Exploration of allelic diversity reveals a novel FAD2 (Oleate desaturase) gene in Brassica juncea
Rajesh Kumar, J Radhamani and S Rajkumar
Abstract: Indian mustard (Brassica juncea) is an important contributor towards edible oil supply in India. Traditional Indian mustard varieties contain high proportion of 18C polyunsaturated fatty acids (linoleic and linolenic acids) and large amounts of long-chain monounsaturated FAs, mainly erucic acid, in seeds. Oleate desaturase (FAD2) regulates the composition of 18C PUFAs in cellular membranes and TAG in seed oil. The present study was conducted to gain insight into the allelic diversity of the FAD2 gene in Indian mustard. Analyses of cloned FAD2 genes of three Indian mustard varieties revealed a novel FAD2 gene that has a longer ORF (1167 bp) owing to insertions and several SNPs across its length that distinguish it from the more prevalent native FAD2 gene. Overall, the Indian mustard varieties possess three FAD2 alleles, but there is limited nucleotide diversity among members of each FAD2 type across varieties, suggesting narrow genetic diversity among the varieties examined.