77 Questions
Endosymbionts play a minor role in the modulation of vector susceptibility to viruses and their transmission
False
The gut commensal microbiome has been fully established as a regulator of host defenses against viral infections of gut epithelial cells
False
Gut microbiota are not involved in persistent plant virus transmissions by insect vectors
False
The diversity of intestinal symbiotic microorganisms in sap-feeding insects is significantly high due to high microbial contents in plant sap
False
Obligate symbionts can exist within specialized cells to escape the insect host's immune system
True
Persistent plant viruses can be transmitted by Hemiptera insects such as aphids, whiteflies, leafhoppers, and planthoppers.
True
Non-persistent viruses are mainly retained by the vector in the foregut.
False
Persistent viruses are taken up together with the plant sap during insect sucking.
True
Semi-persistent viruses are retained by the vector in the stylet (food canal).
False
Persistent plant viruses can be transmitted to healthy plant hosts during the course of sucking plant sap.
True
True or false: Buchnera provides essential nutrients and vitamins to the aphid host that can be obtained from the diet or from other symbionts.
False
True or false: Bemisia tabaci is a natural vector of persistently transmitted begomoviruses.
True
True or false: Portiera aleyrodidarum is the obligate endosymbiont for all whitefly species.
True
True or false: In whiteflies, Portiera is transmitted to progenies through a unique mechanism in which intact bacteriocytes migrate to the ovaries and enter eggs.
True
True or false: Insects do not require Wolbachia for vitamin B synthesis.
False
Persistent propagative viruses infect the reproductive systems of insects and are horizontally transmitted.
False
Obligate symbionts are not strictly dependent on their insect hosts and can survive independently.
False
Facultative symbionts have a narrower range of roles for insect hosts compared to obligate symbionts.
False
Nearly all aphids are infected with the facultative endosymbiont Buchnera aphidicola.
False
Insects with diverse symbiont communities are not important agricultural pests that transmit plant viruses.
False
Potato leafroll virus interacts with the symbionin expressed by the obligate endosymbiont of M. persicae, Buchnera.
True
Administration of antibiotics to aphids results in the absence of symbionin in the Frontiers in Microbiology article published on 4 January 2022.
True
The absence of symbionin in the hemolymph of aphids leads to virus degradation and loss of infectivity.
True
The N-terminal region of the luteovirus RTD determines virus binding to Buchnera GroEL and is essential for virion stability.
True
The transmission of Tomato spotted wilt virus by thrips is not affected by the number of symbiotic bacteria Erwinia sp. present in the gut of thrips larvae.
False
Rapid climate change and the globalization of trade through free trade agreements encourage the transmission of vectors and viruses from country to country. Another factor affecting the emergence of viruses is the cultivation of monocultures with low genetic diversity and high plant density. Trade in plant material (germplasm and living plants) also cause the emergence of new viruses. Viruses have a fast adaptation and development in a new environment. Aphids are the most widespread and important vectors of plant viruses. Myzus persicae transmits more than 100 different plant ______s.
viruses
In nature plant viruses are transmitted also by nematodes, fungi, mites, leafhoppers, whiteflies, beetles, and ______.
planthoppers
The symptoms of viral diseases are very diverse and are often confused with symptoms of ______ stress.
abiotic
Plant viruses are a threat to a sustainable economy because they cause economic losses in yields. The epidemiology of plant viruses is of particular interest because of their dynamic spread by insect vectors and their transmission by ______.
seeds
The speed and direction of viral evolution are determined by the selective environment in which they are found. Knowledge of the ecology of plant viruses is critical to the transmission of many plant ______s.
viruses
Viruses enter plants through the ______ and mesophyll cells
epidermis
Short-distance movement of viruses requires modification of plasmodesmata by viral ______ proteins
movement
Preventing the spread of viral diseases involves strict regulations on the biological safety of plants, monitoring symptoms of ______, and testing seeds for the presence of viruses
seeds
Several methods for preventing viral diseases include soil sterilization, sterilization of garden tools, use of certified seeds, and application of ______
nanoparticles
Nanoparticles are applied directly to seeds, leaves, or soil for plant protection, but direct application to soil can affect soil ______-organisms
micro
Globalization and population growth increase the risk of viral diseases spreading, potentially leading to food chain disruption and famine. Monoculture farming of annual plants contributes to frequent viral ______
diseases
Viruses have different transmission routes, including insects, mites, ectoparasitic nematodes, and contact ______
transmission
Insect-borne viruses are classified as persistent, semi-persistent, or non-persistent based on the time the vector remains ______
virulent
Several factors have worsened the global situation of viral diseases, such as the rapid spread of crops from their centers of domestication to other continents, where they are grown as ______
monocultures
Viral transmission involves acquisition, stable retention, and release of ______. Non-persistent viruses are transmitted through aphids with low vector specificity and are found only in the insect's mouthparts.
virions
1
The most suitable system for handling nucleic acids is the class 2 CRISPR system
2
CRISPR class 1 system contains types I, III and IV
3
CRISPR class 2 system includes II, V and VI
4
CRISPR class 1 system can utilize a multi-protein effector complex
5
CRISPR class 2 system achieves target editing using only one effector protein
Seed-borne viruses can survive long periods of drought and facilitate the expansion of geographical ranges. Seed transmission occurs through direct invasion of embryonic tissues or through infection of eggs or pollen. Unlike animal viruses, plant viruses are confined to the intracellular symplast and move between cells through
plasmodesmata
Some plant viruses, such as soybean mosaic virus, are transmitted through seeds and are controlled by homologues of Arabidopsis host genes DCL3 and RDR6, which participate in
RNA silencing
Other modes of transmission include viruses transmitted through nematodes, contact in the field, and through the soil without a
vector
haustoria
Parasitic plants, such as Cuscuta spp., C. campestris and C. subinclusa, can also transmit viruses using their
After inoculation, replication and translation of the viral genome occur in mesophyll and epidermal cells. Cell-associated viral proteins interact with the viral genome to form transport complexes that allow movement between cells via
plasmodesmata
Viral replication and cell-to-cell movement continue in the nuclear phloem, and movement complexes are stored in the SE for long-distance transport.
Persistent viruses are limited to the phloem and require a longer feeding time to be transmitted to plants. Unlike semi-persistent viruses, they circulate in the insect vector's body and show a high degree of specificity for vectors, allowing for long-distance spread and infection of multiple plants. Aphids transmit viruses from the genera Capulavirus, Enamovirus, Luteovirus, Nanovirus, Polerovirus, and indirectly through the auxiliary genus Luteovirus. Whiteflies transmit the genus Begomovirus, thrips transmit Orthotospovirus, and some viruses can be transmitted through
seeds
Explain the difference between persistent, semi-persistent, and non-persistent transmission of insect-borne viruses.
Persistent transmission involves viruses replicating in the vector's tissues and having a high degree of vector specificity, allowing for long-distance spread. Semi-persistent transmission involves viruses being retained in the vector's stylet and can be transmitted over short distances. Non-persistent transmission does not involve replication in the vector and has low vector specificity, allowing for short-distance spread.
What are the transmission routes of plant viruses and how do they differ?
Plant viruses can be transmitted by insects, mites, ectoparasitic nematodes, and through contact transmission. The transmission routes differ in terms of the specific vectors involved and the mechanisms of viral transmission.
Explain the difference between circulating and non-circulating viruses in terms of transmission.
Circulating viruses replicate in the vector's tissues and require a specific viral protein for transmission. Non-circulating viruses are transmitted in a non-persistent manner and do not involve replication in the vector.
What are the genera of non-persistent viruses transmitted through aphids?
Non-persistent viruses belong to the genera Alfamovirus, Cucumovirus, Fabavirus, Macluravirus, and Potyvirus.
What is the difference between vertical and horizontal transmission of plant viruses?
Vertical transmission occurs between parents and offspring, while horizontal transmission involves transmission to new plants.
Explain the mechanisms through which viruses enter and move within plant cells.
Viruses enter plants through the epidermis and mesophyll cells and move from cell to cell for continuous replication. Short-distance movement requires modification of plasmodesmata by viral movement proteins, while long-distance transport through the phloem involves translocation from mesophyll cells to sieve elements.
How do viruses overcome plant defense mechanisms?
Viruses overcome plant defense mechanisms in various ways, and some plants have evolved resistance genes. Multiple compatible interactions must form between viral proteins and cellular factors for the virus to complete its life cycle.
What are some methods for preventing the spread of viral diseases in plants?
Preventing the spread of viral diseases in plants involves strict regulations on the biological safety of plants, monitoring symptoms of seeds, testing seeds for the presence of viruses, soil sterilization, sterilization of garden tools, use of certified seeds, and application of nanoparticles.
What is the significance of nanoparticles in agriculture in relation to plant diseases?
Nanoparticles have gained attention in agriculture for the detection of plant diseases and as carriers of genetic materials due to their unique properties. They can be applied directly to seeds, leaves, or soil for plant protection, but direct application to soil can affect soil micro-organisms.
How do seeds contribute to the spread of viral infections in plants?
Seeds can be a source of viral infections, with up to 20% of plant viruses being transmitted through seeds. Viruses can survive on the surface of seeds or in the seed endosperm, and some can survive for more than 20 years.
Explain the role of CRISPR in plant protection and the differences between CRISPR class 1 and class 2 systems.
CRISPR serves as adaptive immunity against invading nucleic acids in plants. The simplified CRISPR system contains modified RNA (gRNA) and the effector protein Cas. CRISPR is divided into two different classes. The CRISPR class 1 system contains types I, III and IV, which can utilize a multi-protein effector complex. The CRISPR class 2 system includes types II, V and VI, which achieve target editing using only one effector protein.
What are the main strategies for using CRISPR/Cas to control plant viruses?
The two main strategies for using CRISPR/Cas to control plant viruses are: 1. Directing the system to the target, interfering with and destroying the viral genome to inhibit infection and replication of invading viruses. 2. Manipulating host susceptibility factors required for a viral infection to enhance plant immunity and block viral invasion.
What is the most suitable CRISPR system for handling nucleic acids, and which types of Cas proteins are used for RNA and DNA editing?
The most suitable system for handling nucleic acids is the class 2 CRISPR system. Cas type VI proteins are used for RNA editing, and type II and V proteins are used for DNA editing.
Why are resistant varieties considered the most cost-effective and reliable approach to protect crops from virus infection?
Resistant varieties are considered the most cost-effective and reliable approach because a considerable amount of time and expense is required to develop resistant varieties. If resistance is persistent, then the use of resistant crop varieties is the preferred method of controlling agricultural losses.
What are the challenges and benefits of using gene editing technology in plant genetic engineering to create resistance to pathogens and viruses?
The challenges of using gene editing technology in plant genetic engineering include the difficulty of estimating economic losses caused by plant viruses and the unknown mechanisms by which all disease symptoms are generated. The benefits include the rapid introduction of gene editing technology into plant genetic engineering to create resistance to other pathogens and viruses.
Explain the difference between semi-persistent and persistent viruses in terms of transmission and circulation in the insect vector's body.
Semi-persistent viruses are transmitted through the anus of insects, are concentrated in the phloem and surrounding tissues, and are retained by the vector in the stylet (food canal). They do not circulate in the insect vector's body. Persistent viruses, on the other hand, are limited to the phloem, require a longer feeding time to be transmitted to plants, and circulate in the insect vector's body. They show a high degree of specificity for vectors, allowing for long-distance spread and infection of multiple plants.
How do seed-borne viruses contribute to the spread of viruses over long distances, and what is their survival capability?
Seed-borne viruses spread over long distances and serve as an important source of primary inoculum for vertically transmitted viruses. They can survive long periods of drought and facilitate the expansion of geographical ranges. Seed transmission occurs through direct invasion of embryonic tissues or through infection of eggs or pollen.
Describe the movement of plant viruses between cells and their confinement in the intracellular symplast.
Plant viruses are confined to the intracellular symplast and move between cells through plasmodesmata. Cell-associated viral proteins interact with the viral genome to form transport complexes that allow movement between cells via plasmodesmata. Viral replication and cell-to-cell movement continue in the nuclear phloem, and movement complexes are stored in the SE for long-distance transport.
How are some plant viruses, such as soybean mosaic virus, transmitted and controlled in plants?
Some plant viruses, such as soybean mosaic virus, are transmitted through seeds and are controlled by homologues of Arabidopsis host genes DCL3 and RDR6, which participate in RNA silencing.
Explain the role of parasitic plants in the transmission of viruses and provide examples of parasitic plants involved in virus transmission.
Parasitic plants, such as Cuscuta spp., C. campestris, and C. subinclusa, can transmit viruses using their haustoria. They serve as additional vectors for the transmission of plant viruses.
Explain the factors that contribute to the spread of plant viruses and their impact on the economy.
Factors contributing to the spread of plant viruses include rapid climate change, globalization of trade, cultivation of monocultures, and trade in plant material. These factors encourage the transmission of vectors and viruses across countries and the emergence of new viruses. The impact on the economy is significant, as plant viruses cause economic losses in yields.
Discuss the role of aphids in the transmission of plant viruses and provide an example of a widely transmitted plant virus.
Aphids are important vectors of plant viruses, with Myzus persicae transmitting more than 100 different plant viruses. They are the most widespread and important vectors of plant viruses. An example of a widely transmitted plant virus by aphids is Myzus persicae.
How does the cultivation of monocultures contribute to the emergence of new plant viruses?
The cultivation of monocultures with low genetic diversity and high plant density contributes to the emergence of new plant viruses. This lack of genetic diversity makes the crops more susceptible to viral infections and facilitates the spread of viruses within the monoculture.
Explain the role of insect vectors in the global transmission of plant viruses.
Insect vectors play a crucial role in the global transmission of plant viruses. They facilitate the spread of viruses from country to country, especially in the context of rapid climate change and globalization of trade. Insect vectors such as aphids, whiteflies, leafhoppers, and planthoppers contribute to the widespread dissemination of plant viruses.
Why is accurate and timely detection of plant viruses essential for their control?
Accurate and timely detection of plant viruses is essential for their control because it allows for prompt implementation of measures to prevent further spread. Early detection enables targeted interventions to minimize economic losses and mitigate the impact of viral diseases on plant yields.
Study Notes
-
Potato leafroll virus (PLRV) interacts with the symbionin expressed by the obligate endosymbiont of M. persicae, Buchnera.
-
Administration of antibiotics to aphids results in the absence of symbionin in the Frontiers in Microbiology article published on 4 January 2022.
-
The absence of symbionin in the hemolymph of aphids leads to virus degradation and loss of infectivity.
-
The interaction between PLRV and Buchnera GroEL occurs in the equatorial domain.
-
Insect endosymbionts and their products play a crucial role in determining the persistent nature of plant viruses in insects.
-
The N-terminal region of the luteovirus RTD determines virus binding to Buchnera GroEL and is essential for virion stability.
-
The genotype of Buchnera correlates with the ability to efficiently transmit Cereal yellow dwarf virus by aphids.
-
The GroEL protein produced by Hamiltonella facilitates Tomato yellow leaf curl virus transmission.
-
Arsenophonus is involved in the transmission of Cotton leaf curl virus in whiteflies.
-
The transmission of Tomato spotted wilt virus by thrips is not affected by the number of symbiotic bacteria Erwinia sp. present in the gut of thrips larvae.
-
Hamiltonella is closely associated with the acquisition, retention and transmission efficiency of Tomato yellow leaf curl virus by the whitefly.
-
Rickettsia increases Tomato yellow leaf curl virus transmission efficacy by infecting the midgut.
-
Sulcia supports Rice dwarf virus transfer to the next generation in leafhoppers.
-
The interaction between Hamiltonella and the whitefly increases the transmission efficiency of begomovirus.
-
Rickettsia down-regulates whitefly immunity genes to increase the ability of whiteflies to acquire, retain and transmit Tomato yellow leaf curl virus.
-
The gut microbiota of leafhoppers is changed by Wheat dwarf virus, but virus transmission is not affected by the diversity and abundance of gut microbiota.
-
The Wolbachia strain wStri, isolated from the small brown planthopper, Laodelphax striatellus, was introduced into brown planthopper, Nilaparvata lugens, and found to inhibit Rice ragged stunt virus infection and transmission, and mitigate virus-induced symptoms in rice plants.
-
The transmission efficiency of Cotton leaf curl multan virus is enhanced by Rickettsia in whiteflies.
-
Semi-persistent viruses, such as those in the Caulimovirus, Alexievirus, and Comovirus genera, are transmitted through the anus of insects and are concentrated in the phloem and surrounding tissues. The retention period lasts from several hours to days.
-
Persistent viruses are limited to the phloem and require a longer feeding time to be transmitted to plants. Unlike semi-persistent viruses, they circulate in the insect vector's body and show a high degree of specificity for vectors, allowing for long-distance spread and infection of multiple plants.
-
Aphids transmit viruses from the genera Capulavirus, Enamovirus, Luteovirus, Nanovirus, Polerovirus, and indirectly through the auxiliary genus Luteovirus. Whiteflies transmit the genus Begomovirus, thrips transmit Orthotospovirus, and some viruses can be transmitted through seeds.
-
Seed transmission allows viruses to spread over long distances and is an important source of primary inoculum for vertically transmitted viruses. Seed-borne viruses can survive long periods of drought and facilitate the expansion of geographical ranges.
-
Seed transmission occurs through direct invasion of embryonic tissues or through infection of eggs or pollen. Unlike animal viruses, plant viruses are confined to the intracellular symplast and move between cells through plasmodesmata.
-
Some plant viruses, such as soybean mosaic virus, are transmitted through seeds and are controlled by homologues of Arabidopsis host genes DCL3 and RDR6, which participate in RNA silencing.
-
Other modes of transmission include viruses transmitted through nematodes, contact in the field, and through the soil without a vector. Parasitic plants, such as Cuscuta spp., C. campestris and C. subinclusa, can also transmit viruses using their haustoria.
-
After inoculation, replication and translation of the viral genome occur in mesophyll and epidermal cells. Cell-associated viral proteins interact with the viral genome to form transport complexes that allow movement between cells via plasmodesmata. Viral replication and cell-to-cell movement continue in the nuclear phloem, and movement complexes are stored in the SE for long-distance transport.
-
Semi-persistent viruses, such as those in the Caulimovirus, Alexievirus, and Comovirus genera, are transmitted through the anus of insects and are concentrated in the phloem and surrounding tissues. The retention period lasts from several hours to days.
-
Persistent viruses are limited to the phloem and require a longer feeding time to be transmitted to plants. Unlike semi-persistent viruses, they circulate in the insect vector's body and show a high degree of specificity for vectors, allowing for long-distance spread and infection of multiple plants.
-
Aphids transmit viruses from the genera Capulavirus, Enamovirus, Luteovirus, Nanovirus, Polerovirus, and indirectly through the auxiliary genus Luteovirus. Whiteflies transmit the genus Begomovirus, thrips transmit Orthotospovirus, and some viruses can be transmitted through seeds.
-
Seed transmission allows viruses to spread over long distances and is an important source of primary inoculum for vertically transmitted viruses. Seed-borne viruses can survive long periods of drought and facilitate the expansion of geographical ranges.
-
Seed transmission occurs through direct invasion of embryonic tissues or through infection of eggs or pollen. Unlike animal viruses, plant viruses are confined to the intracellular symplast and move between cells through plasmodesmata.
-
Some plant viruses, such as soybean mosaic virus, are transmitted through seeds and are controlled by homologues of Arabidopsis host genes DCL3 and RDR6, which participate in RNA silencing.
-
Other modes of transmission include viruses transmitted through nematodes, contact in the field, and through the soil without a vector. Parasitic plants, such as Cuscuta spp., C. campestris and C. subinclusa, can also transmit viruses using their haustoria.
-
After inoculation, replication and translation of the viral genome occur in mesophyll and epidermal cells. Cell-associated viral proteins interact with the viral genome to form transport complexes that allow movement between cells via plasmodesmata. Viral replication and cell-to-cell movement continue in the nuclear phloem, and movement complexes are stored in the SE for long-distance transport.
Test your knowledge about the symbiotic relationship between aphids and their endosymbionts, including Buchnera and other facultative symbionts. Explore the ecological benefits that these symbionts provide to the aphid host.
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