Molecular characterization of marker-free transgenic lines of indica rice that accumulate carotenoids in seed endosperm.
A single Agrobacterium strain harbouring two binary plasmids was successfully used for the first time to develop a marker-free transgenic rice of improved nutritional value. Sixty-eight T0 co-transformants were obtained in three indica rice cultivars--two popular high-yielding Bangladeshi varieties (BR28 and BR29), and one high-iron rice cultivar (IR68144). Marker-free lines were obtained from 14 out of 24 selected co-transformants screened in the T1 generation. The accumulation of total carotenoids in polished T2 rice seeds of the primary transgenic VPBR29-17-37 reached levels of up to 3.0 microg/g, with the level of beta-carotene reaching 1.8 microg/g. In the cultivars BR28 and IR68144, total carotenoid levels in the transformants reached 2.0 microg/g of polished rice seeds. The levels of lutein and other carotenoids in the seeds were also significantly enhanced. T1 plants obtained from primary transgenics with simple gene-integration patterns tended to have a lower carotenoid content than the original parental lines. This study describes the development of marker-free transgenic rice lines containing high levels of carotenoids, and addresses the relationship between the rearrangement of transgenes and the presence of metabolic end products in transgenic rice.
Parkhi
V
V
International Rice Research Institute, Plant Breeding, Genetics and Biotechnology, DAPO Box 7777, Metro Manila, Philippines.
Rai
M
M
Tan
J
J
Oliva
N
N
Rehana
S
S
Bandyopadhyay
A
A
Torrizo
L
L
Ghole
V
V
Datta
K
K
Datta
S K
SK
D015139:Blotting, Southern; D002338:Carotenoids / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000737:chemistry; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005818:Genetic Engineering; D008040:Genetic Linkage; D005819:Genetic Markers; D005821:Genetic Techniques; D005822:Genetic Vectors; D005838:Genotype; D008957:Models, Genetic; D012275:Oryza / Q000235:genetics*; D010455:Peptides / Q000737:chemistry; D030821:Plants, Genetically Modified / Q000235:genetics; D010957:Plasmids / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012231:Rhizobium / Q000378:metabolism; D012639:Seeds / Q000378:metabolism*; D013045:Species Specificity; D013997:Time Factors; D019076:Transgenes; D019207:beta Carotene / Q000378:metabolism
D005819:Genetic Markers; D010455:Peptides; D019207:beta Carotene; D002338:Carotenoids; D004247:DNA