Genome Sequence of an Okra Leaf Curl Virus from Egypt.

A complete Okra leaf curl virus DNA-A was sequenced from okra in Egypt. Here, we report the complete genome sequence of this monopartite virus, comprising 2,764 bp and encoding 6 open reading frames (ORFs) with a GC content of 44.6% and 88.3% similarity to a virus reported earlier from Cameroon.

Biology and genetic diversity of phasey bean mild yellows virus, a common virus in legumes in Australia.

This study examined the natural and experimental host range and aphid and graft transmission of the tentative polerovirus phasey bean mild yellows virus (PBMYV). Eleven complete coding sequences from PBMYV isolates were determined from a range of hosts and locations. We found two genetically distinct variants of PBMYV. PBMYV-1 was the originally described variant, and PBMYV-2 had a large putative recombination in open reading frame 5 such that PBMYV-1 and PBMYV-2 shared only 65-66% amino acid sequence identity in the P5 protein. The virus was transmitted by a clonal colony of cowpea aphids (Aphis craccivora) and by grafting with infected scions but was not transmitted by a clonal colony of green peach aphids (Myzus persicae). PBMYV was found in natural infections in 11 host species with a range of symptoms and severity, including seven important grain legume crops from across a wide geographic area in Australia. PBMYV was common and widespread in the tropical weed phasey bean (Macroptilium lathyroides), but it is likely that there are other major alternative hosts for the virus in temperate regions of Australia. The experimental host range of PBMYV included the Fabaceae hosts chickpea (Cicer arietinum), faba bean (Vicia faba), pea (Pisum sativum), and phasey bean, but transmissions failed to infect several other members of the families Asteraceae, Cucurbitaceae, Fabaceae and Solanaceae. PBMYV was commonly found in grain legume crops in eastern and western Australia, sometimes at greater than 90% incidence. This new knowledge about PBMYV warrants further assessments of its economic impact on important grain legume crops.

Varietal Response to Groundnut Rosette Disease and the First Report of Groundnut ringspot virus in Ghana.

Twelve cultivars of groundnut were screened in field trials for resistance to groundnut rosette disease (GRD), caused by coinfection with Groundnut rosette assistor virus (GRAV), Groundnut rosette virus (GRV), and its satellite RNA in the coastal savannah of Ghana. 'Oboshie' groundnut was rated as highly resistant; 'Bremaowuo', 'Nkatefufuo', and 'Behenase' as resistant; and 'Nkosuor', 'Kumawu', and 'Otuhia' as moderately resistant. GRAV infection rates of 11.8 to 61.8% (dry season) and 13.9 to 100% (wet season) were found, which included symptomless plants, suggesting that some lacked coinfection with GRV and its satellite. Chlorotic ringspot and line-pattern symptoms were observed, suggesting infection with Groundnut ringspot virus (GRSV). Virus identity was confirmed by enzyme-linked immunosorbent assay, reverse-transcription polymerase chain reaction, and amplicon sequencing. This is the first report of GRSV in Ghana. GRSV infection rates were 0.0 to 69.5% (dry season) and 26.1 to 69.5% (wet season). Mixed infections of GRAV and GRSV were common in all cultivars except Nkosuor and Bremaowuo in the dry season. Most cultivars graft inoculated with GRD showed significantly reduced height, leaf area, chlorophyll content, dry haulm weight, and seed yield compared with healthy plants. The sources of resistance to GRD and possibly GRAV and GRSV identified in this study could be exploited in groundnut breeding programs.