Host biology and genomic properties of Plumeria mosaic virus, a tobamovirus discovered in a temple tree in India co-infecting with frangipani mosaic virus.

Temple tree ( f. ), an important fragrant-flower tree extensively used in the urban landscaping is known to be infected with a tobamovirus, frangipani mosaic virus (FrMV). In this study, we describe another tobamovirus, Plumeria mosaic virus (PluMV) infecting temple tree in India. PluMV was isolated from an old temple tree co-infected with FrMV. The presence of another tobamovirus was initially realized based on the distinct symptoms on (globe amaranth), a non-host of FrMV. PluMV was highly transmissible through simple rub-inoculation. In host-range study, brinjal (), chilli () datura () globe amaranth and tobacco ( cv. Xanthi) could differentiate PluMV from FrMV. The complete genome sequence of PluMV was determined (6,688 nucleotides [nt], GenBank KJ395757), which showed the genome structure typical of tobamovirus encoding four proteins: small replicase (3,549 nt/130 kDa), large replicase (5,061 nt/188 kDa), movement protein (770 nt/29 kDa) and coat protein (527 nt/19 kDa). The 5' and 3' UTR of PluMV contained 91 and 284 nt, respectively. The PluMV genome was 45 nts longer than that of FrMV and shared only 71.4-71.6% sequence identity with FrMV and  < 50% sequence identity with the rest of the other members of the genus . PluMV shared a close but a divergent evolutionary relationship with FrMV. Based on the species demarcation guidelines of ICTV (<90% genome sequence identity), PluMV was considered as a new tobamovirus species. As PluMV was serologically related with FrMV, differential diagnostic assays such as simplex and duplex RT-PCR were developed, which revealed that PluMV naturally existed in both the species of temple tree, f. and f. in India either alone or in mixed infection with FrMV.