Tolerance is a virus-specific defence in plants

Tolerance to Cucumber mosaic virus in Arabidopsis thaliana, following life-history theory predictions, is attained through reprogramming of the plant’s resource allocation from growth to reproduction and alteration in the host developmental schedule. On testing five viruses, of low to high virulence, it was observed that tolerance in A. thaliana to virus infection is a genotype-specific response. Effective tolerance attained through modification of plant life-history traits was observed in response to infection by one out of five assayed viruses, indicating a virus specific defence response.


Viruses are important pathogens of plants, thus the need to understand the defences of the host. Tolerance is the ability of the host to reduce the negative effects of virus infection on its fitness, an under explored and under-exploited defence of plants to viruses. Theoretical predictions assert that tolerance to low virulence pathogens would be achieved through resource reallocation from growth to reproduction. Tolerance to Cucumber mosaic virus (CMV) in Arabidopsis thaliana accords to these predictions. To address if resource reallocation is a non-specific response to the stress of infection or a virus-specific defence, and to understand responses to high virulent pathogens, six A. thaliana wild genotypes, having long or short life-cycle length, were challenged with five viruses with different genomic structures, life histories and transmission modes. The results indicated that, in A. thaliana, tolerance to virus infection is a genotype-specific response and effective tolerance attained through modification of resource allocation is a specific, narrow-spectrum response, as it was observed only in response to one out of the five viruses tested. When the assayed A. thaliana genotypes are clustered according to their life cycle length, long life-cycle genotypes are tolerant to CMV infection, while short life cycle genotypes suffered more severely from CMV infection. At odds with theoretical predictions, tolerance was linked to longer pre-reproductive periods. This study contributes to the understanding of plant-virus interaction.

Figure. Symptoms of virus infection in A.thaliana genotypes.
From A to D (Genotypes with shorter lifecycle): A, Col1 (Mock-inoc), B, Shak (TCV-infected), C, Shak (TuMV-infected) D, Col1 (CaMV-infected)
From E to H (Genotype with longer lifecycle): E, Cum-0 (CMV, asymptomatic), F, Kas-0 (TCV-infected), G, Kas-0, (TuMV-infected), H, Cum-0, (YoMV-infected)

Original Paper:

Shukla, A; Pagán, I; García-Arenal, F. 2017. "Effective tolerance based on resource reallocation is a virus-specific defence in Arabidopsis thaliana". Molecular Plant Pathology. DOI: 10.1111/mpp.12629".