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RoyChowdhury M, Sternhagen J, Xin Y, Lou B, Li X, Li C. Evolution of pathogenicity in obligate fungal pathogens and allied genera. PeerJ 2022; 10:e13794. [PMID: 36042858 PMCID: PMC9420410 DOI: 10.7717/peerj.13794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 07/06/2022] [Indexed: 01/17/2023] Open
Abstract
Obligate fungal pathogens (ascomycetes and basidiomycetes) and oomycetes are known to cause diseases in cereal crop plants. They feed on living cells and most of them have learned to bypass the host immune machinery. This paper discusses some of the factors that are associated with pathogenicity drawing examples from ascomycetes, basidiomycetes and oomycetes, with respect to their manifestation in crop plants. The comparisons have revealed a striking similarity in the three groups suggesting convergent pathways that have arisen from three lineages independently leading to an obligate lifestyle. This review has been written with the intent, that new information on adaptation strategies of biotrophs, modifications in pathogenicity strategies and population dynamics will improve current strategies for breeding with stable resistance.
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Affiliation(s)
- Moytri RoyChowdhury
- Infectious Diseases Program, California Department of Public Health, Richmond, California, United States of America
| | - Jake Sternhagen
- Riverside School of Medicine, University of California, Riverside, Riverside, CA, United States of America
| | - Ya Xin
- Hangzhou Academy of Agricultural Sciences, Hangzhou, P.R. China
| | - Binghai Lou
- Guangxi Academy of Specialty Crops, Guilin, Guangxi, P.R. China
| | - Xiaobai Li
- Zhejiang Academy of Agricultural Sciences, Hangzhou, P.R. China
| | - Chunnan Li
- Hangzhou Academy of Agricultural Sciences, Hangzhou, P.R. China
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Mapuranga J, Zhang L, Zhang N, Yang W. The haustorium: The root of biotrophic fungal pathogens. FRONTIERS IN PLANT SCIENCE 2022; 13:963705. [PMID: 36105706 PMCID: PMC9465030 DOI: 10.3389/fpls.2022.963705] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/15/2022] [Indexed: 05/02/2023]
Abstract
Biotrophic plant pathogenic fungi are among the dreadful pathogens that continuously threaten the production of economically important crops. The interaction of biotrophic fungal pathogens with their hosts necessitates the development of unique infection mechanisms and involvement of various virulence-associated components. Biotrophic plant pathogenic fungi have an exceptional lifestyle that supports nutrient acquisition from cells of a living host and are fully dependent on the host for successful completion of their life cycle. The haustorium, a specialized infection structure, is the key organ for biotrophic fungal pathogens. The haustorium is not only essential in the uptake of nutrients without killing the host, but also in the secretion and delivery of effectors into the host cells to manipulate host immune system and defense responses and reprogram the metabolic flow of the host. Although there is a number of unanswered questions in this area yet, results from various studies indicate that the haustorium is the root of biotrophic fungal pathogens. This review provides an overview of current knowledge of the haustorium, its structure, composition, and functions, which includes the most recent haustorial transcriptome studies.
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Kangara N, Kurowski TJ, Radhakrishnan GV, Ghosh S, Cook NM, Yu G, Arora S, Steffenson BJ, Figueroa M, Mohareb F, Saunders DGO, Wulff BBH. Mutagenesis of Puccinia graminis f. sp. tritici and Selection of Gain-of-Virulence Mutants. FRONTIERS IN PLANT SCIENCE 2020; 11:570180. [PMID: 33072145 PMCID: PMC7533539 DOI: 10.3389/fpls.2020.570180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 08/19/2020] [Indexed: 05/08/2023]
Abstract
Wheat stem rust caused by the fungus Puccinia graminis f. sp. tritici (Pgt), is regaining prominence due to the recent emergence of virulent isolates and epidemics in Africa, Europe and Central Asia. The development and deployment of wheat cultivars with multiple stem rust resistance (Sr) genes stacked together will provide durable resistance. However, certain disease resistance genes can suppress each other or fail in particular genetic backgrounds. Therefore, the function of each Sr gene must be confirmed after incorporation into an Sr-gene stack. This is difficult when using pathogen disease assays due to epistasis from recognition of multiple avirulence (Avr) effectors. Heterologous delivery of single Avr effectors can circumvent this limitation, but this strategy is currently limited by the paucity of cloned Pgt Avrs. To accelerate Avr gene cloning, we outline a procedure to develop a mutant population of Pgt spores and select for gain-of-virulence mutants. We used ethyl methanesulphonate (EMS) to mutagenize urediniospores and create a library of > 10,000 independent mutant isolates that were combined into 16 bulks of ~658 pustules each. We sequenced random mutants and determined the average mutation density to be 1 single nucleotide variant (SNV) per 258 kb. From this, we calculated that a minimum of three independently derived gain-of-virulence mutants is required to identify a given Avr gene. We inoculated the mutant library onto plants containing Sr43, Sr44, or Sr45 and obtained 9, 4, and 14 mutants with virulence toward Sr43, Sr44, or Sr45, respectively. However, only mutants identified on Sr43 and Sr45 maintained their virulence when reinolculated onto the lines from which they were identified. We further characterized 8 mutants with virulence toward Sr43. These also maintained their virulence profile on the stem rust international differential set containing 20 Sr genes, indicating that they were most likely not accidental contaminants. In conclusion, our method allows selecting for virulent mutants toward targeted resistance (R) genes. The development of a mutant library from as little as 320 mg spores creates a resource that enables screening against several R genes without the need for multiple rounds of spore multiplication and mutagenesis.
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Affiliation(s)
| | - Tomasz J. Kurowski
- The Bioinformatics Group, Cranfield Soil and Agrifood Institute, Cranfield University, Bedford, United Kingdom
| | | | - Sreya Ghosh
- Crop Genetics Department, John Innes Centre, Norwich, United Kingdom
| | - Nicola M. Cook
- Crop Genetics Department, John Innes Centre, Norwich, United Kingdom
| | - Guotai Yu
- Crop Genetics Department, John Innes Centre, Norwich, United Kingdom
| | - Sanu Arora
- Crop Genetics Department, John Innes Centre, Norwich, United Kingdom
| | - Brian J. Steffenson
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, United States
| | - Melania Figueroa
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Canberra, NSW, Australia
| | - Fady Mohareb
- The Bioinformatics Group, Cranfield Soil and Agrifood Institute, Cranfield University, Bedford, United Kingdom
- *Correspondence: Brande B. H. Wulff, ; Diane G. O. Saunders, ; Fady Mohareb,
| | - Diane G. O. Saunders
- Crop Genetics Department, John Innes Centre, Norwich, United Kingdom
- *Correspondence: Brande B. H. Wulff, ; Diane G. O. Saunders, ; Fady Mohareb,
| | - Brande B. H. Wulff
- Crop Genetics Department, John Innes Centre, Norwich, United Kingdom
- *Correspondence: Brande B. H. Wulff, ; Diane G. O. Saunders, ; Fady Mohareb,
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Kobayashi Y, Maeda T, Yamaguchi K, Kameoka H, Tanaka S, Ezawa T, Shigenobu S, Kawaguchi M. The genome of Rhizophagus clarus HR1 reveals a common genetic basis for auxotrophy among arbuscular mycorrhizal fungi. BMC Genomics 2018; 19:465. [PMID: 29914365 PMCID: PMC6007072 DOI: 10.1186/s12864-018-4853-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 06/04/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Mycorrhizal symbiosis is one of the most fundamental types of mutualistic plant-microbe interaction. Among the many classes of mycorrhizae, the arbuscular mycorrhizae have the most general symbiotic style and the longest history. However, the genomes of arbuscular mycorrhizal (AM) fungi are not well characterized due to difficulties in cultivation and genetic analysis. In this study, we sequenced the genome of the AM fungus Rhizophagus clarus HR1, compared the sequence with the genome sequence of the model species R. irregularis, and checked for missing genes that encode enzymes in metabolic pathways related to their obligate biotrophy. RESULTS In the genome of R. clarus, we confirmed the absence of cytosolic fatty acid synthase (FAS), whereas all mitochondrial FAS components were present. A KEGG pathway map identified the absence of genes encoding enzymes for several other metabolic pathways in the two AM fungi, including thiamine biosynthesis and the conversion of vitamin B6 derivatives. We also found that a large proportion of the genes encoding glucose-producing polysaccharide hydrolases, that are present even in ectomycorrhizal fungi, also appear to be absent in AM fungi. CONCLUSIONS In this study, we found several new genes that are absent from the genomes of AM fungi in addition to the genes previously identified as missing. Missing genes for enzymes in primary metabolic pathways imply that AM fungi may have a higher dependency on host plants than other biotrophic fungi. These missing metabolic pathways provide a genetic basis to explore the physiological characteristics and auxotrophy of AM fungi.
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Affiliation(s)
- Yuuki Kobayashi
- Division of Symbiotic Systems, National Institute for Basic Biology, Okazaki, Japan
| | - Taro Maeda
- Division of Symbiotic Systems, National Institute for Basic Biology, Okazaki, Japan
| | - Katsushi Yamaguchi
- Functional Genomics Facility, National Institute for Basic Biology, Okazaki, Japan
| | - Hiromu Kameoka
- Division of Symbiotic Systems, National Institute for Basic Biology, Okazaki, Japan
| | - Sachiko Tanaka
- Division of Symbiotic Systems, National Institute for Basic Biology, Okazaki, Japan
| | - Tatsuhiro Ezawa
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Shuji Shigenobu
- Functional Genomics Facility, National Institute for Basic Biology, Okazaki, Japan
- The Graduate University for Advanced Studies (SOKENDAI), Hayama, Japan
| | - Masayoshi Kawaguchi
- Division of Symbiotic Systems, National Institute for Basic Biology, Okazaki, Japan
- The Graduate University for Advanced Studies (SOKENDAI), Hayama, Japan
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Hsieh JF, Chuah A, Patel HR, Sandhu KS, Foley WJ, Külheim C. Transcriptome Profiling of Melaleuca quinquenervia Challenged by Myrtle Rust Reveals Differences in Defense Responses Among Resistant Individuals. PHYTOPATHOLOGY 2018; 108:495-509. [PMID: 29135360 DOI: 10.1094/phyto-09-17-0307-r] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Plants have developed complex defense mechanisms to protect themselves against pathogens. A wide-host-range fungus, Austropuccinia psidii, which has caused severe damage to ecosystems and plantations worldwide, is a major threat to Australian ecosystems dominated by members of the family Myrtaceae. In particular, the east coast wetland foundation tree species Melaleuca quinquenervia, appears to be variably susceptible to this pathogen. Understanding the molecular basis of host resistance would enable better management of this rust disease. We identified resistant and susceptible individuals of M. quinquenervia and explored their differential gene expression in order to discover the molecular basis of resistance against A. psidii. Rust screening of germplasm showed a varying degree of response, with fully resistant to highly susceptible individuals. We used transcriptome profiling in samples collected before and at 5 days postinoculation (dpi). Differential gene expression analysis showed that numerous defense-related genes were induced in susceptible plants at 5 dpi. Mapping reads against the A. psidii genome showed that only susceptible plants contained fungal-derived transcripts. Resistant plants exhibited an overexpression of candidate A. psidii resistance-related genes such as receptor-like kinases, nucleotide-binding site leucine-rich repeat proteins, glutathione S-transferases, WRKY transcriptional regulators, and pathogenesis-related proteins. We identified large differences in the expression of defense-related genes among resistant individuals.
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Affiliation(s)
- Ji-Fan Hsieh
- First, fifth, and sixth authors: Research School of Biology, The Australian National University, 116 Daley Road, Canberra 2601, ACT, Australia; second and third authors: The John Curtin School of Medical Research, The Australian National University, 131 Garran Road, Canberra 2601, ACT, Australia; and fourth author: Plant Breeding Institute, The University of Sydney, 107 Cobbitty Road, Cobbitty 2570, NSW, Australia
| | - Aaron Chuah
- First, fifth, and sixth authors: Research School of Biology, The Australian National University, 116 Daley Road, Canberra 2601, ACT, Australia; second and third authors: The John Curtin School of Medical Research, The Australian National University, 131 Garran Road, Canberra 2601, ACT, Australia; and fourth author: Plant Breeding Institute, The University of Sydney, 107 Cobbitty Road, Cobbitty 2570, NSW, Australia
| | - Hardip R Patel
- First, fifth, and sixth authors: Research School of Biology, The Australian National University, 116 Daley Road, Canberra 2601, ACT, Australia; second and third authors: The John Curtin School of Medical Research, The Australian National University, 131 Garran Road, Canberra 2601, ACT, Australia; and fourth author: Plant Breeding Institute, The University of Sydney, 107 Cobbitty Road, Cobbitty 2570, NSW, Australia
| | - Karanjeet S Sandhu
- First, fifth, and sixth authors: Research School of Biology, The Australian National University, 116 Daley Road, Canberra 2601, ACT, Australia; second and third authors: The John Curtin School of Medical Research, The Australian National University, 131 Garran Road, Canberra 2601, ACT, Australia; and fourth author: Plant Breeding Institute, The University of Sydney, 107 Cobbitty Road, Cobbitty 2570, NSW, Australia
| | - William J Foley
- First, fifth, and sixth authors: Research School of Biology, The Australian National University, 116 Daley Road, Canberra 2601, ACT, Australia; second and third authors: The John Curtin School of Medical Research, The Australian National University, 131 Garran Road, Canberra 2601, ACT, Australia; and fourth author: Plant Breeding Institute, The University of Sydney, 107 Cobbitty Road, Cobbitty 2570, NSW, Australia
| | - Carsten Külheim
- First, fifth, and sixth authors: Research School of Biology, The Australian National University, 116 Daley Road, Canberra 2601, ACT, Australia; second and third authors: The John Curtin School of Medical Research, The Australian National University, 131 Garran Road, Canberra 2601, ACT, Australia; and fourth author: Plant Breeding Institute, The University of Sydney, 107 Cobbitty Road, Cobbitty 2570, NSW, Australia
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Abstract
Fungi are among the dominant causal agents of plant diseases. To colonize plants and cause disease, pathogenic fungi use diverse strategies. Some fungi kill their hosts and feed on dead material (necrotrophs), while others colonize the living tissue (biotrophs). For successful invasion of plant organs, pathogenic development is tightly regulated and specialized infection structures are formed. To further colonize hosts and establish disease, fungal pathogens deploy a plethora of virulence factors. Depending on the infection strategy, virulence factors perform different functions. While basically all pathogens interfere with primary plant defense, necrotrophs secrete toxins to kill plant tissue. In contrast, biotrophs utilize effector molecules to suppress plant cell death and manipulate plant metabolism in favor of the pathogen. This article provides an overview of plant pathogenic fungal species and the strategies they use to cause disease.
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Vela-Corcía D, Bautista R, de Vicente A, Spanu PD, Pérez-García A. De novo Analysis of the Epiphytic Transcriptome of the Cucurbit Powdery Mildew Fungus Podosphaera xanthii and Identification of Candidate Secreted Effector Proteins. PLoS One 2016; 11:e0163379. [PMID: 27711117 PMCID: PMC5053433 DOI: 10.1371/journal.pone.0163379] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 09/06/2016] [Indexed: 01/09/2023] Open
Abstract
The cucurbit powdery mildew fungus Podosphaera xanthii is a major limiting factor for cucurbit production worldwide. Despite the fungus’s agronomic and economic importance, very little is known about fundamental aspects of P. xanthii biology, such as obligate biotrophy or pathogenesis. To design more durable control strategies, genomic information about P. xanthii is needed. Powdery mildews are fungal pathogens with large genomes compared with those of other fungi, which contain vast amounts of repetitive DNA sequences, much of which is composed of retrotransposons. To reduce genome complexity, in this work we aimed to obtain and analyse the epiphytic transcriptome of P. xanthii as a starting point for genomic research. Total RNA was isolated from epiphytic fungal material, and the corresponding cDNA library was sequenced using a 454 GS FLX platform. Over 676,562 reads were obtained and assembled into 37,241 contigs. Annotation data identified 8,798 putative genes with different orthologues. As described for other powdery mildew fungi, a similar set of missing core ascomycete genes was found, which may explain obligate biotrophy. To gain insight into the plant-pathogen relationships, special attention was focused on the analysis of the secretome. After this analysis, 137 putative secreted proteins were identified, including 53 candidate secreted effector proteins (CSEPs). Consistent with a putative role in pathogenesis, the expression profile observed for some of these CSEPs showed expression maxima at the beginning of the infection process at 24 h after inoculation, when the primary appressoria are mostly formed. Our data mark the onset of genomics research into this very important pathogen of cucurbits and shed some light on the intimate relationship between this pathogen and its host plant.
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Affiliation(s)
- David Vela-Corcía
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC), Departamento de Microbiología, Facultad de Ciencias, Málaga, Spain
| | - Rocío Bautista
- Plataforma Andaluza de Bioinformática, Edificio de Bioinnovación, Parque Tecnológico de Andalucía, Málaga, Spain
| | - Antonio de Vicente
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC), Departamento de Microbiología, Facultad de Ciencias, Málaga, Spain
| | - Pietro D. Spanu
- Department of Life Sciences, Imperial College London, United Kingdom
| | - Alejandro Pérez-García
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM−UMA−CSIC), Departamento de Microbiología, Facultad de Ciencias, Málaga, Spain
- * E-mail:
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Torres MF, Ghaffari N, Buiate EAS, Moore N, Schwartz S, Johnson CD, Vaillancourt LJ. A Colletotrichum graminicola mutant deficient in the establishment of biotrophy reveals early transcriptional events in the maize anthracnose disease interaction. BMC Genomics 2016; 17:202. [PMID: 26956617 PMCID: PMC4782317 DOI: 10.1186/s12864-016-2546-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 02/26/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Colletotrichum graminicola is a hemibiotrophic fungal pathogen that causes maize anthracnose disease. It progresses through three recognizable phases of pathogenic development in planta: melanized appressoria on the host surface prior to penetration; biotrophy, characterized by intracellular colonization of living host cells; and necrotrophy, characterized by host cell death and symptom development. A "Mixed Effects" Generalized Linear Model (GLM) was developed and applied to an existing Illumina transcriptome dataset, substantially increasing the statistical power of the analysis of C. graminicola gene expression during infection and colonization. Additionally, the in planta transcriptome of the wild-type was compared with that of a mutant strain impaired in the establishment of biotrophy, allowing detailed dissection of events occurring specifically during penetration, and during early versus late biotrophy. RESULTS More than 2000 fungal genes were differentially transcribed during appressorial maturation, penetration, and colonization. Secreted proteins, secondary metabolism genes, and membrane receptors were over-represented among the differentially expressed genes, suggesting that the fungus engages in an intimate and dynamic conversation with the host, beginning prior to penetration. This communication process probably involves reception of plant signals triggering subsequent developmental progress in the fungus, as well as production of signals that induce responses in the host. Later phases of biotrophy were more similar to necrotrophy, with increased production of secreted proteases, inducers of plant cell death, hydrolases, and membrane bound transporters for the uptake and egress of potential toxins, signals, and nutrients. CONCLUSIONS This approach revealed, in unprecedented detail, fungal genes specifically expressed during critical phases of host penetration and biotrophic establishment. Many encoded secreted proteins, secondary metabolism enzymes, and receptors that may play roles in host-pathogen communication necessary to promote susceptibility, and thus may provide targets for chemical or biological controls to manage this important disease. The differentially expressed genes could be used as 'landmarks' to more accurately identify developmental progress in compatible versus incompatible interactions involving genetic variants of both host and pathogen.
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Affiliation(s)
- Maria F Torres
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY, 40546-0312, USA.
- Present Address: Functional Genomics Laboratory, Weill Cornell Medical College, Cornell University, Qatar Foundation - Education City, Doha, Qatar.
| | - Noushin Ghaffari
- AgriLife Genomics and Bioinformatics, Texas A&M AgriLife Research, Texas A&M University, College Station, TX, 77845, USA.
| | - Ester A S Buiate
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY, 40546-0312, USA.
- Present Address: Monsanto Company Brazil, Uberlândia, Minas Gerais, Brazil.
| | - Neil Moore
- Department of Computer Science, University of Kentucky, Davis Marksbury Building, 328 Rose Street, Lexington, KY, 40506-0633, USA.
| | - Scott Schwartz
- AgriLife Genomics and Bioinformatics, Texas A&M AgriLife Research, Texas A&M University, College Station, TX, 77845, USA.
- Present Address: Department of Integrative Biology, University of Texas, Austin, TX, 78712, USA.
| | - Charles D Johnson
- AgriLife Genomics and Bioinformatics, Texas A&M AgriLife Research, Texas A&M University, College Station, TX, 77845, USA.
| | - Lisa J Vaillancourt
- Department of Plant Pathology, University of Kentucky, 201F Plant Science Building, 1405 Veterans Drive, Lexington, KY, 40546-0312, USA.
- Present Address: Department of Integrative Biology, University of Texas, Austin, TX, 78712, USA.
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Yin C, Downey SI, Klages-Mundt NL, Ramachandran S, Chen X, Szabo LJ, Pumphrey M, Hulbert SH. Identification of promising host-induced silencing targets among genes preferentially transcribed in haustoria of Puccinia. BMC Genomics 2015; 16:579. [PMID: 26238441 PMCID: PMC4524123 DOI: 10.1186/s12864-015-1791-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 07/22/2015] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The cereal rust fungi are destructive pathogens that affect grain production worldwide. Although the genomic and transcript sequences for three Puccinia species that attack wheat have been released, the functions of large repertories of genes from Puccinia still need to be addressed to understand the infection process of these obligate parasites. Host-induced gene silencing (HIGS) has emerged a useful tool to examine the importance of rust fungus genes while growing within host plants. In this study, HIGS was used to test genes from Puccinia with transcripts enriched in haustoria for their ability to interfere with full development of the rust fungi. RESULTS Approximately 1200 haustoria enriched genes from Puccinia graminis f. sp. tritici (Pgt) were identified by comparative RNA sequencing. Virus-induced gene silencing (VIGS) constructs with fragments of 86 Puccinia genes, were tested for their ability to interfere with full development of these rust fungi. Most of the genes tested had no noticeable effects, but 10 reduced Pgt development after co-inoculation with the gene VIGS constructs and Pgt. These included a predicted glycolytic enzyme, two other proteins that are probably secreted and involved in carbohydrate or sugar metabolism, a protein involved in thiazol biosynthesis, a protein involved in auxin biosynthesis, an amino acid permease, two hypothetical proteins with no conserved domains, a predicted small secreted protein and another protein predicted to be secreted with similarity to bacterial proteins involved in membrane transport. Transient silencing of four of these genes reduced development of P. striiformis (Pst), and three of also caused reduction of P. triticina (Pt) development. CONCLUSIONS Partial suppression of transcripts involved in a large variety of biological processes in haustoria cells of Puccinia rusts can disrupt their development. Silencing of three genes resulted in suppression of all three rust diseases indicating that it may be possible to engineer durable resistance to multiple rust pathogens with a single gene in transgenic wheat plants for sustainable control of cereal rusts.
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Affiliation(s)
- Chuntao Yin
- Department of Plant Pathology, Washington State University, Pullman, WA, 99164-6430, USA
| | - Samantha I Downey
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA, 99164-6430, USA
| | - Naeh L Klages-Mundt
- Department of Biology, Carleton College, One North College St., Northfield, MN, 55057, USA
| | - Sowmya Ramachandran
- Department of Plant Pathology, Washington State University, Pullman, WA, 99164-6430, USA
| | - Xianming Chen
- US Department of Agriculture, Agricultural Research Service, Wheat Genetics, Quality, Physiology and Disease Research Unit, Pullman, WA, 99164-6430, USA
| | - Les J Szabo
- US Department of Agriculture, Agricultural Research Service, Cereal Disease Laboratory, St. Paul, MN, 55108, USA
| | - Michael Pumphrey
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA, 99164-6430, USA
| | - Scot H Hulbert
- Department of Plant Pathology, Washington State University, Pullman, WA, 99164-6430, USA.
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Laura M, Borghi C, Bobbio V, Allavena A. The effect on the transcriptome of Anemone coronaria following infection with rust (Tranzschelia discolor). PLoS One 2015; 10:e0118565. [PMID: 25768012 PMCID: PMC4359109 DOI: 10.1371/journal.pone.0118565] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 01/20/2015] [Indexed: 12/25/2022] Open
Abstract
In order to understand plant/pathogen interaction, the transcriptome of uninfected (1S) and infected (2I) plant was sequenced at 3'end by the GS FLX 454 platform. De novo assembly of high-quality reads generated 27,231 contigs leaving 37,191 singletons in the 1S and 38,393 in the 2I libraries. ESTcalc tool suggested that 71% of the transcriptome had been captured, with 99% of the genes present being represented by at least one read. Unigene annotation showed that 50.5% of the predicted translation products shared significant homology with protein sequences in GenBank. In all 253 differential transcript abundance (DTAs) were in higher abundance and 52 in lower abundance in the 2I library. 128 higher abundance DTA genes were of fungal origin and 49 were clearly plant sequences. A tBLASTn-based search of the sequences using as query the full length predicted polypeptide product of 50 R genes identified 16 R gene products. Only one R gene (PGIP) was up-regulated. The response of the plant to fungal invasion included the up-regulation of several pathogenesis related protein (PR) genes involved in JA signaling and other genes associated with defense response and down regulation of cell wall associated genes, non-race-specific disease resistance1 (NDR1) and other genes like myb, presqualene diphosphate phosphatase (PSDPase), a UDP-glycosyltransferase 74E2-like (UGT). The DTA genes identified here should provide a basis for understanding the A. coronaria/T. discolor interaction and leads for biotechnology-based disease resistance breeding.
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Affiliation(s)
- Marina Laura
- CRA—Unità di Ricerca per la Floricoltura e le Specie Ornamentali, Corso Inglesi 508, 18038 Sanremo (IM), Italy
| | - Cristina Borghi
- CRA—Unità di Ricerca per la Floricoltura e le Specie Ornamentali, Corso Inglesi 508, 18038 Sanremo (IM), Italy
| | - Valentina Bobbio
- CRA—Unità di Ricerca per la Floricoltura e le Specie Ornamentali, Corso Inglesi 508, 18038 Sanremo (IM), Italy
| | - Andrea Allavena
- CRA—Unità di Ricerca per la Floricoltura e le Specie Ornamentali, Corso Inglesi 508, 18038 Sanremo (IM), Italy
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Link T, Seibel C, Voegele RT. Early insights into the genome sequence of Uromyces fabae. FRONTIERS IN PLANT SCIENCE 2014; 5:587. [PMID: 25400651 PMCID: PMC4212606 DOI: 10.3389/fpls.2014.00587] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 10/09/2014] [Indexed: 05/29/2023]
Abstract
Uromyces fabae is a major pathogen of broad bean, Vicia faba. U. fabae has served as a model among rust fungi to elucidate the development of infection structures, expression and secretion of cell wall degrading enzymes and gene expression. Using U. fabae, enormous progress was made regarding nutrient uptake and metabolism and in the search for secreted proteins and effectors. Here, we present results from a genome survey of U. fabae. Paired end Illumina sequencing provided 53 Gb of data. An assembly gave 59,735 scaffolds with a total length of 216 Mb. K-mer analysis estimated the genome size to be 329 Mb. Of a representative set of 23,153 predicted proteins we could annotate 10,209, and predict 599 secreted proteins. Clustering of the protein set indicates families of highly likely effectors. We also found new homologs of RTP1p, a prototype rust effector. The U. fabae genome will be an important resource for comparative analyses with U. appendiculatus and P. pachyrhizi and provide information regarding the phylogenetic relationship of the genus Uromyces with respect to other rust fungi already sequenced, namely Puccinia graminis f. sp. tritici, P. striiformis f. sp. tritici, Melampsora lini, and Melampsora larici-populina.
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Affiliation(s)
- Tobias Link
- *Correspondence: Tobias Link and Ralf T. Voegele, Fachgebiet Phytopathologie, Institut für Phytomedizin, Fakultät Agrarwissenschaften, Universität Hohenheim, Otto-Sander-Str. 5, 70599 Stuttgart, Germany e-mail: ;
| | | | - Ralf T. Voegele
- *Correspondence: Tobias Link and Ralf T. Voegele, Fachgebiet Phytopathologie, Institut für Phytomedizin, Fakultät Agrarwissenschaften, Universität Hohenheim, Otto-Sander-Str. 5, 70599 Stuttgart, Germany e-mail: ;
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Chen W, Wellings C, Chen X, Kang Z, Liu T. Wheat stripe (yellow) rust caused by Puccinia striiformis f. sp. tritici. MOLECULAR PLANT PATHOLOGY 2014; 15:433-46. [PMID: 24373199 PMCID: PMC6638732 DOI: 10.1111/mpp.12116] [Citation(s) in RCA: 187] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
UNLABELLED Stripe (yellow) rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a serious disease of wheat occurring in most wheat areas with cool and moist weather conditions during the growing season. The basidiomycete fungus is an obligate biotrophic parasite that is difficult to culture on artificial media. Pst is a macrocyclic, heteroecious fungus that requires both primary (wheat or grasses) and alternate (Berberis or Mahonia spp.) host plants to complete its life cycle. Urediniospores have the capacity for wind dispersal over long distances, which may, under high inoculum pressure, extend to thousands of kilometres from the initial infection sites. Stripe rust, which is considered to be the current major rust disease affecting winter cereal production across the world, has been studied intensively for over a century. This review summarizes the current knowledge of the Pst-wheat pathosystem, with emphasis on the life cycle, uredinial infection process, population biology of the pathogen, genes for stripe rust resistance in wheat and molecular perspectives of wheat-Pst interactions. TAXONOMY The stripe rust pathogen, Puccinia striiformis Westend. (Ps), is classified in kingdom Fungi, phylum Basidiomycota, class Urediniomycetes, order Uredinales, family Pucciniaceae, genus Puccinia. Ps is separated below the species level by host specialization on various grass genera, comprising up to nine formae speciales, of which P. striiformis f. sp. tritici Erikss. (Pst) causes stripe (or yellow) rust on wheat. HOST RANGE Uredinial/telial hosts: Pst mainly infects common wheat (Triticum aestivum L.), durum wheat (T. turgidum var. durum L.), cultivated emmer wheat (T. dicoccum Schrank), wild emmer wheat (T. dicoccoides Korn) and triticale (Triticosecale). Pst can infect certain cultivated barleys (Hordeum vulgare L.) and rye (Secale cereale L.), but generally does not cause severe epidemics. In addition, Pst may infect naturalized and improved pasture grass species, such as Elymus canadensis L., Leymus secalinus Hochst, Agropyron spp. Garetn, Hordeum spp. L., Phalaris spp. L and Bromus unioloides Kunth. Pycnial/aecial (alternative) hosts: Barberry (Berberis chinensis, B. koreana, B. holstii, B. vulgaris, B. shensiana, B. potaninii, B. dolichobotrys, B. heteropoda, etc.) and Oregon grape (Mahonia aquifolium). DISEASE SYMPTOMS Stripe rust appears as a mass of yellow to orange urediniospores erupting from pustules arranged in long, narrow stripes on leaves (usually between veins), leaf sheaths, glumes and awns on susceptible plants. Resistant wheat cultivars are characterized by various infection types from no visual symptoms to small hypersensitive flecks to uredinia surrounded by chlorosis or necrosis with restricted urediniospore production. On seedlings, uredinia produced by the infection of a single urediniospore are not confined by leaf veins, but progressively emerge from the infection site in all directions, potentially covering the entire leaf surface. Individual uredinial pustules are oblong, 0.4-0.7 mm in length and 0.1 mm in width. Urediniospores are broadly ellipsoidal to broadly obovoid, (16-)18-30(-32) × (15-)17-27(-28) μm, with a mean of 24.5 × 21.6 μm, yellow to orange in colour, echinulate, and with 6-18 scattered germ pores. Urediniospores can germinate rapidly when free moisture (rain or dew) occurs on leaf surfaces and when the temperatures range is between 7 and 12 °C. At higher temperatures or during the later growing stages of the host, black telia are often produced, which are pulvinate to oblong, 0.2-0.7 mm in length and 0.1 mm in width. The teliospores are predominantly two-celled, dark brown with thick walls, mostly oblong-clavate, (24-)31-56(-65) × (11-)14-25(-29) μm in length and width, and rounded or flattened at the apex.
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Affiliation(s)
- Wanquan Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, West Yuan Ming Yuan Road, Beijing, 100193, China
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13
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Link TI, Lang P, Scheffler BE, Duke MV, Graham MA, Cooper B, Tucker ML, van de Mortel M, Voegele RT, Mendgen K, Baum TJ, Whitham SA. The haustorial transcriptomes of Uromyces appendiculatus and Phakopsora pachyrhizi and their candidate effector families. MOLECULAR PLANT PATHOLOGY 2014; 15:379-93. [PMID: 24341524 PMCID: PMC6638672 DOI: 10.1111/mpp.12099] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Haustoria of biotrophic rust fungi are responsible for the uptake of nutrients from their hosts and for the production of secreted proteins, known as effectors, which modulate the host immune system. The identification of the transcriptome of haustoria and an understanding of the functions of expressed genes therefore hold essential keys for the elucidation of fungus-plant interactions and the development of novel fungal control strategies. Here, we purified haustoria from infected leaves and used 454 sequencing to examine the haustorial transcriptomes of Phakopsora pachyrhizi and Uromyces appendiculatus, the causal agents of soybean rust and common bean rust, respectively. These pathogens cause extensive yield losses in their respective legume crop hosts. A series of analyses were used to annotate expressed sequences, including transposable elements and viruses, to predict secreted proteins from the assembled sequences and to identify families of candidate effectors. This work provides a foundation for the comparative analysis of haustorial gene expression with further insights into physiology and effector evolution.
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Affiliation(s)
- Tobias I Link
- Institut für Phytomedizin, FG Phytopathologie, Universität Hohenheim, Otto-Sander-Straße 5, 70599, Stuttgart, Germany
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14
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Dynamics and innovations within oomycete genomes: insights into biology, pathology, and evolution. EUKARYOTIC CELL 2012; 11:1304-12. [PMID: 22923046 DOI: 10.1128/ec.00155-12] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The eukaryotic microbes known as oomycetes are common inhabitants of terrestrial and aquatic environments and include saprophytes and pathogens. Lifestyles of the pathogens extend from biotrophy to necrotrophy, obligate to facultative pathogenesis, and narrow to broad host ranges on plants or animals. Sequencing of several pathogens has revealed striking variation in genome size and content, a plastic set of genes related to pathogenesis, and adaptations associated with obligate biotrophy. Features of genome evolution include repeat-driven expansions, deletions, gene fusions, and horizontal gene transfer in a landscape organized into gene-dense and gene-sparse sectors and influenced by transposable elements. Gene expression profiles are also highly dynamic throughout oomycete life cycles, with transcriptional polymorphisms as well as differences in protein sequence contributing to variation. The genome projects have set the foundation for functional studies and should spur the sequencing of additional species, including more diverse pathogens and nonpathogens.
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15
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Kemen E, Jones JDG. Obligate biotroph parasitism: can we link genomes to lifestyles? TRENDS IN PLANT SCIENCE 2012; 17:448-57. [PMID: 22613788 DOI: 10.1016/j.tplants.2012.04.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 04/11/2012] [Accepted: 04/15/2012] [Indexed: 05/06/2023]
Abstract
Although the oomycetes and fungi are evolutionarily very distantly related, both taxa evolved biotrophy on plant hosts several times independently, giving rise to rust- and mildew-like phenotypes. Differences in host colonization and adaptation may be reflected in genome size and by gain and loss of genes. In this opinion article we combine classical knowledge with recently sequenced pathogen genomes and present new hypotheses about the convergent evolution that led to these two distinct phenotypes in obligate biotrophs.
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Affiliation(s)
- Eric Kemen
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK
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16
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Abstract
Biotrophy is a pervasive trait that evolved independently in plant pathogenic fungi and oomycetes. Comparative genomics of the first sequenced biotrophic pathogens highlight remarkable convergences, including gene losses in the metabolism of inorganic nitrogen, inorganic sulfur, and thiamine, and genes encoding carbohydrate active enzymes and secondary metabolism enzymes. Some biotrophs, but not all, display marked increases in overall genome size because of a proliferation of retrotransposons. I argue here that the release of constraints on transposon activity is driven by the advantages conferred by the genetic variability that results from transposition, in particular by the creation and diversification of broad palettes of effector genes. Increases in genome size and gene losses are the consequences of this trade-off. Genes that are not necessary for growth on a plant disappeared, but we still do not know what lost functions make some of these pathogens obligate.
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Affiliation(s)
- Pietro D Spanu
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom.
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17
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Voegele RT, Schmid A. RT real-time PCR-based quantification of Uromyces fabae in planta. FEMS Microbiol Lett 2011; 322:131-7. [PMID: 21707731 DOI: 10.1111/j.1574-6968.2011.02343.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Quantification of obligate biotrophic parasites has been a long-standing problem in plant pathology. Many attempts have been made to determine how much of a pathogen is present in infected plant tissue. Methods of quantification included scoring disease symptoms, microscopic evaluation, determination of specific compounds like Ergosterol, and lately nucleic acid-based technologies. All of these methods have their drawbacks, and even real-time PCR may not be quantitative if for example the organism of interest has specific and differing numbers of nuclei in different infection structures. We applied reverse transcription (RT) real-time PCR to quantify Uromyces fabae within its host plant Vicia faba. We used three different genes, which have been shown to be constitutively expressed. Our analyses show an exponential increase of fungal material between 4 and 9 days post inoculation and thereafter reaching a steady state of around 45% of total RNA. We also used haustorium-specific genes to determine the amount of haustoria present at each time point. These analyses parallel the development of the whole fungus with the exception of the steady-state level, which is only around 5% of the total RNA. This indicates that RT real-time PCR is a suitable method for quantification of obligate biotrophic parasites, and also for the differentiation of developmental stages.
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Affiliation(s)
- Ralf T Voegele
- Fachgebiet Phytopathologie, Institut für Phytomedizin, Universität Hohenheim, Stuttgart, Germany.
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18
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Kemen E, Gardiner A, Schultz-Larsen T, Kemen AC, Balmuth AL, Robert-Seilaniantz A, Bailey K, Holub E, Studholme DJ, MacLean D, Jones JDG. Gene gain and loss during evolution of obligate parasitism in the white rust pathogen of Arabidopsis thaliana. PLoS Biol 2011; 9:e1001094. [PMID: 21750662 PMCID: PMC3130010 DOI: 10.1371/journal.pbio.1001094] [Citation(s) in RCA: 213] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 05/10/2011] [Indexed: 01/21/2023] Open
Abstract
Biotrophic eukaryotic plant pathogens require a living host for their growth and form an intimate haustorial interface with parasitized cells. Evolution to biotrophy occurred independently in fungal rusts and powdery mildews, and in oomycete white rusts and downy mildews. Biotroph evolution and molecular mechanisms of biotrophy are poorly understood. It has been proposed, but not shown, that obligate biotrophy results from (i) reduced selection for maintenance of biosynthetic pathways and (ii) gain of mechanisms to evade host recognition or suppress host defence. Here we use Illumina sequencing to define the genome, transcriptome, and gene models for the obligate biotroph oomycete and Arabidopsis parasite, Albugo laibachii. A. laibachii is a member of the Chromalveolata, which incorporates Heterokonts (containing the oomycetes), Apicomplexa (which includes human parasites like Plasmodium falciparum and Toxoplasma gondii), and four other taxa. From comparisons with other oomycete plant pathogens and other chromalveolates, we reveal independent loss of molybdenum-cofactor-requiring enzymes in downy mildews, white rusts, and the malaria parasite P. falciparum. Biotrophy also requires “effectors” to suppress host defence; we reveal RXLR and Crinkler effectors shared with other oomycetes, and also discover and verify a novel class of effectors, the “CHXCs”, by showing effector delivery and effector functionality. Our findings suggest that evolution to progressively more intimate association between host and parasite results in reduced selection for retention of certain biosynthetic pathways, and particularly reduced selection for retention of molybdopterin-requiring biosynthetic pathways. These mechanisms are not only relevant to plant pathogenic oomycetes but also to human pathogens within the Chromalveolata. Plant pathogens that cannot grow except on their hosts are called obligate biotrophs. How such biotrophy evolves is poorly understood. In this study, we sequenced the genome of the obligate biotroph white rust pathogen (Albugo laibachii, Oomycota) of Arabidopsis. From comparisons with other oomycete plant pathogens, diatoms, and the human pathogen Plasmodium falciparum, we reveal a loss of important metabolic enzymes. We also reveal the appearance of defence-suppressing “effectors”, some carrying motifs known from other oomycete effectors, and discover and experimentally verify a novel class of effectors that share a CHXC motif within 50 amino acids of the signal peptide cleavage site. Obligate biotrophy involves an intimate association within host cells at the haustorial interface (where the parasite penetrates the host cell's cell wall), where nutrients are acquired from the host and effectors are delivered to the host. We found that A. laibachii, like Hyaloperonospora arabidopsidis and Plasmodium falciparum, lacks molybdopterin-requiring biosynthetic pathways, suggesting relaxed selection for retention of, or even selection against, this pathway. We propose that when defence suppression becomes sufficiently effective, hosts become such a reliable source of nutrients that a free-living phase can be lost. These mechanisms leading to obligate biotrophy and host specificity are relevant not only to plant pathogenic oomycetes but also to human pathogens.
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Affiliation(s)
- Eric Kemen
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
| | - Anastasia Gardiner
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
| | | | - Ariane C. Kemen
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
| | - Alexi L. Balmuth
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
- The GenePool, The University of Edinburgh, Edinburgh, United Kingdom
| | | | - Kate Bailey
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
| | - Eric Holub
- School of Life Sciences, University of Warwick, Wellesbourne Campus, United Kingdom
| | | | - Dan MacLean
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
| | - Jonathan D. G. Jones
- The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom
- * E-mail:
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Chamoun R, Jabaji S. Expression of genes of Rhizoctonia solani and the biocontrol Stachybotrys elegans during mycoparasitism of hyphae and sclerotia. Mycologia 2010; 103:483-93. [PMID: 21193602 DOI: 10.3852/10-235] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Knowledge of mycoparasitism has been focused on how antagonists affect pathogens in relation to mechanisms, metabolites and gene expression. Just as microbial antagonists use a diverse arsenal of mechanisms to dominate interactions with hosts, hosts also have diverse responses to counteract antagonism. In this study differential gene expression of eight mycoparasitism-induced genes and eight host-response genes was monitored during in vivo interactions between the mycoparasite Stachybotrys elegans and hyphae and sclerotia of the host, Rhizoctonia solani over 5 d of interaction. Using real time reverse transcription polymerase chain reaction, comparative analyses demonstrated that hyphal and sclerotial structures triggered different expression patterns. These results indicated that multiple regulatory mechanisms might be involved. The high elevated expression of some genes belonging to the mycoparasite and the host suggest that these genes play an important role during the mycoparasitic process and host defense respectively.
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Affiliation(s)
- Rony Chamoun
- Department of Plant Science, Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Quebec H9X 3V9
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20
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Hacquard S, Delaruelle C, Legué V, Tisserant E, Kohler A, Frey P, Martin F, Duplessis S. Laser capture microdissection of uredinia formed by Melampsora larici-populina revealed a transcriptional switch between biotrophy and sporulation. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:1275-86. [PMID: 20831407 DOI: 10.1094/mpmi-05-10-0111] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The foliar rust caused by the basidiomycete Melampsora larici-populina is the main disease affecting poplar plantations in Europe. The biotrophic status of rust fungi is a major limitation to study gene expression of cell or tissue types during host infection. At the uredinial stage, infected poplar leaves contain distinct rust tissues such as haustoria, infection hyphae, and uredinia with sporogenous hyphae and newly formed asexual urediniospores. Laser capture microdissection (LCM) was used to isolate three areas corresponding to uredinia and subjacent zones in the host mesophyll for expression analysis with M. larici-populina whole-genome exon oligoarrays. Optimization of tissue preparation prior to LCM allowed isolation of RNA of good integrity for genome-wide expression profiling. Our results indicate that the poplar rust uredinial stage is marked by distinct genetic programs related to biotrophy in the host palisade mesophyll and to sporulation in the uredinium. A strong induction of transcripts encoding small secreted proteins, likely containing rust effectors, is observed in the mesophyll, suggesting a late maintenance of suppression of host defense in the tissue containing haustoria and infection hyphae. On the other hand, cell cycle and cell defense rescue transcripts are strongly accumulated in the sporulation area. This combined LCM-transcriptomic approach brings new insights on the molecular mechanisms underlying urediniospore formation in rust fungi.
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Affiliation(s)
- Stéphane Hacquard
- Unité Mixte de Recherche 1136 INRA/Nancy Université Interactions Arbres/Micro-organismes, Champenoux, France
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Cloning and expression analysis of three secreted protein genes from wheat stripe rust fungus Puccinia striiformis f. sp. tritici. World J Microbiol Biotechnol 2010. [DOI: 10.1007/s11274-010-0565-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Yin C, Chen X, Wang X, Han Q, Kang Z, Hulbert SH. Generation and analysis of expression sequence tags from haustoria of the wheat stripe rust fungus Puccinia striiformis f. sp. Tritici. BMC Genomics 2009; 10:626. [PMID: 20028560 PMCID: PMC2805700 DOI: 10.1186/1471-2164-10-626] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Accepted: 12/23/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases of wheat (Triticum aestivum L.) worldwide. In spite of its agricultural importance, the genomics and genetics of the pathogen are poorly characterized. Pst transcripts from urediniospores and germinated urediniospores have been examined previously, but little is known about genes expressed during host infection. Some genes involved in virulence in other rust fungi have been found to be specifically expressed in haustoria. Therefore, the objective of this study was to generate a cDNA library to characterize genes expressed in haustoria of Pst. RESULTS A total of 5,126 EST sequences of high quality were generated from haustoria of Pst, from which 287 contigs and 847 singletons were derived. Approximately 10% and 26% of the 1,134 unique sequences were homologous to proteins with known functions and hypothetical proteins, respectively. The remaining 64% of the unique sequences had no significant similarities in GenBank. Fifteen genes were predicted to be proteins secreted from Pst haustoria. Analysis of ten genes, including six secreted protein genes, using quantitative RT-PCR revealed changes in transcript levels in different developmental and infection stages of the pathogen. CONCLUSIONS The haustorial cDNA library was useful in identifying genes of the stripe rust fungus expressed during the infection process. From the library, we identified 15 genes encoding putative secreted proteins and six genes induced during the infection process. These genes are candidates for further studies to determine their functions in wheat-Pst interactions.
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Affiliation(s)
- Chuntao Yin
- Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, USA
| | - Xianming Chen
- Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, USA
- US Department of Agricultural Research Service, Wheat Genetic, Quality, Physiology and Disease Research Unit, Pullman, WA 99164-6430, USA
| | - Xiaojie Wang
- College of Plant Protection and Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Qingmei Han
- College of Plant Protection and Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Zhensheng Kang
- College of Plant Protection and Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Scot H Hulbert
- Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, USA
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Ma J, Huang X, Wang X, Chen X, Qu Z, Huang L, Kang Z. Identification of expressed genes during compatible interaction between stripe rust (Puccinia striiformis) and wheat using a cDNA library. BMC Genomics 2009; 10:586. [PMID: 19995415 PMCID: PMC3087560 DOI: 10.1186/1471-2164-10-586] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 12/08/2009] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases of wheat worldwide. To establish compatibility with the host, Pst forms special infection structures to invade the plant with minimal damage to host cells. Although compatible interaction between wheat and Pst has been studied using various approaches, research on molecular mechanisms of the interaction is limited. The aim of this study was to develop an EST database of wheat infected by Pst in order to determine transcription profiles of genes involved in compatible wheat-Pst interaction. RESULTS Total RNA, extracted from susceptible infected wheat leaves harvested at 3, 5 and 8 days post inoculation (dpi), was used to create a cDNA library, from which 5,793 ESTs with high quality were obtained and clustered into 583 contigs and 2,160 singletons to give a set of 2,743 unisequences (GenBank accessions: GR302385 to GR305127). The BLASTx program was used to search for homologous genes of the unisequences in the GenBank non-redundant protein database. Of the 2,743 unisequences, 52.8% (the largest category) were highly homologous to plant genes; 16.3% to fungal genes and 30% of no-hit. The functional classification of all ESTs was established based on the database entry giving the best E-value using the Bevan's classification categories. About 50% of the ESTs were significantly homologous to genes encoding proteins with known functions; 20% were similar to genes encoding proteins with unknown functions and 30% did not have significant homology to any sequence in the database. The quantitative real-time PCR (qRT-PCR) analysis determined the transcription profiles and their involvement in the wheat-Pst interaction for seven of the gene. CONCLUSION The cDNA library is useful for identifying the functional genes involved in the wheat-Pst compatible interaction, and established a new database for studying Pst pathogenesis genes and wheat defense genes. The transcription patterns of seven genes were confirmed by the qRT-PCR assay to be differentially expressed in wheat-Pst compatible and incompatible interaction.
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Affiliation(s)
- Jinbiao Ma
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Xueling Huang
- College of Plant Protection and Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Xiaojie Wang
- College of Plant Protection and Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Xianming Chen
- USDA-ARS and Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, USA
| | - Zhipeng Qu
- College of Plant Protection and Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Lili Huang
- College of Plant Protection and Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
| | - Zhensheng Kang
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
- College of Plant Protection and Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, PR China
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Thibivilliers S, Joshi T, Campbell KB, Scheffler B, Xu D, Cooper B, Nguyen HT, Stacey G. Generation of Phaseolus vulgaris ESTs and investigation of their regulation upon Uromyces appendiculatus infection. BMC PLANT BIOLOGY 2009; 9:46. [PMID: 19397807 PMCID: PMC2684537 DOI: 10.1186/1471-2229-9-46] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 04/27/2009] [Indexed: 05/04/2023]
Abstract
BACKGROUND Phaseolus vulgaris (common bean) is the second most important legume crop in the world after soybean. Consequently, yield losses due to fungal infection, like Uromyces appendiculatus (bean rust), have strong consequences. Several resistant genes were identified that confer resistance to bean rust infection. However, the downstream genes and mechanisms involved in bean resistance to infection are poorly characterized. RESULTS A subtractive bean cDNA library composed of 10,581 unisequences was constructed and enriched in sequences regulated by either bean rust race 41, a virulent strain, or race 49, an avirulent strain on cultivar Early Gallatin carrying the resistance gene Ur-4. The construction of this library allowed the identification of 6,202 new bean ESTs, significantly adding to the available sequences for this plant. Regulation of selected bean genes in response to bean rust infection was confirmed by qRT-PCR. Plant gene expression was similar for both race 41 and 49 during the first 48 hours of the infection process but varied significantly at the later time points (72-96 hours after inoculation) mainly due to the presence of the Avr4 gene in the race 49 leading to a hypersensitive response in the bean plants. A biphasic pattern of gene expression was observed for several genes regulated in response to fungal infection. CONCLUSION The enrichment of the public database with over 6,000 bean ESTs significantly adds to the genomic resources available for this important crop plant. The analysis of these genes in response to bean rust infection provides a foundation for further studies of the mechanism of fungal disease resistance. The expression pattern of 90 bean genes upon rust infection shares several features with other legumes infected by biotrophic fungi. This finding suggests that the P. vulgaris-U. appendiculatus pathosystem could serve as a model to explore legume-rust interaction.
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Affiliation(s)
- Sandra Thibivilliers
- National Center for Soybean Biotechnology, Center for Sustainable Energy, Divisions of Plant Sciences and Biochemistry, University of Missouri, Columbia, MO, 65211, USA
| | - Trupti Joshi
- Computer Science Department and Christopher S Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
| | - Kimberly B Campbell
- Soybean Genomics and Improvement Laboratory, USDA-ARS, Beltsville, MD, 20705, USA
| | - Brian Scheffler
- MSA Genomics Laboratory, USDA-ARS, Stoneville, MS, 38776, USA
| | - Dong Xu
- Computer Science Department and Christopher S Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
| | - Bret Cooper
- Soybean Genomics and Improvement Laboratory, USDA-ARS, Beltsville, MD, 20705, USA
| | - Henry T Nguyen
- National Center for Soybean Biotechnology, Center for Sustainable Energy, Divisions of Plant Sciences and Biochemistry, University of Missouri, Columbia, MO, 65211, USA
| | - Gary Stacey
- National Center for Soybean Biotechnology, Center for Sustainable Energy, Divisions of Plant Sciences and Biochemistry, University of Missouri, Columbia, MO, 65211, USA
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25
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Puthoff DP, Neelam A, Ehrenfried ML, Scheffler BE, Ballard L, Song Q, Campbell KB, Cooper B, Tucker ML. Analysis of expressed sequence tags from Uromyces appendiculatus hyphae and haustoria and their comparison to sequences from other rust fungi. PHYTOPATHOLOGY 2008; 98:1126-35. [PMID: 18943459 DOI: 10.1094/phyto-98-10-1126] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Hyphae, 2 to 8 days postinoculation (dpi), and haustoria, 5 dpi, were isolated from Uromyces appendiculatus infected bean leaves (Phaseolus vulgaris cv. Pinto 111) and a separate cDNA library prepared for each fungal preparation. Approximately 10,000 hyphae and 2,700 haustoria clones were sequenced from both the 5' and 3' ends. Assembly of all of the fungal sequences yielded 3,359 contigs and 927 singletons. The U. appendiculatus sequences were compared with sequence data for other rust fungi, Phakopsora pachyrhizi, Uromyces fabae, and Puccinia graminis. The U. appendiculatus haustoria library included a large number of genes with unknown cellular function; however, summation of sequences of known cellular function suggested that haustoria at 5 dpi had fewer transcripts linked to protein synthesis in favor of energy metabolism and nutrient uptake. In addition, open reading frames in the U. appendiculatus data set with an N-terminal signal peptide were identified and compared with other proteins putatively secreted from rust fungi. In this regard, a small family of putatively secreted RTP1-like proteins was identified in U. appendiculatus and P. graminis.
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Affiliation(s)
- D P Puthoff
- Soybean Genomics and Improvement Lab, USDA-ARS, Beltsville, MD 20705, USA
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26
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Ruiz-Roldán C, Puerto-Galán L, Roa J, Castro A, Di Pietro A, Roncero MIG, Hera C. The Fusarium oxysporum sti35 gene functions in thiamine biosynthesis and oxidative stress response. Fungal Genet Biol 2008; 45:6-16. [DOI: 10.1016/j.fgb.2007.09.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 06/27/2007] [Accepted: 09/12/2007] [Indexed: 01/07/2023]
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Hu G, Kamp A, Linning R, Naik S, Bakkeren G. Complementation of Ustilago maydis MAPK mutants by a wheat leaf rust, Puccinia triticina homolog: potential for functional analyses of rust genes. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2007; 20:637-47. [PMID: 17555272 DOI: 10.1094/mpmi-20-6-0637] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
From a large expressed sequence tag (EST) database representing several developmental stages of Puccinia triticina, we discovered a mitogen-activated protein kinase (MAPK) with homology to kinases with known pathogenic functions in other fungi. This PtMAPK1 is similar to the Ustilago maydis MAPK, Ubc3/Kpp2, but has a longer N-terminal extension of 43 amino acids (aa) with identities to U. maydis Kpp6, a homolog of Ubc3/Kpp2 with a 170-aa N-terminal extension. Ubc3/Kpp2 is involved in mating and subsequent pathogenic development, whereas Kpp6 functions during invasive growth in corn tissue. PtMAPK1, expressed from a Ustilago sp.-specific promoter, was able to complement a ubc3/kpp2 deletion mutant and restore mating. It also substantially increased virulence on corn, measured as tumor formation, of a kpp6 deletion mutant. Moreover, this construct restored to near-full pathogenicity a ubc3/kpp2 kpp6 nonpathogenic double deletion mutant. Complementation of the ubc3/kpp2 mutant with the complete PtMAPK gene and verification of expression by reverse-transcription polymerase chain reaction indicated that the rust promoter is recognized in U. maydis. Phylogenetically, these basidiomycete plant pathogens are related, which was reflected in comparison of P. triticina ESTs to U. maydis gene sequences. The U. maydis heterologous expression system allows functional analysis of rust genes, currently frustrated by the lack of efficient transformation and selection procedures.
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Affiliation(s)
- Guanggan Hu
- Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Summerland, BC VOH 1Z0, Canada
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28
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Broeker K, Bernard F, Moerschbacher BM. An EST library from Puccinia graminis f. sp. tritici reveals genes potentially involved in fungal differentiation. FEMS Microbiol Lett 2006; 256:273-81. [PMID: 16499617 DOI: 10.1111/j.1574-6968.2006.00127.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The rust fungus Puccinia graminis f. sp. tritici is an obligately biotrophic pathogen on wheat plants and thus difficult to investigate. Hence, little is known about this fungus at the molecular level. We constructed a differential suppression subtractive hybridization cDNA-library from rust-infected vs. healthy wheat plants. The majority of expressed sequence tags (ESTs) showed similarities to fungal sequences. Semiquantitative RT-PCR using mRNA from rust-infected leaves, and from axenically grown, differentiating and nondifferentiating young rust colonies as well as sporulating and nonsporulating mature mycelia revealed rather diverse expression patterns for different ESTs, shedding new light on their potential involvement in differentiation and host-pathogen interaction.
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Affiliation(s)
- Katja Broeker
- Institut für Biochemie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität Münster, Münster, Germany
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29
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Voegele RT, Wirsel S, Möll U, Lechner M, Mendgen K. Cloning and characterization of a novel invertase from the obligate biotroph Uromyces fabae and analysis of expression patterns of host and pathogen invertases in the course of infection. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2006; 19:625-34. [PMID: 16776296 DOI: 10.1094/mpmi-19-0625] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Invertases are key enzymes in carbon partitioning in higher plants. They gain additional importance in the distribution of carbohydrates in the event of wounding or pathogen attack. Although many researchers have found an increase in invertase activity upon infection, only a few studies were able to determine whether the source of this activity was host or parasite. This article analyzes the role of invertases involved in the biotrophic interaction of the rust fungus Uromyces fabae and its host plant, Vicia faba. We have identified a fungal gene, Uf-INV1, with homology to invertases and assessed its contribution to pathogenesis. Expression analysis indicated that transcription began upon penetration of the fungus into the leaf, with high expression levels in haustoria. Heterologous expression of Uf-INV1 in Saccharomyces cerevisiae and Pichia pastoris allowed a biochemical characterization of the enzymatic activity associated with the secreted gene product INV1p. Expression analysis of the known vacuolar and cell-wall-bound invertase isoforms of V. faba indicated a decrease in the expression of a vacuolar invertase, whereas one cell-wall-associated invertase exhibited increased expression. These changes were not confined to the infected tissue, and effects also were observed in remote plant organs, such as roots. These findings hint at systemic effects of pathogen infection. Our results support the hypothesis that pathogen infection establishes new sinks which compete with physiological sink organs.
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Affiliation(s)
- Ralf T Voegele
- Phytopathologie, Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany.
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30
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Rampitsch C, Bykova NV, McCallum B, Beimcik E, Ens W. Analysis of the wheat andPuccinia triticina (leaf rust) proteomes during a susceptible host-pathogen interaction. Proteomics 2006; 6:1897-907. [PMID: 16479535 DOI: 10.1002/pmic.200500351] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Wheat leaf rust is caused by the fungus Puccinia triticina. The genetics of resistance follows the gene-for-gene hypothesis, and thus the presence or absence of a single host resistance gene renders a plant resistant or susceptible to a leaf rust race bearing the corresponding avirulence gene. To investigate some of the changes in the proteomes of both host and pathogen during disease development, a susceptible line of wheat infected with a virulent race of leaf rust were compared to mock-inoculated wheat using 2-DE (with IEF pH 4-8) and MS. Up-regulated protein spots were excised and analyzed by MALDI-QqTOF MS/MS, followed by cross-species protein identification. Where possible MS/MS spectra were matched to homologous proteins in the NCBI database or to fungal ESTs encoding putative proteins. Searching was done using the MASCOT search engine. Remaining unmatched spectra were then sequenced de novo and queried against the NCBInr database using the BLAST and MS BLAST tools. A total of 32 consistently up-regulated proteins were examined from the gels representing the 9-day post-infection proteome in susceptible plants. Of these 7 are host proteins, 22 are fungal proteins of known or hypothetical function and 3 are unknown proteins of putative fungal origin.
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31
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Spanu PD. Why do some fungi give up their freedom and become obligate dependants on their host? THE NEW PHYTOLOGIST 2006; 171:447-50. [PMID: 16866952 DOI: 10.1111/j.1469-8137.2006.01802.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
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32
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Jakupović M, Heintz M, Reichmann P, Mendgen K, Hahn M. Microarray analysis of expressed sequence tags from haustoria of the rust fungus Uromyces fabae. Fungal Genet Biol 2005; 43:8-19. [PMID: 16289953 DOI: 10.1016/j.fgb.2005.09.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2005] [Revised: 07/24/2005] [Accepted: 09/09/2005] [Indexed: 10/25/2022]
Abstract
Rust fungi are plant parasites which colonise host tissue with an intercellular mycelium that forms haustoria within living plant cells. To identify genes expressed during biotrophic growth, EST sequencing was performed with a haustorium-specific cDNA library from Uromyces fabae. One thousand seventeen ESTs were generated, which assembled into 530 contigs. Several of the most frequently represented sequences in the EST database were identical to the in planta induced genes (PIGs) identified previously (Hahn, M., Mendgen, K., 1997. Characterisation of in planta-induced rust genes isolated from a haustorium-specific cDNA library, Mol. Plant-Microbe Interact. 10, 427-437). Virus-encoded sequences were identified, providing evidence for two novel RNA mycoviruses in U. fabae. Microarray hybridisation revealed many cDNAs that were significantly activated in rust-infected leaves compared to germinated uredospores. Very strong in planta expression was found for two PIGs encoding putative metallothioneins. Furthermore, several genes involved in ribosome biogenesis and translation, glycolysis, amino acid metabolism, stress response, and detoxification showed an increased expression in the parasitic mycelium. These data indicate a strong shift in gene expression in rust fungi between germination and the biotrophic stage of development.
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Affiliation(s)
- Mirza Jakupović
- Department of Biology, University of Kaiserslautern, Post Box 3049, 67653 Kaiserslautern, Germany
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33
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Kemen E, Kemen AC, Rafiqi M, Hempel U, Mendgen K, Hahn M, Voegele RT. Identification of a protein from rust fungi transferred from haustoria into infected plant cells. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2005; 18:1130-9. [PMID: 16353548 DOI: 10.1094/mpmi-18-1130] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The formation of haustoria is one of the hallmarks of the interaction of obligate biotrophic fungi with their host plants. In addition to their role in nutrient uptake, it is hypothesized that haustoria are actively involved in establishing and maintaining the biotrophic relationship. We have identified a 24.3-kDa protein that exhibited a very unusual allocation. Rust transferred protein 1 from Uromyces fabae (Uf-RTP1p) was not only detected in the host parasite interface, the extrahaustorial matrix, but also inside infected plant cells by immunofluorescence and electron microscopy. Uf-RTP1p does not exhibit any similarity to sequences currently listed in the public databases. However, we identified a homolog of Uf-RTP1p in the related rust fungus Uromyces striatus (Us-RTP1p). The localization of Uf-RTP1p and Us-RTP1p inside infected plant cells was confirmed, using four independently raised polyclonal antibodies. Depending on the developmental stage of haustoria, Uf-RTP1p was found in increasing amounts in host cells, including the host nucleus. Putative nuclear localization signals (NLS) were found in the predicted RTP1p sequences. However, functional efficiency could only be verified for the Uf-RTP1p NLS by means of green fluorescent protein fusions in transformed tobacco protoplasts. Western blot analysis indicated that Uf-RTP1p and Us-RTP1p most likely enter the host cell as N-glycosylated proteins. However, the mechanism by which they cross the extrahaustorial membrane and accumulate in the host cytoplasm is unknown. The localization of RTP1p suggests that it might play an important role in the maintenance of the biotrophic interaction.
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Affiliation(s)
- Eric Kemen
- Phytopathologie, Fachbereich Biologie, Universität Konstanz, Germany
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34
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Genetics of Morphogenesis in Basidiomycetes. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s1874-5334(05)80017-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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35
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Abstract
Fungi and Oomycetes are the two most important groups of eukaryotic plant pathogens. Fungi form a separate kingdom and are evolutionarily related to animals. Oomycetes are classified in the kingdom Protoctista and are related to heterokont, biflagellate, golden-brown algae. Fundamental differences in physiology, biochemistry and genetics between fungi and Oomycetes have been described previously. These differences are also reflected in the large variations observed in sensitivity to conventional fungicides. Recently, more pronounced differences have been revealed by genomics approaches. However, in this review we compare the mode of colonization of the two taxonomically distinct groups and show that their strategies have much in common.
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Affiliation(s)
- Maita Latijnhouwers
- Laboratory of Phytopathology, Wageningen University, Binnenhaven 5, 6709 PD, Wageningen, Netherlands
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36
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Bakkeren G, Gold S. The path in fungal plant pathogenicity: many opportunities to outwit the intruders? GENETIC ENGINEERING 2004; 26:175-223. [PMID: 15387298 DOI: 10.1007/978-0-306-48573-2_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
The number of genes implicated in the infection and disease processes of phytopathogenic fungi is increasing rapidly. Forward genetic approaches have identified mutated genes that affect pathogenicity, host range, virulence and general fitness. Likewise, candidate gene approaches have been used to identify genes of interest based on homology and recently through 'comparative genomic approaches' through analysis of large EST databases and whole genome sequences. It is becoming clear that many genes of the fungal genome will be involved in the pathogen-host interaction in its broadest sense, affecting pathogenicity and the disease process in planta. By utilizing the information obtained through these studies, plants may be bred or engineered for effective disease resistance. That is, by trying to disable pathogens by hitting them where it counts.
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Affiliation(s)
- Guus Bakkeren
- Agriculture & Agri-Food Canada,Pacific Agri-Food Research Centre, Summerland, BC, Canada V0H 1Z0
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37
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Haerter AC, Voegele RT. A novel beta-glucosidase in Uromyces fabae: feast or fight? Curr Genet 2003; 45:96-103. [PMID: 14648113 DOI: 10.1007/s00294-003-0461-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2003] [Revised: 10/02/2003] [Accepted: 10/14/2003] [Indexed: 10/26/2022]
Abstract
Efficient nutrient mobilization is a key element for biotrophic plant parasites such as the rust fungi. In the course of a cDNA library screen for elements involved in sugar utilization in Uromyces fabae, we identified a sequence with homology to beta-glucosidases. Full-length genomic and cDNA clones of the gene, termed BGL1, were isolated and sequenced. The BGL1 gene comprises 3,372 nucleotides, including nine introns. The open reading frame encompasses 2,532 bases and codes for a polypeptide of 843 amino acids with an apparent molecular mass of 92.4 kDa. Analysis of the polypeptide revealed a potential secretion signal, indicating an extracellular localization of mature BGL1p (89.8 kDa). BGL1 seems to be expressed in all stages of growth, including haustoria, the feeding structures of rust fungi. In the course of immunolocalization studies, the gene product BGL1p was localized in the periphery of intercellular hyphae and haustoria. On the basis of sequence homology, the BGL1 gene was identified as a fungal beta-glucosidase.
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Affiliation(s)
- Ariane C Haerter
- Phytopathologie, Fachbereich Biologie, Universität Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany
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38
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Panstruga R. Establishing compatibility between plants and obligate biotrophic pathogens. CURRENT OPINION IN PLANT BIOLOGY 2003; 6:320-326. [PMID: 12873525 DOI: 10.1016/s1369-5266(03)00043-8] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The apparent under-representation of the term 'plant disease susceptibility' as opposed to 'plant disease resistance' in the current scientific literature might indicate that 'compatibility' has not gained the same appreciation as 'resistance' in the past. However, these seemingly contrary phenomena are intimately linked, and progress in understanding one process inherently contributes to our comprehension of the other. Recent progress in analyzing plant-biotroph compatibility includes the molecular isolation and functional characterization of haustorium-specific cDNAs that encode presumptive hexose- and amino-acid-transporter proteins for proton-driven nutrient uptake. Accumulating evidence from cytological, pharmacological, phytopathological and molecular studies indicates that pathogens mediate the suppression of host defenses in a range of plant-biotroph interactions. Arabidopsis thaliana mutants that are resistant to powdery or downy mildew but that do not exhibit constitutively activated defense could be affected in host-compatibility factors.
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Affiliation(s)
- Ralph Panstruga
- Max-Planck-Institut für Züchtungsforschung, Department of Plant-Microbe Interactions, Carl-von-Linné-Weg 10, 50829 Köln, Germany.
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Ernst M, Mendgen KW, Wirsel SGR. Endophytic fungal mutualists: seed-borne Stagonospora spp. enhance reed biomass production in axenic microcosms. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2003; 16:580-587. [PMID: 12848423 DOI: 10.1094/mpmi.2003.16.7.580] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Fungal endophytes mainly belong to the phylum Ascomycota and colonize plants without producing symptoms. We report on the isolation of seed-borne fungal endophytes from Phragmites australis (common reed) that were ascribed to the genus Stagonospora. Nested polymerase chain reaction (PCR) assays revealed that a Stagonospora sp. regularly colonized reed as shown for a period of three years. In spring, it was only detected in roots, whereas in autumn, it could frequently be found in all organs, including seeds. Microcosm experiments revealed that seeds harbored viable propagules of the fungus that colonized the developing germling, indicating vertical transmission. Endophytic growth was confirmed by immunofluorescence microscopy, reisolation of the fungus after surface sterilization, and PCR. Aseptic microcosms were established for studying fungal contributions towards host vitality. Several Stagonospora isolates enhanced reed biomass. Seed-borne endophytic Stagonospora spp. thus can provide improved vigor to common reed, which could be most important when seed-derived germlings establish new reed stands.
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Affiliation(s)
- Michael Ernst
- Lehrstuhl Phytopathologie, Fachbereich Biologie, Universität Konstanz, Universitätstr. 10, D-78457 Konstanz, Germany
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40
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Abstract
Haustoria are morphological features of an extremely successful class of plant parasites, the obligate biotrophs. The broad phylogenetic spectrum of organisms producing haustoria suggests that these structures have arisen many times in the course of evolution and represent specific adaptations of these organisms to the close interaction with their respective host plants. This close interaction and the fact that these structures cannot be produced in vitro have hampered an analysis of the roles of haustoria in biotrophy for many decades. Only recently has it become possible to analyse haustorial function at a molecular level. A picture is beginning to emerge indicating that haustoria do not only serve in nutrient uptake - a task postulated for these elements ever since their discovery. Moreover, they seem to perform enormous biosynthetic duties. They also seem to be engaged in the suppression of host defense responses and in redirecting or reprogramming the host's metabolic flow. This review intends to summarize current knowledge about the structure and function especially of rust haustoria.
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Affiliation(s)
- Ralf T Voegele
- Universität Konstanz, Fachbereich Biologie, Lehrstuhl Phytopathologie, Universitätsstr. 10, 78457 Konstanz, Germany
| | - Kurt Mendgen
- Universität Konstanz, Fachbereich Biologie, Lehrstuhl Phytopathologie, Universitätsstr. 10, 78457 Konstanz, Germany
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41
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Solomon PS, Tan KC, Oliver RP. The nutrient supply of pathogenic fungi; a fertile field for study. MOLECULAR PLANT PATHOLOGY 2003; 4:203-10. [PMID: 20569380 DOI: 10.1046/j.1364-3703.2003.00161.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
SUMMARY Phytopathogenic fungi must feed on their hosts to propagate and cause disease. Their ability to access the rich nutrient supply offered by living plants is one of the most obvious properties that distinguish pathogens from saprophytes. Successful invasion by pathogens depends as much on their ability to utilize the available nutrient sources offered by plants as on their ability to penetrate plants and evade defensive mechanisms. Here, we review current knowledge on the nature of the nutrient supplies utilized by pathogens during infection. The available evidence is rudimentary in most cases. There is much evidence to suggest that fungal metabolism can be divided into at least two phases. The first is based on lipolysis and occurs during germination and penetration of the host. The second phase uses glycolysis and predominates during the invasion of host tissue. We also propose, mainly on theoretical grounds, that a third phase of nutrition occurs late in infection during which new spores are produced. Contrary to early assumptions, the nitrogen sources available to some pathogens appear to be abundant. The idea that nitrogen starvation is a cue that controls fungal gene expression during infection may need to be reassessed. Very little is known about the micronutrient (Fe, S, P) or vitamin supply. The knowledge gained from this research may enable the design of new antifungal strategies targeting potential weaknesses in fungal metabolism and will also impact on agronomic practices.
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Affiliation(s)
- Peter S Solomon
- The Australian Centre for Necrotrophic Fungal Pathogens, SABC, DSE, Murdoch University, Perth 6150, Western Australia, Australia
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42
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Thara VK, Fellers JP, Zhou JM. In planta induced genes of Puccinia triticina. MOLECULAR PLANT PATHOLOGY 2003; 4:51-6. [PMID: 20569362 DOI: 10.1046/j.1364-3703.2003.00142.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
SUMMARY Wheat leaf rust disease, caused by the biotrophic fungus Puccinia triticina, is a result of complex interactions requiring the coordinated activities of the two organisms involved. In an effort to understand the molecular basis of wheat-rust interactions, we isolated and characterized cDNA corresponding to in planta induced fungal genes (PIGs) from susceptible wheat leaves infected with P. triticina by using suppression subtractive hybridization to construct a cDNA library. 350 clones were sequenced, of which 104 were unique. Forty-four cDNA clones encode ribosomal proteins, comprising the single largest category of clones isolated. Twenty-five of these ribosomal protein genes are likely to be of fungal origin, as was suggested by sequence homology. Hybridization of 56 selected non-ribosomal protein clones to rust germling cDNA or genomic DNA probes showed that at least 44 were of fungal origin, demonstrating that the library was highly enriched for fungal cDNA. Differential expression analysis identified 26 non-ribosomal protein genes that were induced in rust-infected leaves. At least 21 of the induced genes were from the rust fungus, indicating that the majority of the induced genes were rust PIGs that are likely to play a role in parasitism. Some of the induced genes share homology to known PIGs or virulence genes in other fungi, suggesting similarities in parasitism among different fungi. Eight clones correspond to novel PIGs that have not been reported in any organism. This paper reports, for the first time, the isolation of P. triticina PIGs and discusses the use of total rust genomic DNA to identify the source of genes.
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Affiliation(s)
- Venkatappa K Thara
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66506-5502, USA
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43
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Abstract
To exploit plants as living substrates, biotrophic fungi have evolved remarkable variations of their tubular cells, the hyphae. They form infection structures such as appressoria, penetration hyphae and infection hyphae to invade the plant with minimal damage to host cells. To establish compatibility with the host, controlled secretory activity and distinct interface layers appear to be essential. Colletotrichum species switch from initial biotrophic to necrotrophic growth and are amenable to mutant analysis and molecular studies. Obligate biotrophic rust fungi can form the most specialized hypha: the haustorium. Gene expression and immunocytological studies with rust fungi support the idea that the haustorium is a transfer apparatus for the long-term absorption of host nutrients.
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Affiliation(s)
- Kurt Mendgen
- Dept of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany.
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Wirsel SG, Voegele RT, Mendgen KW. Differential regulation of gene expression in the obligate biotrophic interaction of Uromyces fabae with its host Vicia faba. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2001; 14:1319-1326. [PMID: 11763130 DOI: 10.1094/mpmi.2001.14.11.1319] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Classical analysis of obligate biotrophic fungi revealed changes of enzyme activities or the concentration of metabolites in infected areas. However, due to the intricate integration of host and parasite metabolism, it was not possible to delineate the individual contributions of the two organisms. Here, we used reverse-transcription-polymerase chain reaction to monitor expression of genes from the rust fungus Uromyces fabae and its host Vicia faba. We focused on genes relevant for amino acid and sugar uptake and metabolism in both organisms. In the fungus, mRNA for plasma membrane ATPase was detected in spores and all infection structures. Two genes for fungal amino acid transporters showed dissimilar regulation. Transcripts for one were detected during all developmental stages, whereas those of the other appeared to be under developmental control. The latter result was also obtained for the so far only hexose transporter known from U. fabae and for one gene of the thiamine biosynthesis pathway. In the host plant, transcripts for two ATPases analyzed generally declined upon infection. Sucrose synthase expression increased in leaves, but decreased in roots. Transcript levels of glucose and sucrose transporter genes appeared unchanged. Markers for amino acid metabolism did not show a uniform trend: transcripts for asparagine synthetase increased, whereas those for two amino acid transporters either decreased or increased. Our analyses revealed that not only expression of genes in the immediate vicinity of the primary infection site is altered, but infection also influences transcription of certain genes in remote organs, like stems and roots. This demonstrates alterations in the source-sink relationships.
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MESH Headings
- Basidiomycota/genetics
- Basidiomycota/pathogenicity
- Fabaceae/genetics
- Fabaceae/microbiology
- Gene Expression Regulation, Fungal
- Gene Expression Regulation, Plant
- Genes, Fungal
- Genes, Plant
- Plant Diseases/microbiology
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Plant/genetics
- RNA, Plant/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- S G Wirsel
- Lehrstuhl Phytopathologie, Fachbereich Biologie, Universität Konstanz, Germany.
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Hahn M, Mendgen K. Signal and nutrient exchange at biotrophic plant-fungus interfaces. CURRENT OPINION IN PLANT BIOLOGY 2001; 4:322-7. [PMID: 11418342 DOI: 10.1016/s1369-5266(00)00180-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Biotrophic interfaces are formed in mutualistic and parasitic plant-fungus interactions. They result from coordinated developmental programs in both partners and represent specialized platforms for the exchange of information and nutritional metabolites. New data on the establishment and the components of functional interfaces have been obtained in a number of ways. First, by isolation of symbiotically defective mutants; second, by characterization of new genes and their products; and, third, by the identification and localization of components of biotrophic interfaces, such as cell-wall proteins, H+-ATPases and nutrient transporters.
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Affiliation(s)
- M Hahn
- University of Kaiserslautern, Department of Biology, Post Box 3049, 67653, Kaiserslautern, Germany.
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Perfect SE, Green JR. Infection structures of biotrophic and hemibiotrophic fungal plant pathogens. MOLECULAR PLANT PATHOLOGY 2001; 2:101-8. [PMID: 20572997 DOI: 10.1046/j.1364-3703.2001.00055.x] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Summary Biotrophic plant pathogenic fungi are one of the major causes of crop losses. The infection processes they exhibit are typified by infected host plant cells remaining alive for several days. This requires the development of specialized infection structures such as haustoria which are produced by obligate biotrophs, and intracellular hyphae which are produced by many hemibiotrophs. These infection hyphae are surrounded by the host plant plasma membrane, and in the case of haustoria the extrahaustorial membrane differs biochemically and structurally from the normal membrane. An interfacial matrix separates haustoria and intracellular hyphae from the invaginated membrane and this seems to be characteristic of biotrophic interactions. There is clear evidence for molecular differentiation of the haustorial plasma membrane in powdery mildews and rusts in comparison with the other fungal membranes. Relatively few pathogenicity genes related to biotrophy, and the switch from biotrophy to necrotrophy in hemibiotrophs, have been identified.
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Affiliation(s)
- S E Perfect
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
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Gold SE, García-Pedrajas MD, Martínez-Espinoza AD. New (and used) approaches to the study of fungal pathogenicity. ANNUAL REVIEW OF PHYTOPATHOLOGY 2001; 39:337-365. [PMID: 11701869 DOI: 10.1146/annurev.phyto.39.1.337] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The fungi are the most economically important plant pathogens and continue to be the focus of extensive research with a wide variety of methodologies. Enhancements in microscopy techniques have increased our ability to visualize the intimate interaction of fungi and their host plants. Improving methods allow pharmacological inhibition and genetic dissection of the determinants of fungal pathogenicity in a gene-by-gene approach. Identification and analysis of genes differentially transcribed in ways pertinent to pathogenicity continues to be a frequent research approach. Genome-wide analysis is gaining favor in biological research and fungal plant pathogens are no exception. Several industrial research groups are exploring fungal plant pathogenesis based on genomic sequence data and genome-wide mutagenesis. In March 2001 the first publicly available complete genome of a filamentous fungus (Neurospora crassa) was released. N. crassa is of course a saprophyte and there is no complete sequence available for a plant pathogenic fungus in public databases. However, freely accessible entire genome sequences for both plant pathogenic fungi and their hosts are on the horizon. Sequence availability promises to revolutionize the rate at which data relevant to disease processes will be accrued. In this review we describe approaches currently applied to the study of plant pathogenic fungi and explore developments of potential future benefit with existing technologies not yet applied to this group of important organisms.
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Affiliation(s)
- S E Gold
- Department of Plant Pathology, University of Georgia, Athens, Georgia 30602-7274, USA.
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