Development of Aster Yellows on Crop and Noncrop Species from the Canadian Prairies

Abstract

Aster yellows phytoplasmas (AYp) are a group of obligate parasites that infect a wide range of plant species, including crops such as canola and cereals and noncrops such as dandelion and wild mustard. In the Canadian Prairies, these microorganisms are mainly transmitted by a migratory species of leafhopper (Macrosteles quadrilineatus Forbes). Although a low incidence of the disease associated with this pathogen has been reported for most years in canola fields, several outbreaks have been documented in this region. A selection of crop and noncrop species commonly found in the Canadian Prairies and Arabidopsis thaliana were used to assess the suitability of these plant species as hosts for AYp (16SrI-B). Symptom expression and phytoplasma levels were examined at different time points following exposure to infective insects. A. thaliana, barley, and canola were susceptible to infection with AYp, yet symptoms differed among these plant species. A. thaliana and canola exhibited symptoms of infection as early as 2 weeks following exposure to infected insects, whereas symptoms in barley were observed at 5 weeks. A lower incidence rate was observed in wheat, and levels of AYp in phytoplasma-infected wheat plants were low. Dandelion and sowthistle tested negative for the presence of AYp at all time points, suggesting that these are unsuitable hosts for these microorganisms. Moreover, we observed a partial disassociation between the plant species that were suitable hosts for AYp and those that had been characterized as more suitable or suitable hosts for aster leafhopper oviposition and nymphal development in previous studies. [Figure: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Keywords

• aster yellows
• disease development
• Macrosteles quadrilineatus
• phytoplasmas
• plant-host interaction