Plant Breeding Breakthrough: Offspring with genes from only one parent

[2Lazy]

A reliable method for producing plants that carry genetic material from only one of their parents has been discovered by plant biologists at UC Davis. The technique, to be published March 25 in the journal Nature, could dramatically speed up the breeding of crop plants for desirable traits.

The discovery came out of a chance observation in the lab that could easily have been written off as an error.

"We were doing completely 'blue skies' research, and we discovered something that is immediately useful," said Simon Chan, assistant professor of plant biology at UC Davis and co-author on the paper.

Like most organisms that reproduce through sex, plants have paired chromosomes, with each parent contributing one chromosome to each pair. Plants and animals with paired chromosomes are called diploid. Their eggs and sperm are haploid, containing only one chromosome from each pair.

Plant breeders want to produce plants that are homozygous -- that carry the same trait on both chromosomes. When such plants are bred, they will pass the trait, such as pest resistance, fruit flavor or drought tolerance, to all of their offspring. But to achieve this, plants usually have to be inbred for several generations to make a plant that will "breed true."
The idea of making a haploid plant with chromosomes from only one parent has been around for decades, Chan said. Haploid plants are immediately homozygous, because they contain only one version of every gene. This produces true-breeding lines instantly, cutting out generations of inbreeding.

Existing techniques to make haploid plants are complicated, require expensive tissue culture and finicky growing conditions for different varieties, and only work with some crop species or varieties. The new method discovered by Chan and postdoctoral scholar Ravi Maruthachalam should work in any plant and does not require tissue culture.

Ravi and Chan were studying a protein called CENH3 in the laboratory plant Arabidopsis thaliana. CENH3 belongs to a group of proteins called histones, which package DNA into chromosomes. Among the histones, CENH3 is found only in the centromere, the part of the chromosome that controls how it is passed to the next generation.

When cells divide, microscopic fibers spread from each end of the cell and attach at the centromeres, then pull the chromosomes apart into new cells. That makes CENH3 essential for life.
Ravi had prepared a modified version of CENH3 tagged with a fluorescent protein, and was trying to breed the genetically modified plants with regular Arabidopsis. According to theory, the cross should have produced offspring containing one mutant gene (from the mother) and one normal gene (from the father). Instead, he got only plants with the normal gene.
"At first we threw them away," Chan said. Then it happened again.
Ravi, who has a master's degree in plant breeding, looked at the plants again and realized that the offspring had only five chromosomes instead of 10, and all from the same parent.
The plants appear to have gone through a process called genome elimination, Chan said. When plants from two different but related species are bred, chromosomes from one of the parents are sometimes eliminated.
Genome elimination is already used to make haploid plants in a few species such as maize and barley. But the new method should be much more widely applicable, Ravi said, because unlike the process for maize and barley, its molecular basis is firmly understood.
"We should be able to create haploid-inducing lines in any crop plant," Ravi said. Once the haploid-inducing lines are created, the technique is easy to use and requires no tissue culture -- breeders could start with seeds. The method would also be useful for scientists trying to study genes in plants, by making it faster to breed genetically pure lines.

After eliminating half the chromosomes, Chan and Ravi had to stimulate the plants to double their remaining chromosomes so that they would have the correct diploid number. Plants with the haploid number of chromosomes are sterile.

The research also casts some interesting light on how species form in plants. CENH3 plays the same crucial role in cell division in all plants and animals. Usually, such important genes are highly conserved -- their DNA is very similar from yeast to whales. But instead, CENH3 is among the fastest-evolving sequences in the genome.

"It may be that centromere differences create barriers to breeding between species," Chan said. Ravi and Chan plan to test this idea by crossing closely-related species.

The work was supported by a grant from the Hellman Family Foundation.

Source:http://www.sciencedaily.com/releases/2010/03/100324142012.htm

So clones from seeds!!! It might be a year or more away but at least they have a better process for making fem seeds now.

 

[meduser180056]

wow that's pretty cool stuff...

Kinda like a skip to go and collect $200 card haha

 

[dank.frank]

very interesting....

 

[Pallidus127]

That's amazing. I can't wait to hear more about this. This will really speed up research for developing illness specific strains.

 

[medmaker420]

sounds great

 

[SOTF420]

 

[Grat3fulh3ad]

Genetically, the seeds produced will be no different from standard selfing techniques. It seems as though this technique will be most useful with plant species that are more difficult than cannabis to sexually reverse. Nice find.

 

[blackone]

Haploid plants are immediately homozygous, because they contain only one version of every gene.

Obviously wrong.

EDIT: No - I'm wrong - thanks 2Lazy

 

[2Lazy]

Blackone, you probably didn't fully conceptualize the idea.

Through elimination we can determine that they are clearly not heterozygous, as there is only one allele there cannot be a different allele for any trait.

It is more hemizygous if anything as one set of alleles would be missing. But I think they are arguing that since a the entire structure is without complementary alleles then the plant acts as a homozygous replica of only one parent's genetics in every allele instance.

Though if you read this line perhaps you see it come full circle:

Chan and Ravi had to stimulate the plants to double their remaining chromosomes so that they would have the correct diploid number. Plants with the haploid number of chromosomes are sterile.

The plants may be missing the complementary set of alleles, but the first set is mirrored to manufacture the second set which creates a diploid homozygous plant.

 

[Tatz]

I´ve only got one ?.

The CENH3-protein, when it hits the environment, how will this affect diff lifeforms ?

 

[catman]

As soon as I saw this article I had to check to see if it was posted on ICMAG yet lol

Thank you scientists!

 

[blackone]

Blackone, you probably didn't fully conceptualize the idea.

Through elimination we can determine that they are clearly not heterozygous, as there is only one allele there cannot be a different allele for any trait.

It is more hemizygous if anything as one set of alleles would be missing. But I think they are arguing that since a the entire structure is without complementary alleles then the plant acts as a homozygous replica of only one parent's genetics in every allele instance.

Though if you read this line perhaps you see it come full circle:
The plants may be missing the complementary set of alleles, but the first set is mirrored to manufacture the second set which creates a diploid homozygous plant.

Indeed I was too fast there - thanks for pointing that out. I see the scope of the discovery now... amazing.
Imagine a clone like that... No matter how herm prone it is or how many males your neighbor has it would only create bud and no seeds Or perhaps it would create sterile seeds... that would suck.
I wonder how the actual haploid plant would grow though...

I kinda hope this doesn't spread too much... so much genetic material would be lost especially in more heterozygous lines.

 

[UpInTheCut]

Yes, a truly great discovery for humanity.Think, drought resistant crops in Israel. We could breed Ug99 fungus resistance into crops in a couple seasons with this technique. We would have such a edge on Mother Nature.
Shit Man, if this pans out I could see a Nobel Peace Prize in the works, We'll see in a decade (usually how long it takes to win a Nobel, after a discovery)
Never mind the possibilities of new plant species like CannaHops? CannaPoppy?
-Up

 

[Dr_Tre]

Expect many "new" strains from GHS!

 

[bigwity]

Expect many "new" strains from GHS!

LMAO quality

 

[The_Grim_Reefer]

exciting news, cheers for the linkage

 

[Hydro-Soil]

What effect, if any, does this have on the medicinal aspect of finished bud?

 

[festivus]

I've put forth a theory that some female cannabis produces what I've called primordial seeds, without male pollen. On numerous occasions, I've found a few seeds on an otherwise unpollenated plant. My theory is that some females have the ability to self-pollenate as a survival trait, once peak flowering has come and gone (see "Primordial Seeds?" on my profile).

When I posted this, several people said it couldn't happen without the male sperm, and the seed formation was attributed to stray pollen. After reading this, I think maybe there's something else going on.

Thanks 2Lazy!

 

[rooted]

amazing

2lazy thank you for posting this!

 

[dakin3d]

Thanks for posting, man! It is much appreciated... This is pretty amazing stuff here.

I'm curious to see the protocol / methodologies used. If you don't have to utilized tissue culture and the general molecular process, then they must already have alternative motive.... You can kinda tell they already have something in mind in the way of a 'kit' that you'll have to purchase from Invitrogen or whomever UCDavis uses to subcontract and manufacture proprietary laboratory procedure (making it either hard, or impossible to obtain unless you work in a lab). I'm anxious to read their publication on this. Thanks again, bro. Cheers