Open AccessThe origin and evolution of fragrance in rice ( Oryza sativa L.)
Author(s) -
Michael J. Kovach,
Mariafe Calingacion,
Melissa Fitzgerald,
Susan R. McCouch
Publication year - 2009
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0904077106
Subject(s) - biology , japonica , allele , oryza sativa , aromatic rice , introgression , genetics , haplotype , indel , gene , trait , genotype , botany , single nucleotide polymorphism , computer science , programming language
Fragrance in the grain is one of the most highly valued grain quality traits in rice, yet the origin and evolution of the betaine aldehyde dehydrogenase gene (BADH2 ) underlying this trait remains unclear. In this study, we identify eight putatively nonfunctional alleles of theBADH2 gene and show that these alleles have distinct geographic and genetic origins. Despite multiple origins of the fragrance trait, a single allele,badh2.1 , is the predominant allele in virtually all fragrant rice varieties today, including the widely recognized Basmati and Jasmine types. Haplotype analysis allowed us to establish a single origin of thebadh2.1 allele within theJaponica varietal group and demonstrate the introgression of this allele fromJaponica toIndica . Basmati-like accessions were nearly identical to the ancestralJaponica haplotype across a 5.3-Mb region flankingBADH2 regardless of their fragrance phenotype, demonstrating a close evolutionary relationship between Basmati varieties and theJaponica gene pool. These results clarify the relationships among fragrant rice varieties and challenge the traditional assumption that the fragrance trait arose in theIndica varietal group.