Feeding 9 Billion: Innovations in Agricultural Modeling
Agricultural & Forestry Science
New Study Identifies Gene Behind Unique Color Patterns in African Violet Flowers
Flowers are central to plant reproduction and have held cultural and ornamental significance for centuries. Among them, the African violet (Streptocarpus sect. Saintpaulia ionanthus Wendl.) is particularly admired for its striking variety of petal color patterns. These patterns result from the accumulation of anthocyanins—pigments that create a spectrum of hues.
One variety, the white-striped African violet, has been cultivated for its unique appearance. Until now, scientists believed these stripes were caused by periclinal chimera—genetically distinct cell layers producing different colors. However, new research has revealed that specific gene regulation, rather than chimera, drives this distinctive trait.
Research Led by Kindai University
A team of scientists led by Professor Munetaka Hosokawa and Dr. Daichi Kurata from the Graduate School of Agriculture at Kindai University, Japan, set out to investigate the genetic basis of pigment variation in Saintpaulia. Their findings, published online on June 13, 2025, and in the August 1, 2025 issue of New Phytologist, provide new insights into flower color regulation.
“Just as domestication in crops has led to the selection of specific genes, I became interested in uncovering which traits humans have favored in ornamental flowers,” says Prof. Hosokawa. “To conduct such studies, a suitable model plant is necessary, and we have continued our experiments with the belief that Saintpaulia could serve as a good model species.”
From Tissue Culture to Gene Discovery
The researchers first used tissue culture techniques to produce plants with pink, white, and white-striped petals. They observed variations in anthocyanin accumulation, with pink petals containing higher levels of flavonoid-based compounds compared to white petals.
Genomic sequencing revealed that key anthocyanin biosynthesis genes (ABGs) were suppressed in white petals. Further investigation using quantitative reverse transcription-PCR and phylogenetic analysis pointed to two candidate regulators: SiMYB2 and SibHLH2.
By studying methylation levels, the team identified SiMYB2 as the critical gene influencing pigment instability. Mapping revealed two distinct transcripts: SiMYB2-Long, expressed in colored tissues, and SiMYB2-Short, expressed in non-colored tissues.
This genetic mechanism explains the unstable pigmentation observed in African violet flowers during tissue culture propagation.
Future Implications for Ornamental Plant Breeding
Prof. Hosokawa emphasized the broader significance of the findings:
“Humans have long created many flower cultivars by making use of mutations. Research on floral patterns, however, is still in its early stages, and we are just beginning to understand how these patterns arise. In the next 5 to 10 years, the genetic basis of flower patterning may become clearer, potentially enabling more deliberate breeding of patterned flowers.”
About Kindai University
Founded in 1949, Kindai University is a leading Japanese institution with six campuses, 18 research centers, and more than 2,200 full-time faculty members. The university provides comprehensive education across disciplines and is accredited by Japan’s Ministry of Education, Culture, Sports, Science and Technology as well as the National Institution for Academic Degrees and University Evaluation.
About Professor Munetaka Hosokawa
Prof. Hosokawa is a faculty member at Kindai University’s Graduate School of Agriculture. His research spans environmental science, agricultural science, and horticulture. He has published over 100 papers, cited more than 1,500 times, and served as Chief Editor for Horticultural Research (Japanese Society for Horticultural Science) between 2020 and 2022.
Funding
This study was supported by the Sasakawa Scientific Research Grant from the Japan Science Society (2024-4050) and a grant from the Agricultural Technology and Innovation Research Institute (ATIRI), Kindai University.
Summary of Findings
- Subject of Study: African violet (Saintpaulia) flower color variation
- Key Discovery: The gene SiMYB2 regulates pigment accumulation in petals
- Mechanism: Two transcripts of SiMYB2—Long (colored tissues) and Short (non-colored tissues)—determine pigmentation
- Impact: Provides genetic basis for floral patterning, with implications for ornamental plant breeding
Original Publication
Authors: Daichi Kurata, Tomohisa Tsuzaki, Fumi Tatsuzawa, Kenta Shirasawa, Hideki Hirakawa and Munetaka Hosokawa.
Journal: New Phytologist
DOI: 10.1111/nph.70286
Method of Research: Experimental study
Subject of Research: Not applicable
Article Title: Unstable anthocyanin pigmentation in Streptocarpus sect. Saintpaulia (African violet) is due to transcriptional selectivity of a single MYB gene
Article Publication Date: 1-Aug-2025
Original Source: https://doi.org/10.1111/nph.70286
Frequently Asked Questions
What causes the unstable pigmentation in African violet flowers?
The unstable pigmentation is linked to a gene called SiMYB2, which has two variants: SiMYB2-Long, associated with color, and SiMYB2-Short, associated with lack of color. The expression of these variants is influenced by epigenetic changes.
How do the white-striped petals in African violets form?
The white-striped petals may result from an epigenetic mechanism rather than being purely genetic. This means that different layers of cells in the petals can have distinct epigenetic backgrounds, leading to the observed color patterns.
What role does DNA methylation play in the pigmentation of African violets?
DNA methylation affects the expression of the SiMYB2 gene. Higher methylation levels in the SiMYB2 gene are found in non-pigmented tissues, which contributes to the lack of anthocyanin production, resulting in white or striped petals.
Most Read Articles
