scholarly journals Semipersistently Transmitted, Phloem Limited Plant Viruses Are Inoculated during the First Subphase of Intracellular Stylet Penetrations in Phloem Cells

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 137
Author(s):  
Jaime Jiménez ◽  
Aránzazu Moreno ◽  
Alberto Fereres
Keyword(s):  
Sugar Beet ◽  
Green Peach Aphid ◽  
Plant Viruses ◽  
Sieve Element ◽  
Transmission Mechanisms ◽  
Probing Behavior ◽  
Epg Technique ◽  
Electrical Penetration Graphs ◽  
Beet Yellows Virus ◽  
Feeding Process

The green peach aphid Myzus persicae Sulzer is the main vector of the semipersistently transmitted and phloem-limited Beet yellows virus (BYV, Closterovirus). Studies monitoring the M. persicae probing behavior by using the Electrical penetration graphs (EPG) technique revealed that inoculation of BYV occurs during unique brief intracellular punctures (phloem-pds) produced in companion and/or sieve element cells. Intracellular stylet punctures (or pds) are subdivided in three subphases (II-1, II-2 and II-3), which have been related to the delivery or uptake of non-phloem limited viruses transmitted in a non-persistent or semipersistent manner. As opposed to non-phloem limited viruses, the specific pd subphase(s) involved in the successful delivery of phloem limited viruses by aphids remain unknown. Therefore, we monitored the feeding process of BYV-carrying M. persicae individuals in sugar beet plants by the EPG technique and the feeding process was artificially terminated at each phloem-pd subphase. Results revealed that aphids that only performed the subphase II-1 of the phloem-pd transmitted BYV at similar efficiency than those allowed to perform subphase II-2 or the complete phloem-pd. This result suggests that BYV inoculation occurs during the first subphase of the phloem-pd. The specific transmission mechanisms involved in BYV delivery in phloem cells are discussed.

scholarly journals Studies on the transmission of sugar-beet yellows virus by the aphis, Myzus persicae (Sulz.)

1940 ◽  
Vol 128 (853) ◽  
pp. 535-552 ◽  
Keyword(s):  
Sugar Beet ◽  
Myzus Persicae ◽  
Plant Viruses ◽  
Insect Vectors ◽  
Source Of Infection ◽  
Persistent Viruses ◽  
Beet Yellows Virus ◽  
The Relationship

Previous studies on the relationship between plant viruses and their insect vectors have been carried out which viruses which are easily mechanically transmissible and whose vectors lose their infectivity within a few hours of removal from the source of infection. This type of virus has been called (Watson and Roberts 1939) non-persistent , for it was observed that the property in which viruses of this type resemble each other, and differ from those viruses whose vectors retain their infectivity for long periods, namely, the persistent viruses. It seems that these differences must lie in the nature of the viruses themselves, for viruses of both types can be transmitted by the same vector. Sugar-beet yellows virus (Petherbridge and Stirrup 1935) seems to be a member of the persistent class, for its vector, Myzus persicae , the same insect as was used in previous work on non-persistent viruses (Watson 1936, 1938; Watson and Roberts 1939), remains infective for several days after removal from the source of infection (Roland 1939). Also it is not transmissible mechanically by any of the usual methods (Quanjer 1934, 1936). The present paper, therefore, describes some studies on the vector-virus relationships of this virus by the methods which have been used previously only on the non-persistent types.

scholarly journals Aphid endosymbiont facilitates virus transmission by modulating the volatile profile of host plants

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiao-Bin Shi ◽  
Shuo Yan ◽  
Chi Zhang ◽  
Li-Min Zheng ◽  
Zhan-Hong Zhang ◽  
...  
Keyword(s):  
Host Plants ◽  
Green Peach Aphid ◽  
Virus Transmission ◽  
Feeding Preference ◽  
Plant Viruses ◽  
Volatile Profile ◽  
Cmv Infection ◽  
Buchnera Aphidicola ◽  
Plant Volatile ◽  
Volatile Profiles

Abstract Background Most plant viruses rely on vectors for their transmission and spread. One of the outstanding biological questions concerning the vector-pathogen-symbiont multi-trophic interactions is the potential involvement of vector symbionts in the virus transmission process. Here, we used a multi-factorial system containing a non-persistent plant virus, cucumber mosaic virus (CMV), its primary vector, green peach aphid, Myzus persicae, and the obligate endosymbiont, Buchnera aphidicola to explore this uncharted territory. Results Based on our preliminary research, we hypothesized that aphid endosymbiont B. aphidicola can facilitate CMV transmission by modulating plant volatile profiles. Gene expression analyses demonstrated that CMV infection reduced B. aphidicola abundance in M. persicae, in which lower abundance of B. aphidicola was associated with a preference shift in aphids from infected to healthy plants. Volatile profile analyses confirmed that feeding by aphids with lower B. aphidicola titers reduced the production of attractants, while increased the emission of deterrents. As a result, M. persicae changed their feeding preference from infected to healthy plants. Conclusions We conclude that CMV infection reduces the B. aphidicola abundance in M. persicae. When viruliferous aphids feed on host plants, dynamic changes in obligate symbionts lead to a shift in plant volatiles from attraction to avoidance, thereby switching insect vector’s feeding preference from infected to healthy plants.

scholarly journals Probing behavior of Dysmicoccus brevipes mealybug in pineapple plants1

2016 ◽  
Vol 46 (4) ◽  
pp. 458-463
Author(s):  
Lenira Viana Costa Santa-Cecília ◽  
◽  
Ernesto Prado ◽  
Brígida Souza ◽  
Keyword(s):  
Insect Vector ◽  
Recording Time ◽  
Defense Strategies ◽  
Phenolic Contents ◽  
Probing Behavior ◽  
Epg Technique ◽  
Dysmicoccus Brevipes ◽  
Mealybug Wilt ◽  
Pineapple Mealybug Wilt ◽  
Pineapple Mealybug

ABSTRACT Differences in susceptibility to viruses in plants may be partially explained by the insect vector probing behavior and by the presence of phenolic compounds, which are often associated with defense strategies. This study aimed at detecting barriers that may difficult the probing activity of the Dysmicoccus brevipes (Pseudococcidae) pineapple mealybug, a vector of the pineapple mealybug wilt-associated virus, as well as evaluating the phenolic content of plants, in order to verify any possible relationship with the probing behavior, by using the electrical penetration graphs (EPG) technique. Seedlings of 'Smooth Cayenne' and 'Pérola' pineapple cultivars were used in the experiments. Only 28 % and 21 % of the mealybugs reached the phloem of the 'Smooth Cayenne' and 'Pérola' cultivars, respectively, over 16 h of recording, with an average of 9 h to reach the phloem vessels. The xylem phase was extended in both cultivars and represented approximately 31 % ('Smooth Cayenne') and 44 % ('Pérola') of the recording time. The phenolic contents of both cultivars were similar.

The effect of plant spacing, nitrogen fertilizer and irrigation on the appearance of symptoms and spread of virus yellows in sugar-beet crops

1974 ◽  
Vol 82 (1) ◽  
pp. 53-60 ◽  
Author(s):  
G. D. Heathcote
Keyword(s):  
Sugar Beet ◽  
Plant Density ◽  
N Fertilizer ◽  
Growth And Yield ◽  
Plant Spacing ◽  
Virus Diseases ◽  
Potential Yield ◽  
Virus Incidence ◽  
Beet Yellows Virus ◽  
Yellowing Virus

SUMMARYSatisfactory comparisons of the incidence of virus yellows in sugar-beet fields or experimental plots with different amounts of N fertilizer can be made from visual symptoms early in the growing season, but not later because dressings of N fertilizer may then mask or delay the appearance of symptoms. Sugar-beet plants in the field infected with beet mild yellowing virus (BMYV) are less likely to show symptoms than those with beet yellows virus (BYV), and plants with BMYV in the glasshouse often fail to show clear symptoms.Crop yield will be affected by the spread of viruses and colonization of plants by aphids, which in turn are affected by such factors as plant density, nitrogen supply and irrigation. The presence or absence of virus diseases and of aphids should therefore be considered during studies on the effects of these agronomic factors on the growth and yield of sugar beet. Where ample rather than little N fertilizer is used a small increase in the percentage of plants infected with yellows can be expected, and aphids will be more numerous, if plants are not treated with insecticide. Irrigation may also increase yellows incidence (e.g. from 16% to 20% of plants at Broom's Barn in 1967), but any loss of potential yield from increased virus incidence will be small compared with that gained from the use of fertilizer or irrigation. However, plant density can appreciably affect yellows incidence. For example, at Broom's Barn in 1972, 51% of plants in crops with 17500 plants/ha contracted BMYV but only 15 % of plants in crops with 126500 plants/ha. The less dense crop lost 3–4% more of its potential yield due to yellows than the dense crop; this represents a difference due to virus of about 0·25 t sugar/ha.

Some notes on the relationship of plant viruses with vector and non-vector insects

Parasitology ◽  
1941 ◽  
Vol 33 (1) ◽  
pp. 110-116 ◽  
Author(s):  
Kenneth M. Smith
Keyword(s):  
Sugar Beet ◽  
Experimental Evidence ◽  
Plant Viruses ◽  
Artificial Feeding ◽  
The Body ◽  
The Other ◽  
Insect Vector ◽  
Feeding Methods ◽  
Relationship Of ◽  
The Relationship

Extracts of caterpillars and other insects are shown to inhibit the infective power of tobacco mosaic and tobacco necrosis viruses. The inhibitor is not sedimented after spinning for 2½ hr. at 30,000 r.p.m. Experiments with non-vector insects such as caterpillars have shown that the virus of sugar-beet curly-top, of tobacco ringspot and other viruses, are destroyed within the body of the insect. On the other hand, tobacco mosaic virus passes through the body of the caterpillar unchanged though greatly reduced in concentration. By the use of the specific insect vector and artificial feeding methods it was possible to recover the virus of curly-top 24 hr. after it had been injected into the blood of the caterpillar but the viruses of tobacco mosaic and tobacco necrosis could not be so recovered. Experimental evidence is given to show that the virus of beet curly-top is present in the saliva of viruliferous insects.

Über die Korrelation zwischen Partikellänge und Infektiosität beim Vergilbungsvirus der Rüben

1958 ◽  
Vol 13 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Karl-Wolfgang Mundry
Keyword(s):  
Sugar Beet ◽  
Room Temperature ◽  
Distribution Curve ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Infectious Agent ◽  
Minimal Length ◽  
Spherical Particles ◽  
Normal Length ◽  
Beet Yellows Virus

Crude leaf sap of plants suffering from sugar beet yellows was partially purified by density gradient centrifugation in the cold at different values of pʜ (6,2-9,0). After standing over night at 2° C the material was dialysed against buffer of pʜ 6,8 at room temperature. - As estimated by electron microscopy the most frequent length of the threadlike particles (Fig. 2) which were believed to be the infectious agent of sugar beet yellows shows a gradual shift from longer to shorter ones with rising pʜ (Fig. 1 a-e). The infectivity of the suspensions depends upon the pʜ of the preparation too. From the distribution curve of the particle lengths the relative concentrations of particles with different given minimal lengths were estimated. The dependence from the pʜ of the preparation of these relative concentrations was compared with that of the infectivity. Best agreement was observed with particles of 12 700 - 12 800 A minimal length (Fig. 3). This length seems to be identical with the “normal length” of the particles found in exsudates (12 400 -12 500 A). From these results it was concluded that a) particles which possess the normal length as found in exsudates are the infective entities of this disease, b) shorter particles are non-infectious, c) the infectious entities of the sugar beet yellows virus are of the threadlike type. There is no evidence that spherical particles are necessary for starting an infection with the sugar beet yellows virus.

scholarly journals Citrus tristeza virus P33 Protein Is Required for Efficient Transmission by the Aphid Aphis (Toxoptera) citricidus (Kirkaldy)

Viruses ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1131
Author(s):  
Turksen Shilts ◽  
Choaa El-Mohtar ◽  
William O. Dawson ◽  
Nabil Killiny
Keyword(s):  
Citrus Tristeza Virus ◽  
Transmission Rate ◽  
Control Strategies ◽  
Virus Transmission ◽  
Plant Viruses ◽  
Transmission Mechanisms ◽  
Infectious Clones ◽  
Underlying Mechanisms ◽  
Tristeza Virus ◽  
Citrus Tristeza

Plant viruses are threatening many valuable crops, and Citrus tristeza virus (CTV) is considered one of the most economically important plant viruses. CTV has destroyed millions of citrus trees in many regions of the world. Consequently, understanding of the transmission mechanism of CTV by its main vector, the brown citrus aphid, Aphis (Toxoptera) citricidus (Kirkaldy), may lead to better control strategies for CTV. The objective of this study was to understand the CTV–vector relationship by exploring the influence of viral genetic diversity on virus transmission. We built several infectious clones with different 5′-proximal ends from different CTV strains and assessed their transmission by the brown citrus aphid. Replacement of the 5′- end of the T36 isolate with that of the T30 strain (poorly transmitted) did not increase the transmission rate of T36, whereas replacement with that of the T68-1 isolate (highly transmitted) increased the transmission rate of T36 from 1.5 to 23%. Finally, substitution of p33 gene of the T36 strain with that of T68 increased the transmission rate from 1.5% to 17.8%. Although the underlying mechanisms that regulate the CTV transmission process by aphids have been explored in many ways, the roles of specific viral proteins are still not explicit. Our findings will improve our understanding of the transmission mechanisms of CTV by its aphid vector and may lead to the development of control strategies that interfere with its transmission by vector.

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