Rhizomania: Hide and Seek of Polymyxa betae and the Beet Necrotic Yellow Vein Virus with Beta vulgaris

Alain Decroës, Mathieu Mahillon, Margaux Genard, Charlotte Lienard, Gipsi Lima-Mendez, David Gilmer, Claude Bragard, Anne Legrève

Research output: Contribution to journalArticlepeer-review


The molecular interactions between Polymyxa betae, the protist vector of sugar beet viruses, beet necrotic yellow vein virus (BNYVV), the causal agent of rhizomania, and Beta vulgaris have not been extensively studied. Here, the transmission of BNYVV to sugar beet by P. betae zoospores was optimized using genetically characterized organisms. Molecular interactions of aviruliferous and viruliferous protist infection on sugar beet were highlighted by transcriptomic analysis. P. betae alone induced limited gene expression changes in sugar beet, as a biotrophic asymptomatic parasite.Most differentially expressed plant genes were down-regulated and included resistance gene analogs and cell wall peroxidases. Several enzymes involved in stress regulation, such as the glutathione-Stransferases, were significantly induced.With BNYVV, the first stages of the P. betae life cycle on sugar beet were accelerated with a faster increase of relative protistDNAlevel and an earlier appearance of sporangia and sporosori in plants roots. A clear activation of plant defenses and themodulation of genes involved in plant cell wall metabolism were observed. The P. betae transcriptome in the presence ofBNYVVrevealed induction of genes possibly involved in the switch to the survival stage. The interactions were different depending on the presence or absence of the virus. P. betae alone alleviates plant defense response, playing hide-and-seek with sugar beet and allowing for their mutual development. Conversely, BNYVV manipulates plant defense and promotes the rapid invasion of plant roots by P. betae. This accelerated colonization is accompanied by the development of thick-walled resting spores, supporting the virus survival.

Original languageEnglish
Pages (from-to)989-1005
Number of pages17
JournalMolecular Plant-Microbe Interactions
Issue number11
Publication statusPublished - Nov 2022
Externally publishedYes


  • Beet necrotic yellow vein virus
  • Plasmodiophorida
  • Polymyxa betae
  • Rhizaria
  • RNA-seq
  • sugar beet
  • virus vector


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