Abstract Detail

Crops and Wild Relatives

Bahmani, Keivan [1], Robinson, Anestacia [1], Majumder, Sambadi [1], LaVardera, Angelina [1], Dowell, Jordan [3], Goolsby, Eric [4], Mason, Chase [5].

Broad diversity in monoterpene-sesquiterpene balance across wild sunflowers: implications of leaf and floral volatiles for biotic interactions.

Premise of the study. As plant lineages diversify across environmental gradients, species are predicted to encounter divergent biotic pressures from herbivores, pathogens, florivores, and pollinators. This study investigates the evolution of volatile secondary metabolism across Helianthus, a genus of diverse wild relatives of cultivated sunflower. • Methods. Leaves and petals of 40 species of wild Helianthus were analyzed via solid-phase microextration gas chromatography-mass-spectrometry to describe volatile secondary metabolite profiles. • Key results. across all species, 500 compounds were identified including 40% sesquiterpenes, 18% monoterpenes, 3% diterpenes, 4% fatty acid derivatives, and 35% other compounds such as phenolics and small organic compounds. Qualitatively, annuals and species from more arid western climates had leaf compositions with a higher proportion of total monoterpenes, while erect perennials and species from more mesic eastern habitats contained a higher proportion of total sesquiterpenes. Among species, mass-based leaf monoterpene and sesquiterpene abundance were identified as largely orthogonal axes of variation by principal components analysis, though total leaf terpene abundance was correlated with a higher proportion of sesquiterpenes and with a higher compound diversity. Leaf and petal profiles were not strongly correlated. • Conclusions. Wide diversity in volatile metabolism was observed among wild Helianthus, indicating the value of this genus as both a model system for studying the evolution of terpene biosynthesis, and as a rich genetic resource for breeding purposes in cultivated sunflower. The independence of leaf and petal volatile profiles indicates a low level of phenotypic integration between vegetative and reproductive structures, implying that vegetative defense and reproductive defense or pollinator attraction functions mediated by terpenoid profiles in these two organs can evolve without major constraints or tradeoffs. The major biosynthetic pathways that manufacture the major terpenoid compounds identified in wild Helianthus have been well described to date, providing a road map to deeper inquiry into the drivers of this diversity and potential manipulation of terpenoid profiles in cultivated sunflower.

1 - University Of Central Florida, Biological Sciences, 4110 Libra Dr, Orlando, FL, 32816, United States
2 - University Of Central Florida, Biological Sciences, 4110 Libra Dr, Orlando, FL, 32816, United States
3 - University of California, Davis, Department of Plant Sciences, One Shields Ave, Davis, CA, 95616, USA
4 - University Of Central Florida, 4000 Central Florida Blvd, BLDG20, BL301, Orlando, FL, 32816, United States
5 - University Of Central Florida, Department Of Biology, 4110 Libra Dr, Orlando, FL, 32816, United States

phenotypic integration

Presentation Type: Oral Paper
Number: CWR1006
Abstract ID:320
Candidate for Awards:None

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