Roses are red, roses are blue…

Maura Imbert on the geneticist’s dream of developing flowers in new and exciting colours

Anthurium in traditional colours of red, pink, white. Photograph courtesy Kairi BloomsPhotograph by Kevon Webster

Love songs and Valentine cards celebrate what we know  — roses are red, violets blue. But, to some people, this suggests the question: “Why not the other way around?” The novelty of a blue rose would make it a best seller, and the geneticist who produced it would gain worldwide acclaim.

Until very recently, I thought a blue rose had existed for a number of years but, upon investigating the matter, I found that it is still a geneticist’s dream. A “bluish” lavender rose does exist, but it is not a true blue rose. I also found, to my surprise, that claims for the existence of a black rose were also false. There is a very dark “blackish” rose with a deep red undertone, but not a genuine black rose.

Who cannot be moved by the beauty and fragrance of a dew-spangled, newly-opened, satiny-pink rose? A blue rose may be another matter (and it might not be fragrant at all, as is often the case with hybrid flowers), but in the multi-million-dollar floriculture business, the idea of a blue rose never fades. In this case, the colour would not depend on hybridization; it would be due to the manipulation of rose genes. Roses, carnations and chrysanthemums do not naturally have the genes to produce the blue colour which is present in petunias and other blue flowers. Flower colour depends on a number of genes which are segments of DNA (desoxyribonucleic acid).

Information coded in the DNA segments, which form particular genes, directs enzymatic and other activities within the cell, which are responsible for flower shape and colour and all other plant characteristics. The chemistry of plant pigments is well known, and most of the key enzymes involved in their synthesis have also been identified. Compounds called flavonoids and carotenoids comprise most flower pigments, and subtle modifications of the simple basic structure of the flavonoid naringenin provides a wide array of colours from light orange to deep violet. Many genes may be involved, and it has been shown with petunias that at least 35 genes are involved in producing flower colour.

Since 1970, geneticists have devised methods to alter or manipulate the DNA structure within genes, to introduce new genes from one organism into another, to take out a bit here or put in a bit there, to — as geneticist Jos Mol puts it when speaking of plants — give flowers a “floral facelift”. Flowering plants can be provided with new genes or existing ones can be “switched off” to provide a wide spectrum of economically important floral shapes and colours.

 

hich brings us to a particular flower currently being investigated at the University of the West Indies (UWI), St Augustine, Trinidad: a blue anthurium. Like roses, carnations and chrysanthemums, anthuriums do not possess the genetic make-up for blue colour, and a blue anthurium would, therefore, be as greatly prized — and as valuable — as a blue rose.

I spoke with Dr Uma Rahaman, who is leading this research in plant genetics, and he told me that — despite reports to the contrary a blue anthurium still does not exist. He believes, though, that he and his team have almost solved all the problems in producing one. Trinidad and Tobago could be the first to make this breakthrough in anthuriums!

According to Dr Rahaman, most anthuriums grown in the Caribbean are based on imported varieties from Holland. These blooms are attractive but they are susceptible to bacterial blight and leaf spot diseases which make investment risky because of the high cost of management.

Dr Rahaman explained that The University of the West Indies (UWI), St Augustine, is engaged in research towards developing attractive varieties of anthuriums which are resistant to these bacterial diseases, through plant breeding. “Novelty in anthuriums,” says Dr Rahaman, “like any other floriculture crops, fetches premium prices.” UWI has also invested in “bio-engineering anthuriums for novel bloom colours.”

The understanding of the flavonoid biosynthetic and the advancement of molecular genetics have allowed molecular biologists to tinker with the biochemical pathways towards the development of novel colours that do not exist within the species. To this end, UWI has, in collaboration with Crop and Food Research in New Zealand, isolated the genes involved in the flavonoid pathway, and developed methodologies to genetically engineer anthuriums. Anthuriums are presently being bio-engineered to produce variations that may provide local anthuriums an edge in the market.

Notice there is no actual mention of a blue anthurium in Dr Rahaman’s account of ongoing research at UWI, but blue is the principal “novel colour” at the focus of this interesting area of Caribbean bio-engineering.

Not far from UWI, at Malabar Farms, Kairi Blooms exports anthuriums to the US. According to manager Christopher Avey, the company has been exporting Dutch Hybrid Anthuriums from Trinidad since 1989. Starting as a small family business, it has grown to 10 acres of shade houses, shipping 600,000 stems per year. “We are currently working on our own breeding programme and hope to have our own hybrids on the market in the next 30 months,” says Avey. I was very interested to hear that he works closely with Dr Rahaman in a fruitful relationship. Maybe that blue anthurium isn’t so far away, after all.