Podcast
Questions and Answers
______ account for the transmission of 50% of the insect-vectored viruses
______ account for the transmission of 50% of the insect-vectored viruses
aphids
______ are exquisitely designed for their roles as vector. Piercing–sucking mouthparts facilitate the delivery of virions into plant cells without causing irrevocable damage
______ are exquisitely designed for their roles as vector. Piercing–sucking mouthparts facilitate the delivery of virions into plant cells without causing irrevocable damage
aphids
______ are globally distributed and there are more than 200 vector species identified, a number that is most likely a gross underestimate
______ are globally distributed and there are more than 200 vector species identified, a number that is most likely a gross underestimate
aphids
Most plant ______ are the result of a coevolution of virus and vector
Most plant ______ are the result of a coevolution of virus and vector
Signup and view all the answers
The CP translational readthrough protein binds symbionin, a protein homologue of the Escherichia coli chaperonin GroEL that is produced by the ______ endosymbiotic bacteria Buchnera spp. and released into the haemolymph
The CP translational readthrough protein binds symbionin, a protein homologue of the Escherichia coli chaperonin GroEL that is produced by the ______ endosymbiotic bacteria Buchnera spp. and released into the haemolymph
Signup and view all the answers
Umbraviruses are mechanically transmissible, but their genomes do not encode a CP and they are aphid-nontransmissible. They achieve aphid transmission competence by associating with luteoviruses in plants dually infected by both viruses
Umbraviruses are mechanically transmissible, but their genomes do not encode a CP and they are aphid-nontransmissible. They achieve aphid transmission competence by associating with luteoviruses in plants dually infected by both viruses
Signup and view all the answers
The circulative propagative plant viruses bear a striking resemblance to animal viruses transmitted by ______. In both cases, viruses replicate in the insect vector and exit via the salivary glands
The circulative propagative plant viruses bear a striking resemblance to animal viruses transmitted by ______. In both cases, viruses replicate in the insect vector and exit via the salivary glands
Signup and view all the answers
Aphid vectors are responsible for positioning viruses at their sites of infection. Because salivation appears to play an essential role in the release of virions, an understanding of virus entry may ultimately require a better understanding of salivation
Aphid vectors are responsible for positioning viruses at their sites of infection. Because salivation appears to play an essential role in the release of virions, an understanding of virus entry may ultimately require a better understanding of salivation
Signup and view all the answers
______, genus Potyvirus, contains the most potyviruses (definitive and tentative) among aphid-transmitted plant viruses, with many species having narrow host ranges
______, genus Potyvirus, contains the most potyviruses (definitive and tentative) among aphid-transmitted plant viruses, with many species having narrow host ranges
Signup and view all the answers
Aphids primarily belong to the subfamily ______, and are responsible for the transmission of most plant viruses through a polyphagous feeding habit, parthenogenetic reproduction, and needle-like stylet
Aphids primarily belong to the subfamily ______, and are responsible for the transmission of most plant viruses through a polyphagous feeding habit, parthenogenetic reproduction, and needle-like stylet
Signup and view all the answers
Feeding behavior and host plant selection of ______ can influence their potential as virus vectors
Feeding behavior and host plant selection of ______ can influence their potential as virus vectors
Signup and view all the answers
______ play a crucial role in the spread and control of viral plant diseases, making understanding their transmission essential for epidemiology.
______ play a crucial role in the spread and control of viral plant diseases, making understanding their transmission essential for epidemiology.
Signup and view all the answers
Noncirculative viruses are primarily associated with the aphid's ______
Noncirculative viruses are primarily associated with the aphid's ______
Signup and view all the answers
Circulative viruses can be nonpropagative or circulative ______, depending on whether they replicate within the vector.
Circulative viruses can be nonpropagative or circulative ______, depending on whether they replicate within the vector.
Signup and view all the answers
The majority of aphid-vectored plant viruses are transmitted ______ and can be classified as nonpersistent or semipersistent.
The majority of aphid-vectored plant viruses are transmitted ______ and can be classified as nonpersistent or semipersistent.
Signup and view all the answers
Potato virus Y and other potyviruses require the helper component (HC) protein for ______, which acts as a bridge to mediate virion binding in the aphid's stylet.
Potato virus Y and other potyviruses require the helper component (HC) protein for ______, which acts as a bridge to mediate virion binding in the aphid's stylet.
Signup and view all the answers
Semipersistent transmission lies in the ______ period of hours to days. The best characterized of the semipersistent, aphid-transmitted viruses are the caulimoviruses and the closteroviruses. Cauliflower mosaic virus, the type member of the genus Caulimovirus, has adopted a helper-dependent transmission strategy, but with the added twist of requiring two viral-encoded, nonstructural proteins, P2 and P3
Semipersistent transmission lies in the ______ period of hours to days. The best characterized of the semipersistent, aphid-transmitted viruses are the caulimoviruses and the closteroviruses. Cauliflower mosaic virus, the type member of the genus Caulimovirus, has adopted a helper-dependent transmission strategy, but with the added twist of requiring two viral-encoded, nonstructural proteins, P2 and P3
Signup and view all the answers
Helper-dependent transmission strategy, but with the added twist of requiring two viral-encoded, nonstructural proteins, P2 and P3 (Blanc et al., 2001). A P2–P3–______ complex is formed, with P2 thought to mediate binding in the aphid whereas P3 binds to s; the ‘bridge’ would be formed via P2–P3 interactions (Drucker et al., 2002; Leh et al., 1999, 2001). Intriguingly, aphids may first acquire P2 from infected mesophyll cells, and P3– complexes can subsequently be taken up from other mesophyll or phloem cells (Drucker et al., 2002; Palacios et al., 2002).
Helper-dependent transmission strategy, but with the added twist of requiring two viral-encoded, nonstructural proteins, P2 and P3 (Blanc et al., 2001). A P2–P3–______ complex is formed, with P2 thought to mediate binding in the aphid whereas P3 binds to s; the ‘bridge’ would be formed via P2–P3 interactions (Drucker et al., 2002; Leh et al., 1999, 2001). Intriguingly, aphids may first acquire P2 from infected mesophyll cells, and P3– complexes can subsequently be taken up from other mesophyll or phloem cells (Drucker et al., 2002; Palacios et al., 2002).
Signup and view all the answers
Because HC and virus particles can be acquired sequentially, it is possible for one virus to assist in the ______ of a second virus. This phenomenon, termed HC-transcomplementation, has been observed in a number of families of plant viruses and can influence the epidemiology and spread of plant viruses (Froissart et al., 2002). Examples of semipersistent aphid ______ can be found in three other genera of plant viruses (Table 1). Among them, Parsnip yellow fleck virus (PYFV) (genus: Sequivirus) also employs a helper strategy in its ______.
Because HC and virus particles can be acquired sequentially, it is possible for one virus to assist in the ______ of a second virus. This phenomenon, termed HC-transcomplementation, has been observed in a number of families of plant viruses and can influence the epidemiology and spread of plant viruses (Froissart et al., 2002). Examples of semipersistent aphid ______ can be found in three other genera of plant viruses (Table 1). Among them, Parsnip yellow fleck virus (PYFV) (genus: Sequivirus) also employs a helper strategy in its ______.
Signup and view all the answers
Viruses belonging to the family ______ have particles that are composed of at least two forms of capsid proteins: the major CP and the minor CP (CPm). Although little is known about the determinants of aphid transmission for the viruses in this family, evidence from one member, the whitefly-transmitted Lettuce infectious yellows virus (genus: Crinivirus), indicates they are present on the CPm (Tian et al., 1999).
Viruses belonging to the family ______ have particles that are composed of at least two forms of capsid proteins: the major CP and the minor CP (CPm). Although little is known about the determinants of aphid transmission for the viruses in this family, evidence from one member, the whitefly-transmitted Lettuce infectious yellows virus (genus: Crinivirus), indicates they are present on the CPm (Tian et al., 1999).
Signup and view all the answers
Study Notes
- Aphids are vectors for plant viruses, with two main categories of transmission: circulative and noncirculative.
- Circulative viruses are taken up into aphid cells, cross membrane barriers, and are transported in the haemolymph, eventually exiting the aphid in saliva.
- Circulative viruses can be nonpropagative or circulative propagative, depending on whether they replicate within the vector.
- Noncirculative viruses have a more superficial relationship with the vector and are primarily associated with the aphid's mouthparts and foregut.
- The majority of aphid-vectored plant viruses are transmitted noncirculatively and can be classified as nonpersistent or semipersistent.
- Nonpersistent transmission is characterized by short acquisition and inoculation times (seconds to minutes), and aphids are viruliferous for a short period of time.
- Nonpersistent transmission occurs when virions are retained within the stylet bundle and food canal or foregut, and salivation aids in the release of bound virions for inoculation.
- The viral capsid protein is a primary determinant of both aphid transmissibility and specificity.
- CMV, a common aphid-transmitted virus, is dependent on the viral capsid protein alone for transmission.
- Potato virus Y and other potyviruses require the helper component (HC) protein for transmission, which acts as a bridge to mediate virion binding in the aphid's stylet.
- Transmission-defective HC mutants exhibit alterations in conserved HC protein domains, leading to the disruption of the HC's ability to bind CP and virions in vitro.
- Semipersistent transmission occurs when virions are retained in the vector for longer periods, allowing for the possibility of multiple transmission events from a single vector.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on the fundamental distinction of virus transmission in vectors, focusing on the retention of virions, movement within the vector, and exit from the vector. Explore the classification of circulative and noncirculative viruses and their impact on virus transmission.
