Calcium and jasmonate signals mediate biosynthesis of the floral fragrance regulated by light quality in snapdragon

Floral fragrance provides a critical ecological function, potential economic applications, and is influenced by many environmental factors, in which light quality plays a vital role. However, how light quality affects the biosynthesis and emission of floral fragrance is unclear. In this study, three light qualities, red, green, and blue, were utilized to treat model snapdragon plants. Emissions of the main floral fragrance components and expression of their synthetic genes were measured, as well as calmodulin ( CAM ) gene expression and net Ca 2+ flux. Exogenous LaCl 3 (Ca 2+ channel blocker) was used to validate the role of the calcium signal. In addition, the contribution of the jasmonate (JA) pathway was detected and combined with an application of phenidone (JA synthesis inhibitor). The results showed that blue light led to the highest release of ocimene, myrcene, and methyl benzoate compared to that of green and red light. The same results were observed in the gene expression levels of ocimene synthetase ( OCS ), myrcene synthetase ( MYRS ), benzoic acid carboxyl methyl transferase ( BAMT ), and CAM , as well as net Ca 2+ flux. The LaCl 3 treatment effectively inhibited the emission of the three main components, expression of their synthetic genes, and the net Ca 2+ influx induced by blue light, which demonstrated participation by the calcium signal. Moreover, the expression levels of the JA pathway genes, lipoxygenase ( LOX ), allene oxide cyclase ( AOC ), 12-oxo-phytodienoic acid reductase ( OPR ), and coronatine-insensitive 1 ( COI1 , JA receptor) were enhanced significantly by blue light but were significantly reduced by phenidone. The expression of the emission and synthetic genes of the three main components also decreased. Thus, JA signaling contributed to the biosynthesis and emission of the floral fragrance induced by blue light. In summary, the calcium signal was triggered after exposure to different light qualities, and the JA signal was initiated, thereby affecting gene expression, and regulating the synthesis of the snapdragon floral fragrance. However, the specific regulatory mechanism requires further study.