CSB351Y1 Lecture Notes - Lecture 15: Salivary Gland, Cuscuta, Hemolymph
26 May 2018
School
Department
Course
Professor
Lecture 15: Plant Virus Transmission
• Viruses do not have intrinsic motility – found ways to be transmitted
1. Mechanical transmission
- Infected plants brush against healthy ones in the field
- Animals rub against infected plants and then against healthy ones
- Contaminated hands and tools during planting
2. Vegetative transmission
- Any part of systemically infected plants used for vegetative propagation gives rise to infected plants
- Virus transmission through grafting (or dodder)
3. Seed and pollen transmission
- Most not transmitted this way but at least 50 (PSTV) transmitted this way
- Virus stuck on external surface of seeds
- Virus in endosperm or embryo
4. Vector transmission
- Aphids – largest group of insect vectors with stylets
- Agricultural pests – suck sap from phloem of plants (mode of feeding)
Other vectors
Transmission by soil vectors
1. Nematodes – feed on plant roots
2. Fungi – viruses persist in soil
Transmission by Insect Vectors
1. Leaf hoppers and plant hoppers – more damage to plants by piercing
2. White flies – multiply under leaves and feed to acquire virus (virus itself do not multiply in them)
3. Thrips – TSWV and TRV shortest acquisition but latent period where they retain virus for life but not transmitted
to progeny
4. Beetles – virus persists in insects and detected
• Virus encoded determinants specifically interact with vector to facilitate virus transmission and for plant viruses
to utilize different but specific vectors to facilitate their spread
Types of Vector Transmission
• Non-persistent
- Non-circulative
- Stylet-borne/ foregut – attach directly or indirectly via helper components
- Introduced into plants during insect salivation and regurgitation
• Persistent circulative
- Moves inside vector
- Replenished from host
- Do not replicate in insect and usually enter salivary glands from hemolymph
• Persistent propagative
- Replicates inside vector (tissues and organs of insect) and may enter salivary glands either from
hemolymph or other connecting tissues
- Some transovarial (produce infected eggs and nymphs)
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Lecture 15: plant virus transmission: viruses do not have intrinsic motility found ways to be transmitted, mechanical transmission. Infected plants brush against healthy ones in the field. Animals rub against infected plants and then against healthy ones. Contaminated hands and tools during planting: vegetative transmission. Any part of systemically infected plants used for vegetative propagation gives rise to infected plants. Virus transmission through grafting (or dodder: seed and pollen transmission. Most not transmitted this way but at least 50 (pstv) transmitted this way. Virus stuck on external surface of seeds. Virus in endosperm or embryo: vector transmission. Aphids largest group of insect vectors with stylets. Agricultural pests suck sap from phloem of plants (mode of feeding) Transmission by soil vectors: nematodes feed on plant roots, fungi viruses persist in soil. Stylet-borne/ foregut attach directly or indirectly via helper components. Introduced into plants during insect salivation and regurgitation: persistent circulative.
