Genetic analysis and mapping of anthocyanin mutants of IR64 rice variety

• Main Authors: Hsiang-Chun Chen, 陳湘君
• Other Authors: 王強生
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/11623414781776954455

碩士 === 國立中興大學 === 農藝學系所 === 100 === Pigmentation in plant is mostly due to accumulation of anthocyanins resulting visible and diverse phenotypes. Therefore, colored mutants provide good materials for studying genetic variation and gene regulation. Six (42231, 42231.1, 50168, 42303, 50143, 42226) stable colored mutants screened from a mutation pool derived from sodium azide mutagenesis on a popular indica rice variety, IR64, were applied to study the inheritance and mapping the gene for colored phenotype. All the F1 plants from mutants crossed with IR64 showed pigmentation (purple or red) suggests that these mutants contain functional anthocyanin pathway and show dominant inheritance. Variations in the F2 tissues imply the involvement of regulatory gene. A mutant, 42303, shows pigmentation in most tissues was crossed to its wild type to obtain the 42303/IR64 F2 population. Genetic analysis on the pigmentations of leaf sheath, ligule, auricle, and apiculus of F2 fits 3 colored : 1 non-colored ratio suggesting that they are controlled by a single dominant locus. Simple sequence repeat (SSR) markers were screened and 84 polymorphic SSRs were applied to map the pigment gene using 92 F2 plants of 42303/IR64 cross. The result indicates thatRM6773, RM5754, RM253, and RM2615 are significantly linked to the colored phenotype. Among them, RM253 explains 78% phenotype variation of F2 suggesting that both are linked. PMore SSRs were further applied to locate the region to 830kb between RM5754 and RM2615. In this region three genes, Myb, 3GT, and bHLH, annotated and related to anthocyanins biosynthesis are cloned, sequenced, and analyzed. Two genes, Myb, and 3GT, show significant variations between wild type and 42303, and genetic analysis on F2 both fit single dominant inheritance model and explain 68% and 74% of phenotype variation, respectively. These results suggest that both 3GT and Myb are together conditioned the phenotype of 42303 mutant.