Common hollyhock (Alcea rosea) is a ubiquitous ornamental in temperate climates but is highly adaptable and can be found growing in the tropics and subtropics. In 2019, an A. rosea plant showing symptoms of irregular chlorotic flecking on the basal leaves, with symptoms becoming gradually less severe toward the apex, was sampled in Pretoria, Gauteng province, South Africa. Total RNA was used to prepare an RNAtag-seq library, which was sequenced using an Illumina HiSeq 2500 instrument. Subsequent analysis of the data revealed the presence of two bipartite RNA viruses, namely orchid fleck virus (OFV) (segment 1: MW073772; segment 2: MW073773) and sweet potato chlorotic stunt virus (SPCSV) (segment 1: MW073774; segment 2: MW073775). OFV from this study was closely related to a strain from South Africa, associated with citrus leprosis disease, while SPCSV represented a novel strain. RT-PCR and bidirectional Sanger sequencing were used to confirm the presence of both viruses. Further samples were collected in 2020, which showed severe interveinal chlorosis, and were tested with RT-PCR; however only SPCSV was associated with these plants. This is the first time that both viruses have been associated with A. rosea, which should be considered a potential reservoir host of these agriculturally important viruses.
Supplementary figure 1: Images of leaves collected from Alcea rosea plants expressing symptoms suspected of being of viral infection. B - Basal leaves; M - Leaves collected from the midpoint of the main stem; A – Leaves collected from the apex of each plant.
Supplementary figure 2: Agarose gel image showing the bands of PCR confirmation products for orchid fleck virus (OFV) and sweet potato chlorotic stunt virus (SPCSV).