Thread by @kakape

Roses are red
but never blue.
If you’re wondering why,
I’ve got a thread for you

(and a book of course ;))

#tuesdayisbluesday

Last week I wrote a thread about the beautiful blue of the cornflower and the chemistry behind it, but I also mentioned that blue is rare in flowers. So let’s talk about the blue that isn’t there today. And the scientists trying to change that

https://twitter.com/kakape/status/1425089378133712900

Many flowers don’t naturally come in true blue:
tulips, carnations, chrysanthemums or orchids, for instance (the blue orchids you can buy in stores are usually artificially coloured), and - most famously - roses.

No wonder that the quest for blue roses crops up again and again in fairy tales and stories.

Rudyard Kipling wrote a whole poem about it:
"Roses red and roses white
Plucked I for my love's delight.
She would none of all my posies--
Bade me gather her blue roses"

The quest usually ends badly, of course. Take Kipling’s poem:

"Half the world I wandered through,
Seeking where such flowers grew.
Half the world unto my quest
Answered me with laugh and jest.

Home I came at wintertide,
But my silly love had died”

Talk about feeling blue...

Breeders too, were stumped. They had successfully bent the rose to our whims: making their blossoms fuller, for instance, and flower longer. They expanded the pallete as well: Around 1900 they succeeded in creating a yellow garden rose.
But a blue rose remained out of reach

In 1904 the "Rose Gazette" carried a report on the red W. Francis Bennett rose that was worth 22,000 marks!
"Anyone who could make a cornflower-blue rose, even if it were only a simple one, even if it had just one purely blue petal, could expect just as much,” the author wrote.

So why couldn’t anyone accomplish this?
As I said in last week’s thread the rose produces cyanidin and some flowers manage to build complexes with this anthocyanin that makes them appear blue. But the rose has not learnt this trick.

There is another more common way for flowers to appear blue: They tweak cyanidin a little further to produce delphinidin.
It’s a tiny change, just an extra oxygen atom. Delphinidin is on the left, cyanidin on the right:

But here is the thing: The rose lacks the enzyme needed to make this change. And not just the rose itself, but the whole rose family, which includes for instance apples, cherries and strawberries.
There was no way to breed this ability into the garden rose.

That changed of course when genetic engineering came along.
And here things get a bit weird.
Do you remember the Japanese Whisky brand Suntory? That’s the one from “Lost in Translation”.
This one:

Well, Suntory is a huge company and in the 1980s when tax hikes drove up the price of Whisky in Japan it decided to diversify more. One area it decided to invest in was cut flowers. And one goal they wanted to pursue was, you got it, creating a blue rose...

It started well. In 1991 Yoshikazu Tanaka and his colleagues identified the gene that allows petunias to produce delphinidin. The idea was to transfer it to roses and, presto, there is your blue rose.
But it didn’t work.
The rose didn’t produce any delphinidin.

After countless attempts with different roses and different genes, Tanaka finally produced a rosein 2002 that produced mostly delphinidin and in 2004 this was announced to the world. The rose is on sale since 2009. It is called “Applause”.

In 2018 when I was in Japan, I used the chance to meet Tanaka in Kyoto and see the flowers at his lab.
They are beautiful, but not very blue. I asked Tanaka what he had thought the first time he saw the rose. “Could be bluer”, he said.
(Torin Boyd took this photo that day:)

Tanaka didn’t stop with “Applause”. When I visited his lab he showed me hundreds of tiny rose flowers growing. One of them he hoped could be the right combination of genes and plant to give a better bluer rose. The quest continues…

The obvious question of course:
Is this worth all the energy?

Different people will come to different conclusions on this.

Kipling‘s poem ends:
„Mine was but an idle quest--
Roses white and red are best!“

And that article in the Rose Gazette? It‘s judgement on a blue rose was mixed:
„Whether it would be beautiful is another question; but it would be new, and novelty is what is most effective nowadays.” (Yes, that was 1904…)

The ironic thing in all of this: We may not have a truly blue rose yet, but the effort has led to other blue flowers.

In 2017 another Japanese researcher, Naonobu Noda, who worked in collaboration with Tanaka, announced a true blue chrysanthemum:

advances.sciencemag.org/content/3/7/e1…

Noda got lucky. He had ferried the gene to produce delphinidin to the chrysanthemum as well as a gene to attach a sugar molecule to it. This he hoped would allow the flower to attach more chemical groups to the delphinidin and make the flower bluer.

But the flower did not attach any other groups. The sugar was enough for the delphinidin to aggregate with other molecules and turn the flower blue.
Of course, I visited Noda's lab too.
He had kept a few of these flowers refrigerated for me.
They are beautiful.

If there is any moral to this quest for a blue rose, it’s probably one we all know very well:
That we always want what we cannot have and that we are willing to put a lot more effort into getting it than into appreciating or preserving what is already there.

Or, as Johannes Trojan put it in verse:

Beautiful roses, wild and tame,
Set the garden and fields aflame.
Red, white, and yellow with heady scent —
But people, you know, are never content,
And ask, what’s all this hullabaloo?
Why do you never see one that is blue?