Virus yellows of sugar beet – exploring pathogen diversity and host resistance : groundwork for resistance breeding

Abstract

Sugar beet (Beta vulgaris ssp. vulgaris) is a crop primarily cultivated in temperate regions of the world for its high content of sucrose stored in the tap root, which is processed to obtain sugar. The yielding capacity of the crop is threatened by several biotic stresses with virus yellows (VY) being among the viral diseases causing significant yield losses. In Europe, VY is caused by beet mild yellowing virus (BMYV), beet chlorosis virus (BChV) and beet yellows virus (BYV). The main vectors for these viruses are the green peach aphid and the black bean aphid. Insecttransmitted diseases are on rise due to climate change and pose a large threat. We explored the diversity of viruses causing VY in Swedish sugar beet and the incidence of turnip yellows virus (TuYV) in oilseed rape with samples collected from different parts of Sweden in the year 2019. The analyses revealed mixed infections of BMYV and BChV in most of the sugar beet samples and two samples had a triple infection together with TuYV. The survey in oilseed rape revealed a high TuYV incidence with an average infection rate of 75% in the counties of Skåne, Kalmar and Östergötland. With the ban of neonicotinoid chemicals used for managing aphid vectors, there is a greater need for developing resistant or tolerant cultivars as a sustainable alternative. In this study, our aim was also to gain more insights into BMYV – host interactions using transcriptomics and a BMYV-resistant genotype of wild beet in comparison to a susceptible genotype of sugar beet. Virus quantification by RT-qPCR revealed that the wild beet was partially resistant. In the susceptible genotype, a large number of genes were differentially expressed as a response to BMYV infection, while the transcriptomic response of resistant plants was weaker. In the resistant genotype, the differentially expressed genes included seven significantly upregulated genes, which encoded proteins involved in protein processing in the endoplasmic reticulum (ER). This could be one of the mechanisms contributing to the ability of the wild beet genotype to manage ER stress induced by BMYV infection and to reduce the virus level. To identify genomic regions associated with symptom development and BMYV titre, QTLseq and QTL mapping were carried out using F2, S1 and S2 populations of wild beet × sugar beet. These Virus yellows of sugar beet – exploring pathogen diversity and host resistance: Groundwork for resistance breeding studies showed that not a single gene was responsible for the responses to BMYV and reduced virus titre, but rather that these traits are governed by multiple loci with minor effects. One significant QTL was identified on chromosome 1 that was linked to reduced virus titre in leaves and explaining 16.7% variation in the trait. Overall, these results would lay a strong foundation for resistance breeding against VY disease in sugar beet.

Keywords

BMYV; genetic mapping; QTLs; sugar beet; transcriptomics; TuYV; virus yellows; wild beet

Published in

Acta Universitatis Agriculturae Sueciae
2025, number: 2025:2
Publisher: Swedish University of Agricultural Sciences

SLU Authors

• Puthanveed, Vinitha

  • Department of Plant Biology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Botany
Genetics and Breeding

Publication identifier

• DOI: https://doi.org/10.54612/a.aru8g37tkj
• ISBN: 978-91-8046-437-6
• eISBN: 978-91-8046-487-1

Permanent link to this page (URI)

https://res.slu.se/id/publ/132942