Do Trees get Viruses?
Amidst the covid-19 outbreak, I decided to write a blog on viruses but from a slightly different angle than the conventional media in order to avoid redundancies.
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Let’s begin by looking at what a virus is:
A virus is an infective agent (a germ) that can get into our system and make us sick. But in general, illnesses caused by viruses cannot be cured by medicine―antibiotics won’t work on them since they are not bacteria―and the only way to recover is to develop an immunity towards the virus. The common cold is a well known example―we can treat the symptoms of a cold, but we cannot cure the cold itself. You may be wondering how it is possible that we cannot take medicine to get rid of viruses yet health authorities keep telling us to wash our hands and sanitize surfaces in order to stop the spread of the coronavirus. Isn’t this a contradiction? Can we or can we not eliminate viruses? |
The common cold is a well known example of a virus
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Here's the thing: When viruses aren’t in a biological environment (i.e. in the body), cleaning products can break down their structure and cause them to die… although dying might not be the appropriate word to use since viruses aren’t technically alive.
See, viruses are strange. Let me explain:
Modern cell theory states that all living things are composed of one or more cells, but a virus is nothing more than genetic information (e.g. DNA) enclosed within a coat or shell of proteins and lipids. They are much smaller than a cell―in fact, most viruses are so small that they cannot be observed with regular microscopes―and they lack the biological components of a cell. Thus, viruses violate this tenet of modern cell theory that we use to identify living things.
Viruses also don’t metabolize: That is, they don't eat, grow, or eliminate waste! An animal will eat food, use that food as energy to build organic compounds to sustain life, and eliminate nitrogenous byproducts from this process. Similarly, trees will capture carbon dioxide from the atmosphere, get energy by breaking those molecules apart to make organic compounds for growth, then release the byproducts through stomatal pores. But a virus, it doesn’t do any of that.
See, viruses are strange. Let me explain:
Modern cell theory states that all living things are composed of one or more cells, but a virus is nothing more than genetic information (e.g. DNA) enclosed within a coat or shell of proteins and lipids. They are much smaller than a cell―in fact, most viruses are so small that they cannot be observed with regular microscopes―and they lack the biological components of a cell. Thus, viruses violate this tenet of modern cell theory that we use to identify living things.
Viruses also don’t metabolize: That is, they don't eat, grow, or eliminate waste! An animal will eat food, use that food as energy to build organic compounds to sustain life, and eliminate nitrogenous byproducts from this process. Similarly, trees will capture carbon dioxide from the atmosphere, get energy by breaking those molecules apart to make organic compounds for growth, then release the byproducts through stomatal pores. But a virus, it doesn’t do any of that.
Artistic representation of a virus
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Reproduction also falls in a grey zone with viruses. A virus finds a cell and injects its genetic information into it. The cell then begins to follow the virus's instructions. Two things can happen here: 1) When the cell multiplies, it will also replicate the virus's genetic material so all the new copies of the cell will have the virus or 2) the cell will be “hijacked” and the virus will order the cell to make endless copies of itself. This will happen until the cell bursts from pressure allowing all the virus copies to spread to neighboring cells. So viruses can replicate themselves, but not via normal cell-division and not without a host cell.
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As you can see, categorizing exactly what a virus is turns out to be a daunting task since they do not fit our definition of what constitutes a living organism. Yet considering them non-living also seems incorrect since they are carbon-based entities that have the ability to evolve and can lose their ability to function (uh, die?). And say we were to change our definition of what a living thing is to include viruses, we might inadvertently begin to categorize other things like computer malware and AI as alive.
What do you think? Are viruses alive? If not, what are they?
Do trees get viruses?
Yes, but not covid-19. Viruses can evolve and ‘jump’ from one species to another, but to phylogenetically similar species. In other words, a virus affecting one species of mammal is more likely to spread to another species of mammal than it is to a plant, and vice versa. So trees won’t get covid-19, but they have their own varieties of viruses to deal with.
Interestingly, some tree species seem to be affected by only one or two types of viruses while others are affected by a much greater number.
What do you think? Are viruses alive? If not, what are they?
Do trees get viruses?
Yes, but not covid-19. Viruses can evolve and ‘jump’ from one species to another, but to phylogenetically similar species. In other words, a virus affecting one species of mammal is more likely to spread to another species of mammal than it is to a plant, and vice versa. So trees won’t get covid-19, but they have their own varieties of viruses to deal with.
Interestingly, some tree species seem to be affected by only one or two types of viruses while others are affected by a much greater number.
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It may be extremely difficult to know that a tree is afflicted by a viral disease. Sometimes an infected tree will show conspicuous signs of sickness such as deformities, dieback, or ringspots, lines patterns, and/or mottling on the leaves. However, it is possible that symptoms only appear for a few weeks of the year and on only a small part of the tree making them extremely hard to detect. Other times, no symptoms at all appear but the tree still experiences reduced production and stunted growth.
Most research on viruses in trees relate to commercially important fruit trees such as apple, pear, and cherry trees. This is because viral diseases can have significant economic impacts: For example, in Kootenay, British Columbia, Sweet Cherry (Prunus avium) fruit production dropped 90 percent over the span of 30 years following the appearance of a virus. That makes a lot of lost revenue! |
Apple mosaic virus (ApMV) showing conspicuous symptoms on tree
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Studies on viruses relating to forests and shade trees are much rarer than those on fruit trees and relatively little is known about them. This leads to the impression that they are uncommon and therefore insignificant, but they could be the cause of much more trouble than we currently attribute to them.
This concludes my special post relating to covid-19. I hope you enjoyed it and learnt something new. Stay safe, wash your hands, and spread information―not germs!
This concludes my special post relating to covid-19. I hope you enjoyed it and learnt something new. Stay safe, wash your hands, and spread information―not germs!