Resistance to Turnip Mosaic Virus in the Family Brassicaceae

Abstract

Resistance to diseases caused by turnip mosaic virus (TuMV) in crop species of the family Brassicaceae has been studied extensively, especially in members of the genus Brassica. The variation in response observed on resistant and susceptible plants inoculated with different isolates of TuMV is due to a combination of the variation in the plant resistome and the variation in the virus genome. Here, we review the breadth of this variation, both at the level of variation in TuMV sequences, with one eye towards the phylogeny and evolution of the virus, and another eye towards the nature of the various responses observed in susceptible vs. different types of resistance responses. The analyses of the viral genomes allowed comparisons of pathotyped viruses on particular indicator hosts to produce clusters of host types, while the inclusion of phylogeny data and geographic location allowed the formation of the host/ geographic cluster groups, the derivation of both of which are presented here. Various studies on resistance determination in particular brassica crops sometimes led to further genetic studies, in many cases to include the mapping of genes, and in some cases to the actual identification of the genes. In addition to summarizing the results from such studies done in brassica crops, as well as in radish and Arabidopsis (the latter as a potential source of candidate genes for brassica and radish), we also summarize work done using nonconventional approaches to obtaining resistance to TuMV.

Turnip mosaic virus, a virus for all seasons

“…There is little association between phylogenetic groupings and pathotypes, although some isolates with common phylogenetic groupings share the same pathotype, particularly if they came from the same country (Palukaitis & Kim, 2021).…”

“…A number of new approaches to control TuMV have been published including the Genetic Modification (GM) approach of coat protein‐mediated resistance (Lehmann, Jenner, Kozubek, Greenland, & Walsh, 2003). Other GM approaches in brassicas have been reviewed by Palukaitis and Kim (2021). An alternative GM approach involving modifying proteins that cleave resistance proteins and overexpressing them in plants has provided resistance to TuMV (Pottinger et al, 2020).…”

Characterization and Mapping of retr04, retr05 and retr06 Broad-Spectrum Resistances to Turnip Mosaic Virus in Brassica juncea, and the Development of Robust Methods for Utilizing Recalcitrant Genotyping Data

“…To date, at least 20 TuMV resistance-associated genes/loci have been mapped across all species of the Brassica genus ( Li et al, 2019 ; Palukaitis and Kim, 2021 ) with significant efforts to characterize some ( Walsh et al, 1999 ; Jenner et al, 2002a ; Hughes et al, 2003 ; Qian et al, 2013 ; Nellist et al, 2014 ; Shopan et al, 2017 ). No sources of TuMV resistance across any Brassica species have been mapped to the “B” genome, and a single weak quantitative resistance to one TuMV isolate has been identified and mapped on the “C” genome ( Walsh et al, 1999 ).…”

The immune Rysto receptor recognizes a broadly conserved feature of potyviral coat proteins

“…We show here that Rysto-expressing tobacco plants display resistance to both severe and mild PPV isolates, suggesting that Rysto can be a valid alternative to RNAimediated resistance (Hily et al, 2007), provided that consumer resistance and regulatory constraints for GM crops were reduced. Similarly, several resistance genes (including Tu, TuRB01, TuRB02, TuRB04) were described for TuMV, but none were cloned so far, and several resistance-breaking strains were described (Palukaitis and Kim, 2021). Like TuRB04 (Jenner et al, 2002), Rysto confers extreme resistance to TuMV.…”

“…To test whether Rysto mediated recognition of the range of potyviral CPs also enables resistance against potyviruses other than PVY, we chose two economically important viruses, PPV and TuMV. PPV, a causative agent of Sharka disease, is the most important viral disease of stone fruit crops worldwide (Maejima et al, 2020), while TuMV damages various Brassicacae and other crops (Palukaitis and Kim, 2021).…”