is usually a domestication-related gene required for red pericarp in rice
is usually a domestication-related gene required for red pericarp in rice (encodes a basic helix-loop-helix (bHLH) protein that was fine-mapped to an 18. maize (or (Vaughan et al., 2001), neither of which is usually native to the United States. They interbreed freely with cultivated, white-grained types, making transgenic herbicide-resistant varieties impractical. The red pigment in rice grains is usually proanthocyanidin, also called condensed tannins (Oki et al., 2002). Proanthocyanidins are a branch off the anthocyanin pathway and share many of the same biosynthetic genes (Winkel-Shirley, 2001). Proanthocyanidins have been shown to have important deterrent effects on pathogens and predators, so it is not surprising that spontaneous mutations that inhibit pigment production would be selected against in the wild (Shirley, 1998). On the other hand, white grain appears to be associated with the domestication syndrome and remains under strong selection in most rice breeding programs today. Regardless of 42719-32-4 the problems associated with red rice as a weed, the red pigment is usually of interest for nutritional reasons. It serves as a powerful antioxidant that has been demonstrated to reduce atherosclerotic plaque formation, a risk factor associated with cardiovascular disease (Ling et al., 2001). Around the unfavorable side, proanthocyanidin pigments reduce the bioavailability of iron, protein, and carbohydrates (Eggum et al., 1981; Carmona et al., 1996; Glahn et al., 2002), which has important implications for people with low nutritional status. A better understanding of the genetics and molecular biology of red pericarp and the association of this characteristic with other wild/weedy traits will provide important information for the better management of both the negative and positive features associated with red rice. Two loci have been identified using classical genetic analysis, (brown pericarp and seed coat) and (red pericarp and seed coat). When present together, these loci produce red seed color (Kato and Ishikawa, 1921). in the absence of produces brown seeds, whereas alone has no phenotype (Physique 1A). There are three known alleles of (historically, is referred to as a mutant allele because its phenotype differs from that of common rice cultivars, the action of is usually dominant over white pericarp ((red) allele. Both loci have been mapped using standard two-point analysis around the morphological map of rice: on chromosome 7 and on chromosome 1. Physique 1. Phenotypes and Fine-Mapping of ((genes in petunia (((Nesi et al., 2001). The Myb proteins have been shown to interact with a basic helix-loop-helix (bHLH) protein in each of the three model systems. In 42719-32-4 encodes a bHLH protein (Baudry et al., 2004), whereas petunia has two bHLH proteins involved in anthocyanin regulation, AN1 and JAF13 (Spelt et al., 2000). In maize, several genes belonging to the ((gene in in petunia, and by in maize (de Vetten et al., 1997; Baudry et al., 2004; Carey et al., 2004). They have been shown to physically interact with the bHLH protein in petunia and (Walker et 42719-32-4 al., 1997; Sompornpailin et al., 2002). In petunia and Mutant Previous QTL mapping in this laboratory identified a single, significant QTL associated with red grain ((IRGC-105491) from Malaysia and, in one case, a U.S. tropical cultivar, Jefferson, and 42719-32-4 in the other case, a widely planted tropical cultivar, IR64. The log of the odds scores associated with the QTL peaks in these two populations were 99 and 33, respectively, and the QTL was detected in multiple environments (Septiningsih et al., 2003). The peak of both QTLs Rabbit polyclonal to ZNF562 corresponded to the previously mapped position of the mutant locus, brown pericarp, (Kinoshita, 1998). All of the BC2F1 plants had red seeds, indicating that the locus is usually dominant for red color, with the dominant allele donated by the parent. Using the cv Jefferson/population, encompassed a 5.1-centimorgan (cM) region that represented 7.2 Mb straddling the border of the centromere on chromosome 7 (Determine 1B, i). The genetic/physical distance in this region averages 1.4 Mb/cM, much above the genome average of 200 to.