SEQUENCE ANALYSIS OF THE MUTATION IN THE 7TH EXON OF BADH2 GENE IN TRADITIONAL AROMATIC RICE VARIETIES IN SRI LANKA

Abstract

It is revealed that the gene responsible for the fragrance in rice is Betaine aldehyde dehydrogenease (badh2) gene. An 8-bp deletion and three single nucleotide polymorphisms in the exon 7 of badh2 gene, named as badh2.1 allele, was reported to result in accumulation of a major aromatic compound, 2-acetyl 1-pyrroline (2AP) in fragrant rice. Although badh2.1 is the predominant allele in virtually all fragrant varieties, exceptions such as involvement of another genetic loci or allele had been reported by several researchers. This study was conducted aiming at detecting presence or absence of badh2.1 allele in popular traditional Sri Lankan fragrant rice varieties. A 463-bp DNA fragment was amplified covering 7th exon region and sequenced. The results showed that “Lanka Samurdi”, the fragrant high yielding variety, possesses the 8bp deletion while highly fragrant three traditional rice varieties did not show the particular mutation. Hence it confirms that the aroma in most of Sri Lankan traditional fragrant varieties is not resulted by the badh2.1 allele but by another genetic factor.