scholarly journals Characterization of the Roles of SGT1/RAR1, EDS1/NDR1, NPR1, and NRC/ADR1/NRG1 in Sw-5b-Mediated Resistance to Tomato Spotted Wilt Virus

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1447
Author(s):  
Zhengqiang Chen ◽  
Qian Wu ◽  
Cong Tong ◽  
Hongyu Chen ◽  
Dan Miao ◽  
...  

The tomato Sw-5b gene confers resistance to tomato spotted wilt virus (TSWV) and encodes a nucleotide-binding leucine-rich repeat (NLR) protein with an N-terminal Solanaceae-specific domain (SD). Although our understanding of how Sw-5b recognizes the viral NSm elicitor has increased significantly, the process by which Sw-5b activates downstream defense signaling remains to be elucidated. In this study, we used a tobacco rattle virus (TRV)-based virus-induced gene silencing (VIGS) system to investigate the roles of the SGT1/RAR1, EDS1/NDR1, NPR1, and NRC/ADR1/NRG1 genes in the Sw-5b-mediated signaling pathway. We found that chaperone SGT1 was required for Sw-5b function, but co-chaperone RAR1 was not. Sw-5b-mediated immune signaling was independent of both EDS1 and NDR1. Silencing NPR1, which is a central component in SA signaling, did not result in TSWV systemic infection in Sw-5b-transgenic N. benthamiana plants. Helper NLR NRCs (NLRs required for cell death) were required for Sw-5b-mediated systemic resistance to TSWV infection. Suppression of NRC2/3/4 compromised the Sw-5b resistance. However, the helper NLRs ADR1 and NRG1 may not participate in the Sw-5b signaling pathway. Silencing ADR1, NRG1, or both genes did not affect Sw-5b-mediated resistance to TSWV. Our findings provide new insight into the requirement for conserved key components in Sw-5b-mediated signaling pathways.

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1077b-1077
Author(s):  
S.J. Scott ◽  
M. Stevens ◽  
R.C. Gergerich

Seedlings of eight accessions of L. hirsutum and susceptible L. esculentum `VF Pink' controls were spray inoculated twice in the greenhouse with tomato spotted wilt virus (TSWV) Arkansas 85-9. Plants lacking symptoms were reinoculated, then evaluated for TSWV by enzyme-linked immunosorbent assay (ELISA). Controls were consistently infected; sixty noninfected L. hirsutum were propagated by cuttings and inoculated with TSWV isolates T2 (lettuce), G-87 (gloxinia), 87-34 (tomato) and a mixture of the four isolates. All selections became infected in at least one test, but systemic infection was often delayed. Additional wild Lycopersicon species and numbers of accessions evaluated for resistance to TSWV include L. cheesmanii (9), L. chmielewskii (17), L. hirsutum (24), L. hirsutum f. glabratum (17), L. parviflorum (4) and L. pennellii (44). No new sources of strong resistance have been identified yet. Evaluation of additional species and accessions is continuing.


2008 ◽  
Vol 98 (2) ◽  
pp. 196-204 ◽  
Author(s):  
B. Mandal ◽  
S. Mandal ◽  
A. S. Csinos ◽  
N. Martinez ◽  
A. K. Culbreath ◽  
...  

Tomato spotted wilt virus (TSWV) is an economically important virus of flue-cured tobacco. Activation of systemic acquired resistance (SAR) by acibenzolar-S-methyl (ASM) in flue-cured tobacco was studied under greenhouse conditions by challenge inoculation with a severe isolate of TSWV. ASM restricted virus replication and movement, and as a result reduced systemic infection. Activation of resistance was observed within 2 days after treatment with ASM and a high level of resistance was observed at 5 days onward. Expression of the pathogenesis-related (PR) protein gene, PR-3, and different classes of PR proteins such as PR-1, PR-3, and PR-5 were detected at 2 days post-ASM treatment which inversely correlated with the reduction in the number of local lesions caused by TSWV. Tobacco plants treated with increased quantities of ASM (0.25, 0.5, 1.0, 2.0, and 4.0 g a.i./7,000 plants) showed increased levels of SAR as indicated by the reduction of both local and systemic infections by TSWV. The highest level of resistance was at 4 g a.i., but this rate of ASM also caused phytotoxicity resulting in temporary foliar spotting and stunting of plants. An inverse correlation between the TSWV reduction and phytotoxicity was observed with the increase of ASM concentration. ASM at the rate of 1 to 2 g a.i./7,000 plants activated a high level of resistance and minimized the phytotoxicity. Use of gibberellic acid in combination with ASM reduced the stunting caused by ASM. Present findings together with previous field experiments demonstrate that ASM is a potential option for management of TSWV in flue-cured tobacco.


Viruses ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 647 ◽  
Author(s):  
Xin Qian ◽  
Qing Xiang ◽  
Tongqing Yang ◽  
Hongyu Ma ◽  
Xin Ding ◽  
...  

Tospovirus is a tripartite negative stranded RNA virus and is considered as one of the most devastating plant viruses. Successful virus infection in plant requires many host factors. To date, very few host factors have been identified as important in Tospovirus infection in plants. We reported earlier that NSm protein encoded by Tomato spotted wilt virus (TSWV), a type species of the genus Orthotospovirus, plays critical roles in viral cell-to-cell and long-distance movement. In this study, we determined that molecular co-chaperone NbSGT1 interacted with TSWV NSm in Nicotiana benthamiana. TSWV infection significantly upregulated the expression of NbSGT1 gene and transient overexpression of NbSGT1 in N. benthamiana leaves accelerated TSWV infection. In contrast, silencing the NbSGT1 gene expression using a virus-induced gene silencing (VIGS) approach strongly inhibited TSWV NSm cell-to-cell movement, as well as TSWV local and systemic infection in N. benthamiana plants. Furthermore, NbSGT1 was found to regulate the infection of both American and Euro/Asia type tospoviruses in N. benthamiana plant. Collectively, our findings presented in this paper and the results published previously indicated that molecular co-chaperone NbSGT1 plays important roles in modulating both positive stranded and tripartite negative stranded RNA virus infection in plants.


Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1617
Author(s):  
Anna Depta ◽  
Teresa Doroszewska ◽  
Anna Czubacka

Nicotiana mutabilis is a recently discovered species within the genus Nicotiana. The aim of the present study was to evaluate its resistance to Potato virus Y (PVY) and Tomato spotted wilt virus (TSWV). Molecular analysis was performed to detect the Va gene determining susceptibility to PVY and the SCAR marker associated with resistance to TSWV. Resistance tests were carried out under greenhouse conditions through artificial inoculation with one TSWV and two PVY isolates. In order to confirm the presence of the viruses in plants, DAS-ELISA tests were performed using antibodies against PVY and TSWV. The results indicated the absence of the PVY susceptibility gene and the presence of the TSWV resistance gene in the genome of N. mutabilis. This species was considered tolerant to the two PVY isolates tested because, despite the positive DAS-ELISA results, the infected plants showed vein clearing and chlorotic spots but no vein necrosis. As a result of TSWV inoculation, N. mutabilis showed a hypersensitive response; however, after four months, 30% of the inoculated plants showed systemic infection. This species extends the genetic variation in the genus Nicotiana and, because of its tolerance to PVY and partial resistance to TSWV, it may be a potential source of resistance to these viruses.


Plant Disease ◽  
2002 ◽  
Vol 86 (9) ◽  
pp. 939-944 ◽  
Author(s):  
B. Mandal ◽  
H. R. Pappu ◽  
A. K. Culbreath ◽  
C. C. Holbrook ◽  
D. W. Gorbet ◽  
...  

Screening of peanut germ plasm for resistance to Tomato spotted wilt virus (TSWV) has been largely inefficient due to the lack of a screening technique based on mechanical transmission of the virus under controlled environmental conditions. We have studied the reaction of three peanut cultivars (Georgia Green, Georgia Runner, C-99R) and one breeding line (C11-2-39) using a highly efficient mechanical inoculation procedure. The disease response was studied at two temperature regimes, 25 to 30°C (low temperature) and 30 to 37°C (high temperature). Based on percent transmission, symptomatology, distribution of TSWV, and relative levels of TSWV nucleocapsid (N) protein, Georgia Runner and Georgia Green were found to be susceptible, whereas C-99R and C11-2-39 were resistant. Of the four genotypes tested, C11-2-39 had the highest level of resistance to TSWV. The results correlated with the field performance of the genotypes except in the case of Georgia Green, which could not be distinguished from TSWV-susceptible Georgia Runner. Exposure of the inoculated plants to higher temperature (30 to 37°C) resulted in a better resistant response as reflected by reduced systemic infection, localized symptom expression, restricted viral movement, and reduced levels of TSWV antigen. To our knowledge, this is the first report of differential response of peanut genotypes to TSWV using mechanical inoculation. The four peanut genotypes should be useful as reference standards for the initial screening and identification of sources of TSWV resistance in peanut germ plasm.


Plant Disease ◽  
2009 ◽  
Vol 93 (8) ◽  
pp. 845-845 ◽  
Author(s):  
J. M. Crosslin ◽  
I. Mallik ◽  
N. C. Gudmestad

In the summer of 2008, potato (Solanum tuberosum L.) tubers (cvs. FL1867, FL2053, and FL1922) from commercial fields near Dalhart, TX were observed with distinct external erumpent rings and severe internal discolorations including blotches, spots, and dry, cork-like tissue. The presence of rings suggested the possible involvement of one or more viruses. Nucleic acid from seven of eight symptomatic tubers received in Washington (cvs. FL1867 and FL1922) tested positive for Tomato spotted wilt virus (TSWV) by reverse transcription (RT)-PCR with primers TSWV 1 and 2 (3). Similarly, tubers (cvs. FL1867 and FL2053) received in North Dakota tested positive for TSWV with forward (S1983) and reverse (S2767) primers of Tsompana et al. (4). The 777-bp amplicon obtained with primers TSWV 1 and 2 and the 803-bp amplicon obtained with primers S1983 and S2767 were cloned and three clones of each were sequenced. Analysis of the consensus sequences and BLAST comparisons confirmed the Washington and North Dakota sequences were indeed TSWV in origin and were each 98 to 99% identical to the corresponding nucleocapsid region of a number of TSWV isolates and most closely related to an isolate detected in eastern black nightshade from Colorado (GenBank No. AY777475). The deduced amino acid sequences of the 777-bp nucleocapsid open reading frame differed from AY777475 at only two residues in each of the Washington and North Dakota sequences. The Washington and North Dakota derived sequences were deposited with GenBank (Nos. FJ882069 and FJ882070, respectively). None of the eight symptomatic tubers tested positive for Tobacco rattle virus (TRV), Alfalfa mosaic virus (AMV), or the necrotic strains of Potato virus Y (PVY) by RT-PCR. Mechanical transmission tests were conducted by grinding symptomatic tissue of a TSWV-positive FL1867 tuber in 10 volumes of 30 mM potassium phosphate buffer, pH 8.0, containing 10 mM of sodium diethyldithiocarbamate and 10 mM of sodium thioglycollate and rub inoculated onto Carborundum-dusted leaves of Samsun NN tobacco. Approximately 10 days after inoculation, chlorotic-necrotic rings were present on the inoculated leaves and circular necrotic lesions developed on the upper leaves. Dark stem lesions were also present on inoculated tobacco, and after 3 weeks, the upper leaves developed severe, spreading lesions. Tissue from the symptomatic tobacco tested positive for TSWV by RT-PCR (primers TSWV 1 and 2) and also with a TSWV-specific ImmunoStrip (Agdia, Inc., Elkhart, IN), but tested negative for TRV, AMV, and PVY by RT-PCR. TSWV has been reported on field-grown potatoes in North Carolina (1) and has been reported on potatoes in Australia (2) and in other parts of the world (referenced in 1). To our knowledge, this is the first report associating TSWV with tuber necrosis on potatoes in Texas. References: (1) J. A. Abad et al. Am. J. Potato Res. 82:255, 2005. (2) L. J. Latham and R. A. C. Jones. Aust. J. Agric. Res. 48:359, 1997. (3) R. Navarre et al. Am. J. Potato Res. 86:88, 2009. (4) M. Tsompana et al. Mol. Ecol. 14:53, 2005.


Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 320
Author(s):  
Alexander Nilon ◽  
Karl Robinson ◽  
Hanu R. Pappu ◽  
Neena Mitter

Tomato spotted wilt virus (TSWV) is the type member of the genus Orthotospovirus in the family Tospoviridae and order Bunyavirales. TSWV, transmitted by several species of thrips, causes significant disease losses to agronomic and horticultural crops worldwide, impacting both the yield and quality of the produce. Management strategies include growing virus-resistant cultivars, cultural practices, and managing thrips vectors through pesticide application. However, numerous studies have reported that TSWV isolates can overcome host-plant resistance, while thrips are developing resistance to pesticides that were once effective. RNA interference (RNAi) offers a means of host defence by using double-stranded (ds) RNA to initiate gene silencing against invading viruses. However, adoption of this approach requires production and use of transgenic plants and thus limits the practical application of RNAi against TSWV and other viruses. To fully utilize the potential of RNAi for virus management at the field level, new and novel approaches are needed. In this review, we summarize RNAi and highlight the potential of topical or exogenous application of RNAi triggers for managing TSWV and thrips vectors.


Sign in / Sign up

Export Citation Format

Share Document