Study Reveals Similarities and Differences in How Tomato Plants Recognize Fungal Pathogens Through Cf-4 and Cf-5 Proteins
Researchers compared the immune responses triggered by two tomato receptor-like proteins, Cf-4 and Cf-5, which recognize fungal effectors from the pathogen Fulvia fulva. While Cf-4 triggers faster and stronger cell death than Cf-5, both receptors rely on the same core upstream signaling components and ultimately confer comparable resistance to the fungus. The findings suggest that the intensity and timing of immune cell death responses do not determine the overall robustness of plant resistance.
A study posted to bioRxiv examined the molecular similarities and differences between two tomato (Solanum lycopersicum) receptor-like proteins, Cf-4 and Cf-5, which mediate resistance against the fungal pathogen Fulvia fulva by recognizing its secreted effectors Avr4 and Avr5, respectively. Although Cf-4 is known to trigger a stronger and faster hypersensitive response (HR)-related cell death than Cf-5, both receptors were found to share the same core upstream signaling components in Nicotiana benthamiana. In tomato, both receptors induced rapid MAPK activation, though this activation was more sustained in the Cf-5/Avr5 combination. Both Avr4 and Avr5 independently triggered an apoplastic burst of reactive oxygen species (ROS), with both bursts dependent on the enzyme RBOHB. Full transcriptome analysis at 3 and 7 hours post-activation revealed a large shared set of differentially expressed genes, but also qualitative and quantitative differences, with Cf-5/Avr5 inducing broader transcriptional reprogramming. Despite these downstream signaling divergences, Cf-4 and Cf-5 conferred equivalent levels of resistance to F. fulva, indicating that variation in HR cell death dynamics does not translate into differences in resistance robustness.
What's missing
As a preprint, this study has not yet undergone formal peer review, and its findings should be interpreted with caution. The study does not address whether the observed signaling differences between Cf-4 and Cf-5 have functional consequences under field conditions or across different tomato cultivars.
What different sources said
- bioRxivCenter
Cf-4- and Cf-5-triggered plant immunity: Similarities and differences
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