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Basu S, Singh AK, Singh D, Sahu SK, Chakraborty S. Role of viral suppressors governing asymmetric synergism between tomato-infecting begomoviruses. Appl Microbiol Biotechnol 2021; 105:1107-1121. [PMID: 33417040 DOI: 10.1007/s00253-020-11070-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 12/01/2020] [Accepted: 12/17/2020] [Indexed: 11/29/2022]
Abstract
Mixed viral infections are common in fields and frequently exacerbate disease severity via synergistic interactions among individual viral genomic components leading to major crop loss. Two predominant species of tomato-infecting begomoviruses, Tomato leaf curl New Delhi virus (ToLCNDV) and Tomato leaf curl Gujarat virus (ToLCGuV), are known to cause severe leaf curl disease of tomato in India. Previously, we have demonstrated asymmetric synergism between these two distinct begomovirus species during mixed infection in solanaceous hosts. In the present study, we have identified the underlying proteins that positively regulate asymmetric synergism and their effect on plant defense machinery. During co-infection, the AC2 and AV2 of ToLCGuV enhanced ToLCNDV DNA accumulation in Nicotiana benthamiana as well as in their natural host, tomato. Furthermore, we found that AC2 and AV2 of ToLCNDV and AV2 of ToLCGuV play a critical role in suppression of post transcriptional gene silencing (PTGS) machinery. Taken together, AC2 and AV2 encoded proteins of ToLCGuV are the crucial viral factors promoting asymmetric synergism with ToLCNDV. KEY POINTS: • Begomoviral suppressors play vital roles in viral synergism. • AC2 and AV2 of ToLCGuV asymmetrically enhance ToLCNDV accumulation. • AC2 and AV2 of ToLCNDV and ToLCGuV AV2 are major PTGS suppressors.
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Affiliation(s)
- Saumik Basu
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India
- Department of Entomology, Washington State University, Pullman, WA, USA
| | - Ashish Kumar Singh
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India
| | - Divya Singh
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India
| | - Sanjeeb Kumar Sahu
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India
- Salk Institute for Biological Studies, 10010 N. Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110 067, India.
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Abstract
Plants have developed diverse molecular mechanisms to resist viruses. RNA silencing plays a dominant role in antiviral defense. Recent studies have correlated plant antiviral silencing to epigenetic modification in genomic DNA and protein by remodeling the expression levels of coding genes. The plant host methylation level is reprogrammed in response to viral challenge. Genomes of some viruses have been implicated in the epigenetic modification via small RNA-mediated transcriptional gene silencing and post-transcriptional gene silencing. These mechanisms can be primed prior to a virus attack through methylation changes for antiviral defense. This review highlights the findings concerning the methylation changes in plant-virus interactions and demonstrates a possible direction to improve the understanding of plant host methylation regulation in response to viral infection.
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Affiliation(s)
- Chenguang Wang
- College of Plant Protection, China Agricultural University, Beijing, 100083, China
- Chinese Academy of Inspection and Quarantine, Beijing, 100176, China
| | - Chaonan Wang
- College of Plant Protection, China Agricultural University, Beijing, 100083, China
- Chinese Academy of Inspection and Quarantine, Beijing, 100176, China
| | - Jingze Zou
- College of Biological Sciences, China Agricultural University, Beijing, 100083, China
| | - Yunshu Yang
- Beijing Academy of Food Sciences, Beijing, 100162, China
| | - Zhihong Li
- College of Plant Protection, China Agricultural University, Beijing, 100083, China
| | - Shuifang Zhu
- College of Plant Protection, China Agricultural University, Beijing, 100083, China.
- Chinese Academy of Inspection and Quarantine, Beijing, 100176, China.
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Zhao Q, Gao C, Lee P, Liu L, Li S, Hu T, Shen J, Pan S, Ye H, Chen Y, Cao W, Cui Y, Zeng P, Yu S, Gao Y, Chen L, Mo B, Liu X, Xiao S, Zhao Y, Zhong S, Chen X, Jiang L. Fast-suppressor screening for new components in protein trafficking, organelle biogenesis and silencing pathway in Arabidopsis thaliana using DEX-inducible FREE1-RNAi plants. J Genet Genomics 2015; 42:319-30. [PMID: 26165498 DOI: 10.1016/j.jgg.2015.03.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 03/21/2015] [Accepted: 03/27/2015] [Indexed: 12/20/2022]
Abstract
Membrane trafficking is essential for plant growth and responses to external signals. The plant unique FYVE domain-containing protein FREE1 is a component of the ESCRT complex (endosomal sorting complex required for transport). FREE1 plays multiple roles in regulating protein trafficking and organelle biogenesis including the formation of intraluminal vesicles of multivesicular body (MVB), vacuolar protein transport and vacuole biogenesis, and autophagic degradation. FREE1 knockout plants show defective MVB formation, abnormal vacuolar transport, fragmented vacuoles, accumulated autophagosomes, and seedling lethality. To further uncover the underlying mechanisms of FREE1 function in plants, we performed a forward genetic screen for mutants that suppressed the seedling lethal phenotype of FREE1-RNAi transgenic plants. The obtained mutants are termed as suppressors of free1 (sof). To date, 229 putative sof mutants have been identified. Barely detecting of FREE1 protein with M3 plants further identified 84 FREE1-related suppressors. Also 145 mutants showing no reduction of FREE1 protein were termed as RNAi-related mutants. Through next-generation sequencing (NGS) of bulked DNA from F2 mapping population of two RNAi-related sof mutants, FREE1-RNAi T-DNA inserted on chromosome 1 was identified and the causal mutation of putative sof mutant is being identified similarly. These FREE1- and RNAi-related sof mutants will be useful tools and resources for illustrating the underlying mechanisms of FREE1 function in intracellular trafficking and organelle biogenesis, as well as for uncovering the new components involved in the regulation of silencing pathways in plants.
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Affiliation(s)
- Qiong Zhao
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Caiji Gao
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - PoShing Lee
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Lin Liu
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Shaofang Li
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Tangjin Hu
- CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China
| | - Jinbo Shen
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Shuying Pan
- CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China
| | - Hao Ye
- CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China
| | - Yunru Chen
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Wenhan Cao
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Yong Cui
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Peng Zeng
- Beijing Genomics Institute at Shenzhen, Shenzhen 518083, China
| | - Sheng Yu
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Yangbin Gao
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Liang Chen
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Beixin Mo
- Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences, Shenzhen University, Shenzhen 518060, China
| | - Xin Liu
- Beijing Genomics Institute at Shenzhen, Shenzhen 518083, China
| | - Shi Xiao
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Yunde Zhao
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Silin Zhong
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Xuemei Chen
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Liwen Jiang
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China; CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen 518057, China.
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Abstract
Extracorporeal Photochemotherapy (ECP) consists in illumination of the patient's leukocytes in the presence of 8-Methoxy Psoralen (8-MOP) and its reinjection to the same patient. ECP is responsible for many cellular events, the most important being the induction of cell apoptosis. Apoptosis appears first in lymphocytes and activated lymphocytes (allo or auto) which are more sensitive and undergo faster apoptosis rather than other cells. Monocytes develop apoptosis later. The injection of apoptotic cells induces tolerance in patients with graft versus host disease (GvHD) and acute heart or lung graft rejection. In these patients, phagocytosis of apoptotic cells by antigen-presenting cells (APCs) and in particular dendritic cells is responsible for a shift from Th1 to Th2 immune response, an increase in anti-inflammatory cytokines such as interleukine 10 (IL-10) and Tumor Growth Factor Beta (TGF-β), a decrease in pro-inflammatory cytokines and finally, for the proliferation of regulatory cells. Among CD4/CD25 positive cells, only CD4(+)CD25(hi) are T-regulatory cells (T-regs). One subpopulation of T-regs produces IL-10 and inhibits Th1 CD4 cells, whereas other populations act as suppressors and inhibit the cytotoxic T-cells responsible for organ rejection and GvHD in an antigen specific fashion. It is not clear why the injection of early apoptotic cells induces tolerance in GvHD and organ graft rejection, but in Sézary syndrome, it induces up-regulation of anti-tumor immune response. Immune response modulation (up- or down-regulation) after ECP depends on many factors: early apoptotic cell injection; anti-inflammatory environment; impaired function of dendritic cells; dendritic type 2 cell dominance, lead to immune tolerance, whereas late apoptotic or necrotic cell injection and pro-inflammatory cytokines enhance immune response. Therefore, immune response to ECP depends on various factors responsible for the diversity of its mode of action in different diseases and further investigations are required.
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