- Department of Plant Protection Biology, Swedish University of Agricultural Sciences
Fattorini, Roisin; Egan, Paul A.; Rosindell, James; Farrell, Iain W.; Stevenson, Philip C.
Grayanotoxin I (GTX I) is a major toxin in leaves of Rhododendron species, where it provides a defence against insect and vertebrate herbivores. Surprisingly, it is also present in R. ponticum nectar, and this can hold important implications for plant-pollinator mutualisms. However, knowledge of GTX I distributions across the genus Rhododendron and in different plant materials is currently limited, despite the important ecological function of this toxin. Here we characterise GTX I expression in the leaves, petals, and nectar of seven Rhododendron species. Our results indicated interspecific variation in GTX I concentration across all species. GTX I concentrations were consistently higher in leaves compared to petals and nectar. Our findings provide preliminary evidence for phenotypic correlation between GTX I concentrations in defensive tissues (leaves and petals) and floral rewards (nectar), suggesting that Rhododendron species may commonly experience functional trade-offs between herbivore defence and pollinator attraction.
Rhododendron; Ericaceae; Plant defence; Functional trade-offs; Phenotypic correlation; Nectar chemicals; Grayanotoxin
2023, Volume: 212, article number: 113707
Publisher: PERGAMON-ELSEVIER SCIENCE LTD
Biochemistry and Molecular Biology