Sequential breakdown of the Cf-9 leaf mould resistance locus in tomato by Fulvia fulva.
New Phytol
; 243(4): 1522-1538, 2024 Aug.
Article
in En
| MEDLINE
| ID: mdl-38922927
ABSTRACT
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 encodes five paralogous receptor-like proteins. Two of these proteins confer resistance Cf-9C recognises 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 can 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, transient expression assays and gene complementation experiments were used to identify Avr9B, while gene sequencing was used to assess Avr9B allelic variation across a world-wide 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 Cf-9 locus and stresses the urgent need for commercial tomato cultivars that carry novel, stacked resistance genes active against this pathogen.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Plant Diseases
/
Solanum lycopersicum
/
Plant Leaves
/
Disease Resistance
Language:
En
Journal:
New Phytol
/
New phytol. (Online)
/
New phytologist (Online)
Journal subject:
BOTANICA
Year:
2024
Type:
Article
Affiliation country:
New Zealand