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.

Global warming impairs the chemical attractiveness to pollinators

“…It also raises the questions to which extent increased temperatures will affect pollinator attraction in natural settings and in uence ecosystem functioning, and how increased temperatures will affect the activity of pollinators and their ower-visiting behavior. Currently, the molecular and biochemical processes in the biosynthesis of oral scent affected by heat stress are mostly unknown (Dudareva et al 2013;Borghi et al 2019; Barman and Mitra, 2021), and therefore, more efforts are needed to elucidate the effects of increased temperatures on oral scent production and emission at a molecular level. This will help to develop breeding programs with the aim to increase oral scent emissions at increased temperatures and to generate more heat-tolerant crops.…”

“…Temperature affects the vaporization of oral scent compounds as well as the physiological processes involved in the biosynthesis and release of scents. Its effects differ among compounds and species, resulting in species-speci c impacts of temperature on qualitative and quantitative scent properties (Sagae et al 2008;Borghi et al 2019; Farré-Armengol et al 2020; Barman and Mitra, 2021). Surprisingly, it is unknown whether and how temperature-induced changes in scent emission affect pollinator behavior and thus pollination in natural and agricultural settings.…”

Global warming impairs chemical communication between plants and pollinators

“…It also raises the question of how increased temperatures will affect pollinator attraction in natural settings and in uence ecosystem functioning. Currently, the molecular and biochemical processes in the biosynthesis of oral scent affected by heat stress are mostly unknown 5,14,40 , and therefore, more efforts are needed to elucidate the effects of increased temperatures on oral scent production and emission at a molecular level. This will help to develop breeding programs to increase the oral scent emissions of less heat-tolerant crops to avoid a mismatch with their pollinators and strong yield losses.…”

“…Temperature exerts a great impact on oral scents. Due to their low molecular weight and high vapor pressure, changes of a few degrees affect the vaporization of oral scent compounds 5,13,14 . In addition, physiological processes are in uenced by temperature, and overall, temperature was shown to affect qualitative and quantitative scent properties 15 .…”

“…Our ndings are consistent with other studies that also found that oral scents change under heat stress 6, [27][28][29] . In one study it was demonstrated that such changes are due to temperature dependent activities of enzymes and genes involved in the biosynthesis of scent compounds 14 . Overall, the oral scent strongly differed between the two different scenarios to an extent known not only within species but also among plant species 8,30,31 , suggesting that increased temperatures will strongly affect the communication between strawberry owers and their pollinators.…”