The rice R gene family: two distinct subfamilies containing several miniature inverted-repeat transposable elements

• Published in: Plant molecular biology Vol. 42; no. 5; pp. 667 - 678
• Main Authors: Hu, J, Reddy, V S, Wessler, S R
• Format: Journal Article
• Language: English
• Published: Netherlands Springer Nature B.V 01.03.2000
• Subjects: Amino Acid Sequence; anthocyanin; B gene; Base Sequence; Cells, Cultured; chromosome 1; chromosome 4; Cloning, Molecular; Corn; DNA Transposable Elements; DNA, Complementary - chemistry; DNA, Complementary - genetics; DNA, Plant - chemistry; DNA, Plant - genetics; Gene Expression; Genes; Genes, Plant - genetics; Genetics; miniature inverted-repeat transposable element; Molecular Sequence Data; Multigene Family - genetics; Nuclear Proteins - genetics; Oryza - genetics; Oryza sativa; Pigmentation; Plant Proteins - genetics; R gene; Ra1 gene; Rb gene; Recombinant Fusion Proteins - genetics; Rice; Sequence Alignment; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Sequence Homology, Nucleic Acid; Zea mays; Zea mays - cytology; Zea mays - genetics
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1023/a:1006355510883

The R and B genes of maize regulate the anthocyanin biosynthetic pathway and constitute a small gene family whose evolution has been shaped by polyploidization and transposable element activity. To compare the evolution of regulatory genes in the distinct but related genomes of rice and maize, we previously isolated two R homologues from rice (Oryza sativa). The Ra1 gene on chromosome 4 can activate the anthocyanin pathway, whereas the Rb gene, of undetermined function, maps to chromosome 1. In this study, rice R genes have been further characterized. First, we found that an Rb cDNA can induce pigmentation in maize suspension cells. Second, another rice R homologue (Ra2) was identified that is more closely related to Ra1 than to Rb. Domesticated rice and its wild relatives harbor multiple Ra-like and Rb-like genes despite the fact that rice is a true diploid with the smallest genome of all the grass species analyzed to date. Finally, several miniature inverted-repeat transposable elements (MITEs) were found in R family members. Their possible role in hastening the divergence of R genes is discussed.