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heat How to make the hottest peppers - if you know a good plant geneticist

Nigel

Nigel

All you`d need to do is add more copies of the gene that encodes the rate-limiting enzyme in the metabolic pathway that produces capsaicin. Simple. Maybe start here!
 
 
 



[SIZE=8pt]The Plant Journal [/SIZE][SIZE=8pt](2005) [/SIZE][SIZE=8pt]42[/SIZE][SIZE=8pt], 675–688 doi: 10.1111/j.1365-313X.2005.02410.x [/SIZE]




[SIZE=17pt]The [/SIZE][SIZE=17pt]Pun1 [/SIZE][SIZE=17pt]gene for pungency in pepper encodes a putative acyltransferase [/SIZE]
[SIZE=9pt]Charles Stewart Jr[/SIZE][SIZE=6pt]1,†[/SIZE][SIZE=9pt], Byoung-Cheorl Kang[/SIZE][SIZE=6pt]2,†[/SIZE][SIZE=9pt], Kede Liu[/SIZE][SIZE=6pt]3,†[/SIZE][SIZE=9pt], Michael Mazourek[/SIZE][SIZE=6pt]1,†[/SIZE][SIZE=9pt], Shanna L. Moore[/SIZE][SIZE=6pt]2[/SIZE][SIZE=9pt], Eun Young Yoo[/SIZE][SIZE=6pt]4[/SIZE][SIZE=9pt], Byung-Dong Kim[/SIZE][SIZE=6pt]4[/SIZE][SIZE=9pt], Ilan Paran[/SIZE][SIZE=6pt]5 [/SIZE][SIZE=9pt]and Molly M. Jahn[/SIZE][SIZE=6pt]1,2,*[/SIZE]
[SIZE=6pt]1[/SIZE][SIZE=9pt]Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA,[/SIZE]
[SIZE=6pt]2[/SIZE][SIZE=9pt]Department of Plant Breeding and Genetics, Cornell University, Ithaca, NY 14853, USA, [/SIZE]
[SIZE=6pt]3[/SIZE][SIZE=9pt]National Key Laboratory of Crop Genetic Improvement, Huazhong Agriculture University, Wuhan 430070, Hubei Province, China,[/SIZE]
[SIZE=6pt]4[/SIZE][SIZE=9pt]Center for Plant Molecular Genetics and Breeding Research, Seoul National University, San 56-1, Shillim 9-dong, Kwanak-gu, Seoul 151-742, South Korea, and [/SIZE]
[SIZE=6pt]5[/SIZE][SIZE=9pt]Department of Plant Genetics and Breeding, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel [/SIZE]
[SIZE=7pt]Received 9 January 2005; revised 17 February 2005; accepted 22 February 2005. [/SIZE][SIZE=5pt]*[/SIZE][SIZE=7pt]For correspondence (fax 607 255 6683; e-mail mmj9@cornell.edu).[/SIZE]
[SIZE=5pt]†[/SIZE][SIZE=7pt]These authors contributed equally to this work. [/SIZE]
[SIZE=9pt]Summary [/SIZE]
[SIZE=9pt]Pungency in [/SIZE][SIZE=9pt]Capsicum [/SIZE][SIZE=9pt]fruits is due to the accumulation of the alkaloid capsaicin and its analogs. The biosynthesis of capsaicin is restricted to the genus [/SIZE][SIZE=9pt]Capsicum [/SIZE][SIZE=9pt]and results from the acylation of an aromatic moiety, vanillylamine, by a branched-chain fatty acid. Many of the enzymes involved in capsaicin biosynthesis are not well characterized and the regulation of the pathway is not fully understood. Based on the current pathway model, candidate genes were identified in public databases and the literature, and genetically mapped. A published EST co-localized with the [/SIZE][SIZE=9pt]Pun1 [/SIZE][SIZE=9pt]locus which is required for the presence of capsaicinoids. This gene, [/SIZE][SIZE=9pt]AT3[/SIZE][SIZE=9pt], has been isolated and its nucleotide sequence has been determined in an array of genotypes within the genus. AT3 showed significant similarity to acyltransferases in the BAHD superfamily. The recessive allele at this locus contains a deletion spanning the promoter and first exon of the predicted coding region in every non-pungent accession tested. Transcript and protein expression of [/SIZE][SIZE=9pt]AT[/SIZE][SIZE=9pt]3 was tissue-specific and developmentally regulated. Virus-induced gene silencing of [/SIZE][SIZE=9pt]AT3 [/SIZE][SIZE=9pt]resulted in a decrease in the accumulation of capsaicinoids, a phenotype consistent with [/SIZE][SIZE=9pt]pun1[/SIZE][SIZE=9pt]. In conclusion, gene mapping, allele sequence data, expression profile and silencing analysis collectively indicate that the [/SIZE][SIZE=9pt]Pun1 [/SIZE][SIZE=9pt]locus in pepper encodes a putative acyltransferase, and the [/SIZE][SIZE=9pt]pun1 [/SIZE][SIZE=9pt]allele, used in pepper breeding for nearly 50 000 years, results from a large deletion at this locus. [/SIZE]



 
 
It`s much harder to put genes in plants than everything else put together. I`ve been involved in putting green fluorescent protein in mice, but we used to put green, yellow, red or cyan-fluorescent protein in mammalian cells in culture all the time. 
 
That kickstarter campaign is very interesting. Plant geneticists use Arabidopsis a great deal, as it has a very fast life cycle and small genome. 

After this Kickstarter campaign, Kickstarter has banned anyone from offering genetically modified organisms as part of the campaign.
 
thegreenman said:
why not spend the money making commercially grown tomatoes that actually taste good in stead of like wet cardboard. 
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Given the current arms race in hot pepper heat levels, I figured this was my best tongue-in-cheek response, whilst throwing the idea out there. 
 
The tomato problem is really one of getting them to market. If you buy at Farmer`s markets they taste like they should, but cost more. Big Agri-business gets rid of flavour, in order to provide uniform-looking product as cheaply as possible. 
 
thegreenman said:
why not spend the money making commercially grown tomatoes that actually taste good in stead of like wet cardboard. 
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I took the seeds from a commercially grown cherry tomato earlier this year and grew 7 plants. The tomatoes are delicious.. much better tasting then the original. I think commercial tomatoes are just picked to early.
 
scotchnaga85 said:
I took the seeds from a commercially grown cherry tomato earlier this year and grew 7 plants. The tomatoes are delicious.. much better tasting then the original. I think commercial tomatoes are just picked to early.
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On top of that, most commercially grown tomatoes possess a gene that gives them more uniform coloration, but reduces their flavor.
 
craigerator said:
On top of that, most commercially grown tomatoes possess a gene that gives them more uniform coloration, but reduces their flavor.
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The ones I've grown are some the best tomato's I've had... though evidently the 'cherry tomato' that I took my seeds from was not a stable veriety. A few of my plants are growing full sized tomato's :D
 
Nigel said:
All you`d need to do is add more copies of the gene that encodes the rate-limiting enzyme in the metabolic pathway that produces capsaicin. Simple. Maybe start here!
 
 
 



The Plant Journal (2005) 42, 675–688 doi: 10.1111/j.1365-313X.2005.02410.x




The Pun1 gene for pungency in pepper encodes a putative acyltransferase
Charles Stewart Jr1,†, Byoung-Cheorl Kang2,†, Kede Liu3,†, Michael Mazourek1,†, Shanna L. Moore2, Eun Young Yoo4, Byung-Dong Kim4, Ilan Paran5 and Molly M. Jahn1,2,*
1Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA,
2Department of Plant Breeding and Genetics, Cornell University, Ithaca, NY 14853, USA,
3National Key Laboratory of Crop Genetic Improvement, Huazhong Agriculture University, Wuhan 430070, Hubei Province, China,
4Center for Plant Molecular Genetics and Breeding Research, Seoul National University, San 56-1, Shillim 9-dong, Kwanak-gu, Seoul 151-742, South Korea, and
5Department of Plant Genetics and Breeding, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
Received 9 January 2005; revised 17 February 2005; accepted 22 February 2005. *For correspondence (fax 607 255 6683; e-mail mmj9@cornell.edu).
†These authors contributed equally to this work.
Summary
Pungency in Capsicum fruits is due to the accumulation of the alkaloid capsaicin and its analogs. The biosynthesis of capsaicin is restricted to the genus Capsicum and results from the acylation of an aromatic moiety, vanillylamine, by a branched-chain fatty acid. Many of the enzymes involved in capsaicin biosynthesis are not well characterized and the regulation of the pathway is not fully understood. Based on the current pathway model, candidate genes were identified in public databases and the literature, and genetically mapped. A published EST co-localized with the Pun1 locus which is required for the presence of capsaicinoids. This gene, AT3, has been isolated and its nucleotide sequence has been determined in an array of genotypes within the genus. AT3 showed significant similarity to acyltransferases in the BAHD superfamily. The recessive allele at this locus contains a deletion spanning the promoter and first exon of the predicted coding region in every non-pungent accession tested. Transcript and protein expression of AT3 was tissue-specific and developmentally regulated. Virus-induced gene silencing of AT3 resulted in a decrease in the accumulation of capsaicinoids, a phenotype consistent with pun1. In conclusion, gene mapping, allele sequence data, expression profile and silencing analysis collectively indicate that the Pun1 locus in pepper encodes a putative acyltransferase, and the pun1 allele, used in pepper breeding for nearly 50 000 years, results from a large deletion at this locus. 



 
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Gah, it's so simple!  How did I not see it before? :shocked:
 
I'm no scientist, but I tried google and wikipedia to translate this (to me) garbledygook.  I'm sure there are mistakes, and I'm sure it's oversimplified, but I tried as much as I could to put this in layman's terms.  Corrections are always encouraged. 
 
Everything in red is my attempt to translate what I was reading.
 
[SIZE=12pt]Pungency in Capsicum fruits is due to the accumulation of the alkaloid capsaicin and its analogs. Peppers are spicy because of capsaicin and capsaicin like chemicals. The biosynthesis of capsaicin is restricted to the genus Capsicum and results from the acylation of an aromatic moiety, vanillylamine, by a branched-chain fatty acid.  Only peppers within the genus capsicum produce capsaicin and does it by introducing an acyl radical called vanillylamine by a branch chained fatty acid.[/SIZE] Many of the enzymes involved in capsaicin biosynthesis are not well characterized and the regulation of the pathway is not fully understood. We are still not sure how the enzymes are involved in making capsaicin. Based on the current pathway model, candidate genes were identified in public databases and the literature, and genetically mapped. We genetically mapped certain genes we already knew about. A published EST co-localized with the Pun1 locus which is required for the presence of capsaicinoids.  (I think based on the next sentence) We Identified a gene that is required to make capsaicin and capsaicin like chemicals. This gene, AT3, has been isolated and its nucleotide sequence has been determined in an array of genotypes within the genus.  AT3 is the name of the isolated gene and has been found in a lot of types of peppers. AT3 showed significant similarity to acyltransferases in the BAHD superfamily. AT3 does a lot of the same things as a certain family of enzymes called BAHD.  The recessive allele at this locus recessive gene on this species contains a deletion mutation caused by missing genetic material spanning the promoter and first exon the place in the DNA that starts translating the gene and the sequence that helps make proteins of the predicted coding region in every non-pungent accession tested. Transcript and protein expression of AT3 was tissue-specific and developmentally regulated. Only certain tissues were affected by the AT3 gene and it was regulated developmentally. Virus-induced gene silencing of AT3 resulted in a decrease in the accumulation of capsaicinoids, When AT3 was exposed to certain viruses it was shut off and fewer Capsaicinoids were produced a phenotype consistent with pun1. In conclusion, gene mapping, allele sequence data, expression profile and silencing analysis collectively a bunch of tests indicate that the Pun1 locus AT3 gene in pepper encodes a putative acyltransferase accepted enzyme, and the pun1 allele recessive gene, used in pepper breeding for nearly 50 000 years, results from a large deletion mutation caused by a missing piece of genetic material at this locus in this species.
 
So, a gene (AT3) helps to create capsaicin in a similar way as a large family of enzymes. The recessive gene in this species (capsicum) contains a mutation causing less capsaicin to be produced.  AT3 affects certain tissues and as the pepper grows certain amounts of capasaicin is created. Some viruses can shut down capsaicin development at the AT3 level.
 
Oww.  My brain hurts.
 
How close am I?
 
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