Tolerance of plant virus disease: Its genetic, physiological, and epidemiological significance

Abstract

The development and use of tolerance have been proposed as an alternative or complementary method to host resistance in the management of plant diseases, including those caused by viruses. There has been much ambiguity among plant pathologists, plant breeders, and agronomists in the meaning of tolerance and how it can be operationally defined, but a modern consensus seems to have emerged. Tolerance is a relative term that means a limited reduction in host plant fitness (reproduction or survival) in relation to pathogen load throughout or during a defined period of plant development and growth such as the reproductive stage. This emphasizes the need to study reproductive stage disease tolerance. Despite this apparent consensus, there remain questions over the use of model plant systems, the genetic background of tolerance, its physiological expression, and epidemiological consequences of its deployment in crops, in comparison with host resistance. Most examples of tolerance reviewed here are for plant virus systems, although other pathogen taxa are referred to, as is tolerance as a natural phenomenon in wild plants including crop relatives. An argument is made for studying commonalities and interactions in host responses to biotic and abiotic stressors; in particular, whether virus infection can mitigate the impact of heat, cold, drought and salinity stress in plants. Finally, we review the use of mathematical models as a means of evaluating the strategy of using tolerance in disease and crop management.

Chemical Composition of Healthy and Raspberry Leaf Blotch Emaravirus-Infected Red Raspberry ‘Willamette’ Fruits

“…Tolerance is described as a cultivar's ability to result in a reduced yield or quality loss as a result of disease severity or pathogen development as compared to other cultivars or crops [45]. Agriculture specialists define it as minimal symptom development or a reduction in plant vigor or production in a cultivar despite a normal viral accumulation that would be expected in a sensitive cultivar [46]. In this research, it cannot be concluded that the RLBV infection caused great changes in the examined phenolic profile in the raspberry 'Willamette' samples, but it is also unclear the effect that the virus caused.…”

Environmental stress in crops: Effects and responses during reproduction

“…This compelling review highlights the need for more intensive studies of disease tolerance at the reproductive stage. Jeger (2023) argues that it is important to define the interactions and host responses to biotic and abiotic stresses more clearly. Similarly, this article considers whether virus infection can reduce the severity of different abiotic stresses, as well as providing an understanding of the role of abiotic stress tolerance in reducing vulnerability to plant pathogens.…”

“…The review by Jeger (2023) provides a comprehensive and unifying description of term ‘tolerance’, which is defined as the ability of the host plant to mitigate the effects of infection on reproductive and survival fitness. This tolerance is robust, regardless of the pathogen load.…”

“…Similarly, this article considers whether virus infection can reduce the severity of different abiotic stresses, as well as providing an understanding of the role of abiotic stress tolerance in reducing vulnerability to plant pathogens. Finally, Jeger (2023) emphasizes the need for more field studies on tolerance, together with the use of mathematical models for the development of disease management strategies.…”

Selective autophagy receptor‐encoding sequences in shallot transcriptome: In silico identification and expression patterns in response to asymptomatic shallot virus X infection

“…Plant disease tolerance was first described in a study of Australian rust ( Uredineae )–wheat interaction (Cobb, 1894) and currently disease tolerance is considered as an inherent component of immunity in the broadest context (Martins et al., 2019). Recently published detailed reviews analysing a wide range of experimental data related to tolerance as a key plant defence response to parasites, including viruses (Jeger, 2022; Pagán & García‐Arenal, 2020; Paudel & Sanfaçon, 2018), as well as a number of recent experimental works (Amoroso et al., 2022; Shukla et al., 2022) show that plant host tolerance is a complex genetic trait that involves multiple molecular mechanisms and, in particular, selective autophagy processes.…”