The spread of hop latent viroid (HLVd) across cannabis grows in the United States and Europe is prompting researchers to find ways to control this pervasive parasite. Some cannabis strains, like Gelato 33, show natural resistance, though the reasons remain unclear.
HLVd, remnants of ancient RNA, first identified in 1987, disrupts cannabis cultivation by stunting plant growth and reducing THC levels. This viroid causes an estimated $4 billion in annual losses to growers, according to a study in “Viruses.”
Transmission and Impact
HLVd spreads through tools, shared water, insects, and even within seeds, where it can remain viable for years. Detecting and controlling this viroid is crucial for growers.
Research and Resistance
Researchers are seeking ways to make cannabis resistant to HLVd. Professor Zamir Punja from Simon Fraser University highlights the ongoing uncertainty about what makes certain strains more resilient. Concerns also arise about viruses from other crops potentially infecting cannabis.
Some strains show less susceptibility to HLVd, but identifying resistant genetics is complex. Research on different cannabis varieties reveals that certain strains, like Gelato 33, Motorhead, and Oreoz, have low viroid levels, while others like Chilled Cherries and Wedding Pie show high infection rates.
Interestingly, some strains carry high viroid loads without symptoms, indicating possible resistance mechanisms.
Future Directions
Researchers aim to identify genes responsible for HLVd resistance, potentially using Crispr-Cas9 gene-editing technology. Understanding viroid-host interactions could guide the development of resistant plants.
For now, intense testing, sanitation, and eradication of infected plants are essential to manage HLVd. Collaboration among researchers could accelerate the development of resistant cannabis strains, though the process remains unpredictable and partly reliant on finding key genetic factors.
