Abstract Detail

Physiology

Einstein, Elliott [1], De La O, Desire [2], Katz, Benjamin [1], Kelz, Jessica [1], Martin, Rachel [1], Pineda, Allison [1], Woodcock, Sofiya [1], Takahashi, Gemma [1], Rocha, Megan [1], Einstein, David [2].

Identification of Flavonoids and Anthocyanins from Streptocarpus ionanthus.

Streptocarpus sect. Saintpaulia (African violets) are one of the most popular flowering houseplants in the world due to their year-round display of blooms and vivid coloration with the more pronounced colors being violet or pink. However, the focus is on yellow- and ivory-colored cultivars which are unusual for African violets because of their lack of chromoplast, an organelle responsible for the production and storage of both carotenoids and xanthophyll pigments normally responsible for visible yellow and orange colors, respectively. Despite this, some African violet cultivars do have a phenotypic expression of yellow, ivory, or peach coloration. We sought to elucidate why these plants exhibit a yellow phenotype despite not having carotenoid or xanthophyll pigments, which led us to attempt to find the biochrome or biochrome conjugates responsible for the yellow coloration in one African violet species and seven cultivars: S. ionanthus, 'Ethel's Wild Side', 'AE-Blue System', 'Rebel's Splatter Kake', 'Peach Perfect', 'Emerald Love', and 'Majesty.' Using liquid chromatography-mass spectrometry (LC-MS) in combination with a novel ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS) method, we established a characterization protocol to identify the yellow pigment from African violet petals.   We identified four purified extract elutants by HPLC, uncovering one flavonoid and three anthocyanin compounds: Apigenin 7-O-glucuronide, Malvidin-3-acetyl-rutinoside-5-glucoside, Peonidin-glucoside-acetyl-rhamnoside-glucoside, and Perlargonidin-glucoside-acetyl-rhamnoside-glucoside, respectively. Apigenin-7-O-glucuronide (AP7G) was found in high abundance in all eight plants, suggesting its role as a copigment. We investigated AP7G's role as a copigment in 'Rebel's Splatter Kake' and S. ionanthus flowers by performing 2-fold dilutions up to an eight-fold range of AP7G in water and characterized the absorbance intensity as a function of wavelength. We observed a decrease in absorption of purified 'Rebel's Splatter Kake' at a 4-fold dilution; the same trend in absorption was noticed for the purified S. ionanthus sample at a 1:1 ratio of AP7G to water. The wavelength shift for both 'Rebel's Splatter Kake' and S. ionanthus increased approximately 20 nm from an initial wavelength of 505 nm and 525 nm respectively. Data collection for the other cultivars is pending. Our current data suggest that AP7G plays a role as a pigment and contributes to prominent blueshift behavior in flowers with a yellow phenotype. We hypothesize that the molecular interaction of AP7G with other pigments can contribute to the yellow coloration.

1 - University of California Irvine, Chemistry, 1403 Natural Sciences 1 University of California Irvine, Irvine, CA, 92697, United States
2 - University of California Irvine, School of Biological Sciences, 1403 Natural Sciences 1 University of California Irvine, Irvine, CA, 92697, United States
3 - University of California Irvine, Chemistry, 1403 Natural Sciences 1 University of California Irvine, Irvine, CA, 92697, United States

Keywords:
Streptocarpus sect. Saintpaulia
Streptocarpus ionanthus
African violet  
anthocyanin
Mass Spectrometry
LCMS
yellow pigment  
liquid chromatography
quadrupole time-of-flight mass spectrometry  
UPLC-Q-TOF-MS/MS
Apigenin 7-O-glucuronide
Malvidin
Peonidin
glucuronide
Pelargonidin.

Presentation Type: Poster
Session: P3, Physiology Posters
Location: Virtual/Virtual
Date: Wednesday, July 21st, 2021
Time: 5:00 PM(EDT)
Number: P3PS001
Abstract ID:1068
Candidate for Awards:Phytochemical Best Poster Award