure	<gbrowseImage2> name=NC_008397:29555718..29557765 source=RiceChromosome04 preset=GeneLocation </gbrowseImage2>
Coding Sequence	<cdnaseq>atggccaccggtctctccggcggcgctatgaccagcttcgccgtcaagaagccgctcctcgcggccgccgtgcgccgccggtcgtggcccccgccgtcgggccgcgcgctgccgttctcgccgctcacgcggaccccgcgcagccgcgggctcgggaccgtcacgtgcttcgtgccgcagggcacggagagccagcaggccccggctccgtccccgccgccgacggtgcccgtgcccgtgccctcgctggaggaagaggcggctgccgcggcggcgcggcgcatcgcggagaggaaggcgcggaagctgtcggagaggcggacgtacctggttgcggccgtcatgtccagcctcggcttcacgtccatggccgtcgccgccgtgtactaccgcttccattggcaactggagggcggggatgtgccgatgaccgagatgtttggcacgtttgcgctctccgtcggcgcagcggttgggatggagttctgggcgcagtgggcgcaccgctcgctgtggcacgcctccctgtggcacatgcacgagtcgcaccaccgtgcgcgcgagggcccgttcgagctcaacgacgtgttcgccatcaccaacgccgtgccggccatctccctcctcgcctacggcttcttccaccggggcatcgtccccggcctctgcttcggcgcgggcctcgggattacgctgttcggcatggcctacatgttcgtccacgacggcctggtccaccgccgcttccccgtcggccccatcgcgaatgtgccctacttccggcgagtggccgcggcccacaagatacaccacacggacaagttcgagggcgtaccgtatgggctgtttcttggacccaaggagctggaggaggttggtggtctggaagagctggagaaggagcttgcgagaatcaaccggagcttgtga</cdnaseq>
Protein Sequence	<aaseq>MATGLSGGAMTSFAVKKPLLAAAVRRRSWPPPSGRALPFSPLTR TPRSRGLGTVTCFVPQGTESQQAPAPSPPPTVPVPVPSLEEEAAAAAARRIAERKARK LSERRTYLVAAVMSSLGFTSMAVAAVYYRFHWQLEGGDVPMTEMFGTFALSVGAAVGM EFWAQWAHRSLWHASLWHMHESHHRAREGPFELNDVFAITNAVPAISLLAYGFFHRGI VPGLCFGAGLGITLFGMAYMFVHDGLVHRRFPVGPIANVPYFRRVAAAHKIHHTDKFE GVPYGLFLGPKELEEVGGLEELEKELARINRSL</aaseq>
Gene Sequence	<dnaseqindica>103..513#652..711#812..1018#1129..1254#1376..1432#1555..1623#gtctctcgattacactcccccgtcacactctcccgctccatccctgtccacgaaagcgcgcgcgggtaagatacgaggccgggagggaagaacgaccacggcatggccaccggtctctccggcggcgctatgaccagcttcgccgtcaagaagccgctcctcgcggccgccgtgcgccgccggtcgtggcccccgccgtcgggccgcgcgctgccgttctcgccgctcacgcggaccccgcgcagccgcgggctcgggaccgtcacgtgcttcgtgccgcagggcacggagagccagcaggccccggctccgtccccgccgccgacggtgcccgtgcccgtgccctcgctggaggaagaggcggctgccgcggcggcgcggcgcatcgcggagaggaaggcgcggaagctgtcggagaggcggacgtacctggttgcggccgtcatgtccagcctcggcttcacgtccatggccgtcgccgccgtgtactaccgcttccattggcaactggaggtacatctcctcttcgcttctacttccattatagtatgcggagaagtcatcgccgtaatttttgccggacaagatgtcccagtaatttaagtgtgcaaatggttgttgaccgtggttgatatctgtgcggccgtgcagggcggggatgtgccgatgaccgagatgtttggcacgtttgcgctctccgtcggcgcagcggtaagcggccgtgacaccgcaaaatccctgtttgctcgctgataacgtccttgggatgtcaaaattttgcttaattttgacgctcgctggggggttgcaggttgggatggagttctgggcgcagtgggcgcaccgctcgctgtggcacgcctccctgtggcacatgcacgagtcgcaccaccgtgcgcgcgagggcccgttcgagctcaacgacgtgttcgccatcaccaacgccgtgccggccatctccctcctcgcctacggcttcttccaccggggcatcgtccccggcctctgcttcggcgcggtaagcccagcgccctgcagggagcacgtaacgctctctctggtcggccgggcccacctgtcagagccatccaattgggatctgacctgccacgtgtccgtttcttacagggcctcgggattacgctgttcggcatggcctacatgttcgtccacgacggcctggtccaccgccgcttccccgtcggccccatcgcgaatgtgccctacttccggcgagtggccgcggcccacaaggtacgagaccaccagctgctcactgacgtttactgcaccactactactagtccacgctgctactactactactggctagagagtgtacttttgctgattttctttgtgtggccacgagcagatacaccacacggacaagttcgagggcgtaccgtatgggctgtttcttggacccaaggtgcgtgactggtgcctatgcatttgtcgtctatatgtgcttgtgaccagtacatgacaaagcaatcctggtttccttgtaccgtcttctcgatctcaacgtgtgtgtggtcgtgcgtgcaggagctggaggaggttggtggtctggaagagctggagaaggagcttgcgagaatcaaccggagcttgtgattttgacggcggcaattgcagctagcaagactgcgcctgtcgagctagcagaattgcctttgccttgcaagattttttgtatttctggccgcttcgtcgactccattaattgtcggtaccggagagaaggggactccagaagcggaagcgcttcgagtatacgacgatgtggcagcggtgaagagcacagtatatttgtttgattgtggcctgtggcatgcatgcgtctctgcggctgaacattgtaaggaggatgttctgtgggatggttattctttgaatttcactgcgccaacgtttttggtggagacgttgtgcgtccagtcccctgtcttgtaagaagcaccacattactgtgtataacacatgttagagattgttaaccacttcaatgaaactaaaataggtggttggcaacaatgctg</dnaseqindica>
External Link(s)	NCBI Gene:Os04g0578400, RefSeq:Os04g0578400