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11. Host Plant Adaptation Drives Changes inDiaphorina citriProteome Regulation, Proteoform Expression, and Transmission of ‘CandidatusLiberibacter asiaticus’, the Citrus Greening Pathogen

Author

Ramsey, John S., primary, Ammar, El-Desouky, additional, Mahoney, Jaclyn E., additional, Rivera, Keith, additional, Johnson, Richard, additional, Igwe, David O., additional, Thannhauser, Theodore W., additional, MacCoss, Michael J., additional, Hall, David G., additional, and Heck, Michelle, additional

Published
2022
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18. Host Plant Adaptation Drives Changes in Diaphorina citri Proteome Regulation, Proteoform Expression, and Transmission of 'Candidatus Liberibacter asiaticus', the Citrus Greening Pathogen.

Author

Ramsey, John S., Ammar, El-Desouky, Mahoney, Jaclyn E., Rivera, Keith, Johnson, Richard, Igwe, David O., Thannhauser, Theodore W., MacCoss, Michael J., Hall, David G., and Heck, Michelle

Subjects
*CITRUS greening disease, *CANDIDATUS liberibacter asiaticus, *HOST plants, *PLANT adaptation, *CITRUS, *PROTEIN expression
Abstract

The Asian citrus psyllid (Diaphorina citri) is a pest of citrus and the primary insect vector of the bacterial pathogen, ‘Candidatus Liberibacter asiaticus’ (CLas), which is associated with citrus greening disease. The citrus relative Murraya paniculata (orange jasmine) is a host plant of D. citri but is more resistant to CLas compared with all tested Citrus genotypes. The effect of host switching of D. citri between Citrus medica (citron) and M. paniculata plants on the acquisition and transmission of CLas was investigated. The psyllid CLas titer and the proportion of CLas-infected psyllids decreased in the generations after transfer from CLas-infected citron to healthy M. paniculata plants. Furthermore, after several generations of feeding on M. paniculata, pathogen acquisition (20 to 40% reduction) and transmission rates (15 to 20% reduction) in psyllids transferred to CLas-infected citron were reduced compared with psyllids continually maintained on infected citron. Top-down (difference gel electrophoresis) and bottom-up (shotgun MS/MS) proteomics methods were used to identify changes in D. citri protein expression resulting from host plant switching between Citrus macrophylla and M. paniculata. Changes in expression of insect metabolism, immunity, and cytoskeleton proteins were associated with host plant switching. Both transient and sustained feeding on M. paniculata induced distinct patterns of protein expression in D. citri compared with psyllids reared on C. macrophylla. The results point to complex interactions that affect vector competence and may lead to strategies to control the spread of citrus greening disease. [ABSTRACT FROM AUTHOR]

Published
2022
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31. Epifluorescence and stereomicroscopy of trichomes associated with resistant and susceptible host plant genotypes of the Asian citrus psyllid (Hemiptera: Liviidae), vector of citrus greening disease bacterium

Author

Hall, David G., Ammar, El-Desouky, Bowman, Kim D., and Stover, Ed

Abstract

Foliar trichomes (tiny hair-like structures) are part of the plant defense mechanisms that may confer resistance to some herbivore pests. Trifoliate orange, Poncirus trifoliata, is a genotype resistant to infestations by the Asian citrus psyllid, Diaphorina citri(Hemiptera: Liviidae), vector of the economically important citrus greening (huanglongbing) disease bacterium. We discovered that dense trichomes are associated with young leaves of trifoliate orange plants and hypothesized that these might be responsible for reduced infestation by this psyllid. Thus, epifluorescence and stereomicroscopy were used to study the density and structure of trichomes associated with young flush leaves and stems of trifoliate orange as well as five other plant genotypes that are highly susceptible to colonization by the psyllid: lemon, grapefruit, sweet orange, curry leaf and orange jasmine. Simple unicellular trichomes were observed at moderate to large densities on young leaves and stems of each genotype except lemon and sweet orange, which had considerably fewer trichomes. Trichomes were generally abundant on young leaves of curry leaf and orange jasmine, two genotypes that are often heavily colonized by the psyllid. Although we did not quantify oviposition rates on these genotypes, we observed that psyllid females deposited eggs on young leaves, buds and stems regardless of the density of trichomes present, sometimes directly within or close to a dense bed of trichomes. While trichomes were abundant on young leaves and stems of trifoliate orange, our results strongly suggest that these trichomes may play little or no role in reduced colonization by the psyllid on this genotype.

Published
2024
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36. Large accumulations of Maize streak virus in epithelial cells of the filter chamber of the leafhopper vector Cicadulina mbila

Author

Ammar, El-Desouky, Gargani, Daniel, Lett, Jean-Michel, and Peterschmitt, Michel

Subjects
endocrine system, Géminivirus striure du maïs, viruses, Virus des végétaux, Cicadulina, Vecteur de maladie, neoplasms, Transmission des maladies, H20 - Maladies des plantes
Abstract

Maize streak virus (MSV), family Geminiviridae, genus Mastrevirus, is transmitted in a persistent, circulative manner by several leafhoppers, mainly Cicadulina mbila. Although no evidence is available to support MSV multiplication in its vector, MSV is usually retained through the life of the leafhopper vector. Furthermore, MSV concentration usually increases during sustained feeding of leafhoppers on MSV infected maize, unlike Tomato yellow leaf curl virus for which the accumulation was shown to be limited in its whitefly vector. These observations suggest that MSV is efficiently accumulated in the insect body for an extended period during the vector's lifespan. Spatial distribution of MSV within C. mbila monitored with quantitative polymerase chain reaction (Lett et al., 2002, Phytopathology 92:65-74), showed that MSV is mainly stored in the intestinal tract. Using thin-sectioning electron microscopy (TEM) of leafhoppers that acquired MSV for 14 or 30 days from diseased maize plants, crystalline arrays of MSV-like particles were found in the cytoplasm of epithelial cells of the filter chamber in its vector C. mbila. These viruslike arrays were identified as MSV particles since they reacted with MSV antibodies by immunogold labeling of thin sections. These cytoplasmic MSV accumulations in the leafhopper were somewhat similar to those detected in the nuclei of infected plants also by gold-labeling TEM. In osmium-fixed samples, some MSV accumulations in the midgut epithelium seemed to be bound by membranes. These crystalline arrays were not detected in control leafhoppers that were not exposed to infected plants. The significance of these observations in understanding the mode of MSV transmission by leafhoppers will be discussed. (Texte intégral)

Published
2003

37. Evidence for multiplication of the leafhopper-borne maize yellow stripe tenui-like virus in its vector and suggestion of a new genus for tenuiviruses

Author

Ammar, El-Desouky, Mahmoud, Amal, Khlifa, Elham, Granier, Martine, and Peterschmitt, Michel

Subjects
Géminivirus striure du maïs, Virus des végétaux, H10 - Ravageurs des plantes, Vecteur de maladie, Tenuivirus, Insecte nuisible, H20 - Maladies des plantes, Delphacidae
Abstract

Maize yellow stripe virus (MYSV), found on maize, sorghum and wheat plants in Egypt, causing serious losses in late sown maize, has several features in common with tenuiviruses, but is transmitted by a cicadellid leafhopper rather than delphacid planthoppers. Since tenuiviruses are known to multiply in their vectors, multiplication of MYSV in its vector Cicadulina chinai, following an acquisition access period (AAP) of 1-3 days on infected plants, was studied by two basically different methodologies. Using dot blot hybridisation analysis, that detects viral RNA, MYSV was not detected in leafhoppers one day following a 2-day AAP, but was detected in single or groups of leafhoppers 5-20 days post-acquisition. Additionally, using DAC-ELISA assays of capsid protein in single leafhoppers that had a Ior 3-day AAP, MYSV titer, as indicated by ELISA absorbence values, increased gradually and significantly in vector leafhoppers reaching its highest levels 8-14 days post-acquisition. Transovarial transmission of MYSV was not detected in 600 C. chinai nymphs that hatched from eggs laid by MYSV infective mothers. The above results indicate that, like tenuiviruses, MYSV is propagative in its vector; but unlike most tenuiviruses, MYSV apparently is not efficiently transmitted transovarially through the vector. Based on various differences and similarities between MYSV and tenuiviruses, we suggest that MYSV is the type member of a new genus "Cicatenuivirus" (transmitted by Cicadellidae), within a family "Tenuiviridae" that includes the present Delphacid transmitted tenuiviruses in another genus. (Texte intégral)

Published
2003

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