Characterization of a New Orthotospovirus from Chilli Pepper in Yunnan Province, China

Abstract

Chilli pepper (Capsicum annuum L.) is one of the most important crops in Yunnan Province, China. An orthotospovirus isolate 14YV855 was isolated from a diseased chilli pepper plant exhibiting yellow ringspots and necrosis on leaves in Shiping County, Honghe Hani and Yi Autonomous Prefecture, Yunnan Province in 2014. The complete genome sequence of 14YV855 was determined. The small, medium, and large RNAs are 3,428, 4,781, and 8,917 nucleotides long, respectively. The complete nucleocapsid (N) protein of 14YV855 shares a high amino acid identity of 84.8 to 89.9% to that of Capsicum chlorosis virus (CaCV), Groundnut bud necrosis virus (GBNV), Watermelon bud necrosis virus (WBNV), and Watermelon silver mottle virus (WSMoV), which is slightly less than the 90% identity threshold for the demarcation of new Orthotospovirus sp. Phylogenetic analyses revealed that the N protein and RNA-dependent RNA polymerase of 14YV855 are the most related to WSMoV, while the NSs, NSm, and Gn/Gc proteins are similar to those of GBNV. As expected, 14YV855 is serologically related to CaCV, GBNV, WBNV, and WSMoV when the monoclonal antibody against the N protein of WSMoV was used; however, 14YV855 can be distinguished from other orthotospoviruses by reverse-transcription PCR using the specific primers. Our results indicate that 14YV855 is a new Orthotospovirus sp. belonging to the WSMoV serogroup and is provisionally named Chilli yellow ringspot virus.

Occurrence, Distribution, Evolutionary Relationships, Epidemiology, and Management of Orthotospoviruses in China

“…The orthotospoviruses isolated from Yunnan belonged to four phylogenetic clades, with the majority (seven species) belonging to the WSMoV clade. Three new Orthotospovirus species were first reported in Yunnan: TZSV (Dong et al, 2008), hippeastrum chlorotic Chen et al, 2006, 2007, Chen et al, 2012aZheng et al, 2008;Huang et al, 2010;Yin et al, 2015;Sun et al, 2018 Adam et al, 1993;Zhang et al, 1998Zhang et al, , 2017Liu et al, 2010;Ren et al, 2014;Zheng et al, 2015b;Gao et al, 2016Gao et al, , 2020Jie et al, 2017;Sun et al, 2017;Zhu et al, ringspot orthotospovirus (HCRV; Dong et al, 2013), and chili yellow ringspot virus (CYRSV; Zheng et al, 2020). TSWV and TZSV were the dominant species, based on disease epidemics and severity (Zhang et al, 2016).…”

“…There are currently 30 Orthotospovirus species known worldwide, comprising 11 definitive species (written in italics) and 19 tentative species (written in upright letters) ( Figure 2A ; International Committee on Taxonomy of Viruses Executive Committee [ICTVEC], 2020 ; Zheng et al, 2020 ). Orthotospoviruses can be divided into five phylogenetic clades based on the amino acid sequence of nucleocapsid (N) protein ( Figure 2A ), namely the tomato spotted wilt orthotospovirus (TSWV) clade, watermelon silver mottle orthotospovirus (WSMoV) clade, soybean vein necrosis-associated orthotospovirus (SVNV) clade, iris yellow spot orthotospovirus (IYSV) clade, and groundnut yellow spot orthotospovirus (GYSV) clade ( Peng et al, 2011 ; Oliver and Whitfield, 2016 ).…”

“…Based on the geography of the recent epidemics, viruses from the WSMoV and IYSV clades are mainly found in Asia and Europe ( Figure 3A ). Viruses from the WSMoV clade are most commonly found in East Asia and mainly infect crops in the families Solanaceae, Cucurbitaceae, and Asteraceae, with several new species from this clade reported in recent years ( Dong et al, 2008 ; Yin et al, 2014b ; Zheng et al, 2017 , 2020 ). Viruses from the IYSV clade are mainly found in Central Asia and Europe.…”

“…Of the Orthotospovirus clades found in China, the WSMoV clade is the most diverse. Several new virus species in this clade have been reported for the first time in China ( Dong et al, 2008 ; Yin et al, 2014b ; Zheng et al, 2017 , 2020 ), and it has been speculated that the WSMoV clade originated in China. TSWV, which belongs to the Americas group ( Pappu et al, 2009 ), has become the virus posing the largest threat to agricultural production in China.…”

Analysis of the Defence Responses to Tomato Spotted Wilt Orthotospovirus (TSWV) and Hippeastrum Chlorotic Ringspot Orthotospovirus (HCRV) Infection in Capsicum Annuum Based on Transcriptome

“…Tomato spotted wilt orthotospovirus (TSWV) and Hippeastrum chlorotic ringspot orthotospovirus (HCRV) are orthotospoviruses that are transmitted by thrips (Thysanoptera) and are able to infect over 900 kinds of plant species within more than 90 families [2,3]. TSWV, Impatiens necrotic spot orthotospovirus (INSV) [4], Groundnut ringspot orthotospovirus (GRSV) [5], Watermelon silver mottle orthotospovirus (WSMoV), Tomato chlorotic spot orthotospovirus (TCSV) [6], Groundnut bud necrosis orthotospovirus (GBNV) [5], Pepper necrotic spot orthotospovirus (PNSV), Pepper chlorotic spot orthotospovirus (PCSV), Capsicum chlorosis orthotospovirus (CaCV) [7], Alstroemeria necrotic streak orthotospovirus (ANSV) [8], and Chilli yellow ringspot orthotospovirus (CYRSV) [9] can infect peppers, causing pepper leaf chlorosis, necrosis, concentric rings, necrotic spots, and pepper fruit deformity, which seriously affect yield and quality [10].…”