Viral multi-infections in sugar beet: impact on virus biology and transmission, and control methods

Objectives

In nature, the simultaneous presence of several viruses in the same plant is the rule rather than the exception. Within the plant, interactions between viruses can lead to synergistic or antagonistic mechanisms that can affect virus accumulation in plants and transmission by vectors. Multi-infections can also modify the cellular and subcellular localization of viruses. The mechanisms and molecular players involved in this dialogue between plant, virus and vector, which are implicated in transmission and virus-virus-plant-vector interactions, remain largely unknown and unexplored. Sugar beet is a fabulous model for the study of multi-infections, since in the field it can be infected by four viruses, all transmitted by aphids, and responsible for beet yellowing leading to significant yield losses. In the laboratory, we are seeking to determine the impact of viral multi-infections on sugar beet yield, on the accumulation and localization of viruses in plants, and their transmission by aphids. We are also attempting to identify the viral and cellular determinants responsible for the impact of multi-infections on virus biology. As the four viruses responsible for yellowing are acquired by aphids when they feed on sugar beet, we are also seeking to assess whether selecting sugar beets that are unpalatable to aphids could be a method for reducing virus transmission and the agronomic impact of yellowing.

• Yellows symptoms on sugar beet
• Electron microscopy of beet yellows virus (BYV)
• Aphids on artificial media for virus acquisition

APPROACHES AND RESOURCES

The four viruses at the heart of our studies, which are responsible for yellowing on sugar beet, are beet chlorosis virus (BChV), beet mild yellowing virus (BMYV), beet yellows virus (BYV) and beet mosaic virus (BtMV). These viruses, all transmitted by aphids, have different biologies (acquisition time, retention time, interaction with the vector, cellular localization in the host plant, etc.). We are deploying a whole series of experiments such as

• aphid transmission tests,
• cellular localization of viruses by in situ hybridization,
• evaluation of virus accumulation by RT-qPCR,
• study of gene deregulations in plants by RNA-seq,
• study of aphid feeding behavior by electro-penetrography on multi-infected plants,
• functional validation of identified cellular and viral candidates.

We are also studying the feeding behavior of aphids on different beet varieties to identify those that are least compatible with the acquisition and/or inoculation of viruses by aphids, to be able to propose a new control strategy against these viruses. These studies are completed by metabolic analyses to identify a metabolic signature of the most promising plants for reducing aphid virus transmission.

Staff, ViVe team

• Véronique BRAULT
• Quentin CHESNAIS
• Martin DRUCKER
• Anabella HEINTZ
• Souheyla KHECHMAR
• Alessandra MAIA-GRONDARD (GMV team)
• Gabin MARDOC
• Aurélie MARMONIER
• Hélène SCHLAEFLI
• Fanny SIFFERT
• Claire VILLEROY

Fundings

• PNRI Provibe [2021-2023]
• MODEFY [2021-2024]
• ANR MANIVIR (abstract) [2024-2027]
• ANR AGIR (abstract) [2024-2026]

Results

• Heintz A., Chesnais Q., Gutierez C., Maia-Grondard A., Drucker M., Brault V. (2023). Beet yellows virus infection of sugar beet promotes the performance of its aphid vector Myzus persicae. XII European Congress of Entomology (ECE 2023). Crete – Greece.
• Barreto L. C., Boisroux L., Brault V., Chesnais Q., Drucker M., Heintz A., Koehler M., Laudinat V., Malatesta G., Martinez-Arias R., Monteiro A., Otte S., Orsini E., Schechert A. (2023). MOnitoring and DEFence measures against Yellowing virus diseases in sugar beet. 78TH IIRB Congress. Mons – Belgium.