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#1
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Diseased plant altered genetically?
In another (non-gardening) forum there was a comment regarding a
possibly-diseased plant, and the potential for genetic damage as a possible contraindication to using said plant for cuttings: ----------------- "It really sounds like a fungal infection. You could try an anti-fungal compound, but it's probably best to make a new cutting from the healthy material and discard the diseased part of the plant." "There is a possibility that the disease has affected the genetic make up of your plant which could mean that the plant (and clones made from it) will grow slowly forever more. You might want to consider throwing your diseased plant away and start again with healthy cuttings." ----------------- When the claim that "disease has affected the genetic makeup of the plant" was questioned, this was the reply: ----------------- "The fact that plants will mutate in order to cope with stress is well known." ----------------- ....and this reference was cited: ---------------- http://people.cs.vt.edu/~ramakris/pa...resso-Pine.pdf "The ability of a plant to protect itself against environmental stress is essential to its survival [Alscher et°al., 1997]. Acclimation of plants to extreme environmental conditions or to rapid changes in growth conditions requires a global cellular response and changes in the expression of many genes. Exposure to extremes of light intensity and temperature, drought, and some herbicides can cause the downstream formation of reactive oxygen species (ROS). ROS may be present in the form of superoxide (O2—), hydrogen peroxide (H2O2), or the hydroxyl ion (OH—). ROS, especially OH—, are toxic because they can oxidize any macromolecule in the cell [Scandalios°(ed.), 1997]. This potential threat to cellular function can cause protein unfolding, the inactivation of enzymes, DNA damage, mutation, lipid peroxidation, and consequent disruption of cell membrane function. -------------------- Since then, I've been pondering this, and searching for further references without much success. What I'm wondering in particular is how one judges when a stock plant is so unhealthy as to make propagating from it a bad idea because of the possibility that mutations have occurred which would cause the clones to grow poorly. Obviously propagating from healthy plants is the best course of action; but I'm interested in this from a theoretical point of view as well, as I hadn't been aware that clones could be affected in this way. Does anyone have comments or links to references on this subject? or is there a better newsgroup in which to ask this? Thanks! Bill |
#2
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Diseased plant altered genetically?
It is well known that many garden plants that have long been propagated
vegetatively from single clones have over the years become virus infected and have lost their original vigor as a result. The problem is that the infection can be spread to other plants due to unsanitary garden practices and such insects as aphids and mealy bugs. There is still no cure for virus diseases in plants. The curious thing is that the same virus can express itself different ways in different species. Not all virus diseases express themselves as distorted leaves or variegation and many times the plants appear to show no unusual symptoms at all. Viruses are not spread through seed propagation but most cultivars will only come true when propagated vegetatively. Therein lies the dilemma. VoySager wrote in message ... In another (non-gardening) forum there was a comment regarding a possibly-diseased plant, and the potential for genetic damage as a possible contraindication to using said plant for cuttings: ----------------- "It really sounds like a fungal infection. You could try an anti-fungal compound, but it's probably best to make a new cutting from the healthy material and discard the diseased part of the plant." "There is a possibility that the disease has affected the genetic make up of your plant which could mean that the plant (and clones made from it) will grow slowly forever more. You might want to consider throwing your diseased plant away and start again with healthy cuttings." ----------------- When the claim that "disease has affected the genetic makeup of the plant" was questioned, this was the reply: ----------------- "The fact that plants will mutate in order to cope with stress is well known." ----------------- ...and this reference was cited: ---------------- http://people.cs.vt.edu/~ramakris/pa...resso-Pine.pdf "The ability of a plant to protect itself against environmental stress is essential to its survival [Alscher et°al., 1997]. Acclimation of plants to extreme environmental conditions or to rapid changes in growth conditions requires a global cellular response and changes in the expression of many genes. Exposure to extremes of light intensity and temperature, drought, and some herbicides can cause the downstream formation of reactive oxygen species (ROS). ROS may be present in the form of superoxide (O2-), hydrogen peroxide (H2O2), or the hydroxyl ion (OH-). ROS, especially OH-, are toxic because they can oxidize any macromolecule in the cell [Scandalios°(ed.), 1997]. This potential threat to cellular function can cause protein unfolding, the inactivation of enzymes, DNA damage, mutation, lipid peroxidation, and consequent disruption of cell membrane function. -------------------- Since then, I've been pondering this, and searching for further references without much success. What I'm wondering in particular is how one judges when a stock plant is so unhealthy as to make propagating from it a bad idea because of the possibility that mutations have occurred which would cause the clones to grow poorly. Obviously propagating from healthy plants is the best course of action; but I'm interested in this from a theoretical point of view as well, as I hadn't been aware that clones could be affected in this way. Does anyone have comments or links to references on this subject? or is there a better newsgroup in which to ask this? Thanks! Bill |
#3
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Diseased plant altered genetically?
It is well known that many garden plants that have long been propagated
vegetatively from single clones have over the years become virus infected and have lost their original vigor as a result Is the loss of vigor due to effects of the virus passed on from the parent to the clone, though, rather than to some change in the genome? I always understood it to be the former. |
#4
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Diseased plant altered genetically?
In general, the concept of genetic response to environmental stress died with
Lamarck. That said, the answer to the question is a resounding: anything is possible. I certainly would caution people against trying to reproduce a diseased plant, unless it is the only one of its kind left in the world. Iris, Central NY, Zone 5a, Sunset Zone 40 "If we see light at the end of the tunnel, It's the light of the oncoming train." Robert Lowell (1917-1977) |
#6
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Diseased plant altered genetically?
The reason the economy became so robust had nothing to do with Clinton.
It was because the introduction of technology, which increased the productivity of each individual making companies show a great profit to pay taxes on. He was just lucky because by history, the greatest tax increase he gave us, (so we had less of our own money), normally would have been a disaster. jcart003 wrote: Hello, this is a first for me, but it is full of subjects I now a good bit about! In reality there is no way that a cutting from your diseased plant would be genetically altered. The DNA damage you mention is on a single cell level and is random. Most mutations are fatal, and therefore the damaged cell would die. If it didn't die it would still be only one cell out of a billion or so. The reason for not using diseased material is to avoid spreading disease, mostly viral. The only way to get rid of a viral disease is to do meristem cloning and get lucky.... out of the means of most folks. Now if you were to do (agghhhhh an over 40 moment! I can't recall the term!) the type of cloning (using the meristem, and seperateing it to single cells) that they do in labs now you could create a genetically altered plant from the scenario you laid out... reactive ox. sp. causing DNA damage..... it would be shot inthe dark.... but that is one way to get a new/unusual clone ie in orchids. I will stop here as I feel myself on a ramble through bio/genetics..... there are lots of interesting permutations of this...if you are a nerd. ostheap (VoySager) wrote in message ... In another (non-gardening) forum there was a comment regarding a possibly-diseased plant, and the potential for genetic damage as a possible contraindication to using said plant for cuttings: ----------------- "It really sounds like a fungal infection. You could try an anti-fungal compound, but it's probably best to make a new cutting from the healthy material and discard the diseased part of the plant." "There is a possibility that the disease has affected the genetic make up of your plant which could mean that the plant (and clones made from it) will grow slowly forever more. You might want to consider throwing your diseased plant away and start again with healthy cuttings." ----------------- When the claim that "disease has affected the genetic makeup of the plant" was questioned, this was the reply: ----------------- "The fact that plants will mutate in order to cope with stress is well known." ----------------- ...and this reference was cited: ---------------- http://people.cs.vt.edu/~ramakris/pa...resso-Pine.pdf "The ability of a plant to protect itself against environmental stress is essential to its survival [Alscher et°al., 1997]. Acclimation of plants to extreme environmental conditions or to rapid changes in growth conditions requires a global cellular response and changes in the expression of many genes. Exposure to extremes of light intensity and temperature, drought, and some herbicides can cause the downstream formation of reactive oxygen species (ROS). ROS may be present in the form of superoxide (O2â€"), hydrogen peroxide (H2O2), or the hydroxyl ion (OHâ€"). ROS, especially OHâ€", are toxic because they can oxidize any macromolecule in the cell [Scandalios°(ed.), 1997]. This potential threat to cellular function can cause protein unfolding, the inactivation of enzymes, DNA damage, mutation, lipid peroxidation, and consequent disruption of cell membrane function. -------------------- Since then, I've been pondering this, and searching for further references without much success. What I'm wondering in particular is how one judges when a stock plant is so unhealthy as to make propagating from it a bad idea because of the possibility that mutations have occurred which would cause the clones to grow poorly. Obviously propagating from healthy plants is the best course of action; but I'm interested in this from a theoretical point of view as well, as I hadn't been aware that clones could be affected in this way. Does anyone have comments or links to references on this subject? or is there a better newsgroup in which to ask this? Thanks! Bill |
#7
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Diseased plant altered genetically?
jcart003 wrote:
In reality there is no way that a cutting from your diseased plant would be genetically altered. The DNA damage you mention is on a single cell level and is random. Most mutations are fatal, and therefore the damaged cell would die. If it didn't die it would still be only one cell out of a billion or so. The reason for not using diseased material is to avoid spreading disease, mostly viral. So, if I understand you correctly, the statement: "There is a possibility that the disease has affected the genetic make up of your plant which could mean that the plant (and clones made from it) will grow slowly forever more. You might want to consider throwing your diseased plant away and start again with healthy cuttings." ....is essentially untrue? And that, in the case of viral disease, a clone from an infected plant would be affected by the virus, but not by any genetic mutation that might have been caused in the parent plant by the virus? Now if you were to do (agghhhhh an over 40 moment! I can't recall the term!) the type of cloning (using the meristem, and seperateing it to single cells) that they do in labs now you could create a genetically altered plant from the scenario you laid out... reactive ox. sp. causing DNA damage..... it would be shot inthe dark.... but that is one way to get a new/unusual clone ie in orchids. Tissue culture? So, in fact, from what you're saying, it takes a purposeful attempt to cause mutation in the parent cells that would get passed on to the clones, and even then it's an iffy proposition? I see from your address that you're an educator or researcher? so I could quote your response as a professional opinion from a knowledgable individual? (I don't want to pry and ask you to identify yourself...) Better yet, do you have any suggestions as to sources of info (links) on this subject, preferably not too technical? I did a little bit of reading on the subject of adaptive mutation today that would seem to question whether, in fact, "the concept of genetic response to environmental stress died with Lamarck", as Iris said earlier; but I couldn't even begin to try to argue that, as I'm a dirt gardener, not a scientist. I will stop here as I feel myself on a ramble through bio/genetics..... there are lots of interesting permutations of this...if you are a nerd. Or, for that matter, ramble on if you wish, I at least will read your response; I'm no nerd, I'd have to know more about the subject to even aspire to that status ;-) , but as I said before, I was surprised at the statement above regarding "disease-mutation-affecting-growth", doubted its veracity, and would like to learn enough about the subject to be able to refute it. Thanks for all the responses (except for yours, bayhill ["The reason the economy became so robust had nothing to do with Clinton." etc.]... you're lost in the wrong thread). Bill |
#8
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Diseased plant altered genetically?
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#9
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Diseased plant altered genetically?
a key concept, GERMLINE vs SOMATIC(this may
truly only be an animal term but the concept is the same). For a trait to be passed on it must be in the germ line, that is sex cells. While you can clone plants easily, the original mutation had to occur in the germ line, for the reasons I tried to get across in my first response, a mutation in the somatic cells is only in a single cell and the trait/cell would not be able to multiply enough to take over the whole (unless you go to a single cell tissue culture scenario)...... That's a very clear explanation right there, thanks for your help! Bill |
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