Movement of aphid-transmitted Sugarcane yellow leaf virus (ScYLV) within and between sugarcane plants

Abstract

Sugarcane yellow leaf virus (ScYLV) is distributed worldwide and has been shown to be the cause of the disease sugarcane yellow leaf syndrome (YLS). This study was an investigation of the transmission and spread of ScYLV in Hawaii. Several aphids are known to transmit the virus, but investigation of infestation and transmission efficiency showed Melanaphis sacchari to be the only vector important for field spread of the disease. The initial multiplication of ScYLV in a virus-free plant occurred exclusively in very young sink tissues. When a single leaf was inoculated on a plant, that leaf and all older leaves remained virus-free, based on tissue-blot immunoassay, whereas meristems and all subsequently formed new leaves became infected. Therefore, only after those leaves which had already developed before inoculation had been shed, did the complete plant contain ScYLV. Spread of the viral infection to neighbouring plants in the plantation fields via aphids was relatively slow and in the range of a few metres per year. No indication of long-distance transfer could be seen. This indicates that it may be possible to produce and use virus-free seed cane for planting of high-yielding but YLS-susceptible cultivars.

RT-PCR and quantitative real-time RT-PCR detection of Sugarcane Yellow Leaf Virus (SCYLV) in symptomatic and asymptomatic plants of Hawaiian sugarcane cultivars and the correlation of SCYLV titre to yield

“…These cultivars were thought to be resistant to the virus (Schenck and Lehrer 2000). Lehrer and Komor (2007) reported similar results in a detailed study on YL-symptom development and SCYLV-presence over the growing season and they also found that some plants with YL symptoms tested negative for SCYLV by TBIA. They concluded that there was no close correlation between SCYLV and YL symptoms.…”

“…Like others in this group, SCYLV is phloem-limited (Vega et al 1997;Schenck et al 1997;Lehrer et al 2007). Symptoms in sugarcane include yellowing of the leaf midribs, short terminal internodes, reduced biomass and reduced plant vigour (Grisham et al 2002;Rassaby et al 2003).…”

Sugarcane yellow leaf virus introduction and spread in Hawaiian sugarcane industry: Retrospective epidemiological study of an unnoticed, mostly asymptomatic plant disease

“…An infection of plants after the time when the plantation was closed is very unlikely because a distance of only 100 m was already sufficient to prevent infestation from infected cane for at least 1 year (Lehrer et al 2007) and a distance of several km was not bridged by viruliferous aphids for 30 years (Fig. 4).…”

“…The aphid vector Melanaphis sacchari, which is present throughout Hawaii, will have disseminated the virus among the plants in the breeding station, infecting the cultivar collection and the newly-bred clones. Although the speed of infection propagation from plant to plant is only a few metres per year (Lehrer et al 2007, Fig. 4), it is sufficiently fast to infect susceptible varieties within a few years.…”

“…The de novo infection in fields in Hawaii and in Louisiana by viruliferous aphids such as Melanaphis sacchari is relatively slow (Lehrer et al 2007;McAllister et al 2008). In controlled tests virus-free plants of the susceptible cultivar were planted in plantation fields at different distances from SCYLVinfected plants and tested for SCYLV after 11 months.…”