scholarly journals Genome-Wide Identification Reveals That Nicotiana benthamiana Hypersensitive Response (HR)-Like Lesion Inducing Protein 4 (NbHRLI4) Mediates Cell Death and Salicylic Acid-Dependent Defense Responses to Turnip Mosaic Virus

2021 ◽  
Vol 12 ◽  
Author(s):  
Xinyang Wu ◽  
Yuchao Lai ◽  
Shaofei Rao ◽  
Lanqing Lv ◽  
Mengfei Ji ◽  
...  

Hypersensitive response (HR)-like cell death is an important mechanism that mediates the plant response to pathogens. In our previous study, we reported that NbHIR3s regulate HR-like cell death and basal immunity. However, the host genes involved in HR have rarely been studied. Here, we used transcriptome sequencing to identify Niben101Scf02063g02012.1, an HR-like lesion inducing protein (HRLI) in Nicotiana benthamiana that was significantly reduced by turnip mosaic virus (TuMV). HRLIs are uncharacterized proteins which may regulate the HR process. We identified all six HRLIs in N. benthamiana and functionally analyzed Niben101Scf02063g02012.1, named NbHRLI4, in response to TuMV. Silencing of NbHRLI4 increased TuMV accumulation, while overexpression of NbHRLI4 conferred resistance to TuMV. Transient overexpression of NbHRLI4 caused cell death with an increase in the expression of salicylic acid (SA) pathway genes but led to less cell death level and weaker immunity in plants expressing NahG. Thus, we have characterized NbHRLI4 as an inducer of cell death and an antiviral regulator of TuMV infection in a SA-mediated manner.

2019 ◽  
Vol 20 (7) ◽  
pp. 990-1004 ◽  
Author(s):  
Shu Wang ◽  
Kelei Han ◽  
Jiejun Peng ◽  
Jinping Zhao ◽  
Liangliang Jiang ◽  
...  

2011 ◽  
Vol 24 (3) ◽  
pp. 315-327 ◽  
Author(s):  
A. Manfre ◽  
M. Glenn ◽  
A. Nuñez ◽  
R. A. Moreau ◽  
C. Dardick

Evidence going as far back as the early part of the 20th century suggests that both light and chloroplast function may play key roles in host susceptibility to viruses. Despite the long history of such work, confirmation of these phenomena and a determination of the underlying mechanisms remain elusive. Here, we revisited these questions using modern imaging technologies to study the susceptibility of Nicotiana benthamiana to Turnip mosaic virus (TuMV). We found that both light deficiency and photosystem impairment increased the susceptibility of N. benthamiana to TuMV infection. Time-lapse photography studies indicated that, under these conditions, rub-inoculated plants exhibited greater numbers of infection foci and more rapid foci development. The rate of systemic movement was also accelerated though cell-to-cell movement appeared unchanged. Inhibition of salicylic acid (SA)-mediated defense responses is not likely responsible for changes in susceptibility because SA and pathogen response-1 gene induction were not affected by light deficiency or chloroplast impairment and treatment of plants with SA had no measureable impact on TuMV infection. Taken together, these data suggest that both light and optimal chloroplast function influence virus infection either by limiting the cellular resources needed by TuMV to establish replication complexes or the host's ability to activate SA-independent defenses.


Biology ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 232
Author(s):  
Weiran Zheng ◽  
Haichao Hu ◽  
Qisen Lu ◽  
Peng Jin ◽  
Linna Cai ◽  
...  

Recent studies have shown that a large number of long noncoding RNAs (lncRNAs) can regulate various biological processes in animals and plants. Although lncRNAs have been identified in many plants, they have not been reported in the model plant Nicotiana benthamiana. Particularly, the role of lncRNAs in plant virus infection remains unknown. In this study, we identified lncRNAs in N. benthamiana response to Chinese wheat mosaic virus (CWMV) infection by RNA sequencing. A total of 1175 lncRNAs, including 65 differentially expressed lncRNAs, were identified during CWMV infection. We then analyzed the functions of some of these differentially expressed lncRNAs. Interestingly, one differentially expressed lncRNA, XLOC_006393, was found to participate in CWMV infection as a precursor to microRNAs in N. benthamiana. These results suggest that lncRNAs play an important role in the regulatory network of N. benthamiana in response to CWMV infection.


2015 ◽  
Vol 28 (6) ◽  
pp. 675-688 ◽  
Author(s):  
Masayoshi Hashimoto ◽  
Ken Komatsu ◽  
Ryo Iwai ◽  
Takuya Keima ◽  
Kensaku Maejima ◽  
...  

Systemic necrosis is one of the most severe symptoms caused by plant RNA viruses. Recently, systemic necrosis has been suggested to have similar features to a defense response referred to as the hypersensitive response (HR), a form of programmed cell death. In virus-infected plant cells, host intracellular membrane structures are changed dramatically for more efficient viral replication. However, little is known about whether this replication-associated membrane modification is the cause of the symptoms. In this study, we identified an amino-terminal amphipathic helix of the helicase encoded by Radish mosaic virus (RaMV) (genus Comovirus) as an elicitor of cell death in RaMV-infected plants. Cell death caused by the amphipathic helix had features similar to HR, such as SGT1-dependence. Mutational analyses and inhibitor assays using cerulenin demonstrated that the amphipathic helix–induced cell death was tightly correlated with dramatic alterations in endoplasmic reticulum (ER) membrane structures. Furthermore, the cell death–inducing activity of the amphipathic helix was conserved in Cowpea mosaic virus (genus Comovirus) and Tobacco ringspot virus (genus Nepovirus), both of which are classified in the family Secoviridae. Together, these results indicate that ER membrane modification associated with viral intracellular replication may be recognized to prime defense responses against plant viruses.


1999 ◽  
Vol 12 (8) ◽  
pp. 655-662 ◽  
Author(s):  
Laurent Costet ◽  
Sylvain Cordelier ◽  
Stéphan Dorey ◽  
Fabienne Baillieul ◽  
Bernard Fritig ◽  
...  

In tobacco plants reacting hypersensitively to pathogen infection, localized acquired resistance (LAR) is induced in a sharp zone surrounding hypersensitive response (HR) lesions. Using a fungal glycoprotein inducing HR and LAR when infiltrated at 50 nM into tobacco leaves, we have shown previously that a plant signal(s) is released by HR cells and diffuses to induce LAR. Here we address two questions: does LAR occur when HR is not induced, and is salicylic acid the (or one of the) mobile LAR signal? We found that application to tobacco leaves of 0.25 nM glycoprotein triggered defense responses without HR and without an H2O2 burst. The analyzed responses include changes in expression of O-methyltransferase (OMT), 3-hydroxy-3-methylglutarylCoA reductase, pathogenesis-related (PR) proteins, and changes in levels of the signal salicylic acid. No defense responses and no increased resistance to tobacco mosaic virus infection were found beyond the elicitor-infiltrated tissue, providing strong evidence that there is no LAR without HR. Treatments of NahG tobacco leaves with 50 nM elicitor induced the HR and, in the sharp zone surrounding the HR lesion, a strong activation of OMT and of basic PR proteins, but not of acidic PR-1 proteins. This indicates that a signal different from salicylic acid is diffusing.


2008 ◽  
Vol 21 (2) ◽  
pp. 260-268 ◽  
Author(s):  
Bomin Kim ◽  
Chikara Masuta ◽  
Hideyuki Matsuura ◽  
Hideki Takahashi ◽  
Tsuyoshi Inukai

In the pathosystems of Turnip mosaic virus (TuMV) with Brassicaceae crops, various symptoms, including mosaic and necrosis, are observed. We previously reported a necrosis-inducing factor TuNI in Arabidopsis thaliana, a model species. In this study, we show that the necrotic symptom induced by TuNI, observed along the veins, was actually a form of defense response accompanying a hypersensitive reaction (HR)-like cell death in the veinal area. The virus is often localized in the necrotic region. The necrotic response is associated with the production of H2O2, accumulation of salicylic acid (SA), emission of ethylene, and subsequent expression of defense-related genes. Additionally, this HR-like cell death is eased or erased by a shading treatment. These features are similar to the HR-associated resistance reaction to pathogens. However, unlike HR, two phytohormones—SA and ethylene—are involved in the necrosis induction, and both SA- and ethylene-dependent pathogenesis-related genes are activated. We concluded that the veinal necrosis induced by TuMV is regulated by a complex and unique network of at least two signaling pathways, which differs from the signal transduction for the known HR-associated resistance.


2020 ◽  
Vol 21 (3) ◽  
pp. 706 ◽  
Author(s):  
Yangyang Luo ◽  
Qingyang Wang ◽  
Ru Bai ◽  
Ruixiang Li ◽  
Lu Chen ◽  
...  

In the current study, we identified a transcription factor, MYB14, from Chinese wild grape, Vitis quinquangularis-Pingyi (V. quinquangularis-PY), which could enhance the main stilbene contents and expression of stilbene biosynthesis genes (StSy/RS) by overexpression of VqMYB14. The promoter of VqMYB14 (pVqMYB14) was shown to be induced as part of both basal immunity (also called pathogen-associated molecular pattern (PAMP)-triggered immunity, PTI) and effector-triggered immunity (ETI), triggered by the elicitors flg22 and harpin, respectively. This was demonstrated by expression of pVqMYB14 in Nicotiana benthamiana and Vitis. We identified sequence differences, notably an 11 bp segment in pVqMYB14 that is important for the PTI/ETI, and particularly for the harpin-induced ETI response. In addition, we showed that activation of the MYB14 promoter correlates with differences in the expression of MYB14 and stilbene pattern induced by flg22 and harpin. An experimental model of upstream signaling in V. quinquangularis-PY is presented, where early defense responses triggered by flg22 and harpin partially overlap, but where the timing and levels differ. This translates into a qualitative difference with respect to patterns of stilbene accumulation.


2019 ◽  
Vol 109 (5) ◽  
pp. 904-912 ◽  
Author(s):  
Junsu Gong ◽  
Hye-Kyoung Ju ◽  
Ik-Hyun Kim ◽  
Eun-Young Seo ◽  
In-Sook Cho ◽  
...  

Infectious clones were generated from 17 new Korean radish isolates of Turnip mosaic virus (TuMV). Phylogenetic analysis indicated that all new isolates, and three previously characterized Korean radish isolates, belong to the basal-BR group (indicating that the pathotype can infect both Brassica and Raphanus spp.). Pairwise analysis revealed genomic nucleotide and polyprotein amino acid identities of >87.9 and >95.7%, respectively. Five clones (HJY1, HJY2, KIH2, BE, and prior isolate R007) had lower sequence identities than other isolates and produced mild symptoms in Nicotiana benthamiana. These isolates formed three distinct sequence classes (HJY1/HJY2/R007, KIH2, and BE), and several differential amino acid residues (in P1, P3, 6K2, and VPg) were present only in mild isolates HJY1, HJY2, and R007. The remaining isolates all induced systemic necrosis in N. benthamiana. Four mild isolates formed a phylogenetic subclade separate from another subclade including all of the necrosis-inducing isolates plus mild isolate KIH2. Symptom severity in radish and Chinese cabbage genotypes was not correlated with pathogenicity in N. benthamiana; indeed, Chinese cabbage cultivar Norang was not infected by any isolate, whereas Chinese cabbage cultivar Chusarang was uniformly susceptible. Four isolates were unable to infect radish cultivar Iljin, but no specific amino acid residues were correlated with avirulence. These results may lead to the identification of new resistance genes against TuMV.


2014 ◽  
Vol 27 (6) ◽  
pp. 567-577 ◽  
Author(s):  
Feng Zhu ◽  
De-Hui Xi ◽  
Shu Yuan ◽  
Fei Xu ◽  
Da-Wei Zhang ◽  
...  

Systemic resistance is induced by pathogens and confers protection against a broad range of pathogens. Recent studies have indicated that salicylic acid (SA) derivative methyl salicylate (MeSA) serves as a long-distance phloem-mobile systemic resistance signal in tobacco, Arabidopsis, and potato. However, other experiments indicate that jasmonic acid (JA) is a critical mobile signal. Here, we present evidence suggesting both MeSA and methyl jasmonate (MeJA) are essential for systemic resistance against Tobacco mosaic virus (TMV), possibly acting as the initiating signals for systemic resistance. Foliar application of JA followed by SA triggered the strongest systemic resistance against TMV. Furthermore, we use a virus-induced gene-silencing–based genetics approach to investigate the function of JA and SA biosynthesis or signaling genes in systemic response against TMV infection. Silencing of SA or JA biosynthetic and signaling genes in Nicotiana benthamiana plants increased susceptibility to TMV. Genetic experiments also proved the irreplaceable roles of MeSA and MeJA in systemic resistance response. Systemic resistance was compromised when SA methyl transferase or JA carboxyl methyltransferase, which are required for MeSA and MeJA formation, respectively, were silenced. Moreover, high-performance liquid chromatography–mass spectrometry analysis indicated that JA and MeJA accumulated in phloem exudates of leaves at early stages and SA and MeSA accumulated at later stages, after TMV infection. Our data also indicated that JA and MeJA could regulate MeSA and SA production. Taken together, our results demonstrate that (Me)JA and (Me)SA are required for systemic resistance response against TMV.


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