2024/12/18 by Ayesha Yousaf, Pierre Baldi, Stefano Piazza +5 · 1 voice
Agricultural and Biological Sciences · #Plant Pathogenic Bacteria Studies #Plant Disease Resistance and Genetics #Plant Virus Research Studies
paper · pdf · doi:10.1111/tpj.17214
openalex publication_date 2024/12/18 · openalex created_date 2024/12/19 · openalex updated_date 2026/08/04
To enhance the breeding of new scab-resistant apple cultivars, a comprehensive understanding of the mechanisms governing major scab resistance genes is essential. Rvi12Cd5 was previously identified as the best candidate gene for the Rvi12 scab resistance of the crab apple "Hansen's baccata #2" by gene prediction and in silico analysis. In the present study, Rvi12Cd5 was used to transform the scab-susceptible apple cultivar "Gala Galaxy." Two constructs were prepared: the first carrying Rvi12Cd5 under the control of a 35S promoter and E9 terminator, and the second carrying Rvi12Cd5 under the control of its native promoter and terminator. All the transgenic lines were analyzed for T-DNA integration, copy number, and expression of Rvi12Cd5 and phenotypically evaluated for scab resistance. The "Gala Galaxy" lines carrying the 35S promoter expressed Rvi12Cd5 at a high level, showing partial to high resistance against a mixed inoculum of Venturia inaequalis, with symptoms ranging from class 0 to 3b on the Chevalier scale. The transgenic lines carrying the native promoter showed a lower expression of Rvi12Cd5 compared with the 35S lines. Nevertheless, the low expression was sufficient to induce a resistance level comparable to that of the transgenic lines carrying the 35S promoter. These results indicate that Rvi12Cd5 confers scab resistance to a susceptible apple cultivar and that even a low level of gene transcript can trigger a plant response to V. inaequalis infection. After HcrVf2 and Vr2-C, Rvi12Cd5 is the third major apple scab resistance gene being functionally proven.