A protocol for increased throughput phenotyping of plant resistance to the pollen beetle.

Abstract

Background Improving crop resistance to insect herbivores is a major research objective in breeding programs. Although genomic technologies have increased the speed at which large populations can be genotyped, breeding programs still suffer from phenotyping constraints. The pollen beetle (Brassicogethes aeneus) is a major pest of oilseed rape for which no resistant cultivar is available to date, but previous studies have highlighted the potential of white mustard as a source of resistance and introgression of this resistance appears to be a promising strategy. Here we present a phenotyping protocol allowing mid-throughput (i.e., increased throughput compared to current methods) acquisition of resistance data, which could then be used for genetic mapping of QTLs. Results Contrasted white mustard genotypes were selected from an initial field screening and then evaluated for their resistance under controlled conditions using a standard phenotyping method on entire plants. We then upgraded this protocol for mid-throughput phenotyping, by testing two alternative methods. We found that phenotyping on detached buds did not provide the same resistance contrasts as observed with the standard protocol, in contrast to the phenotyping protocol with miniaturized plants. This protocol was then tested on a large panel composed of hundreds of plants. A significant variation in resistance among genotypes was observed, which validates the large-scale application of this new phenotyping protocol. Conclusion The combination of this mid-throughput phenotyping protocol and white mustard as a source of resistance against the pollen beetle offers a promising avenue for breeding programs aiming to improve oilseed rape resistance. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Plant phenotyping relevance

植物の害虫抵抗性を取得する中スループット表現型プロトコルを開発し、代替法との比較検証と大規模適用まで行っており、表現型取得法が研究の中心である。

Code and data availability

The paper's pollen-beetle resistance phenotyping data (feeding damage on white mustard and OSR genotypes across whole-plant, miniaturized-plant, and detached-bud protocols) are openly deposited on Figshare per the authors' data availability statement.