Abstract Detail

Macroevolution

Tripp, Erin A. [1], Zhuang, Yongbin [2], Schreiber, Matt [2], Stone, Heather [2], Berardi, Andrea [3].

Intercontinental Gradients in Plant Flavonoids: Testing the Impacts of Latitude, Environment, and Phylogeny in Ruellia (Wild Petunias: Acanthaceae).

Flavonoids are important secondary metabolites that play a primary role in protecting plants against UV radiation as well as other forms of stress including drought, salinity, and pathogens. In particular, given widespread impacts of latitude on a multitude of biological systems and a known increase in solar radiation towards equatorial regions, plant flavonoids are expected to increase with decreasing latitude. In this study, we test the hypothesis of a positive latitudinal gradient in plant flavonoids and additionally attempt to disentangle other factors that may be impacting plant flavonoid production such as niche, altitude, evolutionary history, and pleiotropic effects. To accomplish this, we assembled a large comparative matrix of occurrence and quantity of these beneficial metabolites across a species-rich genus that spans one of the largest latitudinal gradients of any lineage of flowering plants (Ruellia). Two flavones–apigenin and luteolin–were detected both in floral petals and in plant vegetative tissues while surprisingly no detectable amount of flavonols were observed across all 72 individuals studied. Instead of a positive latitudinal gradient, our data suggest a trend towards a reverse latitudinal gradient in plant flavone concentration. Additionally, our results revealed a significant relationship between plant flavone content and dry habitats such as seasonally dry tropical forests and savannas. We recovered no relationship between flavone content and altitude but found that flavone content was partially explainable by shared evolutionary history, especially among dry forest lineages. Flavones were furthermore highly correlated between leaf and corolla tissue and were documented in high concentrations in lineages that produce flowers rich in anthocyanin pigments (e.g., pink, purple, and red-flowered species). A complex interplay of ecological, historical, evolutionary, and pleiotropic effects documented here suggests that full understanding of plant flavonoid production often requires consideration of a wide variety of interacting factors.

1 - University Of Colorado Boulder, C105, Ramaley Hall, Campus Box 334, Boulder, CO, 80309, USA
2 - University of Colorado
3 - University of Bern

Keywords:
Anthocyanin
arid
dry
flavonoid
latitude
habitat
phylogeny
pleiotropy.

Presentation Type: Oral Paper
Session: 2, Macroevolution
Location: Fort Worth Ballroom 5/Omni Hotel
Date: Monday, June 26th, 2017
Time: 10:30 AM
Number: 2009
Abstract ID:390
Candidate for Awards:None