Differential expression profiles of anthocyanidin biosynthesis gene during black rice seed development

The anthocyanins belong to a widespread group of secondary metabolites collectively called flavonoids. They present in a flower petal, leaves, fruits, roots, and stem of higher plants and protect them from attracting the pollinators and animals for seed dispersal (Holton & Cornish, 1995). The anthocyanins also have other important roles in plant ecology (Gould, 2004). For example, cyanidin 3-glucoside protects cotton leaves against the tobacco budworm (Hedin et al., 1983). The anthocyanins also have beneficial activities on human health. They possess antidiabetic, antioxidant, antimicrobial, anti-inflammatory, anti-obesity, tumor-arresting activities and it lowers the risk of cardiovascular diseases (Kong et al., 2003; Nam et al., 2005; Xia et al., 2006). Recently, efforts are being made to engineer crops to attain higher anthocyanin levels for the enhanced nutraceutical value (Shirley, 1998; Reddy et al., 2007). Black rice, an important crop in Asia, contains anthocyanin’s as the major pigment components (Saito et al., 1985). The major anthocyanin in the Heugjinju variety, the most widely cultivated black rice in Korea noted for its high anthocyanin content, especially cyanidin 3-glucoside (Choi et al., 1996; Lee et al., 1998).