Tolerance: A key plant defense against pathogens

Israel Pagán and Fernando García-Arenal review the conceptual basis of tolerance and discuss the abundant evidence supporting the key role tolerance as a plant defense mechanism against pathogens.


Tolerance, defined as the reduction in the damage that pathogen infection causes in hosts, is a defense mechanism as widespread in plants as resistance, but much less studied. Advances in the knowledge of tolerance have been hampered by the difficulty to distinguish in experimental settings this defense from quantitative resistance, which are often confounded. In this review, Israel Pagán y Fernando García-Arenal highlight the conceptual unity underlying the different formulations of tolerance proposed over the past century. They also discuss the abundant evidence supporting that this defense strategy is widespread in plants, and plays a key role in the epidemiology and ecology, evolution and co-evolution of plants and pathogens. Lastly, the more limited understanding on the genetic determinants and molecular mechanisms of tolerance are summarized. This work provides a unified conceptual framework that facilitates studies of this key plant defense, and its application to control crop diseases.


Tolerance is a quantitative trait. Tolerance variation in two plant-pathogen interactions. (Left) Frequency distribution of tolerance values in 48 varieties of
Avena spp. to
Septoria spp in two Canadian locations. (Right) Frequency distribution of tolerance values in 80 genotypes of Arabidopsis thaliana to Cucumber mosaic virus (CMV) in plants vernalized for 4 or 8 weeks.

Original Paper:

Pagán, I., García-Arenal, F. 2020. Tolerance of Plants to Pathogens: A Unifying View. Annual Review of Phytopathology. DOI: 10.1146/annurev-phyto-010820-012749