Identification of a Novel Geminivirus in Fraxinus rhynchophylla in Korea

Abstract

Fraxinus rhynchophylla, common name ash, belongs to the family Oleaceae and is found in China, Korea, North America, the Indian subcontinent, and eastern Russia. It has been used as a traditional herbal medicine in Korea and various parts of the world due to its chemical constituents. During a field survey in March 2019, mild vein thickening (almost negligible) was observed in a few ash trees. High-throughput sequencing of libraries of total DNA from ash trees, rolling-circle amplification (RCA), and polymerase chain reaction (PCR) allowed the identification of a Fraxinus symptomless virus. This virus has five confirmed open reading frames along with a possible sixth open reading frame that encodes the movement protein and is almost 2.7 kb in size, with a nonanucleotide and stem loop structure identical to begomoviruses. In terms of its size and structure, this virus strongly resembles begomoviruses, but does not show any significant sequence identity with them. To confirm movement of the virus within the trees, different parts of infected trees were examined, and viral movement was successfully observed. No satellite molecules or DNA B were identified. Two-step PCR confirmed the virion and complementary strands during replication in both freshly collected infected samples of ash tree and Nicotiana benthamiana samples agro-inoculated with infectious clones. This taxon is so distantly grouped from other known geminiviruses that it likely represents a new geminivirus genus.

RETRACTED: Emergence of Asian endemic begomoviruses as a pandemic threat

“…The International Committee on Taxonomy of Viruses group working on the family Geminiviridae proposed a new standard for species identification ( Francki et al, 2012 ). Based on this classification, more than 500 geminiviruses have been distinguished and characterized into 14 distinct genera ( Chiumenti et al, 2021 ; Lal et al, 2021 ). The order of various genera depends on the genome, host range, and viral vectors ( Fauquet et al, 2003 ; Varsani et al, 2014 ).…”

Interspecies Recombination-Led Speciation of a Novel Geminivirus in Pakistan

“…Geminiviruses infect both monocots and dicots [ 23 ] and are transmitted by either whiteflies, leafhoppers, treehoppers, or aphids [ 24 , 25 , 26 ]. Based on the genome organization, host range, and insect vectors, geminiviruses are classified into fourteen genera: Becurtovirus , Begomovirus , Capulavirus , Citlodavirus , Curtovirus , Eragrovirus , Grablovirus, Maldovirus , Mastrevirus , Mulcrilevirus , Opunvirus , Topilevirus , Topocuvirus, Turncurtovirus, [ 13 ] and a few unclassified genera, such as Olea europaea geminivirus [ 27 ] and Fraxinus symptomless virus [ 28 ]. Begomoviruses are the largest plant virus genera within the family Geminiviridae having single-stranded circular DNA genome, either monopartite or bipartite components, ranging from 2.5 to 3.0 kb in size and are transmitted by whiteflies, i.e., Bemisia tabaci [ 18 , 24 , 29 ].…”

Special Issue “State-of-the-Art Plant–Virus Interactions in Asia”

“…(iii) New viruses and/or hosts: Yang and colleagues discovered the coinfection of watermelon mosaic virus and a novel polerovirus, provisionally named cotton leaf roll virus, on cotton plants [ 16 ]. Lal and collaborators identified a novel geminivirus, likely representing a new genus in the family Geminiviridae , in a woody plant, Fraxinus rhynchophylla , using high-throughput sequencing technique [ 17 ]. Huang and coworkers identified distinctive bamboo mosaic virus isolates on an unreported bamboo species in Vietnam [ 18 ].…”