Improved 'golden' indica rice and post-transgeneration enhancement of metabolic target products of carotenoids (b-carotene) in transgenic elite cultivars (IR64 and BR29)

Abstract

Transgene stability and post-translational expression levels of genes are of tremendous interest for developing value-added transgenic crops. Transgenic high-yielding indica rice cultivars (IR64 and BR29) with enhances level of carotenoid accumulation have been developed by Agrobacterium-mediated transformation. Genetic transformation was done using non-antibiotic Positech^TM marker system. Selectable marker gene, phosphomannose Isomerase (pmi), and two carotenogenic pathway genes, phytoene synthase (psy) and phytoene desaturase (crtI) were introduced in two popular Asian rice cultivars, IR64 and BR29. The highest level of total carotenoids obtained in progenies of transgenic BR29 was 9.34 μg/g and β-carotene level alone reached to 3.92 μg/g in polished grains. Whereas the highest ac-cumulation of total carotenoids obtained in transgenic progenies of IR64 was 2.32 μg/g in polished grains. T2 seeds showed higher carotenoid content than the origin-nal parental line which might be attributed to post-transgeneration effect.