First detection of alfalfa mosaic virus in Ficus benjamina in Chile.

Ficus benjamina, commonly known as ficus or weeping fig, is an ornamental tree from Southeast Asia in the Moraceae family. It is an evergreen species grown as an interior plant worldwide, prized for its glossy green leaves, gray stem, and multiple branches. F. benjamina can be pruned and kept as a small shrub when grown indoors, with most commercially available cultivars in the ornamental industry derived from sports and propagated cuttings (Chen et al., 2010). In October 2022, symptoms indicative of alfalfa mosaic virus (AMV) infection, such as intense bright yellow spots, mottling and chlorosis were observed in leaves of F. benjamina growing in office environments in Santiago, Chile (supplementary Fig.1). Seven symptomatic and three asymptomatic plants were sampled and traced back to the same plant nursery, and only leaf tissue samples from the symptomatic plants tested positive for the presence of the AMV using enzyme-linked immunosorbent assay (ELISA) (Agdia Inc., Elkhart, IN). These results were verified using reverse transcription (RT)-PCR with specific primers AMV-F and AMV-R, targeting a region of the AMV CP gene (Xu and Nie, 2006). AMV was detected in all symptomatic leaf samples, producing 351-bp amplicons in the RT-PCR assay for all samples that were positive to AMV by ELISA. No amplification product was observed when seronegative samples or non-template control was used as templates in the RT-PCR assays. Three RT-PCR amplicons were directly sequenced in both directions. BLAST analysis of these sequences showed 100% nucleotide sequence identity to an AMV isolate previously reported (GenBank Accession No. KX458469), confirming the detection of AMV in F. benjamina. This pathogen causes disease in several species, including ornamentals plant such as Viburnum tinus L. (Peña et al., 2011), peony (Belardi and Rubies, 2003), phlox (Holcomb et al., 2006), and weeds such as Cayratia japonica (Thunb.) Gagnep, Justicia procumbens L. and Veronica persica Poir. (Gao et al., 2020). F. benjamina is among the most popular ornamental indoor plants in Chile, so nurseries should ensure AMV-free plants to restrict disease incidence and prevent the spread of this virus. However, Chile lacks specific regulations for ornamental nurseries, making adherence to pest and disease recommendations voluntary, and only imported plant material requires a sanitary certificate.