Abstract:
Fragrance in rice is caused by mutations in the badh2 (betaine aldehyde
dehydrogenase) gene. It was previously reported that exons 1, 2, 7, 10,
13 and 14 of badh2 are hot spots for various mutations leading to fra grance in most aromatic rice. This study was carried out to sequence the
14th exon of badh2 gene of Sri Lankan aromatic rice varieties that lack
the badh2.1 allele. The aims of the study were to predict the aberrant
protein structure and to develop a functional DNA marker. In view of
this, we sequenced the 14th exon of four traditional aromatic accessions
and compared with a published sequence. Four accessions contained a
nucleotide ‘G’ insertion in the 14th exon. This novel mutation can be
classified as the badh2.7 allele. The predicted three-dimensional protein
structure of the mutant shows loss of part of the oligomerization and
coenzyme binding domains, a change that is predicted to result in fra grance. A CAPS-based novel marker, Bad2.7CAPS, was developed to
identify varieties possessing this badh2.7 allele, and it can be utilized in
rice breeding programmes.
