Plant Virus Transmission by Insects

Abstract

Most plant viruses depend on insect vectors for their survival, transmission and spread. They transmit plant viruses by two principal modes, circulative (circulating through the insect's haemocoel, CV) and non-circulative (carried on the cuticle lining of mouthparts or foregut, NC). Transmissibility and specificity between NC viruses and their vectors depends on the coat protein (CP) of the virus in addition to virus-encoded helper proteins. Circulative viruses cross the gut, circulate in the haemocoel and cross the salivary glands to render the insect infective. Circulative luteoviruses depend on small CP and the read-through protein (RTD) for transmission. Electrical penetration graphs have provided evidence on insect feeding behaviour and virus transmission. Recently, studies have shown that viruses can modify vector behaviour in a way that transmission is enhanced. eLS subject area: Virology

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

“…In contrast to the aphid‐borne members of the genus Potyvirus , the ipomoviruses are transmitted by the whitefly vector B. tabaci in a non‐circulative, semi‐persistent manner . Unlike the aphid‐borne non‐persistent viruses, which are characterised by a very short acquisition/transmission/retention period, semi‐persistent viruses are retained within the vector for days or weeks . Non‐persistent and semi‐persistent viruses are acquired from infected plants and transmitted to recipient plants within seconds to minutes.…”

“…Their transmission does not require a latent period and they do not replicate within the vector. Collectively, the non‐ and semi‐persistent viruses are referred to as non‐circulative because they do not enter the haemocoel or cross any vector cell membrane . Semi‐persistent viruses are specifically associated with the epicuticle that lines the arthropod vectors' stylets or foreguts, as demonstrated for the crinivirus Lettuce infectious yellows virus (LIYV) …”

“…Biological activity of HC‐Pro, in terms of aphid transmission, is believed to be mediated by oligomers composed of at least two HC‐Pro molecules . The current model for the bridge hypothesis for potyvirus transmission suggests that one surface of the dimer HC‐Pro is bound to the aphid stylet and another surface is bound to the potyvirus virion . For the two ipomoviruses that possess an HC‐Pro, SPMMV and TomMMoV, the helper strategy may be considered.…”

“…4 Unlike the aphid-borne non-persistent viruses, which are characterised by a very short acquisition/transmission/retention period, semi-persistent viruses are retained within the vector for days or weeks. 102 Non-persistent and semi-persistent viruses are acquired from infected plants and transmitted to recipient plants within seconds to minutes. Their transmission does not require a latent period and they do not replicate within the vector.…”

Optical Manipulations: An Advance Approach for Reducing Sucking Insect Pests

“…Non-persistent viruses must be transmitted within minutes or a few hours after acquisition (Ng and Falk 2006 ) . Insect-borne viral diseases often cause substantial economic damage to growers of crop plants (Raccah and Fereres 2009 ) . The sweet potato white fl y, the onion thrips and the western fl ower thrips are important pests of many protected crops (Cohen and Berlinger 1986 ;Lewis 1997 ) and may be considered as quarantine pests.…”