Jasmine flowers are highly valued as ornamentals and in jasmine tea for fragrance. There have been attempts to create varieties with increased fragrance. But for a plant like jasmine that is propagated through cuttings, selective breeding over generations is difficult. So Adinpunya Mitra and team from IIT Kharagpur decided to use a simpler method: gamma irradiation to induce mutations.
They took 120 jasmine cuttings, divided them into six groups and exposed them to gamma irradiation at different energy levels. The cuttings were then planted and vegetatively propagated for three consecutive years for genetic stabilization.
Cuttings exposed to gamma irradiation above 30 Gray did not survive well.
They analysed the differences in fragrances in flowers from the remaining groups using a gas chromatograph–mass spectrophotometer. Floral volatiles, such as 2-phenylethanol, farnesene and farnesol, that positively influence fragrance, were increased. Linalool, a known stress reliever, was greatly enhanced in flowers of plants subjected to 10-20 Gray doses of gamma irradiation. An irradiation dose of 10 Gray gamma is adequate to create the desirable genetic changes, say the researchers. Increasing the dose further decreased the concentration of benzyl acetate.
The researchers selected two variants randomly for genetic analysis and found a significant level of gene polymorphism at this low dose, confirming genetic mutations induced by gamma irradiation. Analysing the expressions of genes regulating the synthesis of floral volatiles, they found that the monoterpene synthase gene, involved in the accumulation of linalool, was upregulated. The MYB transcription factor, involved in the regulation of the biosynthesis of phenylpropanoid volatiles, was downregulated. Acetyltransferase genes seemed to be suppressed, corresponding to the decline in benzyl acetate.
Since the plant is propagated vegetatively, the mutation thus achieved can be easily transferred across generations.
Fragrant news for jasmine cultivators and exporters.
Industrial Crops and Products, 152: 112545 (2020);
University of North Bengal
STEAMindiaReports: science news you can use
Free for Indian media