Ipomovirus – an atypical genus in the family Potyviridae transmitted by whiteflies

Abstract

Ipomoviruses (genus Ipomovirus) are whitefly-transmitted viruses assigned to the family Potyviridae. They are characterised by filamentous flexible particles and a positive-sense single-stranded RNA (+ssRNA) genome. The viral genome is translated into a polyprotein precursor, which is processed into mature proteins and a short overlapping open reading frame. The genus Ipomovirus contains four accepted species and one unapproved species, and two other tentative members have recently been characterised. Ipomoviruses cause serious economic losses in many important crops, including cassava, sweet potato, cucurbits, tomato and aubergine. These viruses are transmitted by whiteflies in a non-circulative, semi-persistent manner, the virions being retained on the external surface of the vectors' mouthparts for a few days or weeks. Comparison of the available complete genome sequences of different ipomoviruses revealed differences in their genome organisation and a considerable variation in their proteins and conserved motifs that may reflect functional differences. This review summarises the current knowledge of the members within the genus Ipomovirus, focusing on genome organisation, taxonomic classification and the mechanism by which they are transmitted.

Analyses of seven new whole genome sequences of cassava brown streak viruses in Mozambique reveals two distinct clades: evidence for new species

“…A specific domain (RSSRAMKQKRARERRRAQQ) of the P1 protein was observed in Turnip mosaic virus that potentially interacts with nucleic acids (Soumounou & Laliberté, ) and in CBSV, the P1 functions as a suppressor of RNA silencing (Mbanzibwa et al ., ). CBSV and UCBSV might use binding through a ‘bridge’ formed by the virus‐encoded P1 protein with putative receptors located in the whitefly maxillary stylet (Dombrovsky et al ., ). Thus, it is possible that this deletion may affect the transmission efficiency of the virus by whiteflies – a finding that requires extensive further research.…”

Cassava brown streak virus has a rapidly evolving genome: implications for virus speciation, variability, diagnosis and host resistance

“…6K2 is associated with cellular membrane and responsible for systemic infection and viral long distance movement28. The NIb encodes for a nuclear inclusion polymerase and the NIA for a nuclear inclusion protease1829.…”

The HCPro from the Potyviridae family: an enviable multitasking Helper Component that every virus would like to have

“…(C) Ipomovirus . The diversity among members of this genus has been reviewed (Dombrovsky et al ., ). A HAM extra protein (in pink) was also present in a subset of ipomoviruses.…”