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Researchers: Cross-species gene regulation observed for the first time

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Dodder parasitizing a host plant/ Penn State U

From ScienceDaily:

Dodder, a parasitic plant that causes major damage to crops in the US and worldwide every year, can silence the expression of genes in the host plants from which it obtains water and nutrients. This cross-species gene regulation, which includes genes that contribute to the host plant’s defense against parasites, has never before been seen from a parasitic plant.

“Dodder is an obligate parasite, meaning that it can’t live on its own,” said Michael J. Axtell, professor of biology at Penn State and an author of the paper. “Unlike most plants that get energy through photosynthesis, dodder siphons off water and nutrients from other plants by connecting itself to the host vascular system using structures called haustoria. We were able to show that, in addition to the nutrients that flow into dodder from the host plant across the haustoria, dodder passes microRNAs into its host plant that regulate the expression of host genes in a very direct way.”

MicroRNAs are very short bits of nucleic acid — the material of DNA and RNA — that can bind to messenger RNAs that code for protein. This binding of microRNA to messenger RNA prevents the protein from being made, either by blocking the process directly or by triggering other proteins that cut the messenger RNA into smaller pieces. Importantly, the small remnants of the messenger RNA can then function like additional microRNAs, binding to other copies of the messenger RNA, causing further gene silencing.

“Dodder seems to turn on the expression of these microRNAs when it comes into contact with the host plant,” said James H. Westwood, professor of plant pathology, physiology, and weed science at Virginia Tech and another author of the paper. “What was really interesting is that the microRNAs specifically target host genes that are involved in the plant’s defense against the parasite.”Paper. (paywall) – Saima Shahid, Gunjune Kim, Nathan R. Johnson, Eric Wafula, Feng Wang, Ceyda Coruh, Vivian Bernal-Galeano, Tamia Phifer, Claude W. dePamphilis, James H. Westwood, Michael J. Axtell. MicroRNAs from the parasitic plant Cuscuta campestris target host messenger RNAs. Nature, 2018; 553 (7686): 82 DOI: 10.1038/nature25027 More.

From the release: “What was really interesting is that the microRNAs specifically target host genes that are involved in the plant’s defense against the parasite.” No! Surely not! Dodder weed cannot have been explicitly targeting the host plants’ defences against… dodder weed?! That’s almost like there is more to evolution than Darwinism. Watch yer mouth!

Genetics is not remotely like what we thought it was. Neither is the world of life, probably.

See also: There’s a gene for that… or is there?

38 Replies to “Researchers: Cross-species gene regulation observed for the first time

  1. 1
    JSmith says:

    Parasites altering gene expression in their hosts has been known for a long time in animals. In many cases this alters the behaviour of the primary host (e.g., ant) to make it more prone to being eaten by the secondary host (e.g., sheep). It would be naive to expect that it does not also occur in plants.

  2. 2
    ET says:

    JSmith doesn’t get it. The weed turns off the genes in another plant that would fight off the weed. It’s as if the weed knows what to do so it can survive.

  3. 3
    JSmith says:

    ET

    JSmith doesn’t get it. The weed turns off the genes in another plant that would fight off the weed. It’s as if the weed knows what to do so it can survive.

    Since you asked so nicely.

    The animal parasite changes the gene expression of the primary host which results in a change in its behaviour making it more susceptible to predation by the secondary host. How is this different? They are both altering the expression of genes in another species. I find this very interesting.

  4. 4
    ET says:

    I told you, JSmith just doesn’t get it:

    The animal parasite changes the gene expression of the primary host which results in a change in its behaviour making it more susceptible to predation by the secondary host.

    Is the animal parasite also the predator? No.

    Dodder changes the gene expression in its host so it can survive. The moronic parasite you are talking about gets munched along with its host.

  5. 5
    JSmith says:

    Dodder changes the gene expression in its host so it can survive. The moronic parasite you are talking about gets munched along with its host.

    Let’s compare:

    1) The plant parasite changes the gene expression in its host so it can survive.
    2) The animal parasite changes the gene expression of its host so that it can survive.

    Yup, I concede to your infinite wisdom. These are completely different and not similar at all.

  6. 6
    News says:

    ET at 2: You write, “The weed turns off the genes in another plant that would fight off the weed. It’s as if the weed knows what to do so it can survive.” Indeed. That’s the point. Natural selection acting on random mutations supposedly causes dodder weed, after a very very long series of failures to now know exactly what to do. I don’t think so.

  7. 7
    ET says:

    Yes, JSmith, let’s compare:

    1) With the example in the OP the parasite is the weed that changes the gene expression of its host so that it can survive

    2) In your example the parasite gets munched along with its host whose genes were incorrectly expressed.

    Anyone who is not on an agenda can see the difference.

  8. 8
    mullers_ratchet says:

    No! Surely not! Dodder weed cannot have been explicitly targeting the host plants’ defences against… dodder weed?! That’s almost like there is more to evolution than Darwinism.

    How are these two clauses connected?

  9. 9
    JSmith says:

    ET

    In your example the parasite gets munched along with its host whose genes were incorrectly expressed.

    Who said that the animal parasite got munched? It burrows through the intestinal wall and set up shop in the secondary host.

    In both cases, the parasite alters the gene expression of the host, aiding in survival. The only difference is that the animal parasite has two hosts, not one.

  10. 10
    mullers_ratchet says:

    1) With the example in the OP the parasite is the weed that changes the gene expression of its host so that it can survive

    2) In your example the parasite gets munched along with its host whose genes were incorrectly expressed.

    The parasites in (1) have a multi-host lifecycle, they need to get from the insect into the vertebrate in order to reproduce. It’s really the same thing (I think the plant-plant interaction and the miRNA mechanism in the new paper is new and pretty cool)

  11. 11
    ET says:

    LoL! In your example the parasite does not effect the gene expression that allows it to live inside of the first host. It doesn’t turn off the “attack the parasite genes”.

    In the OP’s example the parasite turns off just those genes that, if left alone, would destroy it.

    It’s as if you are oblivious to reality.

  12. 12
    ET says:

    How is it the same thing, muller?

    How does the parasite know that it needs to first get into an invert so it can get into a vertebrate?

  13. 13
    Martha K says:

    I have to side with JSmith and Mullers_ratchet on this one. In both cases the parasites are altering the gene expression of the host by chemical means to increase survival. ET’s rebuttals just seem like arguing for argument sake.

  14. 14
    mullers_ratchet says:

    ET, do you know anything about this topic? Seems like you are learning about it for the first time now. So why are you so confident in you uninformed opinions?

    FWIW, the parasite doesn’t have to “know” anything, why would it? It will certainly have to alter the expression of particular genes to manipulate its host (there is a whole class of genes called “effectors” that do just this) and I don’t doubt part of that will be evading the host immune system.

    There is a rich literature on host-parasite interactions that you might want to learn about.

  15. 15
    ET says:

    Martha:

    In both cases the parasites are altering the gene expression of the host by chemical means to increase survival.

    In one case- the OP- the parasite manipulates only the genes that would have killed it. In the other case the parasite does not manipulate the genes in the host that would have killed it.

  16. 16
    ET says:

    muller- you can take your innuendoes and eat them. Make a case, I dare you to try.

    FWIW, the parasite doesn’t have to “know” anything, why would it?

    If it turns off the wrong genes it dies.

    Do you know anything at all, muller? Anything?

  17. 17
    ET says:

    “What was really interesting is that the microRNAs specifically target host genes that are involved in the plant’s defense against the parasite.”

  18. 18
    mullers_ratchet says:

    If it turns off the wrong genes it dies.

    Sure. But this does not explain why the parasite needs to “know” anything. Gene regulation is controlled by sequence-specific patterns that interact with proteins, genes or transcripts. The regulation of a specific gene is thus coded in the parasite’s genome, no need to “know” anything, just express the right gene in the right environment (as with so many other traits).

  19. 19
    ET says:

    muller:

    But this does not explain why the parasite needs to “know” anything.

    So it all “just happens” is that your science?

    Gene regulation is controlled by sequence-specific patterns that interact with proteins, genes or transcripts.

    It is also controlled by external factors.

    The regulation of a specific gene is thus coded in the parasite’s genome, no need to “know” anything, just express the right gene in the right environment (as with so many other traits).

    We are talking about a parasite controlling the expression of the host’s genes. So by your logic the parasite just happened to have the gene or genes that would produce the chemicals necessary to control the expression of the host’s genes.

    It all just happens.

    In the OP the dodder turns off just those genes that can destroy it. And “it just happened” is a fool’s science.

  20. 20
    mullers_ratchet says:

    So it all “just happens” is that your science?

    No. You should learn a little about these topics. An intro college textbook will have examples like the lac operon or the “genetic switch” in lambda. Regulation can be much mroe complex than those examples,but they would give you an idea of how it works in general.

  21. 21
    ET says:

    LoL! I know how it works. My point is your position’s answer is “it just happened”. Your position cannot account for gene regulation. Genetic switches? Something else your position cannot account for.

  22. 22
    JSmith says:

    ET

    In one case- the OP- the parasite manipulates only the genes that would have killed it. In the other case the parasite does not manipulate the genes in the host that would have killed it.

    So what? The issue is the act of a parasite altering gene expression of a host so that it can survive. They are both doing this.

  23. 23
    ET says:

    JSmith:

    The issue is the act of a parasite altering gene expression of a host so that it can survive.

    No, the issue is:

    “What was really interesting is that the microRNAs specifically target host genes that are involved in the plant’s defense against the parasite.”

  24. 24
    JSmith says:

    ET

    No, the issue is:

    “What was really interesting is that the microRNAs specifically target host genes that are involved in the plant’s defense against the parasite.”

    Well, we are each interested in different things. The insect parasite specifically targeted host genes that are involved in the insect’s defense against being eaten. I find that very interesting.

  25. 25
    mullers_ratchet says:

    Your position cannot account for gene regulation.

    Oh, it’s Joe. What a waste of time.

  26. 26
    ET says:

    JSmith:

    Well, we are each interested in different things.

    True. I am interested in science and reality and you are interested in spreading nonsense.

    The insect parasite specifically targeted host genes that are involved in the insect’s defense against being eaten.

    Cuz insects know they can be eaten.

  27. 27
    ET says:

    Yes muller- arguing with someone who is smarter than you will ever be is a waste of time. And arguing with evos is a total waste of time.

  28. 28
    JSmith says:

    ET

    And arguing with evos is a total waste of time.

    Yet you do it all the time. What does that say about you? 🙂

  29. 29
    ET says:

    JSmith:

    The animal parasite changes the gene expression of the primary host which results in a change in its behaviour making it more susceptible to predation by the secondary host.

    Evidence please. One paper on the topic doesn’t say that the gene expression was altered. So where did you get your information?

  30. 30
    ET says:

    JSmith- You are confused. Correcting people, evos mostly, is not arguing with them. Exposing evos as liars and cowardly bluffers, like you, is not arguing with them.

    Arguing with someone would mean they actually have something of substance to say. Evos do not.

  31. 31
    ET says:

    Toxoplasma gondii, the parasite that has rats liking cat urine “is associated with damage to astrocytes, glial cells which surround and support neurons”.

    There is a fungus that takes over ants but it actually takes over ants, turning the ants cells into fungal cells.

    Still nothing about changing gene expression

  32. 32
    johnnyb says:

    What’s really interesting is that, although this may be the first place where we know the *mechanism* behind this, it is certainly not the only known instance.

    Scott Gilbert has been working on his Ecological Developmental Biology idea for some time, and even a decade and a half ago there were some very striking instances. The paper I initially read on the subject is here.

  33. 33
  34. 34
    ET says:

    And what is the evidence the gene expression caused “results in a change in its behaviour making it more susceptible to predation by the secondary host.”?

  35. 35
    JSmith says:

    ET

    And what is the evidence the gene expression caused “results in a change in its behaviour making it more susceptible to predation by the secondary host.

    Happy reading. You might want to take more that the 15 minutes you gave the other five articles I provided.

    Yanoviak, S., Kaspari, M., Dudley, R. and Poinar, G. (2008). Parasite-Induced Fruit Mimicry in a Tropical Canopy Ant. Am Nat, 171(4), 536-544.

  36. 36
    ET says:

    JSmith:

    You might want to take more that the 15 minutes you gave the other five articles I provided.

    If you think your claim was supported by any of those 5 then please make your case. Or just admit that you didn’t read them.

    BTW your latest paper doesn’t even discuss gene expression.

  37. 37
    mikeenders says:

    ET,

    You have been side tracked into an argument that detracts from the fallacy of the initial premise

    ” It would be naive to expect that it does not also occur in plants.”

    I don’t think anyone seriously doubts that if you go deep into this you will eventually find all kinds of examples of “convergent evolution”

    The question is – how does multiple examples weaken the case for design when in any mathematical analysis the odds against an event taking place through happenstance increases the more often in occurs?

    Citing somewhere else an event takes place in life only increases the odds of a non designed explanation unless you are merely appealing to a framed concept which offers no explanation as a rebuttal.

    Converged Evolution as a framed concept =< God Did it

    A designer has faar more explanatory powers.

  38. 38
    ET says:

    Hi Mike- Yes I was sidetracked but in this case I was also given an opportunity to read peer-reviewed papers I normally wouldn’t have. So it was a win for me.

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