Communication Dans Un Congrès Année : 2024

Interplay between a polerovirus (BChV) and a closterovirus (BYV) infecting sugar beet

Résumé

Viral multi-infection is a very common phenomenon in plants that can change drastically infection parameters including transmission by insect vectors. Sugar beet is a crop frequently infected by several viruses, among them the phloem-restricted beet yellows virus (BYV, Closteroviridae) and beet chlorosis virus (BChV, Solemoviridae). Here we tested transmission of BYV and BChV by the green peach aphid (Myzus persicae) from co-infected sugar beet plants, a situation often found in the field. Co-infection decreased transmission of BChV by 50 %, but had no impact on BYV transmission. RT-qPCR analysis showed a slight decrease in accumulation of BChV in co-infected plants, indicating that lower virus accumulation might be responsible for decreased BChV transmission. Virus localisation experiments by fluorescent in situ hybridization (SABER-FISH) showed that in mono-infected plants BChV and BYV were only detected in the phloem, as expected for phloem-restricted viruses. Co-infection did not result in phloem escape of either virus. In coinfected plants, BYV and BChV colocalised in ~40 % of infected phloem cells, ~20 % of the remaining infected cells were mono-infected with BChV and ~40 % were mono-infected with BYV. BChV and BYV were detected in the phloem of the leaf midribs and the phloem of lower order vessels in mono-infected plants. In contrast, BChV was mainly restricted to the leaf midrib phloem in co-infected plants and BYV accumulated preferentially in the phloem of secondary and lower order vessels. Observation of aphids indicated that they preferred to settle and feed on lower order vessels rather than on midribs of sugar beet leaves. Thus, the differential tissue localisation of BChV in mono-infected and co-infected plants might explain the lower transmission rates of BChV from co-infected plants. Aphid feeding behaviour experiments by EPG showed that BYV mono-infection increased dramatically sap ingestion duration compared to BChV mono-infected, co-infected and healthy plants. We are currently doing transcriptomics to better understand how co-infection lowers BChV transmission, causes relocalisation of BChV and BYV.

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Dates et versions

hal-04753504 , version 1 (25-10-2024)

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  • HAL Id : hal-04753504 , version 1

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Souheyla Khechmar, Véronique Brault, M. Drucker. Interplay between a polerovirus (BChV) and a closterovirus (BYV) infecting sugar beet. 56th meeting of the DPG Working Group “VIRUSKRANKHEITEN DER PFLANZEN“, DPG, Mar 2024, Neustadt an der Weinstrasse, Germany. ⟨hal-04753504⟩
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