Not sure who has seen their recent claim that HLVd is detected more frequently when tissue is sampled from the roots rather than leaves, but for those who have I was wondering if they have any historical data that can back this or links to studies that back this? I cannot find any and Medicinal Genomics did not provide a link to the study
This will help you find papers, even with only a little information about it. It will also help you get to PDF files.
I was a virologist and a polyploid tissue sequencer. I think the viroid is present in the genome and expresses itself in a tissue specific manner. The dark regions with bubbles in polytene chromosomes can randomly generate new sequence arrangements and contain a lot of ancient viruses buried in the sequence and are silenced epigenetically and are functionally broken apart during evolution. Different tissues make different polytene chromosomes ( don’t know anything about root cells). In addition there is a difference in copy number. This difference in copy number could also alter detection.
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I don’t know much about this.
But I always like to call bullshit when studies are not easily shared and data isn’t available for peer review. Which is the norm with Medicinal Genomics, in my experience.
Plus - from the root? how the fuck do you take an uncontaminated sample from ROOTS? Its going to be in growth media of some kind - so that DNA could come from anywhere. Instead of from the leaf/stems.
Plus if you are taking it from the roots - are you killing the plant off? Have you submitted a root sample because you already decided to cull the plant because you can see the “latent” issues with your eyes?
Because I have Google Fu - I was able to read some studies about this, which point to the root ball and stems as having more viroid content of PERENIAL plants. Plants that die back in winter and come back the next year. Pretty sure that’s not applicable to our industry… unless everyone is now growing multi-season plants and letting them “overwinter”. -shrug-
I found two other studies that said similar things about the viroid being stronger in the “lower” parts of the plant. In both studies the speculation was that the viroid MOVES through the plant and starts at the roots just like everything else. And the duration of the portion of the plant being alive means there is more viroid present in it. Both of those studies were with HOPS not with cannabis.
Is this going to help with pulling leaf samples to submit for testing? I mean… are we going to start cutting roots of your plants for this test? Perhaps instead we could stick with what was recommended for the HOPS folks, and take samples from the bottom of the plant (but without soil contamination) on the portions of the plant are are “oldest”.
In some cases - this could actually be the STEM because with clones there is a portion of stem that would be older than the newly set roots. But that would depend on if you are cloning or using tissue culture or growing from seeds.
Also it was noted in both hops studies that thermally treating the materials “helped”.
I don’t know how great of scientists these people were. But again, Google Fu. -shrug-
https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1744-7348.1993.tb04071.x
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Jealous of your experience! Thank you
Ya I read about the thermal treatment + meristem culture being the best option for removing the viroid from hops, but not much cannabis specific. For all the reasons you pointed out this is why I wish medicinal genomics was more transparent. They release info like this with not much to back it up. As far as soil contamination for most grows, if my soil is contaminated with HLVd then it may be safe to assume that my plant growing in that soil either has or will host the viroid. Luckily the HLVd is a pretty unique sequence of RNA from what I’ve read so depending on what region these assays target false-positives might not be likely. The root sampling could be done on fresh clones that will be culled or even on freshly harvested plants so you don’t lose any yield.
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Thank you!!
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