1
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Kamble A, Michavila S, Gimenez-Ibanez S, Redkar A. Shared infection strategy of a fungal pathogen across diverse lineages of land plants, the Fusarium example. Curr Opin Plant Biol 2024; 77:102498. [PMID: 38142620 DOI: 10.1016/j.pbi.2023.102498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 11/30/2023] [Accepted: 11/30/2023] [Indexed: 12/26/2023]
Abstract
Plants engage with a wide variety of microorganisms either in parasitic or mutualistic relationships, which have helped them to adapt to terrestrial ecosystems. Microbial interactions have driven plant evolution and led to the emergence of complex interaction outcomes via suppression of host defenses by evolving pathogens. The evolution of plant-microbe interactions is shaped by conserved host and pathogen gene modules and fast-paced lineage-specific adaptability which determines the interaction outcome. Recent findings from different microbes ranging from bacteria, oomycetes, and fungi suggest recurrent concepts in establishing interactions with evolutionarily distant plant hosts, but also clade-specific adaptation that ultimately contributes to pathogenicity. Here, we revisit some of the latest features that illustrate shared colonization strategies of the fungal pathogen Fusarium oxysporum on distant plant lineages and lineage-specific adaptability of mini-chromosomal units encoding effectors, for shaping host-specific pathogenicity in angiosperms.
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Affiliation(s)
- Avinash Kamble
- Department of Botany, Savitribai Phule Pune University, Ganeshkhind, Pune, 411007, India
| | - Santiago Michavila
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología CSIC, Campus Universidad Autonoma, Madrid, 28049, Spain
| | - Selena Gimenez-Ibanez
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología CSIC, Campus Universidad Autonoma, Madrid, 28049, Spain
| | - Amey Redkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research (NCBS-TIFR), GKVK Campus, Bellary Road, Bengaluru, 560065, India.
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2
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Redkar A, Cevik V, Bailey K, Zhao H, Kim DS, Zou Z, Furzer OJ, Fairhead S, Borhan MH, Holub EB, Jones JDG. The Arabidopsis WRR4A and WRR4B paralogous NLR proteins both confer recognition of multiple Albugo candida effectors. New Phytol 2023; 237:532-547. [PMID: 35838065 PMCID: PMC10087428 DOI: 10.1111/nph.18378] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 07/05/2022] [Indexed: 05/26/2023]
Abstract
The oomycete Albugo candida causes white blister rust, an important disease of Brassica crops. Distinct races of A. candida are defined by their capacity to infect different host plant species. Each A. candida race encodes secreted proteins with a CX2 CX5 G ('CCG') motif that are polymorphic and show presence/absence variation, and are therefore candidate effectors. The White Rust Resistance 4 (WRR4) locus in Arabidopsis thaliana accession Col-0 contains three genes that encode intracellular nucleotide-binding domain leucine-rich repeat immune receptors. The Col-0 alleles of WRR4A and WRR4B confer resistance to multiple A. candida races, although both WRR4A and WRR4B can be overcome by the Col-0-virulent race 4 isolate AcEx1. Comparison of CCG candidate effectors in avirulent and virulent races, and transient co-expression of CCG effectors from four A. candida races in Nicotiana sp. or A. thaliana, revealed CCG effectors that trigger WRR4A- or WRR4B-dependent hypersensitive responses. We found eight WRR4A-recognised CCGs and four WRR4B-recognised CCGs, the first recognised proteins from A. candida for which the cognate immune receptors in A. thaliana are known. This multiple recognition capacity potentially explains the broad-spectrum resistance to several A. candida races conferred by WRR4 paralogues. We further show that of five tested CCGs, three confer enhanced disease susceptibility when expressed in planta, consistent with A. candida CCG proteins being effectors.
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Affiliation(s)
- Amey Redkar
- The Sainsbury LaboratoryUniversity of East AngliaNorwichNR4 7UHUK
- Department of BotanySavitribai Phule Pune UniversityGaneshkhindPune411007India
| | - Volkan Cevik
- The Sainsbury LaboratoryUniversity of East AngliaNorwichNR4 7UHUK
- The Milner Centre for Evolution, Department of Biology and BiochemistryUniversity of BathBathBA2 7AYUK
| | - Kate Bailey
- The Sainsbury LaboratoryUniversity of East AngliaNorwichNR4 7UHUK
| | - He Zhao
- The Sainsbury LaboratoryUniversity of East AngliaNorwichNR4 7UHUK
| | - Dae Sung Kim
- The Sainsbury LaboratoryUniversity of East AngliaNorwichNR4 7UHUK
- Present address:
State Key Laboratory of Biocatalysis and Enzyme EngineeringHubei UniversityWuhan430062China
| | - Zhou Zou
- The Milner Centre for Evolution, Department of Biology and BiochemistryUniversity of BathBathBA2 7AYUK
| | - Oliver J. Furzer
- The Sainsbury LaboratoryUniversity of East AngliaNorwichNR4 7UHUK
- Department of BiologyUniversity of North CarolinaChapel HillNC27599USA
| | - Sebastian Fairhead
- The Sainsbury LaboratoryUniversity of East AngliaNorwichNR4 7UHUK
- School of Life SciencesWarwick Crop Centre, University of WarwickWellesbourneCV35 9EFUK
| | - M. Hossein Borhan
- Agriculture and Agri‐Food Canada107 Science PlaceSaskatoonSKS7N 0X2Canada
| | - Eric B. Holub
- School of Life SciencesWarwick Crop Centre, University of WarwickWellesbourneCV35 9EFUK
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3
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Redkar A, Di Pietro A, Turrà D. Live-Cell Visualization of Early Stages of Root Colonization by the Vascular Wilt Pathogen Fusarium oxysporum. Methods Mol Biol 2023; 2659:73-82. [PMID: 37249886 DOI: 10.1007/978-1-0716-3159-1_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Fungal phytopathogens induce a variety of pathogenicity symptoms on their hosts. The soilborne vascular wilt pathogen Fusarium oxysporum infects roots of more than 150 different crop species. Initial colonization stages are asymptomatic, likely representing a biotrophic phase of infection, followed by a necrotrophic switch after vascular colonization which results in blockage of the plant xylem and killing of the host. Live-cell microscopy techniques have been successfully employed to study interaction events during fungal colonization of root tissues. This technique is widely used to track fungal development during disease progression. Here, we describe a well-established protocol for generation and screening of fluorescently tagged F. oxysporum transformants, as well as for live-cell imaging of the early colonization stages of F. oxysporum on tomato (Solanum lycopersicum) seedlings. The presented experimental design and techniques involved are also applicable to other root infecting fungi.
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Affiliation(s)
- Amey Redkar
- Department of Genetics, University of Córdoba, Córdoba, Spain.
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru, India.
| | | | - David Turrà
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy.
- Center for Studies on Bioinspired Agro-Enviromental Technology, Università di Napoli Federico II, Portici, Italy.
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4
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Redkar A, Sabale M, Schudoma C, Zechmann B, Gupta YK, López-Berges MS, Venturini G, Gimenez-Ibanez S, Turrà D, Solano R, Di Pietro A. Conserved secreted effectors contribute to endophytic growth and multihost plant compatibility in a vascular wilt fungus. Plant Cell 2022; 34:3214-3232. [PMID: 35689625 PMCID: PMC9421472 DOI: 10.1093/plcell/koac174] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 06/03/2022] [Indexed: 05/04/2023]
Abstract
Fungal interactions with plant roots, either beneficial or detrimental, have a crucial impact on agriculture and ecosystems. The cosmopolitan plant pathogen Fusarium oxysporum (Fo) provokes vascular wilts in more than a hundred different crops. Isolates of this fungus exhibit host-specific pathogenicity, which is conferred by lineage-specific Secreted In Xylem (SIX) effectors encoded on accessory genomic regions. However, such isolates also can colonize the roots of other plants asymptomatically as endophytes or even protect them against pathogenic strains. The molecular determinants of endophytic multihost compatibility are largely unknown. Here, we characterized a set of Fo candidate effectors from tomato (Solanum lycopersicum) root apoplastic fluid; these early root colonization (ERC) effectors are secreted during early biotrophic growth on main and alternative plant hosts. In contrast to SIX effectors, ERCs have homologs across the entire Fo species complex as well as in other plant-interacting fungi, suggesting a conserved role in fungus-plant associations. Targeted deletion of ERC genes in a pathogenic Fo isolate resulted in reduced virulence and rapid activation of plant immune responses, while ERC deletion in a nonpathogenic isolate led to impaired root colonization and biocontrol ability. Strikingly, some ERCs contribute to Fo infection on the nonvascular land plant Marchantia polymorpha, revealing an evolutionarily conserved mechanism for multihost colonization by root infecting fungi.
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Affiliation(s)
| | - Mugdha Sabale
- Departamento de Genética, Universidad de Córdoba, 14071 Córdoba, Spain
| | | | - Bernd Zechmann
- Baylor University, Center for Microscopy and Imaging, Waco, Texas 76798, USA
| | - Yogesh K Gupta
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK
| | | | | | - Selena Gimenez-Ibanez
- Plant Molecular Genetics Department, Centro Nacional de Biotecnologıa-CSIC (CNB-CSIC), 28049 Madrid, Spain
| | - David Turrà
- Department of Agriculture and Center for Studies on Bioinspired Agro-enviromental Technology, Università di Napoli Federico II, 80055 Portici, Italy
| | - Roberto Solano
- Plant Molecular Genetics Department, Centro Nacional de Biotecnologıa-CSIC (CNB-CSIC), 28049 Madrid, Spain
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5
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Redkar A, Sabale M, Zuccaro A, Di Pietro A. Determinants of endophytic and pathogenic lifestyle in root colonizing fungi. Curr Opin Plant Biol 2022; 67:102226. [PMID: 35526366 DOI: 10.1016/j.pbi.2022.102226] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 06/14/2023]
Abstract
Plant-fungal interactions in the soil crucially impact crop productivity and can range from highly beneficial to detrimental. Accumulating evidence suggests that some root-colonizing fungi shift between endophytic and pathogenic behaviour depending on the host species and that combinations of effector proteins collectively shape the fungal lifestyle on a given plant. In this review we discuss recent advances in our understanding of how fungal infection strategies on roots can lead to contrasting outcomes for the host. We highlight functional similarities and differences in compatibility determinants that control the colonization of specific-cell layers within plant roots, ultimately shaping the continuum between endophytic and pathogenic lifestyle.
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Affiliation(s)
- Amey Redkar
- Departamento de Genética, Universidad de Córdoba, 14071 Córdoba, Spain; Department of Botany, Savitribai Phule Pune University, Ganeshkhind, Pune, 411007, India.
| | - Mugdha Sabale
- Departamento de Genética, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Alga Zuccaro
- University of Cologne, Institute for Plant Sciences, D-50674, Cologne, Germany; Cluster of Excellence on Plant Sciences (CEPLAS), D-50674, Cologne, Germany
| | - Antonio Di Pietro
- Departamento de Genética, Universidad de Córdoba, 14071 Córdoba, Spain.
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6
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Redkar A, Gimenez Ibanez S, Sabale M, Zechmann B, Solano R, Di Pietro A. Marchantia polymorpha model reveals conserved infection mechanisms in the vascular wilt fungal pathogen Fusarium oxysporum. New Phytol 2022; 234:227-241. [PMID: 34877655 DOI: 10.1111/nph.17909] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 11/30/2021] [Indexed: 06/13/2023]
Abstract
Root-infecting vascular fungi cause wilt diseases and provoke devastating losses in hundreds of crops. It is currently unknown how these pathogens evolved and whether they can also infect nonvascular plants, which diverged from vascular plants over 450 million years ago. We established a pathosystem between the nonvascular plant Marchantia polymorpha (Mp) and the root-infecting vascular wilt fungus Fusarium oxysporum (Fo). On angiosperms, Fo exhibits exquisite adaptation to the plant xylem niche as well as host-specific pathogenicity, both of which are conferred by effectors encoded on lineage-specific chromosomes. Fo isolates displaying contrasting lifestyles on angiosperms - pathogenic vs endophytic - are able to infect Mp and cause tissue maceration and host cell killing. Using isogenic fungal mutants we define a set of conserved fungal pathogenicity factors, including mitogen activated protein kinases, transcriptional regulators and cell wall remodelling enzymes, that are required for infection of both vascular and nonvascular plants. Markedly, two host-specific effectors and a morphogenetic regulator, which contribute to vascular colonisation and virulence on tomato plants are dispensable on Mp. Collectively, these findings suggest that vascular wilt fungi employ conserved infection strategies on nonvascular and vascular plant lineages but also have specific mechanisms to access the vascular niche of angiosperms.
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Affiliation(s)
- Amey Redkar
- Departamento de Genética, Universidad de Córdoba, Córdoba, 14071, Spain
| | - Selena Gimenez Ibanez
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología CSIC, Campus Universidad Autónoma, Madrid, 28049, Spain
| | - Mugdha Sabale
- Departamento de Genética, Universidad de Córdoba, Córdoba, 14071, Spain
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, Waco, TX, 76798, USA
| | - Roberto Solano
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología CSIC, Campus Universidad Autónoma, Madrid, 28049, Spain
| | - Antonio Di Pietro
- Departamento de Genética, Universidad de Córdoba, Córdoba, 14071, Spain
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7
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Furzer OJ, Cevik V, Fairhead S, Bailey K, Redkar A, Schudoma C, MacLean D, Holub EB, Jones JDG. An Improved Assembly of the Albugo candida Ac2V Genome Reveals the Expansion of the "CCG" Class of Effectors. Mol Plant Microbe Interact 2022; 35:39-48. [PMID: 34546764 DOI: 10.1094/mpmi-04-21-0075-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Albugo candida is an obligate oomycete pathogen that infects many plants in the Brassicaceae family. We resequenced the genome of isolate Ac2V using PacBio long reads and constructed an assembly augmented by Illumina reads. The Ac2VPB genome assembly is 10% larger and more contiguous compared with a previous version. Our annotation of the new assembly, aided by RNA-sequencing information, revealed a 175% expansion (40 to 110) in the CHxC effector class, which we redefined as "CCG" based on motif analysis. This class of effectors consist of arrays of phylogenetically related paralogs residing in gene sparse regions, and shows signatures of positive selection and presence/absence polymorphism. This work provides a resource that allows the dissection of the genomic components underlying A. candida adaptation and, particularly, the role of CCG effectors in virulence and avirulence on different hosts.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Oliver J Furzer
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, United Kingdom
| | - Volkan Cevik
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, United Kingdom
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, United Kingdom
| | - Sebastian Fairhead
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, United Kingdom
| | - Kate Bailey
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, United Kingdom
| | - Amey Redkar
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, United Kingdom
- Department of Genetics, University of Córdoba, Córdoba 14071, Spain
| | - Christian Schudoma
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, United Kingdom
| | - Dan MacLean
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, United Kingdom
| | - Eric B Holub
- University of Warwick, School of Life Sciences, Warwick Crop Centre, Wellesbourne, CV35 9EF, United Kingdom
| | - Jonathan D G Jones
- The Sainsbury Laboratory, University of East Anglia, Norwich NR4 7UH, United Kingdom
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8
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Castel B, Fairhead S, Furzer OJ, Redkar A, Wang S, Cevik V, Holub EB, Jones JDG. Evolutionary trade-offs at the Arabidopsis WRR4A resistance locus underpin alternate Albugo candida race recognition specificities. Plant J 2021; 107:1490-1502. [PMID: 34181787 DOI: 10.1111/tpj.15396] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
The oomycete Albugo candida causes white rust of Brassicaceae, including vegetable and oilseed crops, and wild relatives such as Arabidopsis thaliana. Novel White Rust Resistance (WRR) genes from Arabidopsis enable new insights into plant/parasite co-evolution. WRR4A from Arabidopsis accession Columbia (Col-0) provides resistance to many but not all white rust races, and encodes a nucleotide-binding, leucine-rich repeat immune receptor. Col-0 WRR4A resistance is broken by AcEx1, an isolate of A. candida. We identified an allele of WRR4A in Arabidopsis accession Øystese-0 (Oy-0) and other accessions that confers full resistance to AcEx1. WRR4AOy-0 carries a C-terminal extension required for recognition of AcEx1, but reduces recognition of several effectors recognized by the WRR4ACol-0 allele. WRR4AOy-0 confers full resistance to AcEx1 when expressed in the oilseed crop Camelina sativa.
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Affiliation(s)
- Baptiste Castel
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, NR4 7UH, Norwich, United Kingdom
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Sebastian Fairhead
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, NR4 7UH, Norwich, United Kingdom
- Warwick Crop Centre, School of Life Sciences, University of Warwick, CV35 9EF, Wellesbourne, United Kingdom
| | - Oliver J Furzer
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, NR4 7UH, Norwich, United Kingdom
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Amey Redkar
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, NR4 7UH, Norwich, United Kingdom
- Department of Genetics, University of Cordoba, 14071, Cordoba, Spain
| | - Shanshan Wang
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, NR4 7UH, Norwich, United Kingdom
| | - Volkan Cevik
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, NR4 7UH, Norwich, United Kingdom
- Department of Biology and Biochemistry, The Milner Centre for Evolution, University of Bath, BA2 7AY, Bath, United Kingdom
| | - Eric B Holub
- Warwick Crop Centre, School of Life Sciences, University of Warwick, CV35 9EF, Wellesbourne, United Kingdom
| | - Jonathan D G Jones
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, NR4 7UH, Norwich, United Kingdom
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9
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Redkar A, Sabale M, Di Pietro A. A 'Hydrolase Switch' for Vascular Specialization in Plant Pathogenic Bacteria. Trends Plant Sci 2021; 26:427-429. [PMID: 33771467 DOI: 10.1016/j.tplants.2021.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/01/2021] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
Plant vascular diseases are tissue-specific systemic infections provoked by bacterial and fungal pathogens adapted to thrive in the xylem vessels. A recent report by Gluck-Thaler et al. reveals that, in the phytopathogenic bacterium Xanthomonas, the switch from non-vascular to vascular pathogenesis is determined by a single gene encoding a plant cell wall-degrading hydrolase.
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Affiliation(s)
- Amey Redkar
- Departamento de Genética, Universidad de Córdoba, 14071 Córdoba, Spain.
| | - Mugdha Sabale
- Departamento de Genética, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Antonio Di Pietro
- Departamento de Genética, Universidad de Córdoba, 14071 Córdoba, Spain.
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10
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Ngou BPM, Ahn HK, Ding P, Redkar A, Brown H, Ma Y, Youles M, Tomlinson L, Jones JDG. Estradiol-inducible AvrRps4 expression reveals distinct properties of TIR-NLR-mediated effector-triggered immunity. J Exp Bot 2020; 71:2186-2197. [PMID: 32050020 PMCID: PMC7242080 DOI: 10.1093/jxb/erz571] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 01/14/2020] [Indexed: 05/18/2023]
Abstract
Plant nucleotide-binding domain, leucine-rich repeat receptor (NLR) proteins play important roles in recognition of pathogen-derived effectors. However, the mechanism by which plant NLRs activate immunity is still largely unknown. The paired Arabidopsis NLRs RRS1-R and RPS4, that confer recognition of bacterial effectors AvrRps4 and PopP2, are well studied, but how the RRS1/RPS4 complex activates early immediate downstream responses upon effector detection is still poorly understood. To study RRS1/RPS4 responses without the influence of cell surface receptor immune pathways, we generated an Arabidopsis line with inducible expression of the effector AvrRps4. Induction does not lead to hypersensitive cell death response (HR) but can induce electrolyte leakage, which often correlates with plant cell death. Activation of RRS1 and RPS4 without pathogens cannot activate mitogen-associated protein kinase cascades, but still activates up-regulation of defence genes, and therefore resistance against bacteria.
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Affiliation(s)
- Bruno Pok Man Ngou
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Hee-Kyung Ahn
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Pingtao Ding
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Amey Redkar
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, UK
- Department of Genetics, University of Córdoba, Córdoba, Spain
| | - Hannah Brown
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Yan Ma
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Mark Youles
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Laurence Tomlinson
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Jonathan D G Jones
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, UK
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11
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Zuo W, Ökmen B, Depotter JRL, Ebert MK, Redkar A, Misas Villamil J, Doehlemann G. Molecular Interactions Between Smut Fungi and Their Host Plants. Annu Rev Phytopathol 2019; 57:411-430. [PMID: 31337276 DOI: 10.1146/annurev-phyto-082718-100139] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Smut fungi are a large group of biotrophic plant pathogens that infect mostly monocot species, including economically relevant cereal crops. For years, Ustilago maydis has stood out as the model system to study the genetics and cell biology of smut fungi as well as the pathogenic development of biotrophic plant pathogens. The identification and functional characterization of secreted effectors and their role in virulence have particularly been driven forward using the U. maydis-maize pathosystem. Today, advancing tools for additional smut fungi such as Ustilago hordei and Sporisorium reilianum, as well as an increasing number of available genome sequences, provide excellent opportunities to investigate in parallel the effector function and evolution associated with different lifestyles and host specificities. In addition, genome analyses revealed similarities in the genomic signature between pathogenic smuts and epiphytic Pseudozyma species. This review elaborates on how knowledge about fungal lifestyles, genome biology, and functional effector biology has helped in understanding the biology of this important group of fungal pathogens. We highlight the contribution of the U. maydis model system but also discuss the differences from other smut fungi, which raises the importance of comparative genomic and genetic analyses in future research.
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Affiliation(s)
- Weiliang Zuo
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674 Cologne, Germany;
| | - Bilal Ökmen
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674 Cologne, Germany;
| | - Jasper R L Depotter
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674 Cologne, Germany;
| | - Malaika K Ebert
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674 Cologne, Germany;
| | - Amey Redkar
- Current affiliation: Department of Genetics, University of Córdoba, 14071 Córdoba, Spain
| | - Johana Misas Villamil
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674 Cologne, Germany;
| | - Gunther Doehlemann
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, 50674 Cologne, Germany;
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12
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Sabale M, Di Pietro A, Redkar A. A Conserved Microbial Motif 'Traps' Protease Activation in Host Immunity. Trends Plant Sci 2019; 24:665-667. [PMID: 31280986 DOI: 10.1016/j.tplants.2019.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/14/2019] [Accepted: 06/17/2019] [Indexed: 06/09/2023]
Abstract
A recent study (Misas-Villamil et al., Nat. Commun., 2019) reveals that Pit2, an apoplastic effector of the corn smut fungus Ustilago maydis, contains an embedded motif of 14 amino acids that binds to and inhibits plant cysteine proteases, thereby modulating host immunity. Intriguingly, the inhibitory motif acts by mimicking the protease substrate and is conserved across microbial kingdoms.
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Affiliation(s)
- Mugdha Sabale
- Department of Genetics, University of Córdoba, Córdoba 14071, Spain
| | | | - Amey Redkar
- Department of Genetics, University of Córdoba, Córdoba 14071, Spain.
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Castel B, Ngou PM, Cevik V, Redkar A, Kim DS, Yang Y, Ding P, Jones JDG. Diverse NLR immune receptors activate defence via the RPW8-NLR NRG1. New Phytol 2019; 222:966-980. [PMID: 30582759 DOI: 10.1111/nph.15659] [Citation(s) in RCA: 147] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 12/13/2018] [Indexed: 05/09/2023]
Abstract
Most land plant genomes carry genes that encode RPW8-NLR Resistance (R) proteins. Angiosperms carry two RPW8-NLR subclasses: ADR1 and NRG1. ADR1s act as 'helper' NLRs for multiple TIR- and CC-NLR R proteins in Arabidopsis. In angiosperm families, NRG1 co-occurs with TIR-NLR Resistance (R) genes. We tested whether NRG1 is required for signalling of multiple TIR-NLRs. Using CRISPR mutagenesis, we obtained an nrg1a-nrg1b double mutant in two Arabidopsis accessions, and an nrg1 mutant in Nicotiana benthamiana. These mutants are compromised in signalling of all TIR-NLRs tested, including WRR4A, WRR4B, RPP1, RPP2, RPP4 and the pairs RRS1/RPS4, RRS1B/RPS4B, CHS1/SOC3 and CHS3/CSA1. In Arabidopsis, NRG1 is required for the hypersensitive cell death response (HR) and full oomycete resistance, but not for salicylic acid induction or bacterial resistance. By contrast, nrg1 loss of function does not compromise the CC-NLR R proteins RPS5 and MLA. RPM1 and RPS2 (CC-NLRs) function is slightly compromised in an nrg1 mutant. Thus, NRG1 is required for full TIR-NLR function and contributes to the signalling of some CC-NLRs. Some NRG1-dependent R proteins also signal partially via the NRG1 sister clade, ADR1. We propose that some NLRs signal via NRG1 only, some via ADR1 only and some via both or neither.
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Affiliation(s)
- Baptiste Castel
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, UK
| | - Pok-Man Ngou
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, UK
| | - Volkan Cevik
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, UK
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, UK
| | - Amey Redkar
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, UK
- Department of Genetics, University of Córdoba, Córdoba, 14071, Spain
| | - Dae-Sung Kim
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, UK
- Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Ying Yang
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, UK
- Center for Plant Science Innovation, Beadle Center, University of Lincoln-Nebraska, Lincoln, NE, 68588, USA
| | - Pingtao Ding
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, UK
| | - Jonathan D G Jones
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, UK
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Ding P, Redkar A. Pathogens Suppress Host Transcription Factors for Rampant Proliferation. Trends Plant Sci 2018; 23:950-953. [PMID: 30241734 DOI: 10.1016/j.tplants.2018.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 08/24/2018] [Accepted: 08/31/2018] [Indexed: 06/08/2023]
Abstract
Root pathogen Verticillium dahliae deploys an effector called VdSCP41 into plants to disrupt the functions of SARD1 and CBP60g, two central transcriptional regulators of plant immunity. This provides new tools to dissect transcriptional regulation of tissue-specific immunity in the root and to understand dynamic interactions between plants and root-associated microorganisms.
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Affiliation(s)
- Pingtao Ding
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK; Both authors contributed equally to this work.
| | - Amey Redkar
- The Sainsbury Laboratory, Norwich Research Park, Norwich NR4 7UH, UK; Department of Genetics, University of Córdoba, 14071 Córdoba, Spain; Both authors contributed equally to this work.
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Affiliation(s)
- Amey Redkar
- Department of Genetics, University of Córdoba, 14071, Córdoba, Spain
| | - Antonio Di Pietro
- Department of Genetics, University of Córdoba, 14071, Córdoba, Spain
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Redkar A, Jaeger E, Doehlemann G. Visualization of Growth and Morphology of Fungal Hyphae in planta Using WGA-AF488 and Propidium Iodide Co-staining. Bio Protoc 2018. [DOI: 10.21769/bioprotoc.2942] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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17
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Redkar A, Matei A, Doehlemann G. Insights into Host Cell Modulation and Induction of New Cells by the Corn Smut Ustilago maydis. Front Plant Sci 2017; 8:899. [PMID: 28611813 PMCID: PMC5447062 DOI: 10.3389/fpls.2017.00899] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 05/12/2017] [Indexed: 05/19/2023]
Abstract
Many filamentous fungal pathogens induce drastic modulation of host cells causing abnormal infectious structures such as galls, or tumors that arise as a result of re-programming in the original developmental cell fate of a colonized host cell. Developmental consequences occur predominantly with biotrophic phytopathogens. This suggests that these host structures result as an outcome of efficient defense suppression and intimate fungal-host interaction to suit the pathogen's needs for completion of its infection cycle. This mini-review mainly summarizes host cell re-programming that occurs in the Ustilago maydis - maize interaction, in which the pathogen deploys cell-type specific effector proteins with varying activities. The fungus senses the physiological status and identity of colonized host cells and re-directs the endogenous developmental program of its host. The disturbance of host cell physiology and cell fate leads to novel cell shapes, increased cell size, and/or the number of host cells. We particularly highlight the strategies of U. maydis to induce physiologically varied host organs to form the characteristic tumors in both vegetative and floral parts of maize.
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Affiliation(s)
- Amey Redkar
- The Sainsbury Laboratory, Norwich Research ParkNorwich, United Kingdom
- *Correspondence: Amey Redkar,
| | - Alexandra Matei
- Botanical Institute and Cluster of Excellence on Plant Sciences, University of Cologne, BiocenterCologne, Germany
| | - Gunther Doehlemann
- Botanical Institute and Cluster of Excellence on Plant Sciences, University of Cologne, BiocenterCologne, Germany
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Redkar A, Doehlemann G. EdU Based DNA Synthesis and Cell Proliferation Assay in Maize Infected by the Smut Fungus Ustilago maydis. Bio Protoc 2016. [DOI: 10.21769/bioprotoc.1761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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Redkar A, Hoser R, Schilling L, Zechmann B, Krzymowska M, Walbot V, Doehlemann G. A Secreted Effector Protein of Ustilago maydis Guides Maize Leaf Cells to Form Tumors. Plant Cell 2015; 27:1332-51. [PMID: 25888589 PMCID: PMC4558682 DOI: 10.1105/tpc.114.131086] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 03/31/2015] [Indexed: 05/15/2023]
Abstract
The biotrophic smut fungus Ustilago maydis infects all aerial organs of maize (Zea mays) and induces tumors in the plant tissues. U. maydis deploys many effector proteins to manipulate its host. Previously, deletion analysis demonstrated that several effectors have important functions in inducing tumor expansion specifically in maize leaves. Here, we present the functional characterization of the effector See1 (Seedling efficient effector1). See1 is required for the reactivation of plant DNA synthesis, which is crucial for tumor progression in leaf cells. By contrast, See1 does not affect tumor formation in immature tassel floral tissues, where maize cell proliferation occurs independent of fungal infection. See1 interacts with a maize homolog of SGT1 (Suppressor of G2 allele of skp1), a factor acting in cell cycle progression in yeast (Saccharomyces cerevisiae) and an important component of plant and human innate immunity. See1 interferes with the MAPK-triggered phosphorylation of maize SGT1 at a monocot-specific phosphorylation site. We propose that See1 interferes with SGT1 activity, resulting in both modulation of immune responses and reactivation of DNA synthesis in leaf cells. This identifies See1 as a fungal effector that directly and specifically contributes to the formation of leaf tumors in maize.
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Affiliation(s)
- Amey Redkar
- Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, D-35043 Marburg, Germany
| | - Rafal Hoser
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Lena Schilling
- Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, D-35043 Marburg, Germany
| | - Bernd Zechmann
- Baylor University, Center for Microscopy and Imaging, Waco, Texas 76798
| | - Magdalena Krzymowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Virginia Walbot
- Department of Biology, Stanford University, Stanford, California 94305
| | - Gunther Doehlemann
- Max Planck Institute for Terrestrial Microbiology, Department of Organismic Interactions, D-35043 Marburg, Germany Botanical Institute and Cluster of Excellence on Plant Sciences, University of Cologne, 50674 Cologne, Germany
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Redkar A, Villajuana- Bonequi M, Doehlemann G. Conservation of the Ustilago maydis effector See1 in related smuts. Plant Signal Behav 2015; 10:e1086855. [PMID: 26357869 PMCID: PMC4854346 DOI: 10.1080/15592324.2015.1086855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 08/19/2015] [Accepted: 08/19/2015] [Indexed: 05/19/2023]
Abstract
Ustilago maydis is a biotrophic fungus that induces formation of tumors in maize (Zea mays L). In a recent study we identified See1 (Seedling efficient effector 1) as an U. maydis organ-specific effector required for tumor formation in leaves. See1 is required for U. maydis induced reactivation of plant DNA synthesis during leaf tumor progression. The protein is secreted from biotrophic hyphae and localizes to the cytoplasm and nucleus of plant cell. See1 interacts with maize SGT1, a cell cycle and immune regulator, interfering with its MAPK-triggered phosphorylation. Here, we present new data on the conservation of See1 in other closely related smuts and experimental data on the functionality of See1 ortholog in Ustilago hordei, the causal agent of barley covered smut disease.
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Affiliation(s)
- Amey Redkar
- Max Planck Institute for Terrestrial Microbiology; Department of Organismic Interactions; Marburg, Germany
| | - Mitzi Villajuana- Bonequi
- Botanical Institute and Center of Excellence on Plant Sciences (CEPLAS); University of Cologne; BioCenter; Cologne, Germany
| | - Gunther Doehlemann
- Botanical Institute and Center of Excellence on Plant Sciences (CEPLAS); University of Cologne; BioCenter; Cologne, Germany
- Correspondence to: Gunther Doehlemann;
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Schilling L, Matei A, Redkar A, Walbot V, Doehlemann G. Virulence of the maize smut Ustilago maydis is shaped by organ-specific effectors. Mol Plant Pathol 2014; 15:780-9. [PMID: 25346968 PMCID: PMC6638905 DOI: 10.1111/mpp.12133] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
With the exception of Ustilago maydis, smut fungi infecting monocotyledonous hosts systemically colonize infected plants and cause symptoms exclusively in the inflorescences. Ustilago may disinfects primordia of all aerial organs of maize (Zea mays L.) and results in the formation of large plant tumours. Previously, we have found that U. maydis infection of seedling leaves, adult leaves and tassels causes organ-specific transcriptional changes in both the pathogen and the host. Of particular interest, U. may disgenes encoding secreted proteins are differentially expressed depending on the colonized maize organ. Therefore, we hypothesized that the fungus secretes virulence-related proteins (effectors)that act in an organ-specific manner. Here, we present the identification and functional characterization of 20 presumptive organ-specific U. maydis effector genes. Ustilago maydis deletion strains for these genes were generated and tested for infectivity of maize seedling leaves and tassels. This approach identified 11 effector genes required for the full virulence of U. maydis. In nine cases, virulence was only affected in one of the tested plant organs. These results demonstrate that individual fungal effector proteins contribute to fungal virulence in an organ-specific manner.
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Abstract
Cardiogenic fate maps are used to address questions on commitment, differentiation, morphogenesis and organogenesis of the heart. Recently, the accuracy of classical cardiogenic fate maps has been questioned, raising concerns about the conclusions drawn in studies based on these maps. We present accurate fate maps of the heart-forming region (HFR) in avian embryos and show that the putative cardiogenic molecular markers Bmp2 and Nkx2.5 do not govern the boundaries of the HFR as suggested in the literature. Moreover, this paper presents the first fate map of the HFR at stage 4 and addresses a void in the literature concerning rostrocaudal patterning of heart cells between stages 4 and 8.
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Affiliation(s)
- A Redkar
- Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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Redkar A. Sperm-Specific Factors Implicated in Oolemma Binding and / or Fusion. Curr Genomics 2001. [DOI: 10.2174/1389202013350977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Granzier H, Helmes M, Cazorla O, McNabb M, Labeit D, Wu Y, Yamasaki R, Redkar A, Kellermayer M, Labeit S, Trombitás K. Mechanical properties of titin isoforms. Adv Exp Med Biol 2001; 481:283-300; discussion 300-4. [PMID: 10987079 DOI: 10.1007/978-1-4615-4267-4_17] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Titin is a giant filamentous polypeptide of multi-domain construction spanning between the Z- and M-lines of the sarcomere. As a result of differential splicing, length variants of titin are expressed in different skeletal and cardiac muscles. Here we first briefly review some of our previous work that has revealed that titin develops force in sarcomeres either stretched beyond their slack length (passive force) or shortened to below the slack length (restoring force) and that titin's force underlies a large fraction of the diastolic force of cardiac muscle. Next we present our mechanical and immunoelectron microscopical (IEM) studies of skeletal and cardiac muscles that express titin isoforms. The previously deduced molecular properties of titin were used to model titin's extensible region in the sarcomere as serially linked WLCs: rigid segments (containing folded Ig/Fn domains) and more flexible segments (PEVK segment). The model was tested on skeletal muscle fibers that express titin isoforms with tandem Ig and PEVK length variants. The model adequately predicts titin's behavior along a wide sarcomere length range in skeletal muscle, but at long sarcome lengths (SLs), predicted forces are much higher than those determined experimentally. IEM reveals that this may result from Ig domain unfolding. Experiments were also performed on cardiac myocytes from mouse and cow that express predominantly a small cardiac titin isoform (N2B titin) or a large isoform (N2BA titin), respectively. The passive tension-SL relation of myocytes was found to increase more steeply with SL in mouse than in cow. IEM revealed an additional source of extensibility within both of these cardiac titins: the unique N2B sequence (absent in skeletal muscle). Furthermore, the PEVK segment of the N2BA isoform extended to a maximal length of approximately 200 nm, as opposed to approximately 60 nm for the N2B isoform. We propose that, along the physiological SL range, the long PEVK segment found in N2BA titins results in a low PEVK fractional extension and that this underlies the lower passive tensions of N2BA-expressing cow myocytes.
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Affiliation(s)
- H Granzier
- Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, USA
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Trombitás K, Redkar A, Centner T, Wu Y, Labeit S, Granzier H. Extensibility of isoforms of cardiac titin: variation in contour length of molecular subsegments provides a basis for cellular passive stiffness diversity. Biophys J 2000; 79:3226-34. [PMID: 11106626 PMCID: PMC1301197 DOI: 10.1016/s0006-3495(00)76555-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Titin is a giant polypeptide that spans between the Z- and M-lines of the cardiac muscle sarcomere and that develops force when extended. This force arises from titin's extensible I-band region, which consists mainly of three segment types: serially linked immunoglobulin-like domains (Ig segments), interrupted by the PEVK segment, and the N2B unique sequence. Recently it was reported that the myocardium of large mammals co-expresses small (N2B) and large (N2BA) cardiac isoforms and that the passive stiffness of cardiac myocytes varies with the isoform expression ratio. To understand the molecular basis of the differences in passive stiffness we investigated titin's extensibility in bovine atrium, which expresses predominantly N2BA titin, and compared it to that of rat, which expresses predominantly N2B titin. Immunoelectron microscopy was used with antibodies that flank the Ig segments, the PEVK segment, and the unique sequence of the N2B element. The extension of the various segments was then determined as a function of sarcomere length (SL). When slack sarcomeres of bovine atrium were stretched, the PEVK segment extended much more steeply and the unique N2B sequence less steeply than in rat, while the Ig segments behaved similarly in both species. However, the extensions normalized with the segment's contour length (i.e., the fractional extensions) of Ig, PEVK, and unique sequence segments all increase less steeply with SL in cow than in rat. Considering that fractional extension determines the level of entropic force, these differences in fractional extension are expected to result in shallow and steep passive force-SL curves in myocytes that express high levels of N2BA and N2B titin, respectively. Thus, the findings provide a molecular basis for passive stiffness diversity.
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Affiliation(s)
- K Trombitás
- Department of Veterinary and Comparative Anatomy, Pharmacology, and Physiology, Washington State University, Pullman, Washington 99164-6520, USA
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Jones CB, Clements MK, Redkar A, Daoud SS. UCN-01 and camptothecin induce DNA double-strand breaks in p53 mutant tumor cells, but not in normal or p53 negative epithelial cells. Int J Oncol 2000; 17:1043-51. [PMID: 11029511 DOI: 10.3892/ijo.17.5.1043] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previous research has shown synergistic growth inhibition between UCN-01 and camptothecin (CPT) in tumor cells with mutant p53 versus tumor cells with wild-type p53. To determine the possible role of p53 in this drug combination, we tested the hypothesis that the synergistic growth inhibition is due to the absence of p53, and can result from the induction of DNA double-strand breaks (DSBs). Experiments were performed with the use of normal human mammary epithelial cells (HMEC); HMEC transfected with HPV16 E6 protein which inactivates p53 (HE6), or p53-mutant MDA-MB-231 tumor cells. CPT, UCN-01, or a 1:1 combination of both, in either HMEC or HE6 cells did not induce DSBs. In contrast, simultaneous treatment of MDA-MB-231 cells with both UCN-01 and CPT induced significant levels of DSBs while treatment with either drug alone did not. While UCN-01 was surprisingly potent against HMEC, the growth inhibition was only additive between UCN-01 and CPT against these cells. HE6 cells were much less sensitive than HMEC to UCN-01 and slightly less sensitive to the combined treatment with UCN-01 and CPT. The drug combination was synergistic against HE6 cells, due to their lower sensitivity to UCN-01. Unlike what was observed previously in MDA-MB-231 cells, UCN-01 did not abrogate CPT-induced inhibition of DNA synthesis in either HMEC or HE6 cells. These data indicate that synergistic growth inhibition by UCN-01 and CPT against p53 mutant MDA-MB-231 tumor cells may be due to induction of DSBs however the loss of p53 function alone does not sensitize normal cells to the combination of both drugs.
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Affiliation(s)
- C B Jones
- Pharmacology and Toxicology Graduate Program, Washington State University, Pullman, WA 99164-6510, USA
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Bhattacharya D, Redkar A, Mittra I, Sutaria U, MacRae KD. Oestrogen increases S-phase fraction and oestrogen and progesterone receptors in human cervical cancer in vivo. Br J Cancer 1997; 75:554-8. [PMID: 9052410 PMCID: PMC2063290 DOI: 10.1038/bjc.1997.97] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Although cancer of the cervix is traditionally considered not to be responsive to steroid hormones, an in vitro study has reported that the addition of oestrogen increased cellular proliferation in a cervix cancer cell line that was inhibited by progesterone. We investigated whether the reported in vitro effects of oestrogen and progesterone on cellular proliferation can be replicated in locally advanced cervical cancer in vivo and whether these effects, if any, are related to oestrogen and progesterone receptor (ER and PgR) content of the tumour. One hundred post-menopausal patients with locally advanced cervical cancer were systematically allocated by rotation to the four treatment groups: (1) control group receiving no treatment; (2) ethinyl oestradiol 50 micrograms: (3) norethisterone 5 mg: (4) a combination of ethinyl oestradiol and norethisterone. Hormone treatment (five doses) was given orally every 12 h. Tissue biopsies were taken before and 12 h after the last hormone treatment. S-phase fraction (SpF) was measured by flow cytometry, and ER and PgR were measured by enzyme immunoassay. Results were analysed using two-factor analysis of variance, the factors being oestrogen-absent or present- and progesterone-absent or present. The main effects of oestrogen were increases in SpF, ER and PgR, which were statistically significant (P = 0.0056, 0.0009 and 0.01 respectively), indicating that there is much greater change in these three parameters in the presence of oestrogen (mean changes 7.808%, 6.258 fmol mg-1 and 12.716 fmol mg-1 for SpF, ER and PgR respectively) than in its absence (mean change -1.986%,-3.041 fmol mg-1 and 1.736 fmol mg-1 respectively). The progestogen main effect and the oestrogen-progestogen interaction were not significant. The rise in SpF, ER and PgR in the presence of oestrogen had a correlation coefficient with the initial ER values of -0.0565, -0.2863 and -0.1230 respectively, none being statistically significant, suggesting that the oestrogen actions were not strictly related to baseline ER concentrations. The combined median baseline ER and PgR values of the four groups were 1.48 fmol mg-1 and 0.80 fmol mg-1 respectively. Our results show that oestrogen is capable of increasing SpF in locally advanced cervical cancer in vivo and may help to revive interest in the use of oestrogen as a radiosensitizing agent in the treatment of this disease.
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MESH Headings
- Adenocarcinoma/chemistry
- Adenocarcinoma/drug therapy
- Adenocarcinoma/pathology
- Administration, Oral
- Aged
- Antineoplastic Agents, Hormonal/administration & dosage
- Antineoplastic Agents, Hormonal/pharmacology
- Carcinoma, Adenosquamous/chemistry
- Carcinoma, Adenosquamous/drug therapy
- Carcinoma, Adenosquamous/pathology
- Carcinoma, Squamous Cell/chemistry
- Carcinoma, Squamous Cell/drug therapy
- Carcinoma, Squamous Cell/pathology
- Ethinyl Estradiol/administration & dosage
- Ethinyl Estradiol/pharmacology
- Female
- Humans
- Middle Aged
- Receptors, Estrogen/drug effects
- Receptors, Progesterone/drug effects
- S Phase/drug effects
- Uterine Cervical Neoplasms/chemistry
- Uterine Cervical Neoplasms/drug therapy
- Uterine Cervical Neoplasms/pathology
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Affiliation(s)
- D Bhattacharya
- Department of Obstetrics and Gynecology, King Edward Memorial Hospital, Pune, India
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Chakravarty G, Redkar A, Mittra I. A comparative study of detection of p53 mutations in human breast cancer by flow cytometry, single-strand conformation polymorphism and genomic sequencing. Br J Cancer 1996; 74:1181-7. [PMID: 8883402 PMCID: PMC2075935 DOI: 10.1038/bjc.1996.514] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The accuracy of immunodetection by dual parameter flow cytometry (FCM), polymerase chain reaction-mediated single strand conformation polymorphism (PCR-SSCP) and genomic sequencing to detect p53 mutations were compared. Analysis by the last two techniques was restricted to exons 5-8. Initially, 110 breast tumours were screened for p53 expression by FCM. Seventy (64%) of tumours were immunopositive. Fifteen highly immunopositive and 15 completely immunonegative tumours were selected for further analysis by PCR-SSCP and genomic sequencing. Eleven out of 15 immunopositive tumours were found to have mutation by PCR-SSCP. Genomic sequencing confirmed the presence of mutation in 10 of these 11 immunopositive tumours. Therefore, four immunopositive tumours failed to show mutation by SSCP and five by genomic sequencing. Of the 15 immunonegative tumours, one showed mutation by both PCR-SSCP and genomic sequencing and one tumour has undergone deletion of the p53 gene. Overall, immunoreactivity correlated with both PCR-SSCP and genomic sequencing in 80% of cases (24/30), and there was 96.5% (28/29) concordance between PCR-SSCP and genomic sequencing. We conclude that there is good concordance between mutations detected by PCR-SSCP and genomic sequencing, but immunochemical detection of p53 overexpression is not an absolute indicator of p53 gene mutation.
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Affiliation(s)
- G Chakravarty
- Division of Laboratory Medicine, Tata Memorial Hospital, Bombay, India
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30
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Parikh PM, Ashokkumar MS, Pai SK, Redkar A, Chopra HK, Barbhaya SA, Gopal R, Mittra I, Advani SH. Prognostic significance of DNA index by flowcytometry in acute lymphoblastic leukaemia. Indian J Med Res 1995; 102:24-7. [PMID: 7558206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
DNA index (DI) is considered an important prognostic factor in acute lymphoblastic leukaemia (ALL). We undertook this study to correlate DI with other presenting features and response to therapy. Of the 30 patients of ALL treated at our hospital and entered in this study, 15 were put on the aggressive MCP (multi center protocol) 841 protocol and equal number on the Alternate protocol. Eighteen achieved complete remission (13/15 on the former protocol and 5/15 on the later). DI was less than 0.8 in 8 (27%) patients, between 0.8 and 1.2 in 18 (60%) and more than 1.2 in 4 patients (13%). These figures are different from those reported in Caucasians. On multivariate regression analysis, the DI significantly correlated with percentage of blasts in peripheral blood (P = 0.0035). There was no correlation with outcome or response to treatment.
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Affiliation(s)
- P M Parikh
- Department of Medical Oncology & Laboratory Medicine, Tata Memorial Hospital, Bombay
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31
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Bandyopadhyay D, Redkar A, Bharde S, Dani H, Sampat M, Mittra I. Prognostic association of c-erbB-2 oncogene amplification and protein overexpression in human breast cancer using archival tissues. A comparative study. Acta Oncol 1994; 33:493-8. [PMID: 7917361 DOI: 10.3109/02841869409083924] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The prognostic associations of c-erbB-2 gene amplification analysed by dot-blot hybridization and of c-erbB-2 protein overexpression assessed by immunohistochemistry (IHC) were compared in 161 patients with operable breast cancer using formalin fixed paraffin embedded archival tissues. The efficiency of the dot-blot technique to detect c-erbB-2 amplification was first validated by comparing the results of dot-blot with those of Southern blot hybridization in 134 tumour samples and there was an excellent correlation. In the main series of 161 samples, where results of IHC and dot-blot were compared, 35.4% showed c-erbB-2 overexpression and 17.4% showed gene amplification. Tumours showing overexpression of c-erbB-2 protein had a significantly shorter disease-free survival (DSF) and survival(s) compared to tumours showing no overexpression. A multivariate analysis revealed that c-erbB-2 overexpression was independently correlated with poor prognosis. On the other hand, no significant association between c-erbB-2 gene amplification and DFS or S was observed. We conclude that c-erbB-2 protein overexpression assessed by IHC is a superior prognostic indicator in operable breast cancer compared to c-erbB-2 gene amplification analysed by the dot-blot technique.
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Affiliation(s)
- D Bandyopadhyay
- Department of Laboratory Medicine, Tata Memorial Hospital, Bombay, India
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32
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Patil P, Redkar A, Patel SG, Krishnamurthy S, Mistry RC, Deshpande RK, Mittra I, Desai PB. Prognosis of operable squamous cell carcinoma of the esophagus. Relationship with clinicopathologic features and DNA ploidy. Cancer 1993; 72:20-4. [PMID: 8508407 DOI: 10.1002/1097-0142(19930701)72:1<20::aid-cncr2820720106>3.0.co;2-j] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Reports on the influence of various prognostic factors in carcinoma of the esophagus are conflicting. The prognostic value of a set of clinicopathologic factors and DNA ploidy were examined in 74 patients with surgically resected squamous cell carcinoma of the lower and middle third of the esophagus. METHODS All patients had surgery performed in a single thoracic surgical unit at the Tata Memorial Hospital between January, 1984 and December, 1987. The clinicopathologic factors studied were (1) gross residual disease at operation; (2) morphology of the tumor; (3) depth of microscopic invasion; (4) lymph node involvement; (5) histologic grade; (6) vascular and lymphatic embolism; and (7) sex. DNA ploidy and S-phase fraction (SpF) were determined by flow cytometry on archival tissues extracted from paraffin blocks. Ploidy status could be determined successfully in all 74 tumors, whereas SpF could be assessed only in 25. RESULTS Of the various prognostic factors examined with the Cox stepwise regression model, residual disease (P = 0.000), depth of invasion (P = 0.047), and lymph node status (P = 0.077) were found to be correlated with overall survival. CONCLUSIONS DNA ploidy was not related to prognosis. The overall survival of this group of patients at 36 months was 28%, and median survival was 18 months.
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Affiliation(s)
- P Patil
- Department of Surgery, Tata Memorial Hospital, Bombay, India
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