Marker-free transgenic (MFT) near-isogenic introgression lines (NIILs) of 'golden' indica rice (cv. IR64) with accumulation of provitamin A in the endosperm tissue.
We have developed near-isogenic introgression lines (NIILs) of an elite indica rice cultivar (IR64) with the genes for beta-carotene biosynthesis from dihaploid (DH) derivatives of golden japonica rice (cv. T309). A careful analysis of the DH lines indicated the integration of the genes of interest [phytoene synthase (psy) and phytoene desaturase (crtI)] and the selectable marker gene (hygromycin phosphotransferase, hph) in two unlinked loci. During subsequent crossing, progenies could be obtained carrying only the locus with psy and crtI, which was segregated independently from the locus containing the hph gene during meiotic segregation. The NIILs (BC(2)F(2)) showed maximum similarity with the recurrent parent cultivar IR64. Further, progenies of two NIILs were devoid of any fragments beyond the left or right border, including the chloramphenicol acetyltransferase (cat) antibiotic resistance gene of the transformation vector. Spectrophotometric readings showed the accumulation of up to 1.06 microg total carotenoids, including beta-carotene, in 1 g of the endosperm. The accumulation of beta-carotene was also evident from the clearly visible yellow colour of the polished seeds.
Baisakh
Niranjan
N
Plant Breeding, Genetics, and Biotechnology Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines. nbaisakh@agctr.lsu.edu
Rehana
Sayda
S
Rai
Mayank
M
Oliva
Norman
N
Tan
Jing
J
Mackill
David J
DJ
Khush
Gurdev S
GS
Datta
Karabi
K
Datta
Swapan K
SK
D019883:Alkyl and Aryl Transferases / Q000235:genetics; D002338:Carotenoids / Q000096:biosynthesis; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D016172:DNA Fingerprinting; D018014:Gene Transfer Techniques; D005798:Genes, Bacterial; D005818:Genetic Engineering / Q000379:methods; D005819:Genetic Markers; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; D006238:Haploidy; D007178:Inbreeding; D012275:Oryza / Q000235:genetics*; D010088:Oxidoreductases / Q000235:genetics; D010641:Phenotype; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000196:embryology / Q000378:metabolism*; D012639:Seeds / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism*; D014801:Vitamin A / Q000378:metabolism; D019207:beta Carotene / Q000096:biosynthesis* / Q000235:genetics
D005819:Genetic Markers; D010940:Plant Proteins; D019207:beta Carotene; D014801:Vitamin A; D002338:Carotenoids; D010088:Oxidoreductases; C022398:phytoene dehydrogenase; D015500:Chloramphenicol O-Acetyltransferase; D019883:Alkyl and Aryl Transferases; D051232:Geranylgeranyl-Diphosphate Geranylgeranyltransferase; D017853:Phosphotransferases (Alcohol Group Acceptor); C063242:hygromycin-B kinase