Varieties with Color genes

[Darren Abbey]

I've been trying to gather information about example commonly available varieties which are known to contain different color-changing mutations.

For example :

• B : "Caro-Rich", high beta-carotene.
• atv : "Indigo Rose", anthocyanins in fruit skin.
• Aft : "Indigo Rose", anthocyanins in fruit skin.
• gf : "Green Zebra", persistence of chlorophyll in mature fruit.
• gs : "Green Zebra", stripes of darker green on fruit skin.
• etc.

In particular, I've been interested in the range of 'orange' mutations which impact the relative abundance of different carotenoids in the ripe fruit, as well as some of the immature-fruit color genes like 'dg'.

The 'dg' mutation results in immature fruit having a very dark green color due to excess chlorophyll production. I'm interested in putting this mutant into a brown/purple tomato, with the idea that the enhanced chlorophyll may result in a different/better taste.

Do any of you have references that may help me gather this information?

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I'll add references here as I find them:

• http://forums.gardenweb.com/forums/l...251224332.html
• http://treecropsresearch.org/heirloom-tomatoes/
• http://tgc.ifas.ufl.edu/vol36/v36p10a.html

[bower]

Darren, I was reading about crmauch's project the other day, and went looking for the site where I had seen a lot of test data on carotenoids in different tomato varieties a couple of years ago. This is raw data from specific seasons, not the same as direct confirmation of a gene, but it is interesting all the same and gives some good indications if there is no research source available to directly confirm a specific gene.

I finally found it again, here is the site:
http://treecropsresearch.org/heirloom-tomatoes/

[Minnesota Mato]

I am trying to do a very similar thing. I want to put a dark red from hirsutum with a (B) beta -carotene and (gf) green flesh in a meaty heart tomato for a super dark orange heart with extra carotenoids. I've read a lot about (dg) which is an allele of the hp-2 gene and seems to have a lot of negative effects too.http://tgc.ifas.ufl.edu/vol36/v36p10a.html - here is something of interest on (dg). Another thing that is very interesting is a tomato from I think the 1950's called Black Queen (Webb Special) which has hp-1 and hp-2 but I could not find anyone who has it.
craig

[Darren Abbey]

http://www.plantphysiol.org/content/...9/F2.expansion

Apparently the 'dg' mutation is considered to be in the same gene as the 'hp-2' mutation.

[Minnesota Mato]

Most people here say the (hp) genes are not worth playing with. I did find some research that made it sound like (gf) could have close to the same effect without all the negatives.

[Darren Abbey]

Originally Posted by Minnesota Mato

Most people here say the (hp) genes are not worth playing with. I did find some research that made it sound like (gf) could have close to the same effect without all the negatives.

I did find one reference discussing a series of hp alleles, one of which didn't show the growth/viability problems characteristic of the others. …unfortunately, I've lost the link.
----

I did find this link talking about various green-flesh alleles, including a list of different strains with different alleles.
http://forums.gardenweb.com/forums/l...529042.html?13

[bower]

Reading up on the orange fruited genes and carotenoids.

The tangerine allele t has been known for a long time. According to Genetic Improvement of Solanaceous Crops: Tomato, Volume 2 edited by M K Razdan, A. K. Mattoo....."Pigment compositions of nearly all orange-fleshed cultivars available for commercial and home use attribute their color to the tangerine allele."

Elsewhere the variety Tangerine is identified as the type example.
Jubilee is another common example of the t gene (Tangerine X Rutgers).

Interesting data on the carotenoid content of r, t, tr here with a good picture of the colour phenotypes:
http://www.pnas.org/content/early/20...08109.full.pdf

Virescent orange is a TGRC mutant allele of t. Accessions with that mutation are listed at the bottom:
http://tgrc.ucdavis.edu/Data/Acc/GenDetail.aspx?Gene=vo

Beta is dominant to og and crimson. Like Delta, the source is from introgressions from wild Lycopersicon species, afaict, rather than a simple mutation in tomatoes that would be found scattered among the heirlooms. L. cheesmanni accumulates beta-carotene instead of lycopene in fruit due to the Beta allele, and so do some other green fruited Lycopersicon spp. So orange varieties with cheesmanni heritage would probably get it from Beta.
This TGRC page lists accession numbers for both Beta and Delta here and there are photos of the fruit phenotypes. Lots of history and info on each accession if you click on the links.
http://tgrc.ucdavis.edu/Data/Acc/GenDetail.aspx?Gene=B

[Minnesota Mato]

another link I found with hp,hp2 and gf. http://tgc.ifas.ufl.edu/Vol28/Vol28_10.html

[Darren Abbey]

A cool photo showing some research tomatoes. The colors are generated via two transcription factors transferred over from snapdragon and a third from Arabidopsis.

http://www.norfolkplantsciences.com/...ts/4-tomatoes/

As GMOs, they're not likely to end up on the shelves any time soon. (I'm not averse to genetic engineering, but I do really dislike some of the businesses using the technique. This one isn't so offensive to me, yet.) I do like the colors they've come up with, however.

[Darren Abbey]

http://www.ncbi.nlm.nih.gov/pubmed/12589545

The abstract mentions the original 'dg' allele was discovered in the 1960s-era commercial variety "Manapal".

The variety seems to be available : http://www.reimerseeds.com/manapal-tomato.aspx
----

Correction: the 'dg' mutation was first found in "Manapal", but the variety is not characterized by the trait. http://forums.gardenweb.com/forums/l...220447895.html

[bower]

Those colors are amazing, Darren. I don't think anyone could resist a taste.

A little more about Delta:
The mutant is an introgression from S. Penelli, according to the section on color genetics in this excellent article:

http://jxb.oxfordjournals.org/content/58/14/3841.full

There's reference to "high delta tomato seeds" in this article from the '50's. So the allele may be out there in commercial cultivars developed since then.
http://www.jstor.org/discover/10.230...21103767063047

There's another picture of the phenotype here:

http://www.esalq.usp.br/tomato/Del.pdf

Delta is on chromosome 12 and is not allelic to Beta nor tangerine.

Since Delta and Beta are dominant, shouldn't we expect to see orange fruit in the F1? If so, that would immediately distinguish them from fruit with the tangerine t allele. I made several crosses with Zolotoe Serdtse last fall and the F1 seedlings are up. If those F1's are red, can I conclude that the orange color came from tangerine?

[Darren Abbey]

Originally Posted by bower

Since Delta and Beta are dominant, shouldn't we expect to see orange fruit in the F1? If so, that would immediately distinguish them from fruit with the tangerine t allele. I made several crosses with Zolotoe Serdtse last fall and the F1 seedlings are up. If those F1's are red, can I conclude that the orange color came from tangerine?

There are potentially other recessive orange mutations, so to be certain you were dealing with the 'tangerine' gene, you would have to do a test cross into a strain you already know has 'tangerine'. Without that cross, but knowing that 't' is the most common orange gene, it is reasonable to tentatively say that "Zolotoe Serdtse" includes 't' until you have further data.

[bower]

Sherry gene: sh.

The mutation is so detrimental, it won't be found in any OP cultivar for sure.
It is a mutant of the variety 'Canary Export' by ionizing radiation.
Plant is "extremely unfruitful". details here:
http://tgc.ifas.ufl.edu/Vol30/Vol30/Vol30_26.html
http://forums.seedsavers.org/showthread.php?t=552

[bower]

Originally Posted by Darren Abbey

There are potentially other recessive orange mutations, so to be certain you were dealing with the 'tangerine' gene, you would have to do a test cross into a strain you already know has 'tangerine'. Without that cross, but knowing that 't' is the most common orange gene, it is reasonable to tentatively say that "Zolotoe Serdtse" includes 't' until you have further data.

Also, my bad, Beta is not dominant after all. Fruit of F1 offspring of Beta Orange X Rutgers were intermediate in colour (orange red) and in carotenoid profile.
Also the phenotype of Beta was completely masked in yellow fruit (rrBB, rrBb and rrbb indistinguishable).

http://www.genetics.org/content/38/2/117.full.pdf

[bower]

Another recessive: apricot at

The colour is described as a darker or more orange yellow, phenotype is distinguished from yellows by the presence of pink blush in the interior locular walls near the placenta, and by small islands of sharply defined red tissue.

The gene is not allelic to r, t, or B.

The original apricot fruit pheno (which I think is from RRatat) sounds distinctive enough, but combinations of the recessives rr atat and tt , are reported to be difficult or impossible to distingush by visual characteristics.

http://www.genetics.org/content/40/5/715.full.pdf

http://tgrc.ucdavis.edu/Data/Acc/GenDetail.aspx?Gene=at

The flower phenotype is distinctive - nearly white pale petals - if this can be expected in every plant with atat, it would make it easy to tell.