We Have Spent Millions of Dollars on Blue Roses

The quest for a naturally blue rose has been a long-standing challenge, despite the existence of over 30,000 rose cultivars bred in various shapes, sizes, and colors. While blue flowers are common in video games like Animal Crossing, achieving a true-blue rose in real life has proven incredibly difficult, attracting millions of dollars in research and breeding efforts. Roses have been valued for approximately 5,000 years, celebrated for their beauty, used in food and medicine, and now represent a global industry worth around $5 billion annually. The obsession with roses intensified in the 19th century, with a particular desire to cultivate blue varieties. Although dyeing white roses blue is a simple method, breeders have long sought a genetically blue rose. However, a significant biological hurdle stands in the way: roses naturally produce pigments called flavonoids, which result in white, pink, and red hues. Roses lack the genetic machinery to produce blue pigments. In fact, less than 10% of all flowering plants are blue, as blue pigments are complex to synthesize and maintain within living cells. Many blue animals achieve their color through structural reflection rather than pigments. Even plants that do produce blue pigments often have highly sensitive ones that are easily affected by factors like pH. Roses never evolved the pressure to develop blue pigments, leading to their natural absence. Despite these challenges, scientists have pursued genetic and molecular engineering to create blue roses since the 1990s. A key player in this endeavor has been the Japanese beverage company Suntory, which partnered with Australian company Florigene in 1990. Their initial approach was to introduce genes from blue-producing plants, specifically focusing on the delphinidin pigment found in petunias. Researchers identified the genes responsible for delphinidin production in 1991 and attempted to insert them into rose genomes. Early attempts were unsuccessful, as the modified roses did not exhibit a strong blue color. This led to the discovery that pH plays a crucial role; delphinidin in an acidic environment would turn red. By understanding this, researchers aimed to grow roses with a higher pH to preserve the blue hue. In 2004, Suntory announced the successful creation of a blue rose, named SUNTORY ‘blue rose’ APPLAUSE. This rose garnered significant attention, winning an award and being displayed in a museum. However, critics noted that despite a decade of work, APPLAUSE was more "mauve" than truly blue, producing a visible blue pigment but not the desired vibrant blue. The scientific pursuit continued, with a group of Chinese researchers in 2018 exploring a different approach involving bacteria. Recognizing the limitations of delphinidin, they turned to indigoidine, a blue pigment produced by certain microbes. Their strategy involved creating a novel genetic package combining rose and bacterial DNA. They isolated a smaller version of the indigoidine-producing enzyme gene, engineered a bacterial line to insert this gene into rose DNA, and injected these modified bacteria into white roses. Within 12 hours, blue patches appeared on the rose petals at the injection sites. The researchers hailed this as the first biologically engineered blue rose. However, this method also faced scrutiny. The blue color was not uniform, appearing only in splotches, and it was not permanent, fading relatively quickly. Some argued that this technique was akin to a high-tech dyeing process rather than fundamentally altering the rose's biology. As of the transcript, further progress on this bacterial approach has not been published. The persistent effort to create a blue rose raises the question of "why." For companies like Suntory, financial incentives are a factor, with APPLAUSE roses reportedly priced significantly higher than regular roses. Beyond economics, the pursuit also stems from human appreciation for beauty and novelty, the desire to create something new, unimaginable, and seemingly impossible. A genetically engineered blue rose would represent a pinnacle of both scientific and aesthetic achievement.