Abstract Detail

Ecophysiology

Hughes, Nicole Michelle [1], Wommack, Andrew [2], Lila, Mary Ann [3].

Exploring the relationship between anthocyanin structure and function in plant-environment interactions.

Nineteen anthocyanidins and over 530 anthocyanins (anthocyanidins plus their sugar moieties) have been described in plants. Previous studies have demonstrated that Arabidopsis produces distinct anthocyanin “fingerprints” under different types of abiotic stress, and that structural decorations of different anthocyanins attenuate adverse symptoms associated with specific stressors. Yet, beyond these reports, the question of why plants might synthesize one anthocyanin over another has scarcely been explored. We used light microscopy paired with HPLC and LC-MS to characterize anthocyanins in three species belonging to two angiosperm families. Tissues sampled from the terrestrial orchid Tipularia discolor included: brown expanding leaves, fully-expanded green leaves with bright purple undersides, and morphotypes exhibiting adaxial dark purple spots or solid purple adaxial coloration. Red leaf tissues of Photinia glabra and Rhapheolepsis indica (Malinae, Rosaceae) were sampled during different ontogenetic stages (leaf expansion, senescence), and in response to infection by the pathogenic fungus Entomosporium mespili. Our findings were consistent with previous reports that anthocyanin structure is largely influenced by phylogeny. For example, leaf coloration in Tipularia discolor (Orchidaceae) was associated with cyanidin 3,7,3′ -triglucosides; anthocyanins with linkages at 3,7,3′ positions are rare in plants, and unique to the orchid subfamily Epidendroideae (to which Tipularia belongs). Similarly, cyanidin-3-galactosides were the major anthocyanins in red leaf tissues in closely-related Photinia glabra and Rhapheolepsis indica. Surprisingly, all taxa studied appeared to use the same anthocyanins, in similar proportions, in all leaf tissues examined. For example, the same anthocyanins found in red pathogenic leaf spots in P. gabra and R. indica were also found in young and senescing leaves of the same species, and in similar proportions. We also found that the same anthocyanins could result in different leaf colors, depending on their histological location. The same anthocyanins which make expanding leaves of T. discolor appear brown are also responsible for bright abaxial coloration and dark purple adaxial coloration; differences in color appeared due to histological location, rather than chemical structure. These results suggest either that plants can use the same anthocyanins to perform different functions, or, that anthocyanins in each of the examined cases perform analogous functions.

1 - High Point University, Department of Biology, 1 N University Pkwy, Wanek Natural Science 311, High Point, NC, 27268, United States
2 - High Point University, Department of Chemistry, 1 N University Pkwy, High Point, NC, 27268-0002, United States
3 - North Carolina State University, 600 Laureate Way , Kannapolis, NC , 280811, USA

Keywords:
Anthocyanin
Photoprotection
herbivory
chemotaxonomy.

Presentation Type: Oral Paper
Number: EPH2003
Abstract ID:847
Candidate for Awards:None