Floral maturation and changing air temperatures influence scent
volatiles biosynthesis and emission in Jasminum auriculatum Vahl.
Abstract
Benzenoid and terpenoid volatiles are the major compounds contributing
to the unique floral scent of Jasminum auriculatum. Biosynthesis and
emission of specialized scent metabolites showed maturation stage
specific pattern; maximum scent emission was observed when flowers start
unfurling and become fully opened under in situ condition. The
activities of volatile biosynthesizing enzymes and expressions of
several scent-related genes correlated well with the fragrance emission
patterns. We also assessed the impact of varying air temperatures (20°C,
25°C, 30°C and 35°C) on the metabolism as well as vaporization of scent
volatiles. The contents of both emitted and endogenous volatiles were
higher at either 25°C or 30°C and showed relatively lower amounts at
both border-range temperatures (20°C and 35°C). Further, the activities
of key pathway enzymes and expressions of several scent-related genes
under varying temperatures exhibited similar trends with the scent
emission patterns. Analysis of non-volatile metabolite contents from
flowers grown under different air temperatures suggests a perturbation
occurring in the primary metabolism and immediate precursors of scent
compounds. The knowledge base created through these studies shall be
helpful in improving the yield of floral scent production from such
horticulturally important plants in controlled cultivation systems.