Sequential breakdown of the complex Cf-9 leaf mould resistance locus in tomato by Fulvia fulva

作者：Silvia de la Rosa, Christiaan R. Schol, Ángeles Ramos Peregrina, David J. Winter, Anne M. Hilgers, Kazuya Maeda, Yuichiro Iida, Mariana Tarallo, Ruifang Jia, Henriek G. Beenen, Mercedes Rocafort, P.J.G.M. de Wit, Joanna K. Bowen, Rosie E. Bradshaw, M.H.A.J. Joosten, Yuling Bai, Carl H. Mesarich · 发表于：bioRxiv (Cold Spring Harbor Laboratory) · 年份：2023 · DOI：10.1101/2023.08.27.554972 · 被引用次数：3 · 研究领域：Plant-Microbe Interactions and Immunity、Plant Pathogenic Bacteria Studies、Legume Nitrogen Fixing Symbiosis

Summary Leaf mould, caused by Fulvia fulva , is a devastating disease of tomato plants. In many commercial tomato cultivars, resistance to this disease is governed by the Cf-9 locus, which comprises five paralogous genes ( Cf-9A–9E ) that encode receptor-like proteins. Two of these proteins contribute to resistance: Cf-9C recognizes the previously identified F. fulva effector Avr9 and provides resistance during all plant growth stages, while Cf-9B recognises the yet-unidentified F. fulva effector Avr9B and provides mature plant resistance only. In recent years, F. fulva strains have emerged that have overcome the Cf-9 locus, with Cf-9C circumvented through Avr9 deletion. To understand how Cf-9B is circumvented, we set out to identify Avr9B . Comparative genomics, in planta transient expression assays and gene complementation experiments were used to identify Avr9B , while gene sequencing was used to assess Avr9B allelic variation across a worldwide strain collection. A strict correlation between Avr9 deletion and resistance-breaking mutations in Avr9B was observed in strains recently collected from Cf-9 cultivars, whereas Avr9 deletion but no mutations in Avr9B were observed in older strains. This research showcases how F. fulva has evolved to sequentially break down the two functional resistance genes of the complex Cf-9 locus and highlights that this locus now has limited value for controlling leaf mould disease in worldwide commercial tomato production.