Phylogenetic analysis of Tomato spotted wilt virus (TSWV) NSs protein demonstrates the isolated emergence of resistance-breaking strains in pepper

Abstract

Resurgence of Tomato spotted wilt virus (TSWV) worldwide as well as in Hungary causing heavy economic losses directed the attention to the factors contributing to the outbreak of this serious epidemics. The introgression of Tsw resistance gene into various pepper cultivars seemed to solve TSWV control, but widely used resistant pepper cultivars bearing the same, unique resistance locus evoked the rapid emergence of resistancebreaking (RB) TSWV strains. In Hungary, the sporadic appearance of RB strains in pepper-producing region was first observed in 2010-2011, but in 2012 it was detected frequently. Previously, the non-structural protein (NSs) encoded by small RNA (S RNA) of TSWV was verified as the avirulence factor for Tsw resistance, therefore we analyzed the S RNA of the Hungarian RB and wild type (WT) isolates and compared to previously analyzed TSWV strains with RB properties from different geographical origins. Phylogenetic analysis demonstrated that the different RB strains had the closest relationship with the local WT isolates and there is no conserved mutation present in all the NSs genes of RB isolates from different geographical origins. According to these results, we concluded that the RB isolates evolved separately in geographic point of view, and also according to the RB mechanism.

Identification and characterization of a new class of Tomato spotted wilt virus isolates that break Tsw‐based resistance in a temperature‐dependent manner

“…Examples of virus resistance have been reported in which only one or two mutations within the Avr sequence have broken resistance (Bendahmane et al, 1995;Moffett, 2009 shown that the Tsw resistance gene positively selected for certain amino acids in the TSWV NSs sequence (Tentchev et al, 2011), specifically isoleucine (I) at position 79. Tentchev et al (2011) also proposed that the appearance of a resistance-breaking phenotype is probably the result of multiple independent evolutionary events, which is supported by the work of Almasi et al (2015Almasi et al ( , 2017. This is further supported by the present study, in which I79 was not the only amino acid that defined resistance-breaking phenotypes.…”

“…() also proposed that the appearance of a resistance‐breaking phenotype is probably the result of multiple independent evolutionary events, which is supported by the work of Almasi et al . (, ). This is further supported by the present study, in which I79 was not the only amino acid that defined resistance‐breaking phenotypes.…”

“…In addition, the presence (+), absence (À) or intermediate (AE) of RNA silencing suppression (RSS) activity of each tested NSs construct is indicated. The phenotype of the NSs proteins (resistance-inducing (RI) or resistance-breaking (RB)) as described by Margaria et al (2007), Almasi et al (2015) and Debreczeni et al (2015) is shown in square brackets.…”

Occurrence and diversity of Tomato spotted wilt virus isolates breaking the Tsw resistance gene of Capsicum chinense in Yunnan, southwest China

“…This result is in line with the recent publication by Almási et al . (), suggesting that RB isolates of TSWV in Yunnan may have evolved independently from the previously reported RB isolates. Sequence comparison and phylogenetic analysis of NSs showed that all isolates from China share similar sequence characteristics and those isolates are clustered into the same subgroup with isolates from Korea and Japan.…”

FEDERAL RESEARCH CENTER FOR VEGETABLE GROWING — 100-YEAR HISTORY AS A BASIS FOR FUTURE DEVELOPMENTS (review)

“…Основные причины возникающих эпифитотий фитовирусов -появление новых, более агрессивных штаммов, возделывание сортов со слабой устойчивостью, неконтролируемая торговля посадочным и семенным материалом, появление новых видов векторов-переносчиков и недостаточные меры борьбы с ними (44,45 (48,49). Для выделения форм, устойчивых к заболеваниям, разрабатываются и непрерывно модифицируются методы оценки и отбора в зависимости от биологических особенностей растенийхозяев и фитопатогенов в рамках целевой селекции.…”