Vegetable oils rich in oleic acid are more desirable than oils rich in polyunsaturated and saturated fatty acids. The biological switch of oleic acid to linoleic acid is facilitated by fatty acid desaturase 2 enzyme that is further classified into FAD2-1, FAD2-2, FAD2-3, and FAD2-4. The genes coding these enzymes have high sequence similarity, but differ mostly in their expression patterns. The seed-type FAD2 genes had evolved independently after segregation by duplication from constitutively expressed FAD2 genes. Temperature, light and wounding effectively regulate FAD2 expression in plants. FAD2 genes are expressed differently in different tissues of the plant, and the over-expression of FAD2 modifies physiological and vegetative characteristics. The activity of FAD2 leads to an increase in the content of dienoic fatty acids, and hence increases the resistance toward cold and salt stress. The thorough study of the FAD2 gene is important for understanding the expression, regulation and mechanism that will help in improving the quality of oil and stress resistance in plants.

Information on the variability available in lignan and fatty acid content in the oilseed crop of Sesamum indicum has been limited. This article presents and discusses the composition, quantity, and variability available for the two traits in the sesame germplasm that are grown in diverse agro climatic regions of India. HPLC and GC analysis of sesame seeds harvested over a period of three crop seasons revealed a considerable amount of variability in lignan and fatty acids. The antioxidant lignans sesamol, sesamin and sesamolin were observed to be in the range of 0.16-3.24, 2.10-5.98 and 1.52-3.76 mg/g of seed, respectively. Similarly oleic and linoleic acids, respectively, have ranged from 34.71 to 45.61% and 38.49 to 49.60%. The black sesame seeds were found rich in sesamin, sesamolin, total lignan content and oleic acid and are thus identified nutritionally and pharmaceutically more important than white and brown seeds. Pearson statistics showed a strong correlation between the components within a particular trait and also some correlation was found between the traits. The study revealed promising cultivars for use in sesame breeding aimed at improving lignan and fatty acid contents, and can be thus directly used in human foods, nutrition, health and welfare.

Currently, genetic improvement in oil and lignan content is a major objective in sesame breeding. As a prerequisite to meet the objective, the diversity of these traits of sesame germplasm was examined. Solvent extraction of the harvested seeds demonstrated variation in oil content ranging from 39% to 49% across the sesame accessions tested. High performance liquid chromatography of oil samples showed sesamin and sesamolin as the only lignans present in the oil, with their amount in the range of 2.74-10.55 g L −1 and 2.49--13.78 g L −1 , respectively. Coefficient of variation for oil content remained the highest in brown and black seeded accessions, whereas it remained at maximum for sesamin and sesamolin in white seeded ones. Pearson analysis showed a positive correlation between oil and lignan content. It was concluded that Indian sesame accessions exhibit considerable variation in oil and lignans content. The S. indicum varieties with a desirable composition of oil and/or lignans have been identified and recommended for incorporation in breeding programs, as well as for specific human use.

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Band designs of esterase (EST), peroxidase (PO) and polyphenol oxidase (PPO) isozymes in several selected cultivars of Catharanthus roseus by using native polyacrylamide gel electrophoresis (PAGE) were investigated in this study. It was confirmed that cultivar differences in isozyme polymorphism can be revealed by applied electrophoretic patterns. Three isozyme systems produced a total of 16 bands with polymorphism ranged from 66.6-100%. Considering the patterns of isozyme variations in the five cultivars of Catharanthus roseus, it is evident that the cultivar 'First kiss coral' displayed crimson red petal with large white eye' displayed demarked profiles of EST, PO and PPO isozymes than other cultivars. This is the first report on isozyme polymorphism in members of the Cathanarathus roseus (L.) G. Don.