Etiology, occurrence and epidemiology of a begomovirus disease in passionflower in the southwest of Bahia

Abstract

Severe mosaic symptoms, accompanied by yellow spots, abnormally small leaves, fruit malformation and cracking, reduced plant growth, and high levels of whitefly (Bemisia tabaci MEAM1) infestation were observed in passionflower (Passiflora edulis) orchards in southwestern Bahia, Brazil. The aim of this work was to identify the species of begomovirus infecting the passionflowers, its prevalence in southwestern Bahia, and the spatial and temporal dynamics of the disease. Leaf samples from symptomatic plants collected at 57 orchards located in ten counties were evaluated by PCR for begomovirus infection. Complete nucleotide sequences of DNA-A for two isolates revealed 97 % identity with Passionfruit severe leaf distortion virus (PSLDV). The occurrence of PSLDV in 57 orchards was evaluated based on the presence of characteristic disease symptoms. Approximately 235,000 visually assessed plants exhibited symptoms characteristic of begomovirus infection. Epidemiological studies, conducted in two orchards in Dom Basílio County, showed that disease progress was relatively slow until 121 days after transplanting (DAT), but more rapid in the following 35 days, reaching 100 % infected plants by 156 DAT. The exponential model was fitted to the temporal dynamic of the disease for both areas. An aggregated pattern of diseased plants was predominant for almost all evaluations. It is possible that the primary and secondary spread of the pathogen occurred concurrently during the epidemic progression in both areas, especially late in the season. Containment measures to prevent the virus and the vector from spreading to other passionfruit producing areas in Brazil should be implemented.

Nanovirus Disease Complexes: An Emerging Threat in the Modern Era

“…Recent discoveries show the ongoing surge of viral infection evidence in various new host plant species owing to the growing number of metagenomics studies. Generally, symptom development in nanovirid-infected plant species resembles that observed in Geminiviridae infections, such as chlorosis, necrosis, leaf rolling, dwarfing, stunting, leaf yellowing, vein yellowing, leaf deformation, and plant death (Mansoor et al, 2003;Spence et al, 2007;Jeske, 2009;Hull, 2014;Kenyon et al, 2014;Gaafar et al, 2016;Rodrigues et al, 2019;Saucke et al, 2019;Vetten et al, 2019; Figures 4A-D). However, Geminiviridae has a much more diverse assortment of associated symptoms.…”

“…Nanoviruses limitation to narrow host ranges was a major factor in considering them as low impact viruses with an exiguous domain. This is why geminiviruses with the infection severity and outbreaks in broad host range have always been a preferred research area among ssDNA viruses compared to nanoviruses (Harrison, 1985;Mansoor et al, 2003;Jeske, 2009;Kenyon et al, 2014;Kil et al, 2016;Rodrigues et al, 2019). Recent developments have contributed to the discovery of new nanovirus hosts by confirming their presence in various important plant families including both dicots as well as monocots.…”

Characterization of Cucurbit Aphid-Borne Yellows Virus (CABYV) from Passion Fruit in Brazil: Evidence of a Complex of Species within CABYV Isolates

“…Several viruses have been identified in passion fruit plants in Brazil. Outbreaks of various begomoviruses (genus Begomovirus , family Geminiviridae ) have been reported in passion fruit fields in different regions of the country [ 1 , 2 , 3 , 4 ]. Other viruses, such as grapevine virus A (GVA, genus Vitivirus , family Betaflexiviridae ) [ 5 ], passion fruit yellow mosaic virus (PFYMV, genus Tymovirus , family Tymoviridae ) [ 6 ], cucumber mosaic virus (CMV, genus Cucumovirus , family Bromoviridae ) [ 7 ], passion fruit green spot virus (PfGSV, genus Cilevirus , family Kitaviridae ) [ 8 , 9 ], purple granadilla mosaic virus (PGrMV, unclassified) [ 10 ], passion fruit chlorotic mottle virus (PCMoV, genus Citlodavirus , family Geminiviridae ) [ 11 , 12 ], and lettuce chlorosis virus (LCV, genus Crinivirus , family Closteoviridae ) [ 13 ] have also been identified in this crop.…”