101. Secreted in Xylem 6 ( SIX6 ) Mediates Fusarium oxysporum f. sp. fragariae Race 1 Avirulence on FW1 -Resistant Strawberry Cultivars.
- Author
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Dilla-Ermita CJ, Goldman P, Anchieta A, Feldmann MJ, Pincot DDA, Famula RA, Vachev M, Cole GS, Knapp SJ, Klosterman SJ, and Henry PM
- Subjects
- Virulence, Fungal Proteins genetics, Fungal Proteins metabolism, Plant Proteins genetics, Plant Proteins metabolism, Xylem microbiology, Fusarium pathogenicity, Fusarium genetics, Plant Diseases microbiology, Fragaria microbiology, Disease Resistance genetics
- Abstract
Fusarium oxysporum f. sp. fragariae ( Fof ) race 1 is avirulent on cultivars with the dominant resistance gene FW1 , while Fof race 2 is virulent on FW1 -resistant cultivars. We hypothesized there was a gene-for-gene interaction between a gene at the FW1 locus and an avirulence gene ( AvrFW1 ) in Fof race 1. To identify a candidate AvrFW1 , we compared genomes of 24 Fof race 1 and three Fof race 2 isolates. We found one candidate gene that was present in race 1, was absent in race 2, was highly expressed in planta, and was homologous to a known effector, secreted in xylem 6 ( SIX6 ). We knocked out SIX6 in two Fof race 1 isolates by homologous recombination. All SIX6 knockout transformants (Δ SIX6 ) gained virulence on FW1/fw1 cultivars, whereas ectopic transformants and the wildtype isolates remained avirulent. Δ SIX6 isolates were quantitatively less virulent on FW1/fw1 cultivars Fronteras and San Andreas than fw1/fw1 cultivars. Seedlings from an FW1/fw1 × fw1/fw1 population were genotyped for FW1 and tested for susceptibility to a SIX6 knockout isolate. Results suggested that additional minor-effect quantitative resistance genes could be present at the FW1 locus. This work demonstrates that SIX6 acts as an avirulence factor interacting with a resistance gene at the FW1 locus. The identification of AvrFW1 enables surveillance for Fof race 2 and provides insight into the mechanisms of FW1- mediated resistance. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license., Competing Interests: The author(s) declare no conflict of interest.
- Published
- 2024
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