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Abstract
In this review, we discuss recent studies of the interaction between Fusarium graminearum viruses (FgVs) and the fungal host, Fusarium graminearum. Comprehensive transcriptome and proteome analyses have shown changes in the expression of host genes in response to infection by diverse FgVs. Using omics data and reverse genetics, researchers have determined the effects of some fungal host proteins (including FgHex1, FgHal2, FgSwi6, and vr1) on virus accumulation, virus transmission, and host symptom development. Recent reports have revealed the functions of the RNAi component in F. graminearum and the functional redundancy of FgDICERs and FgAGOs in the antiviral defense response against different FgV infections. Studies have also documented a unique mechanism used by FgV1 to overcome the antiviral response of the fungal host.
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52
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Huang CY, Wang H, Hu P, Hamby R, Jin H. Small RNAs - Big Players in Plant-Microbe Interactions. Cell Host Microbe 2019; 26:173-182. [PMID: 31415750 DOI: 10.1016/j.chom.2019.07.021] [Citation(s) in RCA: 147] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/25/2019] [Accepted: 07/29/2019] [Indexed: 01/08/2023]
Abstract
Eukaryotic small RNAs (sRNAs) are short non-coding regulatory molecules that induce RNA interference (RNAi). During microbial infection, host RNAi machinery is highly regulated and contributes to reprogramming gene expression and balancing plant immunity and growth. While most sRNAs function endogenously, some can travel across organismal boundaries between hosts and microbes and silence genes in trans in interacting organisms, a mechanism called "cross-kingdom RNAi." During the co-evolutionary arms race between fungi and plants, some fungi developed a novel virulence mechanism, sending sRNAs as effector molecules into plant cells to silence plant immunity genes, whereas plants also transport sRNAs, mainly using extracellular vesicles, into the pathogens to suppress virulence-related genes. In this Review, we highlight recent discoveries on these key roles of sRNAs and RNAi machinery. Understanding the molecular mechanisms of sRNA biogenesis, trafficking, and RNAi machinery will help us develop innovative strategies for crop protection.
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Affiliation(s)
- Chien-Yu Huang
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521, USA
| | - Huan Wang
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521, USA
| | - Po Hu
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521, USA
| | - Rachael Hamby
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521, USA
| | - Hailing Jin
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521, USA.
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53
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Cai Q, He B, Weiberg A, Buck AH, Jin H. Small RNAs and extracellular vesicles: New mechanisms of cross-species communication and innovative tools for disease control. PLoS Pathog 2019; 15:e1008090. [PMID: 31887135 PMCID: PMC6936782 DOI: 10.1371/journal.ppat.1008090] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- Qiang Cai
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, United States of America
| | - Baoye He
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, United States of America
| | - Arne Weiberg
- Department of Biology, Ludwig-Maximilians University of Munich (LMU), Munich, Germany
| | - Amy H. Buck
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Hailing Jin
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, United States of America
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54
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Xiong F, Liu M, Zhuo F, Yin H, Deng K, Feng S, Liu Y, Luo X, Feng L, Zhang S, Li Z, Ren M. Host-induced gene silencing of BcTOR in Botrytis cinerea enhances plant resistance to grey mould. MOLECULAR PLANT PATHOLOGY 2019; 20:1722-1739. [PMID: 31622007 PMCID: PMC6859489 DOI: 10.1111/mpp.12873] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Botrytis cinerea is the causal agent of grey mould for more than 200 plant species, including economically important vegetables, fruits and crops, which leads to economic losses worldwide. Target of rapamycin (TOR) acts a master regulator to control cell growth and proliferation by integrating nutrient, energy and growth factors in eukaryotic species, but little is known about whether TOR can function as a practicable target in the control of plant fungal pathogens. Here, we characterize TOR signalling of B. cinerea in the regulation of growth and pathogenicity as well as its potential value in genetic engineering for crop protection by bioinformatics analysis, pharmacological assays, biochemistry and genetics approaches. The results show that conserved TOR signalling occurs, and a functional FK506-binding protein 12 kD (FKBP12) mediates the interaction between rapamycin and B. cinerea TOR (BcTOR). RNA sequencing (RNA-Seq) analysis revealed that BcTOR displayed conserved functions, particularly in controlling growth and metabolism. Furthermore, pathogenicity assay showed that BcTOR inhibition efficiently reduces the infection of B. cinerea in plant leaves of Arabidopsis and potato or tomato fruits. Additionally, transgenic plants expressing double-stranded RNA of BcTOR through the host-induced gene silencing method could produce abundant small RNAs targeting BcTOR, and significantly block the occurrence of grey mould in potato and tomato. Taken together, our results suggest that BcTOR is an efficient target for genetic engineering in control of grey mould, and also a potential and promising target applied in the biocontrol of plant fungal pathogens.
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Affiliation(s)
- Fangjie Xiong
- School of Life SciencesChongqing UniversityChongqing401331China
- Key Laboratory of Plant Hormone and Developmental Regulation of ChongqingChongqing401331China
| | - Mei Liu
- School of Life SciencesChongqing UniversityChongqing401331China
- Key Laboratory of Plant Hormone and Developmental Regulation of ChongqingChongqing401331China
| | - Fengping Zhuo
- School of Life SciencesChongqing UniversityChongqing401331China
- Key Laboratory of Plant Hormone and Developmental Regulation of ChongqingChongqing401331China
- School of Chemistry and Chemical EngineeringChongqing University of Science and TechnologyChongqing401331China
| | - Huan Yin
- School of Life SciencesChongqing UniversityChongqing401331China
- Key Laboratory of Plant Hormone and Developmental Regulation of ChongqingChongqing401331China
| | - Kexuan Deng
- School of Life SciencesChongqing UniversityChongqing401331China
- Key Laboratory of Plant Hormone and Developmental Regulation of ChongqingChongqing401331China
| | - Shun Feng
- School of Life SciencesChongqing UniversityChongqing401331China
- Key Laboratory of Plant Hormone and Developmental Regulation of ChongqingChongqing401331China
| | - Yudong Liu
- School of Life SciencesChongqing UniversityChongqing401331China
- Key Laboratory of Plant Hormone and Developmental Regulation of ChongqingChongqing401331China
| | - Xiumei Luo
- School of Life SciencesChongqing UniversityChongqing401331China
- Key Laboratory of Plant Hormone and Developmental Regulation of ChongqingChongqing401331China
| | - Li Feng
- School of Life SciencesChongqing UniversityChongqing401331China
- Key Laboratory of Plant Hormone and Developmental Regulation of ChongqingChongqing401331China
| | - Shumin Zhang
- School of Life SciencesChongqing UniversityChongqing401331China
- Key Laboratory of Plant Hormone and Developmental Regulation of ChongqingChongqing401331China
| | - Zhengguo Li
- School of Life SciencesChongqing UniversityChongqing401331China
- Key Laboratory of Plant Hormone and Developmental Regulation of ChongqingChongqing401331China
| | - Maozhi Ren
- School of Life SciencesChongqing UniversityChongqing401331China
- Key Laboratory of Plant Hormone and Developmental Regulation of ChongqingChongqing401331China
- Institute of Urban AgricultureChinese Academy of Agricultural Sciences/National Chengdu Agricultural Science and Technology CenterChengdu610000China
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55
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He F, Zhang R, Zhao J, Qi T, Kang Z, Guo J. Host-Induced Silencing of Fusarium graminearum Genes Enhances the Resistance of Brachypodium distachyon to Fusarium Head Blight. FRONTIERS IN PLANT SCIENCE 2019; 10:1362. [PMID: 31737001 PMCID: PMC6831556 DOI: 10.3389/fpls.2019.01362] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 10/03/2019] [Indexed: 05/30/2023]
Abstract
Fusarium head blight (FHB) caused by Fusarium pathogens are devastating diseases worldwide. Host-induced gene silencing (HIGS) which involves host expression of double-stranded RNA (dsRNA)-generating constructs directed against genes in the pathogen has been a potential strategy for the ecological sound control of FHB. In this study, we constructed transgenic Brachypodium distachyon lines carrying RNA interference (RNAi) cassettes to target two essential protein kinase genes Fg00677 and Fg08731, and cytochrome P450 lanosterol C14-α-demethylase (CYP51) encoding genes (CYP51A, CYP51B, and CYP51C) of Fusarium graminearum, respectively. Northern blotting confirmed the presence of short interfering RNAs (siRNA) derived from Fg00677, Fg08731, and CYP51 in transgenic B. distachyon plants, and the transcript levels of the corresponding genes were down-regulated in the F. graminearum colonizing B. distachyon spikes. All the corresponding independent, Fg00677-RNAi, Fg08731-RNAi, and CYP51-RNAi transgenic T2 lines exhibited strong resistance to F. graminearum, suggesting that silencing molecules produced by transgenic plants inhibited the corresponding gene function by down-regulating its expression, thereby reducing pathogenicity. Our results indicate that Fg00677 and Fg08731 are effective targets for HIGS and can be applied to construct transgenic HIGS materials to enhance FHB resistance in wheat and other cereal crops.
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56
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Morozov SY, Solovyev AG, Kalinina NO, Taliansky ME. Double-Stranded RNAs in Plant Protection Against Pathogenic Organisms and Viruses in Agriculture. Acta Naturae 2019; 11:13-21. [PMID: 31993231 PMCID: PMC6977960 DOI: 10.32607/20758251-2019-11-4-13-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 11/29/2019] [Indexed: 11/24/2022] Open
Abstract
Recent studies have shown that plants are able to express the artificial genes responsible for the synthesis of double-stranded RNAs (dsRNAs) and hairpin double-stranded RNAs (hpRNAs), as well as uptake and process exogenous dsRNAs and hpRNAs to suppress the gene expression of plant pathogenic viruses, fungi, or insects. Both endogenous and exogenous dsRNAs are processed into small interfering RNAs (siRNAs) that can spread locally and systemically through the plant, enter pathogenic microorganisms, and induce RNA interference-mediated pathogen resistance in plants. There are numerous examples of the development of new biotechnological approaches to plant protection using transgenic plants and exogenous dsRNAs. This review summarizes new data on the use of transgenes and exogenous dsRNAs for the suppression of fungal and insect virulence genes, as well as viruses to increase the resistance of plants to these pathogens. We also analyzed the current ideas about the mechanisms of dsRNA processing and transport in plants.
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Affiliation(s)
- S. Y. Morozov
- International Laboratory «Resistom», The Skolkovo Innovation Center, Moscow, 143026 Russia**
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992 Russia
| | - A. G. Solovyev
- International Laboratory «Resistom», The Skolkovo Innovation Center, Moscow, 143026 Russia**
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992 Russia
| | - N. O. Kalinina
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992 Russia
| | - M. E. Taliansky
- International Laboratory «Resistom», The Skolkovo Innovation Center, Moscow, 143026 Russia**
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, Moscow, 117997 Russia
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57
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Catch Me If You Can! RNA Silencing-Based Improvement of Antiviral Plant Immunity. Viruses 2019; 11:v11070673. [PMID: 31340474 PMCID: PMC6669615 DOI: 10.3390/v11070673] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 07/11/2019] [Accepted: 07/17/2019] [Indexed: 12/27/2022] Open
Abstract
Viruses are obligate parasites which cause a range of severe plant diseases that affect farm productivity around the world, resulting in immense annual losses of yield. Therefore, control of viral pathogens continues to be an agronomic and scientific challenge requiring innovative and ground-breaking strategies to meet the demands of a growing world population. Over the last decade, RNA silencing has been employed to develop plants with an improved resistance to biotic stresses based on their function to provide protection from invasion by foreign nucleic acids, such as viruses. This natural phenomenon can be exploited to control agronomically relevant plant diseases. Recent evidence argues that this biotechnological method, called host-induced gene silencing, is effective against sucking insects, nematodes, and pathogenic fungi, as well as bacteria and viruses on their plant hosts. Here, we review recent studies which reveal the enormous potential that RNA-silencing strategies hold for providing an environmentally friendly mechanism to protect crop plants from viral diseases.
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58
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Small RNA Functions as a Trafficking Effector in Plant Immunity. Int J Mol Sci 2019; 20:ijms20112816. [PMID: 31181829 PMCID: PMC6600683 DOI: 10.3390/ijms20112816] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/01/2019] [Accepted: 06/06/2019] [Indexed: 01/04/2023] Open
Abstract
Small RNAs represent a class of small but powerful agents that regulate development and abiotic and biotic stress responses during plant adaptation to a constantly challenging environment. Previous findings have revealed the important roles of small RNAs in diverse cellular processes. The recent discovery of bidirectional trafficking of small RNAs between different kingdoms has raised many interesting questions. The subsequent demonstration of exosome-mediated small RNA export provided a possible tool for further investigating how plants use small RNAs as a weapon during the arms race between plant hosts and pathogens. This review will focus on discussing the roles of small RNAs in plant immunity in terms of three aspects: the biogenesis of extracellular small RNAs and the transportation and trafficking small RNA-mediated gene silencing in pathogens.
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59
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Blyuss KB, Fatehi F, Tsygankova VA, Biliavska LO, Iutynska GO, Yemets AI, Blume YB. RNAi-Based Biocontrol of Wheat Nematodes Using Natural Poly-Component Biostimulants. FRONTIERS IN PLANT SCIENCE 2019; 10:483. [PMID: 31057585 PMCID: PMC6479188 DOI: 10.3389/fpls.2019.00483] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 03/28/2019] [Indexed: 06/09/2023]
Abstract
With the growing global demands on sustainable food production, one of the biggest challenges to agriculture is associated with crop losses due to parasitic nematodes. While chemical pesticides have been quite successful in crop protection and mitigation of damage from parasites, their potential harm to humans and environment, as well as the emergence of nematode resistance, have necessitated the development of viable alternatives to chemical pesticides. One of the most promising and targeted approaches to biocontrol of parasitic nematodes in crops is that of RNA interference (RNAi). In this study we explore the possibility of using biostimulants obtained from metabolites of soil streptomycetes to protect wheat (Triticum aestivum L.) against the cereal cyst nematode Heterodera avenae by means of inducing RNAi in wheat plants. Theoretical models of uptake of organic compounds by plants, and within-plant RNAi dynamics, have provided us with useful insights regarding the choice of routes for delivery of RNAi-inducing biostimulants into plants. We then conducted in planta experiments with several streptomycete-derived biostimulants, which have demonstrated the efficiency of these biostimulants at improving plant growth and development, as well as in providing resistance against the cereal cyst nematode. Using dot blot hybridization we demonstrate that biostimulants trigger a significant increase of the production in plant cells of si/miRNA complementary with plant and nematode mRNA. Wheat germ cell-free experiments show that these si/miRNAs are indeed very effective at silencing the translation of nematode mRNA having complementary sequences, thus reducing the level of nematode infestation and improving plant resistance to nematodes. Thus, we conclude that natural biostimulants produced from metabolites of soil streptomycetes provide an effective tool for biocontrol of wheat nematode.
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Affiliation(s)
| | - Farzad Fatehi
- Department of Mathematics, University of Sussex, Brighton, United Kingdom
| | - Victoria A. Tsygankova
- Department of Chemistry of Bioactive Nitrogen-Containing Heterocyclic Compounds, Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Liudmyla O. Biliavska
- Department of General and Soil Microbiology, Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Galyna O. Iutynska
- Department of General and Soil Microbiology, Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Alla I. Yemets
- Department of Cell Biology and Biotechnology, Institute of Food Biotechnology and Genomics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Yaroslav B. Blume
- Department of Genomics and Molecular Biotechnology, Institute of Food Biotechnology and Genomics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
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60
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Guo XY, Li Y, Fan J, Xiong H, Xu FX, Shi J, Shi Y, Zhao JQ, Wang YF, Cao XL, Wang WM. Host-Induced Gene Silencing of MoAP1 Confers Broad-Spectrum Resistance to Magnaporthe oryzae. FRONTIERS IN PLANT SCIENCE 2019; 10:433. [PMID: 31024598 PMCID: PMC6465682 DOI: 10.3389/fpls.2019.00433] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 03/21/2019] [Indexed: 05/21/2023]
Abstract
Rice blast caused by Magnaporthe oryzae (M. oryzae) is a major threat to global rice production. In recent years, small interference RNAs (siRNAs) and host-induced gene silencing (HIGS) has been shown to be new strategies for the development of transgenic plants to control fungal diseases and proved a useful tool to study gene function in pathogens. We here tested whether in vitro feeding artificial siRNAs (asiRNAs) could compromise M. oryzae virulence and in vivo HIGS technique could improve rice blast resistance. Our data revealed that silencing of M. oryzae MoAP1 by feeding asiRNAs targeting MoAP1 (i.e., asiR1245, asiR1362, and asiR1115) resulted in inhibited fungal growth, abnormal spores, and decreased pathogenicity. Among the asiRNAs, asiR1115 was the most inhibitory toward the rice blast fungus. Conversely, the asiRNAs targeting three other genes (i.e., MoSSADH, MoACT, and MoSOM1) had no effect on fungal growth. Transgenic rice plants expressing RNA hairpins targeting MoAP1 exhibited improved resistance to 11 tested M. oryzae strains. Confocal microscopy also revealed profoundly restricted appressoria and mycelia in rice blast-infected transgenic rice plants. Our results demonstrate that in vitro asiRNA and in vivo HIGS were useful protection approaches that may be valuable to enhance rice blast resistance.
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Affiliation(s)
- Xiao-Yi Guo
- Rice and Sorghum Research Institute, Sichuan Academy of Agricultural Sciences/Key Laboratory of Southwest Rice Biology and Genetic Breeding, Ministry of Agriculture, Deyang, China
| | - Yan Li
- Rice Research Institute, Sichuan Agricultural University, Chengdu, China
| | - Jing Fan
- Rice Research Institute, Sichuan Agricultural University, Chengdu, China
| | - Hong Xiong
- Rice and Sorghum Research Institute, Sichuan Academy of Agricultural Sciences/Key Laboratory of Southwest Rice Biology and Genetic Breeding, Ministry of Agriculture, Deyang, China
| | - Fu-Xian Xu
- Rice and Sorghum Research Institute, Sichuan Academy of Agricultural Sciences/Key Laboratory of Southwest Rice Biology and Genetic Breeding, Ministry of Agriculture, Deyang, China
| | - Jun Shi
- Mianyang Academy of Agricultural Sciences, Mianyang, China
| | - Yi Shi
- Rice Research Institute, Sichuan Agricultural University, Chengdu, China
| | - Ji-Qun Zhao
- Rice Research Institute, Sichuan Agricultural University, Chengdu, China
| | - Yi-Fu Wang
- Mianyang Academy of Agricultural Sciences, Mianyang, China
| | - Xiao-Long Cao
- Mianyang Academy of Agricultural Sciences, Mianyang, China
| | - Wen-Ming Wang
- Rice Research Institute, Sichuan Agricultural University, Chengdu, China
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61
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Sánchez-Martín J, Keller B. Contribution of recent technological advances to future resistance breeding. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2019; 132:713-732. [PMID: 30756126 DOI: 10.1007/s00122-019-03297-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 02/02/2019] [Indexed: 05/23/2023]
Abstract
The development of durable host resistance strategies to control crop diseases is a primary need for sustainable agricultural production in the future. This article highlights the potential of recent progress in the understanding of host resistance for future cereal breeding. Much of the novel work is based on advancements in large-scale sequencing and genomics, rapid gene isolation techniques and high-throughput molecular marker technologies. Moreover, emerging applications on the pathogen side like effector identification or field pathogenomics are discussed. The combination of knowledge from both sides of cereal pathosystems will result in new approaches for resistance breeding. We describe future applications and innovative strategies to implement effective and durable strategies to combat diseases of major cereal crops while reducing pesticide dependency.
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Affiliation(s)
- Javier Sánchez-Martín
- Department of Plant and Microbial Biology, University of Zürich, Zollikerstrasse 107, 8008, Zurich, Switzerland.
| | - Beat Keller
- Department of Plant and Microbial Biology, University of Zürich, Zollikerstrasse 107, 8008, Zurich, Switzerland
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62
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Song X, Gu K, Duan X, Xiao X, Hou Y, Duan Y, Wang J, Yu N, Zhou M. Secondary amplification of siRNA machinery limits the application of spray-induced gene silencing. MOLECULAR PLANT PATHOLOGY 2018; 19:2543-2560. [PMID: 30027625 PMCID: PMC6638038 DOI: 10.1111/mpp.12728] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Spray-induced gene silencing (SIGS) is an innovative strategy for crop protection. However, the mechanism of SIGS is not known. Here, we first demonstrate that secondary small interfering RNA (siRNA) amplification limits the application of SIGS. A myosin5 gene (Myo5) was chosen as the target of SIGS in an agronomically important pathogen-Fusarium asiaticum. Five segments corresponding to the different regions of the Myo5 gene were found to efficiently silence Myo5, resulting in cell wall defects, life cycle disruption and virulence reduction. Myo5-8 (one of the Myo5 segments) induced sequence-specific RNA interference (RNAi) activity in F. asiaticum, F. graminearum, F. tricinctum and F. oxysporum, but not in other fungi, in vitro. Remarkably, the silencing of Myo5 lasted for only 9 h unless the double-stranded RNA (dsRNA) was continuously supplied, because F. asiaticum is unable to maintain siRNA amplification. After spraying on plants, dsRNAs were more efficiently taken up via the wounded surface. The antifungal activity of dsRNAs taken up by plant cells was higher and longer lasting than that dried onto the plant surface. In contrast with dsRNAs in fungi, dsRNAs in plant cells could efficiently turn into substantial siRNAs via secondary amplification machinery. Our findings provide new implications to develop SIGS as a mainstream disease control strategy against Fusarium and other fungi.
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Affiliation(s)
- Xiu‐Shi Song
- Key Laboratory of Pesticide, College of Plant ProtectionNanjing Agricultural UniversityNanjingJiangsu Province210095China
| | - Kai‐Xin Gu
- Key Laboratory of Pesticide, College of Plant ProtectionNanjing Agricultural UniversityNanjingJiangsu Province210095China
| | - Xiao‐Xin Duan
- Key Laboratory of Pesticide, College of Plant ProtectionNanjing Agricultural UniversityNanjingJiangsu Province210095China
| | - Xue‐Mei Xiao
- Key Laboratory of Pesticide, College of Plant ProtectionNanjing Agricultural UniversityNanjingJiangsu Province210095China
| | - Yi‐Ping Hou
- Key Laboratory of Pesticide, College of Plant ProtectionNanjing Agricultural UniversityNanjingJiangsu Province210095China
| | - Ya‐Bing Duan
- Key Laboratory of Pesticide, College of Plant ProtectionNanjing Agricultural UniversityNanjingJiangsu Province210095China
| | - Jian‐Xin Wang
- Key Laboratory of Pesticide, College of Plant ProtectionNanjing Agricultural UniversityNanjingJiangsu Province210095China
| | - Na Yu
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant ProtectionNanjing Agricultural UniversityNanjingJiangsu Province210095China
| | - Ming‐Guo Zhou
- Key Laboratory of Pesticide, College of Plant ProtectionNanjing Agricultural UniversityNanjingJiangsu Province210095China
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63
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Martínez-Cruz J, Romero D, de la Torre FN, Fernández-Ortuño D, Torés JA, de Vicente A, Pérez-García A. The Functional Characterization of Podosphaera xanthii Candidate Effector Genes Reveals Novel Target Functions for Fungal Pathogenicity. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:914-931. [PMID: 29513627 DOI: 10.1094/mpmi-12-17-0318-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Podosphaera xanthii is the main causal agent of powdery mildew disease in cucurbits. In a previous study, we determined that P. xanthii expresses approximately 50 Podosphaera effector candidates (PECs), identified based on the presence of a predicted signal peptide and the absence of functional annotation. In this work, we used host-induced gene silencing (HIGS), employing Agrobacterium tumefaciens as a vector for the delivery of the silencing constructs (ATM-HIGS), to identify genes involved in early plant-pathogen interaction. The analysis of seven selected PEC-encoding genes showed that six of them, PEC007, PEC009, PEC019, PEC032, PEC034, and PEC054, are required for P. xanthii pathogenesis, as revealed by reduced fungal growth and increased production of hydrogen peroxide by host cells. In addition, protein models and protein-ligand predictions allowed us to identify putative functions for these candidates. The biochemical activities of PEC019, PEC032, and PEC054 were elucidated using their corresponding proteins expressed in Escherichia coli. These proteins were confirmed as phospholipid-binding protein, α-mannosidase, and cellulose-binding protein. Further, BLAST searches showed that these three effectors are widely distributed in phytopathogenic fungi. These results suggest novel targets for fungal effectors, such as host-cell plasma membrane, host-cell glycosylation, and damage-associated molecular pattern-triggered immunity.
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Affiliation(s)
- Jesús Martínez-Cruz
- 1 Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga and Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"-Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29071 Málaga, Spain
| | - Diego Romero
- 1 Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga and Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"-Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29071 Málaga, Spain
| | - Fernando N de la Torre
- 2 Departamento de Biología Molecular y Bioquímica, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain; and
| | - Dolores Fernández-Ortuño
- 3 Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"-Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29750 Algarrobo-Costa, Málaga, Spain
| | - Juan A Torés
- 3 Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"-Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29750 Algarrobo-Costa, Málaga, Spain
| | - Antonio de Vicente
- 1 Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga and Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"-Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29071 Málaga, Spain
| | - Alejandro Pérez-García
- 1 Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga and Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"-Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), 29071 Málaga, Spain
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Ojiambo PS, Battilani P, Cary JW, Blum BH, Carbone I. Cultural and Genetic Approaches to Manage Aflatoxin Contamination: Recent Insights Provide Opportunities for Improved Control. PHYTOPATHOLOGY 2018; 108:1024-1037. [PMID: 29869954 DOI: 10.1094/phyto-04-18-0134-rvw] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Aspergillus flavus is a morphologically complex species that can produce the group of polyketide derived carcinogenic and mutagenic secondary metabolites, aflatoxins, as well as other secondary metabolites such as cyclopiazonic acid and aflatrem. Aflatoxin causes aflatoxicosis when aflatoxins are ingested through contaminated food and feed. In addition, aflatoxin contamination is a major problem, from both an economic and health aspect, in developing countries, especially Asia and Africa, where cereals and peanuts are important food crops. Earlier measures for control of A. flavus infection and consequent aflatoxin contamination centered on creating unfavorable environments for the pathogen and destroying contaminated products. While development of atoxigenic (nonaflatoxin producing) strains of A. flavus as viable commercial biocontrol agents has marked a unique advance for control of aflatoxin contamination, particularly in Africa, new insights into the biology and sexuality of A. flavus are now providing opportunities to design improved atoxigenic strains for sustainable biological control of aflatoxin. Further, progress in the use of molecular technologies such as incorporation of antifungal genes in the host and host-induced gene silencing, is providing knowledge that could be harnessed to develop germplasm that is resistant to infection by A. flavus and aflatoxin contamination. This review summarizes the substantial progress that has been made to understand the biology of A. flavus and mitigate aflatoxin contamination with emphasis on maize. Concepts developed to date can provide a basis for future research efforts on the sustainable management of aflatoxin contamination.
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Affiliation(s)
- Peter S Ojiambo
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
| | - Paola Battilani
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
| | - Jeffrey W Cary
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
| | - Burt H Blum
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
| | - Ignazio Carbone
- First and fifth authors: Center for Integrated Fungal Research, Department of Entomology and Plant Pathology, North Carolina State University, Raleigh 27695; second author: Department of Sustainable Crop Production, Università Cattolica del Sacro Cuore, Via Emilia Parmense 84, 29122 Piacenza, Italy; third author: U.S. Department of Agriculture-Agriculture Research Service, SRRC, New Orleans, LA 70124; and fourth author: Department of Plant Pathology, University of Arkansas, Fayetteville 72701
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65
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Gosal SS, Wani SH. RNAi for Resistance Against Biotic Stresses in Crop Plants. BIOTECHNOLOGIES OF CROP IMPROVEMENT, VOLUME 2 2018. [PMCID: PMC7123769 DOI: 10.1007/978-3-319-90650-8_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
RNA interference (RNAi)-based gene silencing has become one of the most successful strategies in not only identifying gene function but also in improving agronomical traits of crops by silencing genes of different pathogens/pests and also plant genes for improvement of desired trait. The conserved nature of RNAi pathway across different organisms increases its applicability in various basic and applied fields. Here we attempt to summarize the knowledge generated on the fundamental mechanisms of RNAi over the years, with emphasis on insects and plant-parasitic nematodes (PPNs). This chapter also reviews the rich history of RNAi research, gene regulation by small RNAs across different organisms, and application potential of RNAi for generating transgenic plants resistant to major pests. But, there are some limitations too which restrict wider applications of this technology to its full potential. Further refinement of this technology in terms of resolving these shortcomings constitutes one of the thrust areas in present RNAi research. Nevertheless, its application especially in breeding agricultural crops resistant against biotic stresses will certainly offer the possible solutions for some of the breeding objectives which are otherwise unattainable.
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Affiliation(s)
- Satbir Singh Gosal
- School of Agricultural Biotechnology, Punjab Agricultural University, Ludhiana, Punjab India
| | - Shabir Hussain Wani
- Mountain Research Centre for Field Crops, Khudwani, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Srinagar, Jammu and Kashmir India
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66
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Khanal C, McGawley EC, Overstreet C, Stetina SR. The Elusive Search for Reniform Nematode Resistance in Cotton. PHYTOPATHOLOGY 2018; 108:532-541. [PMID: 29116883 DOI: 10.1094/phyto-09-17-0320-rvw] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The reniform nematode (Rotylenchulus reniformis Linford and Oliveira) has emerged as the most important plant-parasitic nematode of cotton in the United States cotton belt. Success in the development of reniform nematode-resistant upland cotton cultivars (Gossypium hirsutum L.) has not been realized despite over three decades of breeding efforts. Research approaches ranging from conventional breeding to triple species hybrids to marker-assisted selection have been employed to introgress reniform nematode resistance from other species of cotton into upland cultivars. Reniform nematode-resistant breeding lines derived from G. longicalyx were developed in 2007. However, these breeding lines displayed stunting symptoms and a hypersensitive response to reniform nematode infection. Subsequent breeding efforts focused on G. barbadense, G. aridum, G. armoreanum, and other species that have a high level of resistance to reniform nematode. Marker-assisted selection has greatly improved screening of reniform nematode-resistant lines. The use of advanced molecular techniques such as CRISPER-Cas9 systems and alternative ways such as delivery of suitable "cry" proteins and specific double-stranded RNA to nematodes will assist in developing resistant cultivars of cotton. In spite of the efforts of cotton breeders and nematologists, successes are limited only to the development of reniform nematode-resistant breeding lines. In this article, we provide an overview of the approaches employed to develop reniform nematode-resistant upland cotton cultivars in the past, progress to date, major obstacles, and some promising future research activity.
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Affiliation(s)
- Churamani Khanal
- First, second, and third authors: Louisiana State University AgCenter, Department of Plant Pathology and Crop Physiology, Baton Rouge 70803; and fourth author: United States Department of Agriculture-Agricultural Research Service, Crop Genetics Research Unit, P.O. Box 345, Stoneville, MS 38776
| | - Edward C McGawley
- First, second, and third authors: Louisiana State University AgCenter, Department of Plant Pathology and Crop Physiology, Baton Rouge 70803; and fourth author: United States Department of Agriculture-Agricultural Research Service, Crop Genetics Research Unit, P.O. Box 345, Stoneville, MS 38776
| | - Charles Overstreet
- First, second, and third authors: Louisiana State University AgCenter, Department of Plant Pathology and Crop Physiology, Baton Rouge 70803; and fourth author: United States Department of Agriculture-Agricultural Research Service, Crop Genetics Research Unit, P.O. Box 345, Stoneville, MS 38776
| | - Salliana R Stetina
- First, second, and third authors: Louisiana State University AgCenter, Department of Plant Pathology and Crop Physiology, Baton Rouge 70803; and fourth author: United States Department of Agriculture-Agricultural Research Service, Crop Genetics Research Unit, P.O. Box 345, Stoneville, MS 38776
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67
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Cai Q, He B, Kogel KH, Jin H. Cross-kingdom RNA trafficking and environmental RNAi-nature's blueprint for modern crop protection strategies. Curr Opin Microbiol 2018; 46:58-64. [PMID: 29549797 PMCID: PMC6499079 DOI: 10.1016/j.mib.2018.02.003] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 01/29/2018] [Accepted: 02/02/2018] [Indexed: 10/17/2022]
Abstract
In plants, small RNA (sRNA)-mediated RNA interference (RNAi) is critical for regulating host immunity against bacteria, fungi, oomycetes, viruses, and pests. Similarly, sRNAs from pathogens and pests also play an important role in modulating their virulence. Strikingly, recent evidence supports that some sRNAs can travel between interacting organisms and induce gene silencing in the counter party, a mechanism termed cross-kingdom RNAi. Exploiting this new knowledge, host-induced gene silencing (HIGS) by transgenic expression of pathogen gene-targeting double-stranded (ds)RNA has the potential to become an important disease-control method. To circumvent transgenic approaches, direct application of dsRNAs or sRNAs (environmental RNAi) onto host plants or post-harvest products leads to silencing of the target microbe/pest gene (referred to spray-induced gene silencing, SIGS) and confers efficient disease control. This review summarizes the current understanding of cross-kingdom RNA trafficking and environmental RNAi and how these findings can be developed into novel effective strategies to fight diseases caused by microbial pathogens and pests.
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Affiliation(s)
- Qiang Cai
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Baoye He
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Karl-Heinz Kogel
- Department of Phytopathology, Interdisciplinary Research Center for Biosystems, Land Use and Nutrition, Justus Liebig University Giessen, Germany
| | - Hailing Jin
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA.
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Liversage J, Coetzee MP, Bluhm BH, Berger DK, Crampton BG. LOVe across kingdoms: Blue light perception vital for growth and development in plant–fungal interactions. FUNGAL BIOL REV 2018. [DOI: 10.1016/j.fbr.2017.11.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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69
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Lu GH, Tang CY, Hua XM, Cheng J, Wang GH, Zhu YL, Zhang LY, Shou HX, Qi JL, Yang YH. Effects of an EPSPS-transgenic soybean line ZUTS31 on root-associated bacterial communities during field growth. PLoS One 2018; 13:e0192008. [PMID: 29408918 PMCID: PMC5800644 DOI: 10.1371/journal.pone.0192008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Accepted: 01/14/2018] [Indexed: 01/01/2023] Open
Abstract
The increased worldwide commercial cultivation of transgenic crops during the past 20 years is accompanied with potential effects on the soil microbial communities, because many rhizosphere and endosphere bacteria play important roles in promoting plant health and growth. Previous studies reported that transgenic plants exert differential effects on soil microbial communities, especially rhizobacteria. Thus, this study compared the soybean root-associated bacterial communities between a 5-enolpyruvylshikimate-3-phosphate synthase -transgenic soybean line (ZUTS31 or simply Z31) and its recipient cultivar (Huachun3 or simply HC3) at the vegetative, flowering, and seed-filling stages. High-throughput sequencing of 16S rRNA gene (16S rDNA) V4 hypervariable region amplicons via Illumina MiSeq and real-time quantitative PCR (qPCR) were performed. Our results revealed no significant differences in the overall alpha diversity of root-associated bacterial communities at the three developmental stages and in the beta diversity of root-associated bacterial communities at the flowering stage between Z31 and HC3 under field growth. However, significant differences in the beta diversity of rhizosphere bacterial communities were found at the vegetative and seed-filling stages between the two groups. Furthermore, the results of next generation sequencing and qPCR showed that the relative abundances of root-associated main nitrogen-fixing bacterial genera, especially Bradyrhizobium in the roots, evidently changed from the flowering stage to the seed-filling stage. In conclusion, Z31 exerts transitory effects on the taxonomic diversity of rhizosphere bacterial communities at the vegetative and seed-filling stages compared to the control under field conditions. In addition, soybean developmental change evidently influences the main symbiotic nitrogen-fixing bacterial genera in the roots from the flowering stage to the seed-filling stage.
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Affiliation(s)
- Gui-Hua Lu
- NJU–NJFU Joint Institute for Plant Molecular Biology, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
- Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, China
| | - Cheng-Yi Tang
- NJU–NJFU Joint Institute for Plant Molecular Biology, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Xiao-Mei Hua
- Research Center for Soil Pollution Prevention and Control, Nanjing Institute of Environmental Sciences, MEP, Nanjing, China
| | - Jing Cheng
- NJU–NJFU Joint Institute for Plant Molecular Biology, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Gu-Hao Wang
- NJU–NJFU Joint Institute for Plant Molecular Biology, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Yin-Ling Zhu
- NJU–NJFU Joint Institute for Plant Molecular Biology, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Li-Ya Zhang
- Crop Research Institute, Anhui Academy of Agricultural Sciences, Hefei, China
| | - Hui-Xia Shou
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Jin-Liang Qi
- NJU–NJFU Joint Institute for Plant Molecular Biology, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
- * E-mail: , (YHY); (JLQ)
| | - Yong-Hua Yang
- NJU–NJFU Joint Institute for Plant Molecular Biology, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
- * E-mail: , (YHY); (JLQ)
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70
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Brant EJ, Budak H. Plant Small Non-coding RNAs and Their Roles in Biotic Stresses. FRONTIERS IN PLANT SCIENCE 2018; 9:1038. [PMID: 30079074 PMCID: PMC6062887 DOI: 10.3389/fpls.2018.01038] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 06/26/2018] [Indexed: 05/04/2023]
Abstract
Non-coding RNAs (ncRNAs) have emerged as critical components of gene regulatory networks across a plethora of plant species. In particular, the 20-30 nucleotide small ncRNAs (sRNAs) play important roles in mediating both developmental processes and responses to biotic stresses. Based on variation in their biogenesis pathways, a number of different sRNA classes have been identified, and their specific functions have begun to be characterized. Here, we review the current knowledge of the biogenesis of the primary sRNA classes, microRNA (miRNA) and small nuclear RNA (snRNA), and their respective secondary classes, and discuss the roles of sRNAs in plant-pathogen interactions. sRNA mobility between species is also discussed along with potential applications of sRNA-plant-pathogen interactions in crop improvement technologies.
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71
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Abstract
Accumulating evidence indicates that small noncoding RNAs (sRNAs) can be transferred across species for interkingdom communication. In addition to the artificial transgene-derived small interfering RNAs (siRNAs), endogenous microRNAs (miRNAs) can also influence interacting organisms to execute a regulatory function. For instance, we have recently found that, in response to infection with Verticillium dahliae (V. dahliae), cotton plants increase accumulation of miR166 and miR159, which can be exported to the fungal hyphae for specific silencing of virulence genes. These findings suggest a great potential for applying interkingdom mobile miRNAs for crop protection against fungal pathogens. The methods described here provide an approach to identify plant miRNAs and their potential targets in invading fungal pathogens, which will help in revealing the underlying mechanisms of these crosstalk phenomena.
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Affiliation(s)
- Yun Jin
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Hui-Shan Guo
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.
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72
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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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73
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Morozov SY, Lazareva EA, Solovyev AG. RNA helicase domains of viral origin in proteins of insect retrotransposons: possible source for evolutionary advantages. PeerJ 2017; 5:e3673. [PMID: 28828268 PMCID: PMC5563155 DOI: 10.7717/peerj.3673] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 07/21/2017] [Indexed: 12/15/2022] Open
Abstract
Recently, a novel phenomenon of horizontal gene transfer of helicase-encoding sequence from positive-stranded RNA viruses to LINE transposons in insect genomes was described. TRAS family transposons encoding an ORF2 protein, which comprised all typical functional domains and an additional helicase domain, were found to be preserved in many families during the evolution of the order Lepidoptera. In the present paper, in species of orders Hemiptera and Orthoptera, we found helicase domain-encoding sequences integrated into ORF1 of retrotransposons of the Jockey family. RNA helicases encoded by transposons of TRAS and Jockey families represented separate brunches in a phylogenetic tree of helicase domains and thus could be considered as independently originated in the evolution of insect transposons. Transcriptome database analyses revealed that both TRAS and Jockey transposons encoding the helicase domain represented transcribed genome sequences. Moreover, the transposon-encoded helicases were found to contain the full set of conserved motifs essential for their enzymatic activities. Taking into account the previously reported ability of RNA helicase encoded by TRAS ORF2 to suppress post-transcriptional RNA silencing, we propose possible scenarios of evolutionary fixation of actively expressed functional helicases of viral origin in insect retrotransposons as genetic elements advantageous for both transposons and their insect hosts.
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Affiliation(s)
- Sergey Y Morozov
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia
| | - Ekaterina A Lazareva
- Department of Virology, Biological Faculty, Moscow State University, Moscow, Russia
| | - Andrey G Solovyev
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia.,Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
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74
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Tiwari IM, Jesuraj A, Kamboj R, Devanna BN, Botella JR, Sharma TR. Host Delivered RNAi, an efficient approach to increase rice resistance to sheath blight pathogen (Rhizoctonia solani). Sci Rep 2017; 7:7521. [PMID: 28790353 PMCID: PMC5548729 DOI: 10.1038/s41598-017-07749-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 07/04/2017] [Indexed: 01/10/2023] Open
Abstract
Rhizoctonia solani, the causal agent of rice sheath blight disease, causes significant losses worldwide as there are no cultivars providing absolute resistance to this fungal pathogen. We have used Host Delivered RNA Interference (HD-RNAi) technology to target two PATHOGENICITY MAP KINASE 1 (PMK1) homologues, RPMK1-1 and RPMK1-2, from R. solani using a hybrid RNAi construct. PMK1 homologues in other fungal pathogens are essential for the formation of appressorium, the fungal infection structures required for penetration of the plant cuticle, as well as invasive growth once inside the plant tissues and overall viability of the pathogen within the plant. Evaluation of transgenic rice lines revealed a significant decrease in fungal infection levels compared to non-transformed controls and the observed delay in disease symptoms was further confirmed through microscopic studies. Relative expression levels of the targeted genes, RPMK1-1 and RPMK1-2, were determined in R. solani infecting either transgenic or control lines with significantly lower levels observed in R. solani infecting transgenic lines carrying the HD-RNAi constructs. This is the first report demonstrating the effectiveness of HD-RNAi against sheath blight and offers new opportunities for durable control of the disease as it does not rely on resistance conferred by major resistance genes.
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Affiliation(s)
- Ila Mukul Tiwari
- National Research Centre on Plant Biotechnology, Pusa Campus, New Delhi, 110012, India
| | - Arun Jesuraj
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Richa Kamboj
- National Research Centre on Plant Biotechnology, Pusa Campus, New Delhi, 110012, India
| | - B N Devanna
- National Research Centre on Plant Biotechnology, Pusa Campus, New Delhi, 110012, India
| | - Jose R Botella
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - T R Sharma
- National Research Centre on Plant Biotechnology, Pusa Campus, New Delhi, 110012, India.
- National Agri-Food Biotechnology Institute (NABI), Mohali, Punjab, India, 160071.
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75
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Wang M, Thomas N, Jin H. Cross-kingdom RNA trafficking and environmental RNAi for powerful innovative pre- and post-harvest plant protection. CURRENT OPINION IN PLANT BIOLOGY 2017; 38:133-141. [PMID: 28570950 PMCID: PMC5720367 DOI: 10.1016/j.pbi.2017.05.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/09/2017] [Accepted: 05/09/2017] [Indexed: 05/19/2023]
Abstract
Small RNA (sRNA) induces RNA interference (RNAi) in almost all eukaryotes. While sRNAs can move within an organism, they can also move between interacting organisms to induce gene silencing, a phenomenon called 'cross-kingdom RNAi'. Some sRNAs from pathogens or pests move into host cells and suppress host immunity in both plants and animals; whereas some host sRNAs travel into pathogen/pest cells to inhibit their virulence. Moreover, uptake of exogenous RNAs from the environment was recently discovered in certain fungal pathogens, which makes it possible to suppress fungal diseases by directly applying pathogen-targeting RNAs on crops and post-harvest products. This new-generation of RNA-based fungicides is powerful, environmentally friendly, and can be easily adapted to control multiple diseases simultaneously.
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Affiliation(s)
- Ming Wang
- Department of Plant Pathology & Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521-0122, United States
| | - Nicholas Thomas
- Department of Plant Pathology & Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521-0122, United States
| | - Hailing Jin
- Department of Plant Pathology & Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521-0122, United States.
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76
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Cooper B, Campbell KB. Protection Against Common Bean Rust Conferred by a Gene-Silencing Method. PHYTOPATHOLOGY 2017; 107:920-927. [PMID: 28437139 DOI: 10.1094/phyto-03-17-0095-r] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Rust disease of the dry bean plant, Phaseolus vulgaris, is caused by the fungus Uromyces appendiculatus. The fungus acquires its nutrients and energy from bean leaves using a specialized cell structure, the haustorium, through which it secretes effector proteins that contribute to pathogenicity by defeating the plant immune system. Candidate effectors have been identified by DNA sequencing and motif analysis, and some candidates have been observed in infected leaves by mass spectrometry. To assess their roles in pathogenicity, we have inserted small fragments of genes for five candidates into Bean pod mottle virus. Plants were infected with recombinant virus and then challenged with U. appendiculatus. Virus-infected plants expressing gene fragments for four of five candidate effectors accumulated lower amounts of rust and had dramatically less rust disease. By contrast, controls that included a fungal gene fragment for a septin protein not expressed in the haustorium died from a synergistic reaction between the virus and the fungus. The results imply that RNA generated in the plant moved across the fungal haustorium to silence effector genes important to fungal pathogenicity. This study shows that four bean rust fungal genes encode pathogenicity determinants and that the expression of fungal RNA in the plant can be an effective method for protecting bean plants from rust.
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Affiliation(s)
- Bret Cooper
- Soybean Genomics and Improvement Laboratory, United States Department of Agriculture-Agricultural Research Service, Beltsville, MD 20705
| | - Kimberly B Campbell
- Soybean Genomics and Improvement Laboratory, United States Department of Agriculture-Agricultural Research Service, Beltsville, MD 20705
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Torres-Martínez S, Ruiz-Vázquez RM. The RNAi Universe in Fungi: A Varied Landscape of Small RNAs and Biological Functions. Annu Rev Microbiol 2017; 71:371-391. [PMID: 28657888 DOI: 10.1146/annurev-micro-090816-093352] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RNA interference (RNAi) is a conserved eukaryotic mechanism that uses small RNA molecules to suppress gene expression through sequence-specific messenger RNA degradation, translational repression, or transcriptional inhibition. In filamentous fungi, the protective function of RNAi in the maintenance of genome integrity is well known. However, knowledge of the regulatory role of RNAi in fungi has had to wait until the recent identification of different endogenous small RNA classes, which are generated by distinct RNAi pathways. In addition, RNAi research on new fungal models has uncovered the role of small RNAs and RNAi pathways in the regulation of diverse biological functions. In this review, we give an up-to-date overview of the different classes of small RNAs and RNAi pathways in fungi and their roles in the defense of genome integrity and regulation of fungal physiology and development, as well as in the interaction of fungi with biotic and abiotic environments.
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Pareek M, Rajam MV. RNAi-mediated silencing of MAP kinase signalling genes (Fmk1, Hog1, and Pbs2) in Fusarium oxysporum reduces pathogenesis on tomato plants. Fungal Biol 2017; 121:775-784. [PMID: 28800849 DOI: 10.1016/j.funbio.2017.05.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 05/22/2017] [Accepted: 05/23/2017] [Indexed: 10/19/2022]
Abstract
Fusarium oxysporum is a soil-borne plant fungal pathogen, and causes colossal losses in several crop plants including tomato. Effective control measures include the use of harmful fungicides and resistant cultivars, but these methods have shown limited success. Conventional methods to validate fungal pathogenic genes are labour intensive. Therefore, an alternative strategy is required to efficiently characterize unknown pathogenic genes. RNA interference (RNAi) has emerged as a potential tool to functionally characterize novel fungal pathogenic genes and also to control fungal diseases. Here, we report an efficient method to produce stable RNAi transformants of F. oxysporum using Agrobacterium-mediated transformation (AMT). We have transformed F. oxysporum spores using RNAi constructs of Fmk1, Hog1, and Pbs2 MAP kinase signalling genes. Fmk1 RNAi fungal transformants showed loss of surface hydrophobicity, reduced invasive growth on tomato fruits and hypo-virulence on tomato seedlings. Hog1 and Pbs2 RNAi transformants showed altered conidial size, and reduced invasive growth and pathogenesis. These results showed that AMT using RNAi constructs is an effective approach for dissecting the role of genes involved in pathogenesis in F. oxysporum and this could be extended for other fungal systems. The obtained knowledge can be easily translated for developing fungal resistant crops by RNAi.
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Affiliation(s)
- Manish Pareek
- Department of Genetics, University of Delhi South Campus, Benito Juarez Marg, New Delhi 110021, India
| | - Manchikatla Venkat Rajam
- Department of Genetics, University of Delhi South Campus, Benito Juarez Marg, New Delhi 110021, India.
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79
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Jiang Q, Sun X, Niu F, Hu Z, Chen R, Zhang H. GmDREB1 overexpression affects the expression of microRNAs in GM wheat seeds. PLoS One 2017; 12:e0175924. [PMID: 28459812 PMCID: PMC5411081 DOI: 10.1371/journal.pone.0175924] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 04/03/2017] [Indexed: 01/07/2023] Open
Abstract
MicroRNAs (miRNAs) are small regulators of gene expression that act on many different molecular and biochemical processes in eukaryotes. To date, miRNAs have not been considered in the current evaluation system for GM crops. In this study, small RNAs from the dry seeds of a GM wheat line overexpressing GmDREB1 and non-GM wheat cultivars were investigated using deep sequencing technology and bioinformatic approaches. As a result, 23 differentially expressed miRNAs in dry seeds were identified and confirmed between GM wheat and a non-GM acceptor. Notably, more differentially expressed tae-miRNAs between non-GM wheat varieties were found, indicating that the degree of variance between non-GM cultivars was considerably higher than that induced by the transgenic event. Most of the target genes of these differentially expressed miRNAs between GM wheat and a non-GM acceptor were associated with abiotic stress, in accordance with the product concept of GM wheat in improving drought and salt tolerance. Our data provided useful information and insights into the evaluation of miRNA expression in edible GM crops.
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Affiliation(s)
- Qiyan Jiang
- Institute of Crop Science, National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xianjun Sun
- Institute of Crop Science, National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fengjuan Niu
- Institute of Crop Science, National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zheng Hu
- Institute of Crop Science, National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Rui Chen
- Tianjin Institute of Agricultural Quality Standard and Testing Technology, Tianjin Academy of Agricultural Sciences, Tianjin, China
- * E-mail: (RC); (HZ)
| | - Hui Zhang
- Institute of Crop Science, National Key Facility for Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing, China
- * E-mail: (RC); (HZ)
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80
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Abstract
Biological processes such as defense mechanisms and microbial offense strategies are regulated through RNA induced interference in eukaryotes. Genetic mutations are modulated through biogenesis of small RNAs which directly impacts upon host development. Plant defense mechanisms are regulated and supported by a diversified group of small RNAs which are involved in streamlining several RNA interference pathways leading toward the initiation of pathogen gene silencing mechanisms. In the similar context, pathogens also utilize the support of small RNAs to launch their offensive attacks. Also there are strong evidences about the active involvement of these RNAs in symbiotic associations. Interestingly, small RNAs are not limited to the individuals in whom they are produced; they also show cross kingdom influences through variable interactions with other species thus leading toward the inter-organismic gene silencing. The phenomenon is understandable in the microbes which utilize these mechanisms to overcome host defense line. Understanding the mechanism of triggering host defense strategies can be a valuable step toward the generation of disease resistant host plants. We think that the cross kingdom trafficking of small RNA is an interesting insight that is needed to be explored for its vitality.
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Affiliation(s)
- Waqar Islam
- a College of Plant Protection , Fujian Agriculture and Forestry University , Fuzhou , Fujian , China
| | - Saif Ul Islam
- a College of Plant Protection , Fujian Agriculture and Forestry University , Fuzhou , Fujian , China
| | - Muhammad Qasim
- a College of Plant Protection , Fujian Agriculture and Forestry University , Fuzhou , Fujian , China
| | - Liande Wang
- a College of Plant Protection , Fujian Agriculture and Forestry University , Fuzhou , Fujian , China
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81
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Nami S, Baradaran B, Mansoori B, Kordbacheh P, Rezaie S, Falahati M, Mohamed Khosroshahi L, Safara M, Zaini F. The Utilization of RNA Silencing Technology to Mitigate the Voriconazole Resistance of Aspergillus Flavus; Lipofectamine-Based Delivery. Adv Pharm Bull 2017; 7:53-59. [PMID: 28507937 PMCID: PMC5426734 DOI: 10.15171/apb.2017.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 12/25/2016] [Accepted: 12/28/2017] [Indexed: 02/01/2023] Open
Abstract
Purpose: Introducing the effect of RNAi in fungi to downregulate essential genes has made it a powerful tool to investigate gene function, with potential strategies for novel disease treatments. Thus, this study is an endeavor to delve into the silencing potentials of siRNA on cyp51A and MDR1 in voriconazole-resistant Aspergillus flavus as the target genes.
Methods: In this study, we designed three cyp51A-specific siRNAs and three MDR1-specific siRNAs and after the co-transfection of siRNA into Aspergillus flavus, using lipofectamine, we investigated the effect of different siRNA concentrations (5, 15, 25, 50nM) on cyp51A and MDR1 expressions by qRT-PCR. Finally, the Minimum Inhibitory Concentrations (MICs) of voriconazole for isolates were determined by broth dilution method.
Results: Cyp51A siRNA induced 9, 22, 33, 40-fold reductions in cyp51A mRNA expression in a voriconazole-resistant strain following the treatment of the cells with concentrations of 5, 15, 25, 50nM siRNA, respectively. Identically, the same procedure was applied to MDR1, even though it induced 2, 3, 4, 10-fold reductions. The results demonstrated a MIC for voriconazole in the untreated group (4µg per ml), when compared to the group treated with cyp51A-specific siRNA and MDR1-specific siRNA, both at concentrations of 25 and 50nM, yielding 2µg per ml and 1µg per ml when 25 nM was applied and 2µg per ml and 0.5µg per ml when the concentration doubled to 50 nM.
Conclusion: In this study, we suggested that siRNA-mediated specific inhibition of cyp51A and MDR1 genes play roles in voriconazole-resistant A.flavus strain and these could be apt target genes for inactivation. The current study promises a bright prospect for the treatment of invasive aspergillosis through the effective deployment of RNAi and gene therapy.
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Affiliation(s)
- Sanam Nami
- Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Behzad Baradaran
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Behzad Mansoori
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Parivash Kordbacheh
- Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Sasan Rezaie
- Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehraban Falahati
- Department of Medical Mycology and Parasitology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | | | - Mahin Safara
- Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Farideh Zaini
- Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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82
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Wang M, Jin H. Spray-Induced Gene Silencing: a Powerful Innovative Strategy for Crop Protection. Trends Microbiol 2016; 25:4-6. [PMID: 27923542 DOI: 10.1016/j.tim.2016.11.011] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 11/21/2016] [Indexed: 11/15/2022]
Abstract
Plant pathogens cause serious crop losses worldwide. Recent new studies demonstrate that spraying double-stranded RNAs (dsRNAs) and small RNAs (sRNAs) that target essential pathogen genes on plant surfaces confer efficient crop protection. This so-called spray-induced gene silencing (SIGS) strategy of disease control is potentially sustainable and environmentally friendly.
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Affiliation(s)
- Ming Wang
- Department of Plant Pathology & Microbiology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521-0122, USA
| | - Hailing Jin
- Department of Plant Pathology & Microbiology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521-0122, USA.
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83
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Wang M, Weiberg A, Lin FM, Thomma B, Huang HD, Jin H. Bidirectional cross-kingdom RNAi and fungal uptake of external RNAs confer plant protection. NATURE PLANTS 2016; 2:16151. [PMID: 27643635 PMCID: PMC5040644 DOI: 10.1038/nplants.2016.151] [Citation(s) in RCA: 389] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Accepted: 09/01/2016] [Indexed: 05/17/2023]
Abstract
Aggressive fungal pathogens such as Botrytis and Verticillium spp. cause severe crop losses worldwide. We recently discovered that Botrytis cinerea delivers small RNAs (Bc-sRNAs) into plant cells to silence host immunity genes. Such sRNA effectors are mostly produced by Botrytis cinerea Dicer-like protein 1 (Bc-DCL1) and Bc-DCL2. Here we show that expressing sRNAs that target Bc-DCL1 and Bc-DCL2 in Arabidopsis and tomato silences Bc-DCL genes and attenuates fungal pathogenicity and growth, exemplifying bidirectional cross-kingdom RNAi and sRNA trafficking between plants and fungi. This strategy can be adapted to simultaneously control multiple fungal diseases. We also show that Botrytis can take up external sRNAs and double-stranded RNAs (dsRNAs). Applying sRNAs or dsRNAs that target Botrytis DCL1 and DCL2 genes on the surface of fruits, vegetables and flowers significantly inhibits grey mould disease. Such pathogen gene-targeting RNAs represent a new generation of environmentally friendly fungicides.
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Affiliation(s)
- Ming Wang
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Arne Weiberg
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
| | - Feng-Mao Lin
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsin-Chu 300, Taiwan
| | - Bart Thomma
- Laboratory of Phytopathology, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Hsien-Da Huang
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsin-Chu 300, Taiwan
| | - Hailing Jin
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521
- Correspondence to Hailing Jin.
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84
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Chen W, Kastner C, Nowara D, Oliveira-Garcia E, Rutten T, Zhao Y, Deising HB, Kumlehn J, Schweizer P. Host-induced silencing of Fusarium culmorum genes protects wheat from infection. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:4979-91. [PMID: 27540093 PMCID: PMC5014151 DOI: 10.1093/jxb/erw263] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Plants producing antisense or double-stranded RNA molecules that target specific genes of eukaryotic pests or pathogens can become protected from their attack. This beneficial effect was also reported for plant-fungus interactions and is believed to reflect uptake of the RNAs by the fungus via an as yet unknown mechanism, followed by target gene silencing. Here we report that wheat plants pre-infected with Barley stripe mosaic virus (BSMV) strains containing antisense sequences against target genes of the Fusarium head blight (FHB) fungus F. culmorum caused a reduction of corresponding transcript levels in the pathogen and reduced disease symptoms. Stable transgenic wheat plants carrying an RNAi hairpin construct against the β-1, 3-glucan synthase gene FcGls1 of F. culmorum or a triple combination of FcGls1 with two additional, pre-tested target genes also showed enhanced FHB resistance in leaf and spike inoculation assays under greenhouse and near-field conditions, respectively. Microscopic evaluation of F. culmorum development in plants transiently or stably expressing FcGls1 silencing constructs revealed aberrant, swollen fungal hyphae, indicating severe hyphal cell wall defects. The results lead us to propose host-induced gene silencing (HIGS) as a plant protection approach that may also be applicable to highly FHB-susceptible wheat genotypes.
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Affiliation(s)
- Wanxin Chen
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Christine Kastner
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Daniela Nowara
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Ely Oliveira-Garcia
- Martin-Luther Universität Halle-Wittenberg, Phytopathologie und Pflanzenschutz, Betty Heimann Straße 3, D-06120 Halle, Germany
| | - Twan Rutten
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Yusheng Zhao
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Holger B Deising
- Martin-Luther Universität Halle-Wittenberg, Phytopathologie und Pflanzenschutz, Betty Heimann Straße 3, D-06120 Halle, Germany
| | - Jochen Kumlehn
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Patrick Schweizer
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
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85
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Whitham SA, Qi M, Innes RW, Ma W, Lopes-Caitar V, Hewezi T. Molecular Soybean-Pathogen Interactions. ANNUAL REVIEW OF PHYTOPATHOLOGY 2016; 54:443-68. [PMID: 27359370 DOI: 10.1146/annurev-phyto-080615-100156] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Soybean hosts a wide variety of pathogens that cause significant yield losses. The importance of soybean as a major oilseed crop has led to research focused on its interactions with pathogens, such as Soybean mosaic virus, Pseudomonas syringae, Phytophthora sojae, Phakopsora pachyrhizi, and Heterodera glycines. Pioneering work on soybean's interactions with these organisms, which represent the five major pathogen groups (viruses, bacteria, oomycetes, fungi, and nematodes), has contributed to our understanding of the molecular mechanisms underlying virulence and immunity. These mechanisms involve conserved and unique features that validate the need for research in both soybean and homologous model systems. In this review, we discuss identification of effectors and their functions as well as resistance gene-mediated recognition and signaling. We also point out areas in which model systems and recent advances in resources and tools have provided opportunities to gain deeper insights into soybean-pathogen interactions.
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Affiliation(s)
- Steven A Whitham
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, Iowa 50011; ,
| | - Mingsheng Qi
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, Iowa 50011; ,
| | - Roger W Innes
- Department of Biology, Indiana University, Bloomington, Indiana 47405;
| | - Wenbo Ma
- Department of Plant Pathology and Microbiology, University of California, Riverside, California 92521;
| | - Valéria Lopes-Caitar
- Department of Plant Sciences, University of Tennessee, Knoxville, Tennessee 37996; ,
| | - Tarek Hewezi
- Department of Plant Sciences, University of Tennessee, Knoxville, Tennessee 37996; ,
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86
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Abstract
Abstract
A large number of pathogenic microorganisms cause rice diseases that lead to enormous yield losses worldwide. Such losses are important because rice is a staple food for more than half of the world's population. Over the past two decades, the extensive study of the molecular interactions between rice and the fungal pathogen Magnaporthe oryzae and between rice and the bacterial pathogen Xanthomonas oryzae pv. oryzae has made rice a model for investigating plant–microbe interactions of monocotyledons. Impressive progress has been recently achieved in understanding the molecular basis of rice pathogen-associated molecular pattern-immunity and effector-triggered immunity. Here, we briefly summarize these recent advances, emphasizing the diverse functions of the structurally conserved fungal effectors, the regulatory mechanisms of the immune receptor complexes, and the novel strategies for breeding disease resistance. We also discuss future research challenges.
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Affiliation(s)
- Wende Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Guo-Liang Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Department of Plant Pathology, Ohio State University, Columbus, OH 43210, USA
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87
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Huang J, Yang M, Zhang X. The function of small RNAs in plant biotic stress response. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2016; 58:312-27. [PMID: 26748943 DOI: 10.1111/jipb.12463] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 01/07/2016] [Indexed: 05/18/2023]
Abstract
Small RNAs (sRNAs) play essential roles in plants upon biotic stress. Plants utilize RNA silencing machinery to facilitate pathogen-associated molecular pattern-triggered immunity and effector-triggered immunity to defend against pathogen attack or to facilitate defense against insect herbivores. Pathogens, on the other hand, are also able to generate effectors and sRNAs to counter the host immune response. The arms race between plants and pathogens/insect herbivores has triggered the evolution of sRNAs, RNA silencing machinery and pathogen effectors. A great number of studies have been performed to investigate the roles of sRNAs in plant defense, bringing in the opportunity to utilize sRNAs in plant protection. Transgenic plants with pathogen-derived resistance ability or transgenerational defense have been generated, which show promising potential as solutions for pathogen/insect herbivore problems in the field. Here we summarize the recent progress on the function of sRNAs in response to biotic stress, mainly in plant-pathogen/insect herbivore interaction, and the application of sRNAs in disease and insect herbivore control.
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Affiliation(s)
- Juan Huang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Meiling Yang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Xiaoming Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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88
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Mbengue M, Navaud O, Peyraud R, Barascud M, Badet T, Vincent R, Barbacci A, Raffaele S. Emerging Trends in Molecular Interactions between Plants and the Broad Host Range Fungal Pathogens Botrytis cinerea and Sclerotinia sclerotiorum. FRONTIERS IN PLANT SCIENCE 2016; 7:422. [PMID: 27066056 PMCID: PMC4814483 DOI: 10.3389/fpls.2016.00422] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 03/18/2016] [Indexed: 05/08/2023]
Abstract
Fungal plant pathogens are major threats to food security worldwide. Sclerotinia sclerotiorum and Botrytis cinerea are closely related Ascomycete plant pathogens causing mold diseases on hundreds of plant species. There is no genetic source of complete plant resistance to these broad host range pathogens known to date. Instead, natural plant populations show a continuum of resistance levels controlled by multiple genes, a phenotype designated as quantitative disease resistance. Little is known about the molecular mechanisms controlling the interaction between plants and S. sclerotiorum and B. cinerea but significant advances were made on this topic in the last years. This minireview highlights a selection of nine themes that emerged in recent research reports on the molecular bases of plant-S. sclerotiorum and plant-B. cinerea interactions. On the fungal side, this includes progress on understanding the role of oxalic acid, on the study of fungal small secreted proteins. Next, we discuss the exchanges of small RNA between organisms and the control of cell death in plant and fungi during pathogenic interactions. Finally on the plant side, we highlight defense priming by mechanical signals, the characterization of plant Receptor-like proteins and the hormone abscisic acid in the response to B. cinerea and S. sclerotiorum, the role of plant general transcription machinery and plant small bioactive peptides. These represent nine trends we selected as remarkable in our understanding of fungal molecules causing disease and plant mechanisms associated with disease resistance to two devastating broad host range fungi.
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89
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Robinson DG, Ding Y, Jiang L. Unconventional protein secretion in plants: a critical assessment. PROTOPLASMA 2016; 253:31-43. [PMID: 26410830 DOI: 10.1007/s00709-015-0887-1] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 09/18/2015] [Indexed: 05/27/2023]
Abstract
Unconventional protein secretion (UPS) is a collective term for mechanisms by which cytosolic proteins that lack a signal peptide ("leaderless secretory proteins" (LSPs)) can gain access to the cell exterior. Numerous examples of UPS have been well documented in animal and yeast cells. In contrast, our understanding of the mechanism(s) and function of UPS in plants is very limited. This review evaluates the available literature on this subject. The apparent large numbers of LSPs in the plant secretome suggest that UPS also occurs in plants but is not a proof. Although the direct transport of LSPs across the plant plasma membrane (PM) has not yet been described, it is possible that as in other eukaryotes, exosomes may be released from plant cells through fusion of multivesicular bodies (MVBs) with the PM. In this way, LSPs, but also small RNAs (sRNAs), that are passively taken up from the cytosol into the intraluminal vesicles of MVBs, could reach the apoplast. Another possible mechanism is the recently discovered exocyst-positive organelle (EXPO), a double-membrane-bound compartment, distinct from autophagosomes, which appears to sequester LSPs.
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Affiliation(s)
- David G Robinson
- Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 230, D-69120, Heidelberg, Germany.
| | - Yu Ding
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Liwen Jiang
- Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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90
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Mueth NA, Ramachandran SR, Hulbert SH. Small RNAs from the wheat stripe rust fungus (Puccinia striiformis f.sp. tritici). BMC Genomics 2015; 16:718. [PMID: 26391470 PMCID: PMC4578785 DOI: 10.1186/s12864-015-1895-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 09/06/2015] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is a costly global disease that burdens farmers with yield loss and high fungicide expenses. This sophisticated biotrophic parasite infiltrates wheat leaves and develops infection structures inside host cells, appropriating nutrients while suppressing the plant defense response. Development in most eukaryotes is regulated by small RNA molecules, and the success of host-induced gene silencing technology in Puccinia spp. implies the existence of a functional RNAi system. However, some fungi lack this capability, and small RNAs have not yet been reported in rust fungi. The objective of this study was to determine whether P. striiformis carries an endogenous small RNA repertoire. RESULTS We extracted small RNA from rust-infected wheat flag leaves and performed high-throughput sequencing. Two wheat cultivars were analyzed: one is susceptible; the other displays partial high-temperature adult plant resistance. Fungal-specific reads were identified by mapping to the P. striiformis draft genome and removing reads present in uninfected control libraries. Sequencing and bioinformatics results were verified by RT-PCR. Like other RNAi-equipped fungi, P. striiformis produces large numbers of 20-22 nt sequences with a preference for uracil at the 5' position. Precise post-transcriptional processing and high accumulation of specific sRNA sequences were observed. Some predicted sRNA precursors possess a microRNA-like stem-loop secondary structure; others originate from much longer inverted repeats containing gene sequences. Finally, sRNA-target prediction algorithms were used to obtain a list of putative gene targets in both organisms. Predicted fungal target genes were enriched for kinases and small secreted proteins, while the list of wheat targets included homologs of known plant resistance genes. CONCLUSIONS This work provides an inventory of small RNAs endogenous to an important plant pathogen, enabling further exploration of gene regulation on both sides of the host/parasite interaction. We conclude that small RNAs are likely to play a role in regulating the complex developmental processes involved in stripe rust pathogenicity.
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Affiliation(s)
- Nicholas A Mueth
- Molecular Plant Sciences, Washington State University, Pullman, WA, USA.
| | | | - Scot H Hulbert
- Molecular Plant Sciences, Washington State University, Pullman, WA, USA.
- Plant Pathology, Washington State University, Pullman, WA, USA.
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91
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Masanga JO, Matheka JM, Omer RA, Ommeh SC, Monda EO, Alakonya AE. Downregulation of transcription factor aflR in Aspergillus flavus confers reduction to aflatoxin accumulation in transgenic maize with alteration of host plant architecture. PLANT CELL REPORTS 2015; 34:1379-1387. [PMID: 25895735 DOI: 10.1007/s00299-015-1794-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Revised: 03/20/2015] [Accepted: 04/11/2015] [Indexed: 06/04/2023]
Abstract
We report success of host-induced gene silencing in downregulation of aflatoxin biosynthesis in Aspergillus flavus infecting maize transformed with a hairpin construct targeting transcription factor aflR. Infestation of crops by aflatoxin-producing fungi results in economic losses as well as negative human and animal health effects. Currently, the control strategies against aflatoxin accumulation are not effective to the small holder farming systems in Africa and this has led to widespread aflatoxin exposure especially in rural populations of sub-Saharan Africa that rely on maize as a staple food crop. A recent strategy called host-induced gene silencing holds great potential for developing aflatoxin-resistant plant germplasm for the African context where farmers are unable to make further investments other than access to the germplasm. We transformed maize with a hairpin construct targeting the aflatoxin biosynthesis transcription factor aflR. The developed transgenic maize were challenged with an aflatoxigenic Aspergillus flavus strain from Eastern Kenya, a region endemic to aflatoxin outbreaks. Our results indicated that aflR was downregulated in A. flavus colonizing transgenic maize. Further, maize kernels from transgenic plants accumulated significantly lower levels of aflatoxins (14-fold) than those from wild type plants. Interestingly, we observed that our silencing cassette caused stunting and reduced kernel placement in the transgenic maize. This could have been due to "off-target" silencing of unintended genes in transformed plants by aflR siRNAs. Overall, this work indicates that host-induced gene silencing has potential in developing aflatoxin-resistant germplasm.
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Affiliation(s)
- Joel Okoyo Masanga
- Institute for Biotechnology Research, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000-00200, Nairobi, Kenya
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92
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Weiberg A, Jin H. Small RNAs--the secret agents in the plant-pathogen interactions. CURRENT OPINION IN PLANT BIOLOGY 2015; 26:87-94. [PMID: 26123395 PMCID: PMC4573252 DOI: 10.1016/j.pbi.2015.05.033] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 05/28/2015] [Accepted: 05/29/2015] [Indexed: 05/15/2023]
Abstract
Eukaryotic regulatory small RNAs (sRNAs) that induce RNA interference (RNAi) are involved in a plethora of biological processes, including host immunity and pathogen virulence. In plants, diverse classes of sRNAs contribute to the regulation of host innate immunity. These immune-regulatory sRNAs operate through distinct RNAi pathways that trigger transcriptional or post-transcriptional gene silencing. Similarly, many pathogen-derived sRNAs also regulate pathogen virulence. Remarkably, the influence of regulatory sRNAs is not limited to the individual organism in which they are generated. It can sometimes extend to interacting species from even different kingdoms. There they trigger gene silencing in the interacting organism, a phenomenon called cross-kingdom RNAi. This is exhibited in advanced pathogens and parasites that produce sRNAs to suppress host immunity. Conversely, in host-induced gene silencing (HIGS), diverse plants are engineered to trigger RNAi against pathogens and pests to confer host resistance. Cross-kingdom RNAi opens up a vastly unexplored area of research on mobile sRNAs in the battlefield between hosts and pathogens.
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Affiliation(s)
- Arne Weiberg
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Hailing Jin
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA.
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93
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94
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Weiberg A, Bellinger M, Jin H. Conversations between kingdoms: small RNAs. Curr Opin Biotechnol 2015. [PMID: 25622136 DOI: 10.1016/j.copbio.2014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Humans, animals, and plants are constantly under attack from pathogens and pests, resulting in severe consequences on global human health and crop production. Small RNA (sRNA)-mediated RNA interference (RNAi) is a conserved regulatory mechanism that is involved in almost all eukaryotic cellular processes, including host immunity and pathogen virulence. Recent evidence supports the significant contribution of sRNAs and RNAi to the communication between hosts and some eukaryotic pathogens, pests, parasites, or symbiotic microorganisms. Mobile silencing signals—most likely sRNAs—are capable of translocating from the host to its interacting organism, and vice versa. In this review, we will provide an overview of sRNA communications between different kingdoms, with a primary focus on the advances in plant-pathogen interaction systems.
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Affiliation(s)
- Arne Weiberg
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Marschal Bellinger
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Hailing Jin
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA.
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95
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Calvo AM, Cary JW. Association of fungal secondary metabolism and sclerotial biology. Front Microbiol 2015; 6:62. [PMID: 25762985 PMCID: PMC4329819 DOI: 10.3389/fmicb.2015.00062] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/18/2015] [Indexed: 11/13/2022] Open
Abstract
Fungal secondary metabolism and morphological development have been shown to be intimately associated at the genetic level. Much of the literature has focused on the co-regulation of secondary metabolite production (e.g., sterigmatocystin and aflatoxin in Aspergillus nidulans and Aspergillus flavus, respectively) with conidiation or formation of sexual fruiting bodies. However, many of these genetic links also control sclerotial production. Sclerotia are resistant structures produced by a number of fungal genera. They also represent the principal source of primary inoculum for some phytopathogenic fungi. In nature, higher plants often concentrate secondary metabolites in reproductive structures as a means of defense against herbivores and insects. By analogy, fungi also sequester a number of secondary metabolites in sclerotia that act as a chemical defense system against fungivorous predators. These include antiinsectant compounds such as tetramic acids, indole diterpenoids, pyridones, and diketopiperazines. This chapter will focus on the molecular mechanisms governing production of secondary metabolites and the role they play in sclerotial development and fungal ecology, with particular emphasis on Aspergillus species. The global regulatory proteins VeA and LaeA, components of the velvet nuclear protein complex, serve as virulence factors and control both development and secondary metabolite production in many Aspergillus species. We will discuss a number of VeA- and LaeA-regulated secondary metabolic gene clusters in A. flavus that are postulated to be involved in sclerotial morphogenesis and chemical defense. The presence of multiple regulatory factors that control secondary metabolism and sclerotial formation suggests that fungi have evolved these complex regulatory mechanisms as a means to rapidly adapt chemical responses to protect sclerotia from predators, competitors and other environmental stressors.
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Affiliation(s)
- Ana M Calvo
- Department of Biological Sciences, Northern Illinois University DeKalb, IL, USA
| | - Jeffrey W Cary
- Southern Regional Research Center, United States Department of Agriculture - Agricultural Research Service New Orleans, LA, USA
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96
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Weiberg A, Bellinger M, Jin H. Conversations between kingdoms: small RNAs. Curr Opin Biotechnol 2015; 32:207-215. [PMID: 25622136 DOI: 10.1016/j.copbio.2014.12.025] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 12/22/2014] [Accepted: 12/30/2014] [Indexed: 12/30/2022]
Abstract
Humans, animals, and plants are constantly under attack from pathogens and pests, resulting in severe consequences on global human health and crop production. Small RNA (sRNA)-mediated RNA interference (RNAi) is a conserved regulatory mechanism that is involved in almost all eukaryotic cellular processes, including host immunity and pathogen virulence. Recent evidence supports the significant contribution of sRNAs and RNAi to the communication between hosts and some eukaryotic pathogens, pests, parasites, or symbiotic microorganisms. Mobile silencing signals—most likely sRNAs—are capable of translocating from the host to its interacting organism, and vice versa. In this review, we will provide an overview of sRNA communications between different kingdoms, with a primary focus on the advances in plant-pathogen interaction systems.
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Affiliation(s)
- Arne Weiberg
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Marschal Bellinger
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Hailing Jin
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA.
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97
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Han L, Luan YS. Horizontal Transfer of Small RNAs to and from Plants. FRONTIERS IN PLANT SCIENCE 2015; 6:1113. [PMID: 26697056 PMCID: PMC4674566 DOI: 10.3389/fpls.2015.01113] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 11/24/2015] [Indexed: 05/21/2023]
Abstract
Genetic information is traditionally thought to be transferred from parents to offspring. However, there is evidence indicating that gene transfer can also occur from microbes to higher species, such as plants, invertebrates, and vertebrates. This horizontal transfer can be carried out by small RNAs (sRNAs). sRNAs have been recently reported to move across kingdoms as mobile signals, spreading silencing information toward targeted genes. sRNAs, especially microRNAs (miRNAs) and small interfering RNAs (siRNAs), are non-coding molecules that control gene expression at the transcriptional or post-transcriptional level. Some sRNAs act in a cross-kingdom manner between animals and their parasites, but little is known about such sRNAs associated with plants. In this report, we provide a brief introduction to miRNAs that are transferred from plants to mammals/viruses and siRNAs that are transferred from microbes to plants. Both miRNAs and siRNAs can exert corresponding functions in the target organisms. Additionally, we provide information concerning a host-induced gene silencing system as a potential application that utilizes the transgenic trafficking of RNA molecules to silence the genes of interacting organisms. Moreover, we lay out the controversial views regarding cross-kingdom miRNAs and call for better methodology and experimental design to confirm this unique function of miRNAs.
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98
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Panwar V, McCallum B, Bakkeren G. A functional genomics method for assaying gene function in phytopathogenic fungi through host-induced gene silencing mediated by agroinfiltration. Methods Mol Biol 2015; 1287:179-189. [PMID: 25740365 DOI: 10.1007/978-1-4939-2453-0_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
With the rapid growth of genomic information, there is an increasing demand for efficient analysis tools to study the function of predicted genes coded in genomes. Agroinfiltration, the delivery of gene constructs into plant cells by Agrobacterium tumefaciens infiltrated into leaves, is one such versatile, simple, and rapid technique that is increasingly used for transient gene expression assay in plants. In this chapter, we focus on the use of agroinfiltration as a functional genomics research tool in molecular plant pathology. Specifically, we describe in detail its use in expressing phytopathogenic fungal gene sequences in a host plant to induce RNA silencing of corresponding genes inside the pathogen, a method which has been termed host-induced gene silencing (HIGS). We target the fungal pathogen Puccinia triticina which causes leaf rust on its wheat host, but the method is applicable to a variety of pathosystems.
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Affiliation(s)
- Vinay Panwar
- Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, PO Box 5000, 4200 Hwy 97, Summerland, BC, Canada, V0H 1Z0
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99
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Ellis JG, Lagudah ES, Spielmeyer W, Dodds PN. The past, present and future of breeding rust resistant wheat. FRONTIERS IN PLANT SCIENCE 2014; 5:641. [PMID: 25505474 PMCID: PMC4241819 DOI: 10.3389/fpls.2014.00641] [Citation(s) in RCA: 250] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 10/29/2014] [Indexed: 05/17/2023]
Abstract
Two classes of genes are used for breeding rust resistant wheat. The first class, called R (for resistance) genes, are pathogen race specific in their action, effective at all plant growth stages and probably mostly encode immune receptors of the nucleotide binding leucine rich repeat (NB-LRR) class. The second class is called adult plant resistance genes (APR) because resistance is usually functional only in adult plants, and, in contrast to most R genes, the levels of resistance conferred by single APR genes are only partial and allow considerable disease development. Some but not all APR genes provide resistance to all isolates of a rust pathogen species and a subclass of these provides resistance to several fungal pathogen species. Initial indications are that APR genes encode a more heterogeneous range of proteins than R proteins. Two APR genes, Lr34 and Yr36, have been cloned from wheat and their products are an ABC transporter and a protein kinase, respectively. Lr34 and Sr2 have provided long lasting and widely used (durable) partial resistance and are mainly used in conjunction with other R and APR genes to obtain adequate rust resistance. We caution that some APR genes indeed include race specific, weak R genes which may be of the NB-LRR class. A research priority to better inform rust resistance breeding is to characterize further APR genes in wheat and to understand how they function and how they interact when multiple APR and R genes are stacked in a single genotype by conventional and GM breeding. An important message is do not be complacent about the general durability of all APR genes.
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Affiliation(s)
- Jeffrey G. Ellis
- Commonwealth Scientific and Industrial Research Organisation, Agriculture FlagshipCanberra, ACT, Australia
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100
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Whisson S, Vetukuri R, Avrova A, Dixelius C. Can silencing of transposons contribute to variation in effector gene expression in Phytophthora infestans? Mob Genet Elements 2014; 2:110-114. [PMID: 22934246 PMCID: PMC3429519 DOI: 10.4161/mge.20265] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Transposable elements are ubiquitous residents in eukaryotic genomes. Often considered to be genomic parasites, they can lead to dramatic changes in genome organization, gene expression, and gene evolution. The oomycete plant pathogen Phytophthora infestans has evolved a genome organization where core biology genes are predominantly located in genome regions that have relatively few resident transposons. In contrast, disease effector-encoding genes are most frequently located in rapidly evolving genomic regions that are rich in transposons. P. infestans, as a eukaryote, likely uses RNA silencing to minimize the activity of transposons. We have shown that fusion of a short interspersed element (SINE) to an effector gene in P. infestans leads to the silencing of both the introduced fusion and endogenous homologous sequences. This is also likely to occur naturally in the genome of P. infestans, as transcriptional inactivation of effectors is known to occur, and over half of the translocated "RXLR class" of effectors are located within 2 kb of transposon sequences in the P. infestans genome. In this commentary, we review the diverse transposon inventory of P. infestans, its control by RNA silencing, and consequences for expression modulation of nearby effector genes in this economically important plant pathogen.
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