The Sisal Virome: Uncovering the Viral Diversity of Agave Varieties Reveals New and Organ-Specific Viruses

Sisal is a common name for different plant varieties in the genus Agave (especially Agave sisalana) used for high-quality natural leaf fiber extraction. Despite the economic value of these plants, we still lack information about the diversity of viruses (virome) in non-tequilana species from the genus Agave. In this work, by associating RNA and DNA deep sequencing we were able to identify 25 putative viral species infecting A. sisalana, A. fourcroydes, and Agave hybrid 11648, including one strain of Cowpea Mild Mottle Virus (CPMMV) and 24 elements likely representing new viruses. Phylogenetic analysis indicated they belong to at least six viral families: Alphaflexiviridae, Betaflexiviridae, Botourmiaviridae, Closteroviridae, Partitiviridae, Virgaviridae, and three distinct unclassified groups. We observed higher viral taxa richness in roots when compared to leaves and stems. Furthermore, leaves and stems are very similar diversity-wise, with a lower number of taxa and dominance of a single viral species. Finally, approximately 50% of the identified viruses were found in all Agave organs investigated, which suggests that they likely produce a systemic infection. This is the first metatranscriptomics study focused on viral identification in species from the genus Agave. Despite having analyzed symptomless individuals, we identified several viruses supposedly infecting Agave species, including organ-specific and systemic species. Surprisingly, some of these putative viruses are probably infecting microorganisms composing the plant microbiota. Altogether, our results reinforce the importance of unbiased strategies for the identification and monitoring of viruses in plant species, including those with asymptomatic phenotypes.