Resistance and tolerance to herbivory vary among accessions of Arabidopsis thaliana

Background/Question/Methods

Plant defence against herbivores includes traits that reduce the amount of damage suffered (resistance) and those that diminish the loss of fitness due to the removal of tissue by herbivores (tolerance). If both kinds of traits are costly, and overlap in function substantially, plants should be resistant or tolerant, but not both. While the mechanisms and costs of resistance are well studied, that is not the case for tolerance. To further understand the mechanisms and costs of tolerance and its relationship with resistance, we subjected ten genetic families of the model plant Arabidopsis thaliana (L.) Heynh. to leaf herbivory using insect larva of Trichoplusia ni (Hubner).

Results/Conclusions

We found more variation in tolerance than in constitutive resistance among accessions, and no evidence of a negative relationship between resistance and tolerance. However, we detected a cost of tolerance significantly greater than zero for some accessions. Delays in plant development and compensatory growth of stem biomass were the main contributors to tolerance.