More Blue

Rose Genetics Flower Pigments
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Blue roses might be achieved (without gene splicing) in a variety of ways. Some more likely than others.

Myricetin, a precursor of delphinidin, is found in some roses. This was reported by Gupta, Pahnajamani and Seshadri in 1957 (Journal of Scientific & Industrial Research). I’m still looking for a copy of the paper, hoping they gave a list of the 20 HTs they found that produce myricetin. Breeding from these roses is not a guaranteed route to delphinidin, but roses with myricetin are more likely to produce a delphinidin colored rose than varieties that lack the precursor.

Another route seems more promising. Some roses already carry blue pigments, the rosacyanins. These pigments have some important advantages. “The accumulation of rosacyanin As may be a better way to engineer blue roses than that of delphinidin, as rosacyanin As are consistently blue even when co-pigments and metal ions are absent and the vacuolar pH is low.”

Tetrahedron 62(41): 9661-9670 (9 October 2006)

Two novel blue pigments with ellagitannin moiety, rosacyanins A1 and A2, isolated from the petals of Rosa hybrida

This was previously reported to this forum by Don, on Mon, Oct 27, 2008

The variety studied was ‘Mme. Violet’. It would be interesting to learn which of its parents, ‘Lady X’ or ‘Sterling Silver’, contributed the pigments.

Breeding for an increase of specific substances has been done in the past. The sugar beet was bred from common beets by selection for increased sugar content. And in a 50 year long breeding experiment on corn, selective breeding for lines with increased content of oil, protein, and amylopecton (a tapioca-like starch) was successful. Once the desired improvements were accomplished, the strains were used for further breeding.

Jugenheimer (1961)

It is likely the same thing could be accomplished for rosacyanins by breeding from ‘Mme Violet’, selecting for the greatest concentration of rosacyanins relative to the concentrations of other pigments (e.g., cyanin).

Crossing ‘Mme Violet’ to other mauve roses is not likely to bring the desired improvement unless they also produce rosacyanins.

Karl

2

It is likely the same thing could be accomplished for rosacyanins by … selecting for the greatest concentration of rosacyanins relative to the concentrations of other pigments

This is the strategy with the greatest potential for success.

The foundation breeders for this projects should include every mauve rose you can get, as all are likely to be rosacyanin producers.

Work-in (cross and back-cross with) very densely pigmented red roses, especially the ones the fade to blue, as theses are most likely to be over-producers of cyanin which is the precursor to rosacyanin. Roses like Chrysler Imperial, Tuscany, Black Velvet, Sweet Chariot, Scarlet Moss, Travemunde, Erinerung an Brod and Last Tango are models. You will have an easier time selecting progeny if you avoid roses having any yellow pigment but this is not a requirement because the pathways for blue are not affected by those for carotenoids (afaik).

Selection of progeny is easy - go for those that are the most blue and the most densely pigmented.

The strategy of starting with the most blue roses you can find and selecting for the most blue offspring may seem like an obvious thing to do, and it is, but until the identification of rosacyanin it was thought that such a strategy would dead-end at mauve. Now, we know, anything is possible.

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Don,

I think that mauve colored roses may come about by different means.

Chemistry and Biochemistry of Plant Pigments. Edit. T. W. Goodwin (1976)

Chapter 16 - Functions of flavonoids in plants (J. B. Harborne)

p 750

Co-pigmentation is also a factor controlling flower colour in the genus Rosa. A blue rose has long been searched for; the rather unsatisfactory mauve and purple varieties (e.g. “Reine de Violette”) so far available contain the cyanidin 3,5-diglucoside of crimson roses co-pigmented with large amounts of gallotannin. The spectral shift in rose is from 507 to 512 nm (Harborne, 1961).

I assume that the monoglucoside of cyanidin (chrysanthemin) co-pigmented with gallotannin would give a mauve.

Others may carry AVIs (anthocyanic vacuolar inclusions).

Gonnet: J. Agric. Food Chem. 2003, 51, 4990-4994 mentioned ‘Rhapsody in Blue’, ‘L’Eveque’ (The Bishop) and ‘Bleu Magenta’ as varieties with this sort of color.

Crossing mauves with different types of “blue” would probably give dull pinks rather than improved mauves.

Karl

4

Karl,

My recommended strategy assumes all of the things you point out are true.

The rosacyanins are likely present in all mauves in small amounts - especially those derived from Gray Pearl, Lady X, Lavande, Blue Moon, Seiryu and similar lines (Fukui, 2009, pers. comm.). Boosting the levels of rosacyanins is the target and this means incorporating roses that have demonstrated up-regulation of the precursors then selecting for the most blue ones.

You will no doubt get a lot of mauve progeny but also some that are more blue than their ancestors, and those are the ones you want to continue on with.

It’s not a project to be taken on casually unless you like very long odds. For a young, serious breeder with a relentless ambition the odds are in their favor.

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@Don, ooo, must make one of those! I have a handheld spectroscope that I got from Edmund Scientific; it’s nice but difficult to use on flowers.

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Don,

The link hasn’t been working for me. I did find a cached version (from June 8, 2012), but it didn’t show the pictures. I get a message that the server isn’t found. Must be a glitch. I’ll try again later.

Have you used it on yellow roses? I had a copied article (now misplaced) that showed the yellow reflectance of carotene and some other substance. It may have been a quercitin derivative. The carotene reflected two narrow spikes or bands in the yellow range. The other substance had only a short peak, but it happened to fall in the valley between the carotene peaks. Thus, it contributed far more to the intensity of the yellow than one might have guessed seeing it all alone.

I’m also interested in how much (and which frequency) of yellow light is reflected by luteolin. While carotenes and quercitin derivatives fade somewhat when exposed to UV, luteolin actually deepens in color. Combined with the other two, the luteolin could reduce apparent fading by darkening while the others lighten.

Karl

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Karl,

It is not really analogous to absorption spectroscopy in the IR where you have sharp peaks corresponding to structure and can fingerprint compounds. I have made spectra from yellow roses and find that the reflectance curves are broad and resemble that from chlorophyll, actually. I think it will be impossible to pick out individual carotenoid pigments because of this. More work needs to be done, though, and I lack standards to work from and the time to devote to it.

I think the technique offers more promise with anthocyanins where we have roses with known petal pigments that can serve as standards and where the peaks are not as broad as with carotenoids. In particular, I think it would be quite useful in the hunt for rosacyanins.

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Karl, With reference to the article by Gupt eta al in Jounral of Scientific and Industrial Research, if you can tell me the page numbers, volume number or article title it would help. Our library has all three parts of the serial but in off-site storage. Part A is general, B/C Biological/Physical (or maybe reverse of this) Looks like it should be vol 16 if the year is 1957. The Biological and Physical were bound together. It is a monthly with 12 issues/vol but maybe rather thin. Lib Cong call # is T1.J63 which would apply at other universities that have it. Perhaps UC-Davis. I can request the actual volumes but it takes a week or so to ship them back here. With correct info they will scan and transmit within a day (after I get home to library)

9

This stuff is way over my head but I did find this.

Abstract

A rapid, simple, sensitive, robust, and improved HPLC method was developed and validated for determination of 10 polyphenols, namely gallic acid, catechin, epicatechin, rutin, m-coumaric acid, quercitrin, myricetin, quercetin, apigenin, and kaempferol in fresh flowers of Rosa bourboniana and R. brunonii and in both fresh flowers and marc (left after industrial distillation of rose oil) of R. damascena. Six polyphenols, gallic acid, rutin, quercitrin, myricetin, quercetin, and kaempferol, were detected and quantified in all extracts.

Link to article.

10

Larry,

S. R. Gupta, K. S. Pankajamani, and T. R. Seshadri, J. Sci. Ind. Res. B. (India) 16, 154 (1957). [Journal of Scientific & Industrial Research]

When I attended K-State in the '70s, I worked part time in the library. I had a great time browsing while I was shelving books. Years later, remembering books I had read, I searched the KSU library online (shelf order) to find books whose titles I have forgotten. I even requested a thesis I had read (Effects of apple (Pyrus malus Linn.) rootstocks and interstems on the leaf characteristics and tree structure of golden delicious cultivar by Syed Z. Ahmed.) through interlibrary loan. That, and Reychler’s fascinating works on traumatic pollination and orchid mutants.

Now I use the KU (Kentucky) library when I can get to Lexington. It’s also pretty good. But it’s a bit strange seeing the wildcats in blue & white rather than purple & white. It makes me feel like an illegal alien.

Steve,

Thanks for the link. The plot thickens. Not only myricetin (potential precursor for delphinin) but rutin. Rutinosides of anthocyanins have been identified in some Rosa spp., but I don’t know what color they would be as dominant pigments. In tulips and irises, rutinosides of delphinidin can be close to blue.

Mikanagi, et al. 2000

Four anthocyanins: Cy 3-rutinoside, Pn 3-rutinoside, Pn 3-rho-coumaroylglucoside-5-glucoside and Cy 3-sophoroside were found for the first time in Rosa flowers. Investigated sections of wild roses showed characteristic distribution of anthocyanins. Cy 3,5-diglucoside was the dominant anthocyanin detected in all three sections, but accumulation of Pn 3,5-diglucoside distinguished sections Cinnamomeae from other sections, and the occurrence of Cy 3-glucoside separates section Chinenses from others.

Cy 3-sophoroside was detected in large amount in some taxa of section Cinnamomeae: e.g., R. moyesii and its related cultivars, and R. rugosa cv. Salmon Pink.

Karl

11

Larry Davis has kindly sent me a copy of the Gupta (1957) paper. It lists the flavonol content of various roses, and indicates that some of them contain traces of myricetin (chemical cousin of delphinidin). Of these, only ‘Una Wallace’ has myricetin as the major component.

I checked the parentage of several of the varieties containing myricetin. Mostly unknown!

The article gives some details on extracting and identifying the flavonols.

Karl