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from the You-can't-kill-a-plant-by-shooting-it-in-the-head dept.
In an interesting feedback loop, some parts of plants are able to modify the genetic expression of their own nucleus in real time in a way not yet fully understood.
An interesting article in ArsTechnica summarizes a paywalled article in Science describing how Chloroplasts (in the leaves of plants) control the RNA transcription process in the roots of plants by a mechanism not yet determined.
Chloroplasts, billions of years ago were free-living individual cells. However, by a mechanism still only guessed at, they became entrapped in plant cells, and persist today in the leaves of every green plant.
Some of the genes in the nucleus are recipes for cellular machinery needed for the chloroplast to do its job:to undertake photosynthesis. It is important that the nucleus transcribes these genes in response to appropriate cues, especially daylight.
Intriguingly, some genes are transcribed based on a signal that comes from the chloroplast itself. Signaling from the chloroplast to the nucleus is called retrograde signalling. It has fascinated scientists for decades because the nature of the signal from the chloroplast is unknown.
Now this story has become even more intriguing. According to the Science paper, it seems that this form of signalling from chloroplasts can do more than direct the transcription of genes. It can also direct modifications of the RNA transcribed from the genes. These transcripts are modified by splicing the RNA, which removes bits of superfluous information from them. Without splicing, most RNAs wouldn't be able to encode proteins.
The Chloroplasts, (long thought to be a captive within plant cells) effectively wrests control of the cell's chemical machinery from the nucleus by signaling (by means unknown) a change in the RNA transcription and splicing process, so as to assure themselves of the raw materials needed to carry out photosynthesis. (Of course this helps both sides of this quasi-symbiotic existence.) This "Post Processing" of the transcription process (directly modifying the transcribed RNA) is quite unique.
The signaling to do this is able to reach distant portions of the plant, usually root cells, from the leaves, in relatively short time periods.
If the Chloroplasts are able to control cellular machinery, from outside the nucleus, it calls into question which cellular life form incorporated the other. Perhaps all green plants are merely zombies controlled for eons by structures they found tasty a billion years ago. Be careful what you eat.
(Score: 2) by wonkey_monkey on Monday April 14 2014, @11:27AM
We're all zombies for all our genes care.
systemd is Roko's Basilisk
(Score: 3, Funny) by marcello_dl on Monday April 14 2014, @11:36AM
When I was young the genes were taught as the definitive building instructions which were passed, along with random variation or the occasional interference by external factors, from one generation to the next in a mechanical process. Now they are more like a manifestation... I want all my bad grades reconsidered!
(Score: 3, Funny) by WizardFusion on Monday April 14 2014, @12:08PM
That's it, no more greens for me.
(Score: 5, Informative) by hatta on Monday April 14 2014, @01:20PM
Mitochondria are "domesticated" bacteria with their own genome, just like chloroplasts. With how critical energy metabolism is, don't be surprised to see two way communication between our nuclei and mitochondria too.
For a biologist, it's not really surprising that this signalling happens. If the plant is to respond to light, obviously the light sensitive organelles have to communicate with the part that controls growth. But determining the mechanism could potentially be very useful in altering the growth of plants with biotech, and if it's conserved with mitochondria it could have medical applications too.
(Score: 3, Interesting) by opinionated_science on Monday April 14 2014, @02:39PM
indeed in the Poplar genome that was published a few years back (first tree sequenced) there were homologous genes found in the mitochondria and the nuclear genome. This would strongly suggest a signaling framework to coordinate some cellular processes.
(Score: 1) by LoRdTAW on Monday April 14 2014, @01:50PM
Chloroplasts, billions of years ago were free-living individual cells. However, by a mechanism still only guessed at, they became entrapped in plant cells, and persist today in the leaves of every green plant.
Yo dawg, we heard you like cells. So we put a cell in yo cell so you can metabolize while you metabolize.
(Score: 0) by Anonymous Coward on Monday April 14 2014, @02:23PM
Organisms have long been known to modify their genetic expression in real time.
http://en.wikipedia.org/wiki/Operator_(biology) [wikipedia.org]
That we are finding another example of this is hardly surprising.
(Score: 4, Informative) by Yog-Yogguth on Monday April 14 2014, @05:59PM
I am not a biologist or geneticist but the following article talks about how gene expression and related mechanisms are incredibly powerful and can be incredibly fast as well, and not only for plants but all life including humans [psmag.com]: "It seemed the genome, without changing its code, could transform an animal into something very like a different subspecies".
I thought I had a link to an article that goes even further(!!!) in relation to the effects on humans but can't find it, maybe someone else has it or knows the one I'm thinking of?
If anyone worries about eating chloroplasts they should be equally or more worried about who they sit next to on the bus, who they hug, and who they hang around with in general: none of those gets the acid sanitation treatment your stomach provides :)
News@11: Cooties exist! You can catch stupid! President will address the nation! :3
Bite harder Ouroboros, bite! tails.boum.org/ linux USB CD secure desktop IRC *crypt tor (not endorsements (XKeyScore))
(Score: 2, Funny) by e_armadillo on Monday April 14 2014, @04:59PM
I am practicing my freedom of "genetic expression", you insensitive clod.
"How are we gonna get out of here?" ... "We'll dig our way out!" ... "No, no, dig UP stupid!"
(Score: 3, Interesting) by Serial_Priest on Monday April 14 2014, @05:36PM
What are plants, from the perspective of chloroplasts or mitochondria? Is the "host" differentiable from the environment? And what larger meta-organisms might we humans unknowingly constitute?
Humans might not be at the "hardware layer" but I'm not sure it's a foregone conclusion that we're the true "OS/application" either.