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Kanakala S, Xavier CAD, Martin KM, Tran HH, Redinbaugh MG, Whitfield AE. Rescue of the first alphanucleorhabdovirus entirely from cloned complementary DNA: An efficient vector for systemic expression of foreign genes in maize and insect vectors. MOLECULAR PLANT PATHOLOGY 2023; 24:788-800. [PMID: 36239302 DOI: 10.1111/mpp.13273] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 06/11/2023]
Abstract
Recent reverse genetics technologies have enabled genetic manipulation of plant negative-strand RNA virus (NSR) genomes. Here, we report construction of an infectious clone for the maize-infecting Alphanucleorhabdovirus maydis, the first efficient NSR vector for maize. The full-length infectious clone was established using agrobacterium-mediated delivery of full-length maize mosaic virus (MMV) antigenomic RNA and the viral core proteins (nucleoprotein N, phosphoprotein P, and RNA-directed RNA polymerase L) required for viral transcription and replication into Nicotiana benthamiana. Insertion of intron 2 ST-LS1 into the viral L gene increased stability of the infectious clone in Escherichia coli and Agrobacterium tumefaciens. To monitor virus infection in vivo, a green fluorescent protein (GFP) gene was inserted in between the N and P gene junctions to generate recombinant MMV-GFP. Complementary DNA (cDNA) clones of MMV-wild type (WT) and MMV-GFP replicated in single cells of agroinfiltrated N. benthamiana. Uniform systemic infection and high GFP expression were observed in maize inoculated with extracts of the infiltrated N. benthamiana leaves. Insect vectors supported virus infection when inoculated via feeding on infected maize or microinjection. Both MMV-WT and MMV-GFP were efficiently transmitted to maize by planthopper vectors. The GFP reporter gene was stable in the virus genome and expression remained high over three cycles of transmission in plants and insects. The MMV infectious clone will be a versatile tool for expression of proteins of interest in maize and cross-kingdom studies of virus replication in plant and insect hosts.
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Affiliation(s)
- Surapathrudu Kanakala
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
| | - César A D Xavier
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
| | - Kathleen M Martin
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
| | - Hong Hanh Tran
- Department of Plant Pathology, The Ohio State University, Wooster, Ohio, USA
| | | | - Anna E Whitfield
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
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2
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Kumar A, Kanak KR, Arunachalam A, Dass RS, Lakshmi PTV. Comparative transcriptome profiling and weighted gene co-expression network analysis to identify core genes in maize ( Zea mays L.) silks infected by multiple fungi. FRONTIERS IN PLANT SCIENCE 2022; 13:985396. [PMID: 36388593 PMCID: PMC9647128 DOI: 10.3389/fpls.2022.985396] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Maize (Zea mays L.) is the third most popular Poaceae crop after wheat and rice and used in feed and pharmaceutical sectors. The maize silk contains bioactive components explored by traditional Chinese herbal medicine for various pharmacological activities. However, Fusarium graminearum, Fusarium verticillioides, Trichoderma atroviride, and Ustilago maydis can infect the maize, produce mycotoxins, hamper the quantity and quality of silk production, and further harm the primary consumer's health. However, the defense mechanism is not fully understood in multiple fungal infections in the silk of Z. mays. In this study, we applied bioinformatics approaches to use the publicly available transcriptome data of Z. mays silk affected by multiple fungal flora to identify core genes involved in combatting disease response. Differentially expressed genes (DEGs) were identified among intra- and inter-transcriptome data sets of control versus infected Z. mays silks. Upon further comparison between up- and downregulated genes within the control of datasets, 4,519 upregulated and 5,125 downregulated genes were found. The DEGs have been compared with genes in the modules of weighted gene co-expression network analysis to relevant specific traits towards identifying core genes. The expression pattern of transcription factors, carbohydrate-active enzymes (CAZyme), and resistance genes was analyzed. The present investigation is supportive of our findings that the gene ontology, immunity stimulus, and resistance genes are upregulated, but physical and metabolic processes such as cell wall organizations and pectin synthesis were downregulated respectively. Our results are indicative that terpene synthase TPS6 and TPS11 are involved in the defense mechanism against fungal infections in maize silk.
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Affiliation(s)
- Amrendra Kumar
- Phytomatics Lab, Department of Bioinformatics, School of Life Sciences, Pondicherry University, Pondicherry, India
| | - Kanak Raj Kanak
- Fungal Genetics and Mycotoxicology Laboratory, Department of Microbiology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - Annamalai Arunachalam
- Postgraduate and Research Department of Botany, Arignar Anna Government Arts College, Villupuram, Tamil Nadu, India
| | - Regina Sharmila Dass
- Fungal Genetics and Mycotoxicology Laboratory, Department of Microbiology, School of Life Sciences, Pondicherry University, Puducherry, India
| | - P. T. V. Lakshmi
- Phytomatics Lab, Department of Bioinformatics, School of Life Sciences, Pondicherry University, Pondicherry, India
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Wang Y, Chai C, Khatabi B, Scheible WR, Udvardi MK, Saha MC, Kang Y, Nelson RS. An Efficient Brome mosaic virus-Based Gene Silencing Protocol for Hexaploid Wheat ( Triticum aestivum L.). FRONTIERS IN PLANT SCIENCE 2021; 12:685187. [PMID: 34220905 PMCID: PMC8253535 DOI: 10.3389/fpls.2021.685187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/07/2021] [Indexed: 05/09/2023]
Abstract
Virus-induced gene silencing (VIGS) is a rapid and powerful method to evaluate gene function, especially for species like hexaploid wheat that have large, redundant genomes and are difficult and time-consuming to transform. The Brome mosaic virus (BMV)-based VIGS vector is widely used in monocotyledonous species but not wheat. Here we report the establishment of a simple and effective VIGS procedure in bread wheat using BMVCP5, the most recently improved BMV silencing vector, and wheat genes PHYTOENE DESATURASE (TaPDS) and PHOSPHATE2 (TaPHO2) as targets. Time-course experiments revealed that smaller inserts (~100 nucleotides, nt) were more stable in BMVCP5 and conferred higher silencing efficiency and longer silencing duration, compared with larger inserts. When using a 100-nt insert and a novel coleoptile inoculation method, BMVCP5 induced extensive silencing of TaPDS transcript and a visible bleaching phenotype in the 2nd to 5th systemically-infected leaves from nine to at least 28 days post inoculation (dpi). For TaPHO2, the ability of BMVCP5 to simultaneously silence all three homoeologs was demonstrated. To investigate the feasibility of BMV VIGS in wheat roots, ectopically expressed enhanced GREEN FLUORESCENT PROTEIN (eGFP) in a transgenic wheat line was targeted for silencing. Silencing of eGFP fluorescence was observed in both the maturation and elongation zones of roots. BMVCP5 mediated significant silencing of eGFP and TaPHO2 mRNA expression in roots at 14 and 21 dpi, and TaPHO2 silencing led to the doubling of inorganic phosphate concentration in the 2nd through 4th systemic leaves. All 54 wheat cultivars screened were susceptible to BMV infection. BMVCP5-mediated TaPDS silencing resulted in the expected bleaching phenotype in all eight cultivars examined, and decreased TaPDS transcript was detected in all three cultivars examined. This BMVCP5 VIGS technology may serve as a rapid and effective functional genomics tool for high-throughput gene function studies in aerial and root tissues and in many wheat cultivars.
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4
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Ding Y, Weckwerth PR, Poretsky E, Murphy KM, Sims J, Saldivar E, Christensen SA, Char SN, Yang B, Tong AD, Shen Z, Kremling KA, Buckler ES, Kono T, Nelson DR, Bohlmann J, Bakker MG, Vaughan MM, Khalil AS, Betsiashvili M, Dressano K, Köllner TG, Briggs SP, Zerbe P, Schmelz EA, Huffaker A. Genetic elucidation of interconnected antibiotic pathways mediating maize innate immunity. NATURE PLANTS 2020; 6:1375-1388. [PMID: 33106639 DOI: 10.1038/s41477-020-00787-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 09/11/2020] [Indexed: 05/24/2023]
Abstract
Specialized metabolites constitute key layers of immunity that underlie disease resistance in crops; however, challenges in resolving pathways limit our understanding of the functions and applications of these metabolites. In maize (Zea mays), the inducible accumulation of acidic terpenoids is increasingly considered to be a defence mechanism that contributes to disease resistance. Here, to understand maize antibiotic biosynthesis, we integrated association mapping, pan-genome multi-omic correlations, enzyme structure-function studies and targeted mutagenesis. We define ten genes in three zealexin (Zx) gene clusters that encode four sesquiterpene synthases and six cytochrome P450 proteins that collectively drive the production of diverse antibiotic cocktails. Quadruple mutants in which the ability to produce zealexins (ZXs) is blocked exhibit a broad-spectrum loss of disease resistance. Genetic redundancies ensuring pathway resiliency to single null mutations are combined with enzyme substrate promiscuity, creating a biosynthetic hourglass pathway that uses diverse substrates and in vivo combinatorial chemistry to yield complex antibiotic blends. The elucidated genetic basis of biochemical phenotypes that underlie disease resistance demonstrates a predominant maize defence pathway and informs innovative strategies for transferring chemical immunity between crops.
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Affiliation(s)
- Yezhang Ding
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | - Philipp R Weckwerth
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | - Elly Poretsky
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | - Katherine M Murphy
- Department of Plant Biology, University of California Davis, Davis, CA, USA
| | - James Sims
- ETH Zurich, Institute of Agricultural Sciences, Zurich, Switzerland
| | - Evan Saldivar
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | - Shawn A Christensen
- Chemistry Research Unit, Center for Medical, Agricultural and Veterinary Entomology, Department of Agriculture, Agricultural Research Service, Gainesville, FL, USA
| | - Si Nian Char
- Division of Plant Sciences, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Bing Yang
- Division of Plant Sciences, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
- Donald Danforth Plant Science Center, St Louis, MO, USA
| | - Anh-Dao Tong
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | - Zhouxin Shen
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | - Karl A Kremling
- Department of Plant Breeding and Genetics, Cornell University, Ithaca, NY, USA
| | - Edward S Buckler
- Department of Plant Breeding and Genetics, Cornell University, Ithaca, NY, USA
- Robert W. Holley Center for Agriculture and Health, Ithaca, US Department of Agriculture, Agricultural Research Service, New York, NY, USA
| | - Tom Kono
- Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN, USA
| | - David R Nelson
- University of Tennessee Health Science Center, Memphis, TN, USA
| | - Jörg Bohlmann
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Matthew G Bakker
- National Center for Agricultural Utilization Research, US Department of Agriculture, Agricultural Research Service, Peoria, IL, USA
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Martha M Vaughan
- National Center for Agricultural Utilization Research, US Department of Agriculture, Agricultural Research Service, Peoria, IL, USA
| | - Ahmed S Khalil
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | - Mariam Betsiashvili
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | - Keini Dressano
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | | | - Steven P Briggs
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | - Philipp Zerbe
- Department of Plant Biology, University of California Davis, Davis, CA, USA
| | - Eric A Schmelz
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | - Alisa Huffaker
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA.
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5
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Yuan W, Jiang T, Du K, Chen H, Cao Y, Xie J, Li M, Carr JP, Wu B, Fan Z, Zhou T. Maize phenylalanine ammonia-lyases contribute to resistance to Sugarcane mosaic virus infection, most likely through positive regulation of salicylic acid accumulation. MOLECULAR PLANT PATHOLOGY 2019; 20:1365-1378. [PMID: 31487111 PMCID: PMC6792131 DOI: 10.1111/mpp.12817] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Sugarcane mosaic virus (SCMV) is a pathogen of worldwide importance that causes dwarf mosaic disease on maize (Zea mays). Until now, few maize genes/proteins have been shown to be involved in resistance to SCMV. In this study, we characterized the role of maize phenylalanine ammonia-lyases (ZmPALs) in accumulation of the defence signal salicylic acid (SA) and in resistance to virus infection. SCMV infection significantly increased SA accumulation and expression of SA-responsive pathogenesis-related protein genes (PRs). Interestingly, exogenous SA treatment decreased SCMV accumulation and enhanced resistance. Both reverse transcription-coupled quantitative PCR and RNA-Seq data confirmed that expression levels of at least four ZmPAL genes were significantly up-regulated upon SCMV infection. Knockdown of ZmPAL expression led to enhanced SCMV infection symptom severity and virus multiplication, and simultaneously resulted in decreased SA accumulation and PR gene expression. Intriguingly, application of exogenous SA to SCMV-infected ZmPAL-silenced maize plants decreased SCMV accumulation, showing that ZmPALs are required for SA-mediated resistance to SCMV infection. In addition, lignin measurements and metabolomic analysis showed that ZmPALs are also involved in SCMV-induced lignin accumulation and synthesis of other secondary metabolites via the phenylpropanoid pathway. In summary, our results indicate that ZmPALs are required for SA accumulation in maize and are involved in resistance to virus infection by limiting virus accumulation and moderating symptom severity.
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Affiliation(s)
- Wen Yuan
- State Key Laboratory for Agro‐BiotechnologyChina Agricultural UniversityBeijing100193China
- Ministry of Agriculture and Rural Affairs, Key Laboratory for Pest Monitoring and Green Management, Department of Plant PathologyChina Agricultural UniversityBeijing100193China
| | - Tong Jiang
- State Key Laboratory for Agro‐BiotechnologyChina Agricultural UniversityBeijing100193China
- Ministry of Agriculture and Rural Affairs, Key Laboratory for Pest Monitoring and Green Management, Department of Plant PathologyChina Agricultural UniversityBeijing100193China
| | - Kaitong Du
- State Key Laboratory for Agro‐BiotechnologyChina Agricultural UniversityBeijing100193China
- Ministry of Agriculture and Rural Affairs, Key Laboratory for Pest Monitoring and Green Management, Department of Plant PathologyChina Agricultural UniversityBeijing100193China
| | - Hui Chen
- State Key Laboratory for Agro‐BiotechnologyChina Agricultural UniversityBeijing100193China
- Ministry of Agriculture and Rural Affairs, Key Laboratory for Pest Monitoring and Green Management, Department of Plant PathologyChina Agricultural UniversityBeijing100193China
| | - Yanyong Cao
- Cereal Crops InstituteHenan Academy of Agricultural ScienceZhengzhou450002China
| | - Jipeng Xie
- State Key Laboratory for Agro‐BiotechnologyChina Agricultural UniversityBeijing100193China
- Ministry of Agriculture and Rural Affairs, Key Laboratory for Pest Monitoring and Green Management, Department of Plant PathologyChina Agricultural UniversityBeijing100193China
| | - Mengfei Li
- State Key Laboratory for Agro‐BiotechnologyChina Agricultural UniversityBeijing100193China
- Ministry of Agriculture and Rural Affairs, Key Laboratory for Pest Monitoring and Green Management, Department of Plant PathologyChina Agricultural UniversityBeijing100193China
| | - John P. Carr
- Department of Plant SciencesUniversity of CambridgeDowning StreetCambridgeCB2 3EAUK
| | - Boming Wu
- Ministry of Agriculture and Rural Affairs, Key Laboratory for Pest Monitoring and Green Management, Department of Plant PathologyChina Agricultural UniversityBeijing100193China
| | - Zaifeng Fan
- State Key Laboratory for Agro‐BiotechnologyChina Agricultural UniversityBeijing100193China
- Ministry of Agriculture and Rural Affairs, Key Laboratory for Pest Monitoring and Green Management, Department of Plant PathologyChina Agricultural UniversityBeijing100193China
| | - Tao Zhou
- State Key Laboratory for Agro‐BiotechnologyChina Agricultural UniversityBeijing100193China
- Ministry of Agriculture and Rural Affairs, Key Laboratory for Pest Monitoring and Green Management, Department of Plant PathologyChina Agricultural UniversityBeijing100193China
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Kant R, Dasgupta I. Gene silencing approaches through virus-based vectors: speeding up functional genomics in monocots. PLANT MOLECULAR BIOLOGY 2019; 100:3-18. [PMID: 30850930 DOI: 10.1007/s11103-019-00854-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 03/02/2019] [Indexed: 05/20/2023]
Abstract
The design and use of existing VIGS vectors for revealing monocot gene functions are described and potential new vectors are discussed, which may expand their repertoire. Virus induced gene silencing (VIGS) is a method of transient gene silencing in plants, triggered by the use of modified viral vectors. VIGS has found widespread use in deciphering the functions of plant genes, mainly for dicots. In the last decade, however, its use in monocots has increased noticeably, involving not only previously described viruses for monocots, but also those described for dicots. Additional viruses have been modified for VIGS to bring a larger collection of monocots under the ambit of this method. For monocots, new methods of inoculation have been tried to obtain increased silencing efficiency. The issue of insert stability and duration of silencing have also been addressed by various research groups. VIGS has been used to unravel the functions of a fairly large collection of monocot genes. This review summarizes the above developments, bringing out some of the gaps in our understanding and identifies directions to develop this technology further in the coming years.
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Affiliation(s)
- Ravi Kant
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Indranil Dasgupta
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
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Block AK, Vaughan MM, Schmelz EA, Christensen SA. Biosynthesis and function of terpenoid defense compounds in maize (Zea mays). PLANTA 2019; 249:21-30. [PMID: 30187155 DOI: 10.1007/s00425-018-2999-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 08/30/2018] [Indexed: 05/19/2023]
Abstract
Maize produces an array of herbivore-induced terpene volatiles that attract parasitoids to infested plants and a suite of pathogen-induced non-volatile terpenoids with antimicrobial activity to defend against pests. Plants rely on complex blends of constitutive and dynamically produced specialized metabolites to mediate beneficial ecological interactions and protect against biotic attack. One such class of metabolites are terpenoids, a large and structurally diverse class of molecules shown to play significant defensive and developmental roles in numerous plant species. Despite this, terpenoids have only recently been recognized as significant contributors to pest resistance in maize (Zea mays), a globally important agricultural crop. The current review details recent advances in our understanding of biochemical structures, pathways and functional roles of maize terpenoids. Dependent upon the lines examined, maize can harbor more than 30 terpene synthases, underlying the inherent diversity of maize terpene defense systems. Part of this defensive arsenal is the inducible production of volatile bouquets that include monoterpenes, homoterpenes and sesquiterpenes, which often function in indirect defense by enabling the attraction of parasitoids and predators. More recently discovered are a subset of sesquiterpene and diterpene hydrocarbon olefins modified by cytochrome P450s to produce non-volatile end-products such kauralexins, zealexins, dolabralexins and β-costic acid. These non-volatile terpenoid phytoalexins often provide effective defense against both microbial and insect pests via direct antimicrobial and anti-feedant activity. The diversity and promiscuity of maize terpene synthases, coupled with a variety of secondary modifications, results in elaborate defensive layers whose identities, regulation and precise functions are continuing to be elucidated.
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Affiliation(s)
- Anna K Block
- Center for Medical, Agricultural and Veterinary Entomology, U.S. Department of Agriculture-Agricultural Research Service, 1700 SW 23rd Drive, Gainesville, FL, 32608, USA.
| | - Martha M Vaughan
- National Center for Agricultural Utilization Research, U.S. Department of Agriculture-Agricultural Research Service, 1815 N. University Street, Peoria, IL, 61604, USA
| | - Eric A Schmelz
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, 92093, USA
| | - Shawn A Christensen
- Center for Medical, Agricultural and Veterinary Entomology, U.S. Department of Agriculture-Agricultural Research Service, 1700 SW 23rd Drive, Gainesville, FL, 32608, USA
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8
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Singh DK, Lee HK, Dweikat I, Mysore KS. An efficient and improved method for virus-induced gene silencing in sorghum. BMC PLANT BIOLOGY 2018; 18:123. [PMID: 29914379 PMCID: PMC6006947 DOI: 10.1186/s12870-018-1344-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 06/06/2018] [Indexed: 05/08/2023]
Abstract
BACKGROUND Although the draft genome of sorghum is available, the understanding of gene function is limited due to the lack of extensive mutant resources. Virus-induced gene silencing (VIGS) is an alternative to mutant resources to study gene function. This study reports an improved and efficient method for Brome mosaic virus (BMV)-based VIGS in sorghum. METHODS Sorghum plants were rub-inoculated with sap prepared by grinding 2 g of infected Nicotiana benthamiana leaf in 1 ml 10 mM potassium phosphate buffer (pH 6.8) and 100 mg of carborundum abrasive. The sap was rubbed on two to three top leaves of sorghum. Inoculated plants were covered with a dome to maintain high humidity and kept in the dark for two days at 18 °C. Inoculated plants were then transferred to 18 °C growth chamber with 12 h/12 h light/dark cycle. RESULTS This study shows that BMV infection rate can be significantly increased in sorghum by incubating plants at 18 °C. A substantial variation in BMV infection rate in sorghum genotypes/varieties was observed and BTx623 was the most susceptible. Ubiquitin (Ubiq) silencing is a better visual marker for VIGS in sorghum compared to other markers such as Magnesium Chelatase subunit H (ChlH) and Phytoene desaturase (PDS). The use of antisense strand of a gene in BMV was found to significantly increase the efficiency and extent of VIGS in sorghum. In situ hybridization experiments showed that the non-uniform silencing in sorghum is due to the uneven spread of the virus. This study further demonstrates that genes could also be silenced in the inflorescence of sorghum. CONCLUSION In general, sorghum plants are difficult to infect with BMV and therefore recalcitrant to VIGS studies. However, by using BMV as a vector, a BMV susceptible sorghum variety, 18 °C for incubating plants, and antisense strand of the target gene fragment, efficient VIGS can still be achieved in sorghum.
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Affiliation(s)
| | - Hee-Kyung Lee
- Noble Research Institute, Ardmore, Oklahoma 73401 USA
| | - Ismail Dweikat
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, Nebraska 68583 USA
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9
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Jarugula S, Willie K, Stewart LR. Barley stripe mosaic virus (BSMV) as a virus-induced gene silencing vector in maize seedlings. Virus Genes 2018; 54:616-620. [PMID: 29752616 DOI: 10.1007/s11262-018-1569-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/04/2018] [Indexed: 01/11/2023]
Abstract
Barley stripe mosaic virus (BSMV) was the first reported and still widely used virus-induced gene silencing (VIGS) vector for monocotyledons including wheat and barley. Despite BSMV's reported infectivity on maize (Zea mays), the use of the virus as a vector in maize has not been optimized. Here, we assayed infectivity of BSMV in different maize cultivars by vascular puncture inoculation. Through knockdown of the endogenous host phytoene desaturase gene, we demonstrate for the first time that BSMV can be used as a VIGS vector in maize. This adds BSMV to the repertoire of tools available for functional studies in maize.
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Affiliation(s)
- Sridhar Jarugula
- Center for Applied Plant Sciences, Ohio State University, 1680 Madison Ave, Wooster, OH, 44691, USA.,Department of Plant Pathology, Washington State University, Irrigated Agriculture Research and Extension center, 24106 N. Bunn Rd, Prosser, WA, USA
| | - Kristen Willie
- Corn, Soybean, and Wheat Quality Research Unit, USDA-ARS, 1680 Madison Ave, Wooster, OH, USA
| | - Lucy R Stewart
- Center for Applied Plant Sciences, Ohio State University, 1680 Madison Ave, Wooster, OH, 44691, USA. .,Corn, Soybean, and Wheat Quality Research Unit, USDA-ARS, 1680 Madison Ave, Wooster, OH, USA.
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10
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Christensen SA, Huffaker A, Sims J, Hunter CT, Block A, Vaughan MM, Willett D, Romero M, Mylroie JE, Williams WP, Schmelz EA. Fungal and herbivore elicitation of the novel maize sesquiterpenoid, zealexin A4, is attenuated by elevated CO 2. PLANTA 2018; 247:863-873. [PMID: 29260396 DOI: 10.1007/s00425-017-2830-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chemical isolation and NMR-based structure elucidation revealed a novel keto-acidic sesquiterpenoid, termed zealexin A4 (ZA4). ZA4 is elicited by pathogens and herbivory, but attenuated by heightened levels of CO 2 . The identification of the labdane-related diterpenoids, termed kauralexins and acidic sesquiterpenoids, termed zealexins, demonstrated the existence of at least ten novel stress-inducible maize metabolites with diverse antimicrobial activity. Despite these advances, the identity of co-occurring and predictably related analytes remains largely unexplored. In the current effort, we identify and characterize the first sesquiterpene keto acid derivative of β-macrocarpene, named zealexin A4 (ZA4). Evaluation of diverse maize inbreds revealed that ZA4 is commonly produced in maize scutella during the first 14 days of seedling development; however, ZA4 production in the scutella was markedly reduced in seedlings grown in sterile soil. Elevated ZA4 production was observed in response to inoculation with adventitious fungal pathogens, such as Aspergillus flavus and Rhizopus microsporus, and a positive relationship between ZA4 production and expression of the predicted zealexin biosynthetic genes, terpene synthases 6 and 11 (Tps6 and Tps11), was observed. ZA4 exhibited significant antimicrobial activity against the mycotoxigenic pathogen A. flavus; however, ZA4 activity against R. microsporus was minimal, suggesting the potential of some fungi to detoxify ZA4. Significant induction of ZA4 production was also observed in response to infestation with the stem tunneling herbivore Ostrinia nubilalis. Examination of the interactive effects of elevated CO2 (E-CO2) on both fungal and herbivore-elicited ZA4 production revealed significantly reduced levels of inducible ZA4 accumulation, consistent with a negative role for E-CO2 on ZA4 production. Collectively, these results describe a novel β-macrocarpene-derived antifungal defense in maize and expand the established diversity of zealexins that are differentially regulated in response to biotic/abiotic stress.
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Affiliation(s)
- Shawn A Christensen
- Chemistry Research Unit, Center for Medical, Agricultural, and Veterinary Entomology, United States Department of Agriculture, Agricultural Research Service, Gainesville, FL, 32608, USA.
| | - Alisa Huffaker
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, 92093-0380, USA
| | - James Sims
- Department of Environmental Systems Science, ETH Zurich, 8092, Zurich, Switzerland
| | - Charles T Hunter
- Chemistry Research Unit, Center for Medical, Agricultural, and Veterinary Entomology, United States Department of Agriculture, Agricultural Research Service, Gainesville, FL, 32608, USA
| | - Anna Block
- Chemistry Research Unit, Center for Medical, Agricultural, and Veterinary Entomology, United States Department of Agriculture, Agricultural Research Service, Gainesville, FL, 32608, USA
| | - Martha M Vaughan
- Mycotoxin Prevention and Applied Microbiology Research, United States Department of Agriculture, Agricultural Research Service, 1815 N. University St., Peoria, IL, 61604, USA
| | - Denis Willett
- Chemistry Research Unit, Center for Medical, Agricultural, and Veterinary Entomology, United States Department of Agriculture, Agricultural Research Service, Gainesville, FL, 32608, USA
| | - Maritza Romero
- Chemistry Research Unit, Center for Medical, Agricultural, and Veterinary Entomology, United States Department of Agriculture, Agricultural Research Service, Gainesville, FL, 32608, USA
| | - J Erik Mylroie
- Bennett Aerospace, Engineer and Research Development Center, Vicksburg, MS, 39180, USA
| | - W Paul Williams
- Crop Science Research Laboratory, United States Department of Agriculture, Agricultural Research Service, Dorman Hall, Stone Blvd., Starkville, MS, 39762, USA
| | - Eric A Schmelz
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, 92093-0380, USA.
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11
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Ziemann S, van der Linde K, Lahrmann U, Acar B, Kaschani F, Colby T, Kaiser M, Ding Y, Schmelz E, Huffaker A, Holton N, Zipfel C, Doehlemann G. An apoplastic peptide activates salicylic acid signalling in maize. NATURE PLANTS 2018; 4:172-180. [PMID: 29483684 DOI: 10.1038/s41477-018-0116-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 01/26/2018] [Indexed: 05/06/2023]
Abstract
Localized control of cell death is crucial for the resistance of plants to pathogens. Papain-like cysteine proteases (PLCPs) regulate plant defence to drive cell death and protection against biotrophic pathogens. In maize (Zea mays), PLCPs are crucial in the orchestration of salicylic acid (SA)-dependent defence signalling. Despite this central role in immunity, it remains unknown how PLCPs are activated, and which downstream signals they induce to trigger plant immunity. Here, we discover an immune signalling peptide, Z. mays immune signalling peptide 1 (Zip1), which is produced after salicylic acid (SA) treatment. In vitro studies demonstrate that PLCPs are required to release bioactive Zip1 from its propeptide precursor. Conversely, Zip1 treatment strongly elicits SA accumulation in leaves. Moreover, transcriptome analyses revealed that Zip1 and SA induce highly overlapping transcriptional changes. Consequently, Zip1 promotes the infection of the necrotrophic fungus Botrytis cinerea, while it reduces virulence of the biotrophic fungus Ustilago maydis. Thus, Zip1 represents the previously missing signal that is released by PLCPs to activate SA defence signalling.
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Affiliation(s)
- Sebastian Ziemann
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, BioCenter, Cologne, Germany
| | - Karina van der Linde
- Department of Biology, Stanford University, Stanford, CA, USA
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Urs Lahrmann
- Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, Division of Personalized Tumor Therapy, Regensburg, Germany
| | - Beyda Acar
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, BioCenter, Cologne, Germany
| | - Farnusch Kaschani
- Centre for Medical Biotechnology, Chemical Biology, Faculty of Biology, University Duisburg-Essen, Essen, Germany
| | - Tom Colby
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Markus Kaiser
- Centre for Medical Biotechnology, Chemical Biology, Faculty of Biology, University Duisburg-Essen, Essen, Germany
| | - Yezhang Ding
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | - Eric Schmelz
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | - Alisa Huffaker
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA, USA
| | - Nicholas Holton
- The Sainsbury Laboratory, Norwich Research Park, Norwich, UK
| | - Cyril Zipfel
- The Sainsbury Laboratory, Norwich Research Park, Norwich, UK
| | - Gunther Doehlemann
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, BioCenter, Cologne, Germany.
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12
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Host-Induced Gene Silencing of Rice Blast Fungus Magnaporthe oryzae Pathogenicity Genes Mediated by the Brome Mosaic Virus. Genes (Basel) 2017; 8:genes8100241. [PMID: 28954400 PMCID: PMC5664091 DOI: 10.3390/genes8100241] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 09/18/2017] [Accepted: 09/20/2017] [Indexed: 11/17/2022] Open
Abstract
Magnaportheoryzae is a devastating plant pathogen, which has a detrimental impact on rice production worldwide. Despite its agronomical importance, some newly-emerging pathotypes often overcome race-specific disease resistance rapidly. It is thus desirable to develop a novel strategy for the long-lasting resistance of rice plants to ever-changing fungal pathogens. Brome mosaic virus (BMV)-induced RNA interference (RNAi) has emerged as a useful tool to study host-resistance genes for rice blast protection. Planta-generated silencing of targeted genes inside biotrophic pathogens can be achieved by expression of M.oryzae-derived gene fragments in the BMV-mediated gene silencing system, a technique termed host-induced gene silencing (HIGS). In this study, the effectiveness of BMV-mediated HIGS in M.oryzae was examined by targeting three predicted pathogenicity genes, MoABC1,MoMAC1 and MoPMK1. Systemic generation of fungal gene-specific small interfering RNA (siRNA) molecules induced by inoculation of BMV viral vectors inhibited disease development and reduced the transcription of targeted fungal genes after subsequent M.oryzae inoculation. Combined introduction of fungal gene sequences in sense and antisense orientation mediated by the BMV silencing vectors significantly enhanced the efficiency of this host-generated trans-specific RNAi, implying that these fungal genes played crucial roles in pathogenicity. Collectively, our results indicated that BMV-HIGS system was a great strategy for protecting host plants against the invasion of pathogenic fungi.
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13
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Ramegowda V, Gill US, Sivalingam PN, Gupta A, Gupta C, Govind G, Nataraja KN, Pereira A, Udayakumar M, Mysore KS, Senthil-Kumar M. GBF3 transcription factor imparts drought tolerance in Arabidopsis thaliana. Sci Rep 2017; 7:9148. [PMID: 28831141 PMCID: PMC5567290 DOI: 10.1038/s41598-017-09542-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 07/24/2017] [Indexed: 11/24/2022] Open
Abstract
Drought transcriptome analysis of finger millet (Eleusine coracana) by cDNA subtraction identified drought responsive genes that have a potential role in drought tolerance. Through virus-induced gene silencing (VIGS) in a related crop species, maize (Zea mays), several genes, including a G-BOX BINDING FACTOR 3 (GBF3) were identified as candidate drought stress response genes and the role of GBF3 in drought tolerance was studied in Arabidopsis thaliana. Overexpression of both EcGBF3 and AtGBF3 in A. thaliana resulted in improved tolerance to osmotic stress, salinity and drought stress in addition to conferring insensitivity to ABA. Conversely, loss of function of this gene increased the sensitivity of A. thaliana plants to drought stress. EcGBF3 transgenic A. thaliana results also suggest that drought tolerance of sensitive plants can be improved by transferring genes from far related crops like finger millet. Our results demonstrate the role of GBF3 in imparting drought tolerance in A. thaliana and indicate the conserved role of this gene in drought and other abiotic stress tolerance in several plant species.
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Affiliation(s)
- Venkategowda Ramegowda
- Department of Crop Physiology, University of Agricultural Sciences, Bengaluru, 560065, India.,Department of Crop, Soil and Environmental Sciences, University of Arkansas, Fayetteville, USA
| | - Upinder Singh Gill
- Noble Research Institute, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Palaiyur Nanjappan Sivalingam
- Noble Research Institute, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA.,ICAR-Central Institute for Arid Horticulture, Indian Council of Agricultural Research, Bikaner, 334006, India.,ICAR-National Institute of Biotic Stress Management, Indian Council of Agricultural Research, Raipur, 493225, India
| | - Aarti Gupta
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, PO Box No. 10531, New Delhi, 110 067, India
| | - Chirag Gupta
- Department of Crop, Soil and Environmental Sciences, University of Arkansas, Fayetteville, USA
| | - Geetha Govind
- Department of Crop Physiology, University of Agricultural Sciences, Bengaluru, 560065, India
| | - Karaba N Nataraja
- Department of Crop Physiology, University of Agricultural Sciences, Bengaluru, 560065, India
| | - Andy Pereira
- Department of Crop, Soil and Environmental Sciences, University of Arkansas, Fayetteville, USA
| | - Makarla Udayakumar
- Department of Crop Physiology, University of Agricultural Sciences, Bengaluru, 560065, India
| | | | - Muthappa Senthil-Kumar
- Department of Crop Physiology, University of Agricultural Sciences, Bengaluru, 560065, India. .,Noble Research Institute, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA. .,National Institute of Plant Genome Research, Aruna Asaf Ali Marg, PO Box No. 10531, New Delhi, 110 067, India.
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14
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Chen H, Cao Y, Li Y, Xia Z, Xie J, Carr JP, Wu B, Fan Z, Zhou T. Identification of differentially regulated maize proteins conditioning Sugarcane mosaic virus systemic infection. THE NEW PHYTOLOGIST 2017; 215:1156-1172. [PMID: 28627019 DOI: 10.1111/nph.14645] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 04/30/2017] [Indexed: 05/25/2023]
Abstract
Sugarcane mosaic virus (SCMV) is the most important cause of maize dwarf mosaic disease. To identify maize genes responsive to SCMV infection and that may be involved in pathogenesis, a comparative proteomic analysis was performed using the first and second systemically infected leaves (termed 1 SL and 2 SL, respectively). Seventy-one differentially expressed proteins were identified in 1 SL and 2 SL upon SCMV infection. Among them, eight proteins showed the same changing patterns in both 1 SL and 2 SL. Functional annotations of regulated proteins and measurement of photosynthetic activity revealed that photosynthesis was more inhibited and defensive gene expression more pronounced in 1 SL than in 2 SL. Knockdown of regulated proteins in both 1 SL and 2 SL by a brome mosaic virus-based gene silencing vector in maize indicated that protein disulfide isomerase-like and phosphoglycerate kinase were required for optimal SCMV replication. By contrast, knockdown of polyamine oxidase (ZmPAO) significantly increased SCMV accumulation, implying that ZmPAO activity might contribute to resistance or tolerance. The results suggest that combining comparative proteomic analyses of different tissues and virus-induced gene silencing is an efficient way to identify host proteins supporting virus replication or enhancing resistance to virus infection.
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Affiliation(s)
- Hui Chen
- State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing, 100193, China
| | - Yanyong Cao
- Cereal Crops Institute, Henan Academy of Agricultural Science, Zhengzhou, 450002, China
| | - Yiqing Li
- College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Zihao Xia
- State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing, 100193, China
| | - Jipeng Xie
- State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing, 100193, China
| | - John P Carr
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Boming Wu
- State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing, 100193, China
| | - Zaifeng Fan
- State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing, 100193, China
| | - Tao Zhou
- State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing, 100193, China
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15
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Kant R, Dasgupta I. Phenotyping of VIGS-mediated gene silencing in rice using a vector derived from a DNA virus. PLANT CELL REPORTS 2017; 36:1159-1170. [PMID: 28540496 DOI: 10.1007/s00299-017-2156-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 05/15/2017] [Indexed: 05/09/2023]
Abstract
Target genes in rice can be optimally silenced if inserted in antisense or hairpin orientation in the RTBV-derived VIGS vector and plants grown at 28 °C and 80% humidity after inoculation. Virus induced gene silencing (VIGS) is a method used to transiently silence genes in dicot as well as monocot plants. For the important monocot species rice, the Rice tungro bacilliform virus (RTBV)-derived VIGS system (RTBV-VIGS), which uses agroinoculation to initiate silencing, has not been standardized for optimal use. Here, using RTBV-VIGS, three sets of conditions were tested to achieve optimal silencing of the rice marker gene phytoene desaturase (pds). The effect of orientation of the insert in the RTBV-VIGS plasmid (sense, antisense and hairpin) on the silencing of the target gene was then evaluated using rice magnesium chelatase subunit H (chlH). Finally, the rice Xa21 gene, conferring resistance against bacterial leaf blight disease (BLB) was silenced using RTBV-VIGS system. In each case, real-time PCR-based assessment indicated approximately 40-80% fall in the accumulation levels of the transcripts of pds, chlH and Xa21. In the case of pds, the appearance of white streaks in the emerging leaves, and for chlH, chlorophyll levels and F v/F m ratio were assessed as phenotypes for silencing. For Xa21, the resistance levels to BLB were assessed by measuring the lesion length and the percent diseased areas of leaves, following challenge inoculation with Xanthomonas oryzae. In each case, the RTBV-MVIGS system gave rise to a discernible phenotype indicating the silencing of the respective target gene using condition III (temperature 28 °C, humidity 80% and 1 mM MES and 20 µM acetosyringone in secondary agrobacterium culture), which revealed the robustness of this gene silencing system for rice.
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Affiliation(s)
- Ravi Kant
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Indranil Dasgupta
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
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16
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Abstract
Biotrophic fungal plant pathogens establish an intimate relationship with their host to support the infection process. Central to this strategy is the secretion of a range of protein effectors that enable the pathogen to evade plant immune defences and modulate host metabolism to meet its needs. In this Review, using the smut fungus Ustilago maydis as an example, we discuss new insights into the effector repertoire of smut fungi that have been gained from comparative genomics and discuss the molecular mechanisms by which U. maydis effectors change processes in the plant host. Finally, we examine how the expression of effector genes and effector secretion are coordinated with fungal development in the host.
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17
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Wang R, Yang X, Wang N, Liu X, Nelson RS, Li W, Fan Z, Zhou T. An efficient virus-induced gene silencing vector for maize functional genomics research. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 86:102-15. [PMID: 26921244 DOI: 10.1111/tpj.13142] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 02/01/2016] [Accepted: 02/08/2016] [Indexed: 05/02/2023]
Abstract
Maize is a major crop whose rich genetic diversity provides an advanced resource for genetic research. However, a tool for rapid transient gene function analysis in maize that may be utilized in most maize cultivars has been lacking, resulting in reliance on time-consuming stable transformation and mutation studies to obtain answers. We developed an efficient virus-induced gene silencing (VIGS) vector for maize based on a naturally maize-infecting cucumber mosaic virus (CMV) strain, ZMBJ-CMV. An infectious clone of ZMBJ-CMV was constructed, and a vascular puncture inoculation method utilizing Agrobacterium was optimized to improve its utility for CMV infection of maize. ZMBJ-CMV was then modified to function as a VIGS vector. The ZMBJ-CMV vector induced mild to moderate symptoms in many maize lines, making it useful for gene function studies in critically important maize cultivars, such as the sequenced reference inbred line B73. Using this CMV VIGS system, expression of two endogenous genes, ZmPDS and ZmIspH, was found to be decreased by 75% and 78%, respectively, compared with non-silenced tissue. Inserts with lengths of 100-300 bp produced the most complete transcriptional and visual silencing phenotypes. Moreover, genes related to autophagy, ZmATG3 and ZmATG8a, were also silenced, and it was found that they function in leaf starch degradation. These results indicate that our ZMBJ-CMV VIGS vector provides a tool for rapid and efficient gene function studies in maize.
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Affiliation(s)
- Rong Wang
- State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing, 100193, China
| | - Xinxin Yang
- State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing, 100193, China
| | - Nian Wang
- State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing, 100193, China
| | - Xuedong Liu
- State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing, 100193, China
| | - Richard S Nelson
- Plant Biology Division, The Samuel Roberts Noble Foundation Inc., 2510 Sam Noble Parkway, Ardmore, OK 73401, USA
| | - Weimin Li
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, 12 South Zhongguancun Street, Beijing, 100081, China
| | - Zaifeng Fan
- State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing, 100193, China
| | - Tao Zhou
- State Key Laboratory for Agro-Biotechnology and Department of Plant Pathology, China Agricultural University, Beijing, 100193, China
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18
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Torres MF, Ghaffari N, Buiate EAS, Moore N, Schwartz S, Johnson CD, Vaillancourt LJ. A Colletotrichum graminicola mutant deficient in the establishment of biotrophy reveals early transcriptional events in the maize anthracnose disease interaction. BMC Genomics 2016; 17:202. [PMID: 26956617 PMCID: PMC4782317 DOI: 10.1186/s12864-016-2546-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 02/26/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Colletotrichum graminicola is a hemibiotrophic fungal pathogen that causes maize anthracnose disease. It progresses through three recognizable phases of pathogenic development in planta: melanized appressoria on the host surface prior to penetration; biotrophy, characterized by intracellular colonization of living host cells; and necrotrophy, characterized by host cell death and symptom development. A "Mixed Effects" Generalized Linear Model (GLM) was developed and applied to an existing Illumina transcriptome dataset, substantially increasing the statistical power of the analysis of C. graminicola gene expression during infection and colonization. Additionally, the in planta transcriptome of the wild-type was compared with that of a mutant strain impaired in the establishment of biotrophy, allowing detailed dissection of events occurring specifically during penetration, and during early versus late biotrophy. RESULTS More than 2000 fungal genes were differentially transcribed during appressorial maturation, penetration, and colonization. Secreted proteins, secondary metabolism genes, and membrane receptors were over-represented among the differentially expressed genes, suggesting that the fungus engages in an intimate and dynamic conversation with the host, beginning prior to penetration. This communication process probably involves reception of plant signals triggering subsequent developmental progress in the fungus, as well as production of signals that induce responses in the host. Later phases of biotrophy were more similar to necrotrophy, with increased production of secreted proteases, inducers of plant cell death, hydrolases, and membrane bound transporters for the uptake and egress of potential toxins, signals, and nutrients. CONCLUSIONS This approach revealed, in unprecedented detail, fungal genes specifically expressed during critical phases of host penetration and biotrophic establishment. Many encoded secreted proteins, secondary metabolism enzymes, and receptors that may play roles in host-pathogen communication necessary to promote susceptibility, and thus may provide targets for chemical or biological controls to manage this important disease. The differentially expressed genes could be used as 'landmarks' to more accurately identify developmental progress in compatible versus incompatible interactions involving genetic variants of both host and pathogen.
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Affiliation(s)
- Maria F Torres
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY, 40546-0312, USA.
- Present Address: Functional Genomics Laboratory, Weill Cornell Medical College, Cornell University, Qatar Foundation - Education City, Doha, Qatar.
| | - Noushin Ghaffari
- AgriLife Genomics and Bioinformatics, Texas A&M AgriLife Research, Texas A&M University, College Station, TX, 77845, USA.
| | - Ester A S Buiate
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY, 40546-0312, USA.
- Present Address: Monsanto Company Brazil, Uberlândia, Minas Gerais, Brazil.
| | - Neil Moore
- Department of Computer Science, University of Kentucky, Davis Marksbury Building, 328 Rose Street, Lexington, KY, 40506-0633, USA.
| | - Scott Schwartz
- AgriLife Genomics and Bioinformatics, Texas A&M AgriLife Research, Texas A&M University, College Station, TX, 77845, USA.
- Present Address: Department of Integrative Biology, University of Texas, Austin, TX, 78712, USA.
| | - Charles D Johnson
- AgriLife Genomics and Bioinformatics, Texas A&M AgriLife Research, Texas A&M University, College Station, TX, 77845, USA.
| | - Lisa J Vaillancourt
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY, 40546-0312, USA.
- Present Address: Department of Integrative Biology, University of Texas, Austin, TX, 78712, USA.
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19
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Parrott DL, Huang L, Fischer AM. Downregulation of a barley (Hordeum vulgare) leucine-rich repeat, non-arginine-aspartate receptor-like protein kinase reduces expression of numerous genes involved in plant pathogen defense. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 100:130-140. [PMID: 26820571 DOI: 10.1016/j.plaphy.2016.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 01/12/2016] [Indexed: 05/24/2023]
Abstract
Pattern recognition receptors represent a first line of plant defense against pathogens. Comparing the flag leaf transcriptomes of barley (Hordeum vulgare L.) near-isogenic lines varying in the allelic state of a locus controlling senescence, we have previously identified a leucine-rich repeat receptor-like protein kinase gene (LRR-RLK; GenBank accession: AK249842), which was strongly upregulated in leaves of early-as compared to late-senescing germplasm. Bioinformatic analysis indicated that this gene codes for a subfamily XII, non-arginine-aspartate (non-RD) LRR-RLK. Virus-induced gene silencing resulted in a two-fold reduction of transcript levels as compared to controls. Transcriptomic comparison of leaves from untreated plants, from plants treated with virus only without any plant sequences (referred to as 'empty virus' control), and from plants in which AK249842 expression was knocked down identified numerous genes involved in pathogen defense. These genes were strongly induced in 'empty virus' as compared to untreated controls, but their expression was significantly reduced (again compared to 'empty virus' controls) when AK249842 was knocked down, indicating that their expression partially depends on the LRR-RLK investigated here. Expression analysis, using datasets from BarleyBase/PLEXdb, demonstrated that AK249842 transcript levels are heavily influenced by the allelic state of the well-characterized mildew resistance a (Mla) locus, and that the gene is induced after powdery mildew and stem rust infection. Together, our data suggest that AK249842 is a barley pattern recognition receptor with a tentative role in defense against fungal pathogens, setting the stage for its full functional characterization.
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Affiliation(s)
- David L Parrott
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717-3150, USA
| | - Li Huang
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717-3150, USA
| | - Andreas M Fischer
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT 59717-3150, USA.
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20
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Mao H, Liu J, Ren F, Peters RJ, Wang Q. Characterization of CYP71Z18 indicates a role in maize zealexin biosynthesis. PHYTOCHEMISTRY 2016; 121:4-10. [PMID: 26471326 DOI: 10.1016/j.phytochem.2015.10.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 09/26/2015] [Accepted: 10/07/2015] [Indexed: 06/05/2023]
Abstract
Maize (Zea mays) produces zealexins as phytoalexins, with the inducible production of these antibiotics providing biochemical protection against fungal infection. However, the biosynthesis of these sesquiterpenoids has remained unclear. In particular, it is unclear how the olefinic precursor, (S)-β-macrocarpene produced by the characterized maize sesquiterpene synthases TPS6/11, is further elaborated to form the bioactive zealexins. The first step is likely to be conversion of carbon-15 (C15) from a methyl group to a carboxylic acid by a cytochrome P450 mono-oxygenase (CYP). In this study, CYP71Z18, whose transcription is strongly induced by fungal infection, was found to catalyze oxidation of C15 in (S)-β-macrocarpene, forming zealexin A1. The inducible transcription of CYP71Z18 matches that observed for TPS6/11 and the accumulation of zealexins, which is consistent with a role for CYP71Z18 in sesquiterpenoid phytoalexin production. This completes identification of zealexin A1 biosynthesis, and represents the initial CYP identified for the production of maize terpenoid phytoalexins.
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Affiliation(s)
- Hongjie Mao
- College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China.
| | - Jiang Liu
- College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China.
| | - Fei Ren
- College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China.
| | - Reuben J Peters
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
| | - Qiang Wang
- College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China; Institute of Ecological Agriculture, Sichuan Agricultural University, Chengdu 611130, China.
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21
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Strategies for altering plant traits using virus-induced gene silencing technologies. Methods Mol Biol 2015; 1287:25-41. [PMID: 25740354 DOI: 10.1007/978-1-4939-2453-0_2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The rapid progress in genome sequencing and transcriptome analysis in model and crop plants has made possible the identification of a vast number of genes potentially associated with economically important complex traits. The ultimate goal is to assign functions to these genes by using forward and reverse genetic screens. Plant viruses have been developed for virus-induced gene silencing (VIGS) to generate rapid gene knockdown phenotypes in numerous plant species. To fulfill its potential for high-throughput phenomics, it is of prime importance to ensure that parameters conditioning the VIGS response, i.e., plant-virus interactions and associated loss-of-function screens, are "fit for purpose" and optimized to unequivocally conclude the role of a gene of interest in relation to a given trait. This chapter will review and discuss the different strategies used for the development of VIGS-based phenomics in model and crop species.
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22
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Zhirnov IV, Trifonova EA, Kochetov AV, Shumny VK. Virus-induced silencing as a method for studying gene functions in higher plants. RUSS J GENET+ 2015. [DOI: 10.1134/s1022795415050099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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23
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Zhu M, Chen Y, Ding XS, Webb SL, Zhou T, Nelson RS, Fan Z. Maize Elongin C interacts with the viral genome-linked protein, VPg, of Sugarcane mosaic virus and facilitates virus infection. THE NEW PHYTOLOGIST 2014; 203:1291-1304. [PMID: 24954157 PMCID: PMC4143955 DOI: 10.1111/nph.12890] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 05/08/2014] [Indexed: 05/18/2023]
Abstract
The viral genome-linked protein, VPg, of potyviruses is involved in viral genome replication and translation. To determine host proteins that interact with Sugarcane mosaic virus (SCMV) VPg, a yeast two-hybrid screen was used and a maize (Zea mays) Elongin C (ZmElc) protein was identified. ZmELC transcript was observed in all maize organs, but most highly in leaves and pistil extracts, and ZmElc was present in the cytoplasm and nucleus of maize cells in the presence or absence of SCMV. ZmELC expression was increased in maize tissue at 4 and 6 d post SCMV inoculation. When ZmELC was transiently overexpressed in maize protoplasts the accumulation of SCMV RNA was approximately doubled compared with the amount of virus in control protoplasts. Silencing ZmELC expression using a Brome mosaic virus-based gene silencing vector (virus-induced gene silencing) did not influence maize plant growth and development, but did decrease RNA accumulation of two isolates of SCMV and host transcript encoding ZmeIF4E during SCMV infection. Interestingly, Maize chlorotic mottle virus, from outside the Potyviridae, was increased in accumulation after silencing ZmELC expression. Our results describe both the location of ZmElc expression in maize and a new activity associated with an Elc: support of potyvirus accumulation.
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Affiliation(s)
- Min Zhu
- State Key Laboratory of Agro-biotechnology and Key Laboratory for Plant Pathology – Ministry of Agriculture, China Agricultural UniversityBeijing, 100193, China
| | - Yuting Chen
- State Key Laboratory of Agro-biotechnology and Key Laboratory for Plant Pathology – Ministry of Agriculture, China Agricultural UniversityBeijing, 100193, China
| | - Xin Shun Ding
- Plant Biology Division, The Samuel Roberts Noble Foundation, Inc.2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Stephen L Webb
- Department of Computing Services, The Samuel Roberts Noble Foundation Inc.2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Tao Zhou
- State Key Laboratory of Agro-biotechnology and Key Laboratory for Plant Pathology – Ministry of Agriculture, China Agricultural UniversityBeijing, 100193, China
| | - Richard S Nelson
- Plant Biology Division, The Samuel Roberts Noble Foundation, Inc.2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Zaifeng Fan
- State Key Laboratory of Agro-biotechnology and Key Laboratory for Plant Pathology – Ministry of Agriculture, China Agricultural UniversityBeijing, 100193, China
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Lanubile A, Ferrarini A, Maschietto V, Delledonne M, Marocco A, Bellin D. Functional genomic analysis of constitutive and inducible defense responses to Fusarium verticillioides infection in maize genotypes with contrasting ear rot resistance. BMC Genomics 2014; 15:710. [PMID: 25155950 PMCID: PMC4153945 DOI: 10.1186/1471-2164-15-710] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 08/04/2014] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Fusarium verticillioides causes ear rot in maize (Zea mays L.) and accumulation of mycotoxins, that affect human and animal health. Currently, chemical and agronomic measures to control Fusarium ear rot are not very effective and selection of more resistant genotypes is a desirable strategy to reduce contaminations. A deeper knowledge of molecular events and genetic basis underlying Fusarium ear rot is necessary to speed up progress in breeding for resistance. RESULTS A next-generation RNA-sequencing approach was used for the first time to study transcriptional changes associated with F. verticillioides inoculation in resistant CO441 and susceptible CO354 maize genotypes at 72 hours post inoculation. More than 100 million sequence reads were generated for inoculated and uninoculated control plants and analyzed to measure gene expression levels. Comparison of expression levels between inoculated vs. uninoculated and resistant vs. susceptible transcriptomes revealed a total number of 6,951 differentially expressed genes. Differences in basal gene expression were observed in the uninoculated samples. CO441 genotype showed a higher level of expression of genes distributed over all functional classes, in particular those related to secondary metabolism category. After F. verticillioides inoculation, a similar response was observed in both genotypes, although the magnitude of induction was much greater in the resistant genotype. This response included higher activation of genes involved in pathogen perception, signaling and defense, including WRKY transcription factors and jasmonate/ethylene mediated defense responses. Interestingly, strong differences in expression between the two genotypes were observed in secondary metabolism category: pathways related to shikimate, lignin, flavonoid and terpenoid biosynthesis were strongly represented and induced in the CO441 genotype, indicating that selection to enhance these traits is an additional strategy for improving resistance against F. verticillioides infection. CONCLUSIONS The work demonstrates that the global transcriptional analysis provided an exhaustive view of genes involved in pathogen recognition and signaling, and controlling activities of different TFs, phytohormones and secondary metabolites, that contribute to host resistance against F. verticillioides. This work provides an important source of markers for development of disease resistance maize genotypes and may have relevance to study other pathosystems involving mycotoxin-producing fungi.
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Affiliation(s)
| | | | | | | | - Adriano Marocco
- Istituto di Agronomia, Genetica e Coltivazioni erbacee, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy.
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Schmelz EA, Huffaker A, Sims JW, Christensen SA, Lu X, Okada K, Peters RJ. Biosynthesis, elicitation and roles of monocot terpenoid phytoalexins. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 79:659-78. [PMID: 24450747 DOI: 10.1111/tpj.12436] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 12/22/2013] [Accepted: 01/10/2014] [Indexed: 05/07/2023]
Abstract
A long-standing goal in plant research is to optimize the protective function of biochemical agents that impede pest and pathogen attack. Nearly 40 years ago, pathogen-inducible diterpenoid production was described in rice, and these compounds were shown to function as antimicrobial phytoalexins. Using rice and maize as examples, we discuss recent advances in the discovery, biosynthesis, elicitation and functional characterization of monocot terpenoid phytoalexins. The recent expansion of known terpenoid phytoalexins now includes not only the labdane-related diterpenoid superfamily but also casbane-type diterpenoids and β-macrocarpene-derived sequiterpenoids. Biochemical approaches have been used to pair pathway precursors and end products with cognate biosynthetic genes. The number of predicted terpenoid phytoalexins is expanding through advances in cereal genome annotation and terpene synthase characterization that likewise enable discoveries outside the Poaceae. At the cellular level, conclusive evidence now exists for multiple plant receptors of fungal-derived chitin elicitors, phosphorylation of membrane-associated signaling complexes, activation of mitogen-activated protein kinase, involvement of phytohormone signals, and the existence of transcription factors that mediate the expression of phytoalexin biosynthetic genes and subsequent accumulation of pathway end products. Elicited production of terpenoid phytoalexins exhibit additional biological functions, including root exudate-mediated allelopathy and insect antifeedant activity. Such findings have encouraged consideration of additional interactions that blur traditionally discrete phytoalexin classifications. The establishment of mutant collections and increasing ease of genetic transformation assists critical examination of further biological roles. Future research directions include examination of terpenoid phytoalexin precursors and end products as potential signals mediating plant physiological processes.
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Affiliation(s)
- Eric A Schmelz
- Center for Medical, Agricultural, and Veterinary Entomology, US Department of Agriculture, Agricultural Research Service, Chemistry Research Unit, Gainesville, FL, 32608, USA
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26
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Brefort T, Tanaka S, Neidig N, Doehlemann G, Vincon V, Kahmann R. Characterization of the largest effector gene cluster of Ustilago maydis. PLoS Pathog 2014; 10:e1003866. [PMID: 24992561 PMCID: PMC4081774 DOI: 10.1371/journal.ppat.1003866] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 11/20/2013] [Indexed: 12/21/2022] Open
Abstract
In the genome of the biotrophic plant pathogen Ustilago maydis, many of the genes coding for secreted protein effectors modulating virulence are arranged in gene clusters. The vast majority of these genes encode novel proteins whose expression is coupled to plant colonization. The largest of these gene clusters, cluster 19A, encodes 24 secreted effectors. Deletion of the entire cluster results in severe attenuation of virulence. Here we present the functional analysis of this genomic region. We show that a 19A deletion mutant behaves like an endophyte, i.e. is still able to colonize plants and complete the infection cycle. However, tumors, the most conspicuous symptoms of maize smut disease, are only rarely formed and fungal biomass in infected tissue is significantly reduced. The generation and analysis of strains carrying sub-deletions identified several genes significantly contributing to tumor formation after seedling infection. Another of the effectors could be linked specifically to anthocyanin induction in the infected tissue. As the individual contributions of these genes to tumor formation were small, we studied the response of maize plants to the whole cluster mutant as well as to several individual mutants by array analysis. This revealed distinct plant responses, demonstrating that the respective effectors have discrete plant targets. We propose that the analysis of plant responses to effector mutant strains that lack a strong virulence phenotype may be a general way to visualize differences in effector function.
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Affiliation(s)
- Thomas Brefort
- Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, Marburg, Germany
| | - Shigeyuki Tanaka
- Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, Marburg, Germany
| | - Nina Neidig
- Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, Marburg, Germany
| | - Gunther Doehlemann
- Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, Marburg, Germany
| | - Volker Vincon
- Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, Marburg, Germany
| | - Regine Kahmann
- Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, Marburg, Germany
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27
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Hof A, Zechmann B, Schwammbach D, Hückelhoven R, Doehlemann G. Alternative cell death mechanisms determine epidermal resistance in incompatible barley-Ustilago interactions. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:403-414. [PMID: 24329174 DOI: 10.1094/mpmi-10-13-0317-r] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Programmed cell death is a key feature of epidermal plant immunity, which is particularly effective against biotrophic microbes that depend on living host tissue. The covered smut fungus Ustilago hordei establishes a compatible biotrophic interaction with its host plant barley. The maize smut U. maydis triggers a nonhost response in barley, which results in epidermal cell death. Similarly, Ustilago mutants being deleted for pep1, a gene encoding a secreted effector, are blocked upon host penetration. We studied the epidermal responses of barley to incompatible Ustilago strains. Molecular and cellular analyses were used to test the impact of Bax inhibitor-1 (BI-1), a suppressor of programmed cell death, on the barley nonhost resistance to U. maydis as well as Ustilago Δpep1 mutants. Overexpression of BI-1 resulted in partial break of barley nonhost resistance to U. maydis. By contrast, the epidermal cell death response triggered by pep1 deletion mutants was not impaired by BI-1. Hypersensitive-response-like cell death caused by U. maydis wild-type infection showed features of necrotic cell death, while Δpep1 mutant-induced host responses involved hallmarks of autophagy. Therefore, we propose that the mechanisms of epidermal cell death in response to different types of incompatible pathogens depend on spatial and temporal appearance of cell-death-triggering stimuli.
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28
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Nuruzzaman M, Sharoni AM, Kikuchi S. Roles of NAC transcription factors in the regulation of biotic and abiotic stress responses in plants. Front Microbiol 2013; 4:248. [PMID: 24058359 PMCID: PMC3759801 DOI: 10.3389/fmicb.2013.00248] [Citation(s) in RCA: 435] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/05/2013] [Indexed: 12/25/2022] Open
Abstract
NAC transcription factors are one of the largest families of transcriptional regulators in plants, and members of the NAC gene family have been suggested to play important roles in the regulation of the transcriptional reprogramming associated with plant stress responses. A phylogenetic analysis of NAC genes, with a focus on rice and Arabidopsis, was performed. Herein, we present an overview of the regulation of the stress responsive NAC SNAC/(IX) group of genes that are implicated in the resistance to different stresses. SNAC factors have important roles for the control of biotic and abiotic stresses tolerance and that their overexpression can improve stress tolerance via biotechnological approaches. We also review the recent progress in elucidating the roles of NAC transcription factors in plant biotic and abiotic stresses. Modification of the expression pattern of transcription factor genes and/or changes in their activity contribute to the elaboration of various signaling pathways and regulatory networks. However, a single NAC gene often responds to several stress factors, and their protein products may participate in the regulation of several seemingly disparate processes as negative or positive regulators. Additionally, the NAC proteins function via auto-regulation or cross-regulation is extensively found among NAC genes. These observations assist in the understanding of the complex mechanisms of signaling and transcriptional reprogramming controlled by NAC proteins.
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Affiliation(s)
- Mohammed Nuruzzaman
- Plant Genome Research Unit, Division of Genome and Biodiversity Research, Agrogenomics Research Center, National Institute of Agrobiological Sciences Tsukuba, Japan ; Graduate School of Science and Engineering, Institute for Environmental Science and Technology, Saitama University Saitama, Japan
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29
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Ramanna H, Ding XS, Nelson RS. Rationale for developing new virus vectors to analyze gene function in grasses through virus-induced gene silencing. Methods Mol Biol 2013; 975:15-32. [PMID: 23386292 DOI: 10.1007/978-1-62703-278-0_2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The exploding availability of genome and EST-based sequences from grasses requires a technology that allows rapid functional analysis of the multitude of genes that these resources provide. There are several techniques available to determine a gene's function. For gene knockdown studies, silencing through RNAi is a powerful tool. Gene silencing can be accomplished through stable transformation or transient expression of a fragment of a target gene sequence. Stable transformation in rice, maize, and a few other species, although routine, remains a relatively low-throughput process. Transformation in other grass species is difficult and labor-intensive. Therefore, transient gene silencing methods including Agrobacterium-mediated and virus-induced gene silencing (VIGS) have great potential for researchers studying gene function in grasses. VIGS in grasses already has been used to determine the function of genes during pathogen challenge and plant development. It also can be used in moderate-throughput reverse genetics screens to determine gene function. However, the number of viruses modified to serve as silencing vectors in grasses is limited, and the silencing phenotype induced by these vectors is not optimal: the phenotype being transient and with moderate penetration throughout the tissue. Here, we review the most recent information available for VIGS in grasses and summarize the strengths and weaknesses in current virus-grass host systems. We describe ways to improve current virus vectors and the potential of other grass-infecting viruses for VIGS studies. This work is necessary because VIGS for the foreseeable future remains a higher throughput and more rapid system to evaluate gene function than stable transformation.
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Affiliation(s)
- Hema Ramanna
- Plant Biology Division, The Samuel Roberts Noble Foundation Inc., Ardmore, OK, USA
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30
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Sun L, Zhang H, Li D, Huang L, Hong Y, Ding XS, Nelson RS, Zhou X, Song F. Functions of rice NAC transcriptional factors, ONAC122 and ONAC131, in defense responses against Magnaporthe grisea. PLANT MOLECULAR BIOLOGY 2013; 81:41-56. [PMID: 23103994 DOI: 10.1007/s11103-012-9981-3] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 10/19/2012] [Indexed: 05/04/2023]
Abstract
NAC (NAM/ATAF/CUC) transcription factors have important functions in regulating plant growth, development, and abiotic and biotic stress responses. Here, we characterized two rice pathogen-responsive NAC transcription factors, ONAC122 and ONAC131. We determined that these proteins localized to the nucleus when expressed ectopically and had transcriptional activation activities. ONAC122 and ONAC131 expression was induced after infection by Magnaporthe grisea, the causal agent of rice blast disease, and the M. grisea-induced expression of both genes was faster and higher in the incompatible interaction compared with the compatible interaction during early stages of infection. ONAC122 and ONAC131 were also induced by treatment with salicylic acid, methyl jasmonate or 1-aminocyclopropane-1-carboxylic acid (a precursor of ethylene). Silencing ONAC122 or ONAC131 expression using a newly modified Brome mosaic virus (BMV)-based silencing vector resulted in an enhanced susceptibility to M. grisea. Furthermore, expression levels of several other defense- and signaling-related genes (i.e. OsLOX, OsPR1a, OsWRKY45 and OsNH1) were down-regulated in plants silenced for ONAC122 or ONAC131 expression via the BMV-based silencing system. Our results suggest that both ONAC122 and ONAC131 have important roles in rice disease resistance responses through the regulated expression of other defense- and signaling-related genes.
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Affiliation(s)
- Lijun Sun
- National Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, Zhejiang, China
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31
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Lange M, Yellina AL, Orashakova S, Becker A. Virus-induced gene silencing (VIGS) in plants: an overview of target species and the virus-derived vector systems. Methods Mol Biol 2013; 975:1-14. [PMID: 23386291 DOI: 10.1007/978-1-62703-278-0_1] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The analysis of gene functions in non-model plant species is often hampered by the fact that stable genetic transformation to downregulate gene expression is laborious and time-consuming, or, for some species, even not achievable. Virus-induced gene silencing (VIGS) can serve as an alternative to mutant collections or stable transgenic plants to allow the characterization of gene functions in a wide range of angiosperm species, albeit in a transient way. VIGS vector systems have been developed from both RNA and DNA plant viral sources to specifically silence target genes in plants. VIGS is nowadays widely used in plant genetics for gene knockdown due to its ease of use and the short time required to generating phenotypes. Here, we summarize successfully targeted eudicot and monocot plant species along with their specific VIGS vector systems which are already available for researchers.
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Affiliation(s)
- Matthias Lange
- Plant Evodevo Group, Justus-Liebig-Universität Gießen, Gießen, Germany
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32
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van der Linde K, Doehlemann G. Utilizing virus-induced gene silencing for the functional characterization of maize genes during infection with the fungal pathogen Ustilago maydis. Methods Mol Biol 2013; 975:47-60. [PMID: 23386294 DOI: 10.1007/978-1-62703-278-0_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
While in dicotyledonous plants virus-induced gene silencing (VIGS) is well established to study plant-pathogen interaction, in monocots only few examples of efficient VIGS have been reported so far. One of the available systems is based on the brome mosaic virus (BMV) which allows gene silencing in different cereals including barley (Hordeum vulgare), wheat (Triticum aestivum), and maize (Zea mays).Infection of maize plants by the corn smut fungus Ustilago maydis leads to the formation of large tumors on stem, leaves, and inflorescences. During this biotrophic interaction, plant defense responses are actively suppressed by the pathogen, and previous transcriptome analyses of infected maize plants showed comprehensive and stage-specific changes in host gene expression during disease progression.To identify maize genes that are functionally involved in the interaction with U. maydis, we adapted a VIGS system based on the Brome mosaic virus (BMV) to maize at conditions that allow successful U. maydis infection of BMV pre-infected maize plants. This setup enables quantification of VIGS and its impact on U. maydis infection using a quantitative real-time PCR (q(RT)-PCR)-based readout.
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Affiliation(s)
- Karina van der Linde
- Department of Organismic Interaction, Max Planck Institute for terrestrial Microbiology, Marburg, Germany
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33
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Cao Y, Shi Y, Li Y, Cheng Y, Zhou T, Fan Z. Possible involvement of maize Rop1 in the defence responses of plants to viral infection. MOLECULAR PLANT PATHOLOGY 2012; 13:732-43. [PMID: 22332840 PMCID: PMC6638897 DOI: 10.1111/j.1364-3703.2011.00782.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The expression of host genes can be altered during the process of viral infection. To investigate the viral infection-induced up-regulated gene expression changes of maize at different time intervals post-inoculation with Sugarcane mosaic virus (SCMV), a suppression subtractive hybridization cDNA library was constructed. A total of 454 cDNA clones were identified to be viral infection-induced up-regulated genes. The influence of Rop1 on the infection of maize by SCMV was investigated. The results showed that transient silencing of the ZmRop1 gene through virus-induced gene silencing enhanced the accumulation and systemic infection of SCMV and another potyvirus (Pennisetum mosaic virus) in maize plants, whereas transient over-expression of ZmRop1 in maize protoplasts reduced SCMV accumulation. Furthermore, it was demonstrated that the heterologous expression of ZmRop1 impaired Potato virus X infection in Nicotiana benthamiana plants. These data suggest that ZmRop1 may play a role in plant defence responses to viral infection.
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Affiliation(s)
- Yanyong Cao
- State Key Laboratory of Agro-biotechnology and Department of Plant Pathology, China Agricultural University, Beijing 100193, China
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Hemetsberger C, Herrberger C, Zechmann B, Hillmer M, Doehlemann G. The Ustilago maydis effector Pep1 suppresses plant immunity by inhibition of host peroxidase activity. PLoS Pathog 2012; 8:e1002684. [PMID: 22589719 PMCID: PMC3349748 DOI: 10.1371/journal.ppat.1002684] [Citation(s) in RCA: 251] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 03/22/2012] [Indexed: 01/25/2023] Open
Abstract
The corn smut Ustilago maydis establishes a biotrophic interaction with its host plant maize. This interaction requires efficient suppression of plant immune responses, which is attributed to secreted effector proteins. Previously we identified Pep1 (Protein essential during penetration-1) as a secreted effector with an essential role for U. maydis virulence. pep1 deletion mutants induce strong defense responses leading to an early block in pathogenic development of the fungus. Using cytological and functional assays we show that Pep1 functions as an inhibitor of plant peroxidases. At sites of Δpep1 mutant penetrations, H₂O₂ strongly accumulated in the cell walls, coinciding with a transcriptional induction of the secreted maize peroxidase POX12. Pep1 protein effectively inhibited the peroxidase driven oxidative burst and thereby suppresses the early immune responses of maize. Moreover, Pep1 directly inhibits peroxidases in vitro in a concentration-dependent manner. Using fluorescence complementation assays, we observed a direct interaction of Pep1 and the maize peroxidase POX12 in vivo. Functional relevance of this interaction was demonstrated by partial complementation of the Δpep1 mutant defect by virus induced gene silencing of maize POX12. We conclude that Pep1 acts as a potent suppressor of early plant defenses by inhibition of peroxidase activity. Thus, it represents a novel strategy for establishing a biotrophic interaction.
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Affiliation(s)
| | | | - Bernd Zechmann
- Institute of Plant Sciences, Karl-Franzens University of Graz, Graz, Austria
| | - Morten Hillmer
- Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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35
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Huang C, Qian Y, Li Z, Zhou X. Virus-induced gene silencing and its application in plant functional genomics. SCIENCE CHINA-LIFE SCIENCES 2012; 55:99-108. [PMID: 22415680 DOI: 10.1007/s11427-012-4280-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Accepted: 12/13/2011] [Indexed: 12/13/2022]
Abstract
Virus-induced gene silencing is regarded as a powerful and efficient tool for the analysis of gene function in plants because it is simple, rapid and transformation-free. It has been used to perform both forward and reverse genetics to identify plant functional genes. Many viruses have been developed into virus-induced gene silencing vectors and gene functions involved in development, biotic and abiotic stresses, metabolism, and cellular signaling have been reported. In this review, we discuss the development and application of virus-induced gene silencing in plant functional genomics.
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Affiliation(s)
- Changjun Huang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
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36
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A new BSMV-based vector with modified β molecule allows simultaneous and stable silencing of two genes. Cell Mol Biol Lett 2011; 17:107-23. [PMID: 22207334 PMCID: PMC6275698 DOI: 10.2478/s11658-011-0041-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 12/08/2011] [Indexed: 11/26/2022] Open
Abstract
Virus-induced gene silencing is an important tool for functional gene analysis and the vector based on Barley stripe mosaic virus (BSMV) is widely used for the purpose in monocots. Of the tripartite BSMV genome, currently the BSMV:γMCS molecule is used to clone a fragment of a target gene. As an alternative, the BSMV:β molecule was engineered with a unique BamHI site between the open reading frame of βc (ORF βc) and poly(A). The mixture of RNA particles α, βBamHI and γMCS was fully infectious. Barley phytoene desaturase and wheat phospholipase Dα fragments were cloned to βBamHI and γMCS. Delivery of the target gene fragment in γMCS induced stronger silencing, while delivery in βBamHI yielded more stable transcript reduction. A quantitative analysis (qRT-PCR) of the transcripts showed that the silencing induced with a fragment carried in both particles was stronger and more stable than that from a fragment placed in one particle. The modification of β enables simultaneous silencing of two genes. Quantifying the β and γ particles in virus-inoculated plants revealed a 2.5-fold higher level of γ than β, while the stability of the insert was higher in β compared with γ. The possible influence of the relative quantity of β and γ particles in virus-inoculated plants on insert stability and gene silencing efficiency is discussed.
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Senthil-Kumar M, Mysore KS. New dimensions for VIGS in plant functional genomics. TRENDS IN PLANT SCIENCE 2011; 16:656-65. [PMID: 21937256 DOI: 10.1016/j.tplants.2011.08.006] [Citation(s) in RCA: 172] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 08/07/2011] [Accepted: 08/22/2011] [Indexed: 05/18/2023]
Abstract
Virus-induced gene silencing (VIGS) is an efficient tool for gene function studies. It has been used to perform both forward and reverse genetics to identify plant genes involved in several plant processes. However, this technology has not yet been used to its full potential. This can be attributed to several of its limitations such as inability to silence genes during seed germination and the non-stable nature of silencing. However, several recent studies have shown that these limitations can now be overcome. In this review, we will discuss the limitations of VIGS and suitable solutions. In addition, we also describe the recent improvements and future prospects of using VIGS in plant biology.
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Affiliation(s)
- Muthappa Senthil-Kumar
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA
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38
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GAO Y, ZHANG YL, ZHANG XF, HAN CG, YU JL, LI DW. Development and Optimization of Tobacco necrosis virus A Induced Gene Silencing in Nicotiana benthamiana*. PROG BIOCHEM BIOPHYS 2011. [DOI: 10.3724/sp.j.1206.2011.00129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Yuan C, Li C, Yan L, Jackson AO, Liu Z, Han C, Yu J, Li D. A high throughput barley stripe mosaic virus vector for virus induced gene silencing in monocots and dicots. PLoS One 2011; 6:e26468. [PMID: 22031834 PMCID: PMC3198768 DOI: 10.1371/journal.pone.0026468] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 09/27/2011] [Indexed: 11/18/2022] Open
Abstract
Barley stripe mosaic virus (BSMV) is a single-stranded RNA virus with three genome components designated alpha, beta, and gamma. BSMV vectors have previously been shown to be efficient virus induced gene silencing (VIGS) vehicles in barley and wheat and have provided important information about host genes functioning during pathogenesis as well as various aspects of genes functioning in development. To permit more effective use of BSMV VIGS for functional genomics experiments, we have developed an Agrobacterium delivery system for BSMV and have coupled this with a ligation independent cloning (LIC) strategy to mediate efficient cloning of host genes. Infiltrated Nicotiana benthamiana leaves provided excellent sources of virus for secondary BSMV infections and VIGS in cereals. The Agro/LIC BSMV VIGS vectors were able to function in high efficiency down regulation of phytoene desaturase (PDS), magnesium chelatase subunit H (ChlH), and plastid transketolase (TK) gene silencing in N. benthamiana and in the monocots, wheat, barley, and the model grass, Brachypodium distachyon. Suppression of an Arabidopsis orthologue cloned from wheat (TaPMR5) also interfered with wheat powdery mildew (Blumeria graminis f. sp. tritici) infections in a manner similar to that of the A. thaliana PMR5 loss-of-function allele. These results imply that the PMR5 gene has maintained similar functions across monocot and dicot families. Our BSMV VIGS system provides substantial advantages in expense, cloning efficiency, ease of manipulation and ability to apply VIGS for high throughput genomics studies.
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Affiliation(s)
- Cheng Yuan
- State Key Laboratory of Agro-Biotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Cui Li
- State Key Laboratory of Agro-Biotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Lijie Yan
- State Key Laboratory of Agro-Biotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Andrew O. Jackson
- Department of Plant and Microbial Biology, University of California, Berkeley, California, United States of America
| | - Zhiyong Liu
- State Key Laboratory of Agro-Biotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Chenggui Han
- State Key Laboratory of Agro-Biotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Jialin Yu
- State Key Laboratory of Agro-Biotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Dawei Li
- State Key Laboratory of Agro-Biotechnology, China Agricultural University, Beijing, People's Republic of China
- * E-mail:
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Huffaker A, Kaplan F, Vaughan MM, Dafoe NJ, Ni X, Rocca JR, Alborn HT, Teal PEA, Schmelz EA. Novel acidic sesquiterpenoids constitute a dominant class of pathogen-induced phytoalexins in maize. PLANT PHYSIOLOGY 2011; 156:2082-97. [PMID: 21690302 PMCID: PMC3149930 DOI: 10.1104/pp.111.179457] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 06/18/2011] [Indexed: 05/18/2023]
Abstract
Nonvolatile terpenoid phytoalexins occur throughout the plant kingdom, but until recently were not known constituents of chemical defense in maize (Zea mays). We describe a novel family of ubiquitous maize sesquiterpenoid phytoalexins, termed zealexins, which were discovered through characterization of Fusarium graminearum-induced responses. Zealexins accumulate to levels greater than 800 μg g⁻¹ fresh weight in F. graminearum-infected tissue. Their production is also elicited by a wide variety of fungi, Ostrinia nubilalis herbivory, and the synergistic action of jasmonic acid and ethylene. Zealexins exhibit antifungal activity against numerous phytopathogenic fungi at physiologically relevant concentrations. Structural elucidation of four members of this complex family revealed that all are acidic sesquiterpenoids containing a hydrocarbon skeleton that resembles β-macrocarpene. Induced zealexin accumulation is preceded by increased expression of the genes encoding TERPENE SYNTHASE6 (TPS6) and TPS11, which catalyze β-macrocarpene production. Furthermore, zealexin accumulation displays direct positive relationships with the transcript levels of both genes. Microarray analysis of F. graminearum-infected tissue revealed that Tps6/Tps11 were among the most highly up-regulated genes, as was An2, an ent-copalyl diphosphate synthase associated with production of kauralexins. Transcript profiling suggests that zealexins cooccur with a number of antimicrobial proteins, including chitinases and pathogenesis-related proteins. In addition to zealexins, kauralexins and the benzoxazinoid 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one-glucose (HDMBOA-glucose) were produced in fungal-infected tissue. HDMBOA-glucose accumulation occurred in both wild-type and benzoxazine-deficient1 (bx1) mutant lines, indicating that Bx1 gene activity is not required for HDMBOA biosynthesis. Together these results indicate an important cooperative role of terpenoid phytoalexins in maize biochemical defense.
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Affiliation(s)
- Alisa Huffaker
- Center for Medical, Agricultural, and Veterinary Entomology, United States Department of Agriculture, Agricultural Research Service, Chemistry Research Unit, Gainesville, Florida 32608, USA.
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