The epidemiology of barley yellow dwarf virus in cereals and grasses

Dempster, Lorraine Crawford (1992) The epidemiology of barley yellow dwarf virus in cereals and grasses. PhD thesis, University of Glasgow.

Abstract

The transmission rates of the RPV, PAV and MAV strains of barley yellow dwarf virus (BYDV) by Rhopalosiphum padi and Sitobion avenae were examined. The transmission of virus was investigated between perennial ryegrass cv. Talbot (Lolium perenne L.) and several winter barley (Hordeum vulgare L.) and oat (Avena sativa L.) cultivars (cv.). The incidence of BYDV in cereal test plants was identified by visual symptoms of the disease, i.e. yellow or red leaves and stunting. The strains of BYDV in infected plants were confirmed by enzyme-linked immunisorbent assay (ELISA). The incidence of BYDV in perennial ryegrass was always identified by ELISA as ryegrass test plants did not exhibit symptoms of the disease. In general, R. padi was a more efficient vector of BYDV than S. avenae from source leaves infected with either one, two, or three strains of BYDV. The three strains of BYDV were transmitted at different rates to each plant cultivar. Generally, the transmission of RPV and PAV by R, padi to oat test plants was similar from oat source leaves infected with either one or other of the strains. However, the transmission of PAV was greater than RPV by R. padi from both ryegrass and oat source leaves to winter barley plants. In contrast, R. padi transmitted the RPV strain at a higher frequency than PAV from oats and barley to ryegrass test plants. S. avenae transmitted MAV at a higher frequency than PAV from barley or oat source leaves to oat test plants. However, the transmission rate of PAV by S. avenae was affected by the age of the source leaves. The vector was more likely to transmit PAV from young leaves than from old ones. The transmission rate of either PAV or MAV by S. avenae was poor to winter barley. S. avenae rarely inoculated any cereal plant with RPV, while R. padi was unable to transmit the MAV strain to cereals from leaves infected with that strain alone. R. padi was, however, able to transmit MAV together with RPV from cereal leaves infected with both strains. Similarly, the same species infected oat plants with PAV + MAV, although less readily, from source leaves containing both strains. S. avenae succeeded in transmitting MAV at a high frequency from the former combination, but did not transmit either strain from the latter, which was unusual as it is a vector of both PAV and MAV. S. avenae transmitted PAV and MAV together from a mixture containing RPV, PAV and MAV from oat cv. M. Tabard to oat cv. Pennalt. Transmission of BYDV by this vector from such mixtures was variable however. For example, S. avenae did transmit BYDV (PAV and MAV either alone or in combination) from perennial ryegrass cv. Talbot to oat cv. Dula, from cv. Dula to winter barley cv. Igri and from cv. Igri to cv. Dula. Transmission did not take place between the latter cultivars in two repeat experiments, or from ryegrass to cv. Igri, or between cv. Dula. R. padi, on the other hand, did transmit BYDV in all experiments from source leaves containing the three strains. Interestingly, RPV + MAV was not transmitted by R. padi from triple-infected source leaves, although PAV + MAV was. The transmission by R. padi of PAV, either alone or in combination, was greater than that of RPV (alone or in a mixture) to cereals from plants containing more than one strain of BYDV. S. avenae rarely transmitted RPV and transmitted PAV and MAV at similar frequencies. In contrast, no PAV alone was transmitted by either vector from winter barley to perennial ryegrass, while MAV either alone, or often in combination with RPV, was detected in the majority of ryegrass plants fed upon by both aphid species. This was unusual as S. avenae is not an efficient vector of RPV + MAV. Similarly, R. padi does not transmit MAV alone at a high frequency. Generally, the transmission of BYDV by both vectors was greater from cereal to grass than from cereal to cereal, which in turn was greater than from grass to cereal. PAV alone and in combination with RPV and/or MAV caused more severe stunting than RPV or MAV alone in winter barley cv. Igri and oat cv. Dula. Further observations revealed that oat plants inoculated at an early age were more readily infected than older plants. (Abstract shortened by ProQuest.).

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: Dr. Stephen Holmes
• Keywords: Plant pathology.
• Colleges/Schools: College of Medical Veterinary and Life Sciences
• Supervisor's Name: Supervisor, not known
• Date of Award: 1992
• Depositing User: Enlighten Team
• Unique ID: glathesis:1992-72971
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 11 Jun 2019 11:06
• Last Modified: 20 Jul 2021 15:57
• URI: https://theses.gla.ac.uk/id/eprint/72971