1
|
Pawlowska TE. Symbioses between fungi and bacteria: from mechanisms to impacts on biodiversity. Curr Opin Microbiol 2024; 80:102496. [PMID: 38875733 DOI: 10.1016/j.mib.2024.102496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 05/20/2024] [Accepted: 05/31/2024] [Indexed: 06/16/2024]
Abstract
Symbiotic interactions between fungi and bacteria range from positive to negative. They are ubiquitous in free-living as well as host-associated microbial communities worldwide. Yet, the impact of fungal-bacterial symbioses on the organization and dynamics of microbial communities is uncertain. There are two reasons for this uncertainty: (1) knowledge gaps in the understanding of the genetic mechanisms underpinning fungal-bacterial symbioses and (2) prevailing interpretations of ecological theory that favor antagonistic interactions as drivers stabilizing biological communities despite the existence of models emphasizing contributions of positive interactions. This review synthesizes information on fungal-bacterial symbioses common in the free-living microbial communities of the soil as well as in host-associated polymicrobial biofilms. The interdomain partnerships are considered in the context of the relevant community ecology models, which are discussed critically.
Collapse
Affiliation(s)
- Teresa E Pawlowska
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA.
| |
Collapse
|
2
|
Abstract
Investigation of fungal biology has been frequently motivated by the fact that many fungal species are important plant and animal pathogens. Such efforts have contributed significantly toward our understanding of fungal pathogenic lifestyles (virulence factors and strategies) and the interplay with host immune systems. In parallel, work on fungal allorecognition systems leading to the characterization of fungal regulated cell death determinants and pathways, has been instrumental for the emergent concept of fungal immunity. The uncovered evolutionary trans-kingdom parallels between fungal regulated cell death pathways and innate immune systems incite us to reflect further on the concept of a fungal immune system. Here, I briefly review key findings that have shaped the fungal immunity paradigm, providing a perspective on what I consider its most glaring knowledge gaps. Undertaking to fill such gaps would establish firmly the fungal immune system inside the broader field of comparative immunology.
Collapse
Affiliation(s)
- Asen Daskalov
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- ImmunoConcEpT, CNRS UMR 5164, University of Bordeaux, Bordeaux, France
- Corresponding author
| |
Collapse
|
3
|
Sun G, Bai S, Guan Y, Wang S, Wang Q, Liu Y, Liu H, Goffinet B, Zhou Y, Paoletti M, Hu X, Haas FB, Fernandez-Pozo N, Czyrt A, Sun H, Rensing SA, Huang J. Are fungi-derived genomic regions related to antagonism towards fungi in mosses? THE NEW PHYTOLOGIST 2020; 228:1169-1175. [PMID: 32578878 DOI: 10.1111/nph.16776] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/19/2020] [Indexed: 05/16/2023]
Affiliation(s)
- Guiling Sun
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Shenglong Bai
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Yanlong Guan
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Shuanghua Wang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Qia Wang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Yang Liu
- Fairy Lake Botanical Garden, Chinese Academy of Sciences, Shenzhen, 518004, China
- BGI-Shenzhen, Shenzhen, 518083, China
| | - Huan Liu
- BGI-Shenzhen, Shenzhen, 518083, China
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen, 518083, China
| | - Bernard Goffinet
- Ecology and Evolutionary Biology, University of Connecticut, 75N Eagleville Rd, Storrs, CT, 06269-3043, USA
| | - Yun Zhou
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Mathieu Paoletti
- Laboratoire de Génétique Moléculaire des Champignons, Institut de Biochimie et de Génétique Cellulaires, UMR 5095 CNRS-Université de Bordeaux 2, 1 rue Camille St Saëns, Bordeaux Cedex, 33077, France
| | - Xiangyang Hu
- College of Life Sciences, Shanghai University, Shanghai, 200444, China
| | - Fabian B Haas
- Plant Cell Biology, Department of Biology, University of Marburg, Marburg, 35043, Germany
| | - Noe Fernandez-Pozo
- Plant Cell Biology, Department of Biology, University of Marburg, Marburg, 35043, Germany
| | - Alia Czyrt
- Plant Cell Biology, Department of Biology, University of Marburg, Marburg, 35043, Germany
| | - Hang Sun
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Stefan A Rensing
- Plant Cell Biology, Department of Biology, University of Marburg, Marburg, 35043, Germany
| | - Jinling Huang
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- Department of Biology, East Carolina University, Greenville, NC, 28590, USA
| |
Collapse
|
4
|
|
5
|
Osdaghi E, Martins SJ, Ramos-Sepulveda L, Vieira FR, Pecchia JA, Beyer DM, Bell TH, Yang Y, Hockett KL, Bull CT. 100 Years Since Tolaas: Bacterial Blotch of Mushrooms in the 21 st Century. PLANT DISEASE 2019; 103:2714-2732. [PMID: 31560599 DOI: 10.1094/pdis-03-19-0589-fe] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Among the biotic constraints of common mushroom (Agaricus bisporus) production, bacterial blotch is considered the most important mushroom disease in terms of global prevalence and economic impact. Etiology and management of bacterial blotch has been a major concern since its original description in 1915. Although Pseudomonas tolaasii is thought to be the main causal agent, various Pseudomonas species, as well as organisms from other genera have been reported to cause blotch symptoms on mushroom caps. In this review, we provide an updated overview on the etiology, epidemiology, and management strategies of bacterial blotch disease. First, diversity of the causal agent(s) and utility of high throughput sequencing-based approaches in the precise characterization and identification of blotch pathogen(s) is explained. Further, due to the limited options for use of conventional pesticides in mushroom farms against blotch pathogen(s), we highlight the role of balanced threshold of relative humidity and temperature in mushroom farms to combat the disease in organic and conventional production. Additionally, we discuss the possibility of the use of biological control agents (either antagonistic mushroom-associated bacterial strains or bacteriophages) for blotch management as one of the sustainable approaches for 21st century agriculture. Finally, we aim to elucidate the association of mushroom microbiome in cap development and productivity on one hand, and blotch incidence/outbreaks on the other hand.
Collapse
Affiliation(s)
- Ebrahim Osdaghi
- Department of Plant Protection, College of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Samuel J Martins
- Plant Pathology & Environmental Microbiology Department, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Laura Ramos-Sepulveda
- Department of Biology, Millersville University of Pennsylvania, Millersville, PA 17551, U.S.A
| | - Fabrício Rocha Vieira
- Plant Pathology & Environmental Microbiology Department, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - John A Pecchia
- Plant Pathology & Environmental Microbiology Department, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - David Meigs Beyer
- Plant Pathology & Environmental Microbiology Department, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Terrence H Bell
- Plant Pathology & Environmental Microbiology Department, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Yinong Yang
- Plant Pathology & Environmental Microbiology Department, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Kevin L Hockett
- Plant Pathology & Environmental Microbiology Department, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Carolee T Bull
- Plant Pathology & Environmental Microbiology Department, The Pennsylvania State University, University Park, PA 16802, U.S.A
| |
Collapse
|
6
|
The mitochondrial translocase of the inner membrane PaTim54 is involved in defense response and longevity in Podospora anserina. Fungal Genet Biol 2019; 132:103257. [PMID: 31351193 DOI: 10.1016/j.fgb.2019.103257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 06/26/2019] [Accepted: 07/22/2019] [Indexed: 11/20/2022]
Abstract
Fungi are very successful microorganisms capable of colonizing virtually any ecological niche where they must constantly cope with competitors including fungi, bacteria and nematodes. We have shown previously that the ascomycete Podopora anserina exhibits Hyphal Interference (HI), an antagonistic response triggered by direct contact of competing fungal hyphae. When challenged with Penicillium chrysogenum, P. anserina produces hydrogen peroxide at the confrontation and kills the hyphae of P. chrysogenum. Here, we report the characterization of the PDC2218 mutant affected in HI. When challenged with P. chrysogenum, the PDC2218 mutant produces a massive oxidative burst at the confrontation. However, this increased production of hydrogen peroxide is not correlated to increased cell death in P. chrysogenum. Hence, the oxidative burst and cell death in the challenger are uncoupled in PDC2218. The gene affected in PDC2218 is PaTim54, encoding the homologue of the budding yeast mitochondrial inner membrane import machinery component Tim54p. We show that PaTim54 is essential in P. anserina and that the phenotypes displayed by the PDC2218 mutant, renamed PaTim542218, are the consequence of a drastic reduction in the expression of PaTim54. Among these pleiotropic phenotypes, PDC2218-PaTim542218- displays increased lifespan, a phenotype in line with the observed mitochondrial defects in the mutant.
Collapse
|
7
|
Gomes T, Pereira JA, Lino-Neto T, Bennett AE, Baptista P. Bacterial disease induced changes in fungal communities of olive tree twigs depend on host genotype. Sci Rep 2019; 9:5882. [PMID: 30971758 PMCID: PMC6458152 DOI: 10.1038/s41598-019-42391-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 03/07/2019] [Indexed: 12/31/2022] Open
Abstract
In nature, pathogens live and interact with other microorganisms on plant tissues. Yet, the research area exploring interactions between bacteria-fungi and microbiota-plants, within the context of a pathobiome, is still scarce. In this study, the impact of olive knot (OK) disease caused by the bacteria Pseudomonas savastanoi pv. savastanoi (Psv) on the epiphytic and endophytic fungal communities of olive tree twigs from three different cultivars, was investigated in field conditions. The ITS-DNA sequencing of cultivable fungi, showed that OK disease disturbs the resident fungal communities, which may reflect changes in the habitat caused by Psv. In particular, a reduction on epiphyte abundance and diversity, and changes on their composition were observed. Compared to epiphytes, endophytes were less sensitive to OK, but their abundance, in particular of potential pathogens, was increased in plants with OK disease. Host genotype, at cultivar level, contributed to plant fungal assembly particularly upon disease establishment. Therefore, besides fungi - Psv interactions, the combination of cultivar - Psv also appeared to be critical for the composition of fungal communities in olive knots. Specific fungal OTUs were associated to the presence and absence of disease, and their role in the promotion or suppression of OK disease should be studied in the future.
Collapse
Affiliation(s)
- Teresa Gomes
- CIMO/Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253, Bragança, Portugal.,Biosystems & Integrative Sciences Institute (BioISI), Plant Functional Biology Center (CBFP), University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - José Alberto Pereira
- CIMO/Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253, Bragança, Portugal
| | - Teresa Lino-Neto
- Biosystems & Integrative Sciences Institute (BioISI), Plant Functional Biology Center (CBFP), University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Alison E Bennett
- Dept of Evolution, Ecology & Organismal Biology, The Ohio State University, 318 W. 12th Ave., 300 Aronoff Laboratory, Columbus, OH, 43210, USA
| | - Paula Baptista
- CIMO/Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253, Bragança, Portugal.
| |
Collapse
|
8
|
Do fungi have an innate immune response? An NLR-based comparison to plant and animal immune systems. PLoS Pathog 2017; 13:e1006578. [PMID: 29073287 PMCID: PMC5658179 DOI: 10.1371/journal.ppat.1006578] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
|
9
|
Morris CE, Barny M, Berge O, Kinkel LL, Lacroix C. Frontiers for research on the ecology of plant‐pathogenic bacteria: fundamentals for sustainability. MOLECULAR PLANT PATHOLOGY 2017; 18:308-319. [PMID: 27862839 PMCID: PMC6638276 DOI: 10.1111/mpp.12508] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/02/2016] [Accepted: 11/07/2016] [Indexed: 05/02/2023]
Abstract
Methods to ensure the health of crops owe their efficacy to the extent to which we understand the ecology and biology of environmental microorganisms and the conditions under which their interactions with plants lead to losses in crop quality or yield. However, in the pursuit of this knowledge, notions of the ecology of plant‐pathogenic microorganisms have been reduced to a plant‐centric and agro‐centric focus. With increasing global change, i.e. changes that encompass not only climate, but also biodiversity, the geographical distribution of biomes, human demographic and socio‐economic adaptations and land use, new plant health problems will emerge via a range of processes influenced by these changes. Hence, knowledge of the ecology of plant pathogens will play an increasingly important role in the anticipation and response to disease emergence. Here, we present our opinion on the major challenges facing the study of the ecology of plant‐pathogenic bacteria. We argue that the discovery of markedly novel insights into the ecology of plant‐pathogenic bacteria is most likely to happen within a framework of more extensive scales of space, time and biotic interactions than those that currently guide much of the research on these bacteria. This will set a context that is more propitious for the discovery of unsuspected drivers of the survival and diversification of plant‐pathogenic bacteria and of the factors most critical for disease emergence, and will set the foundation for new approaches to the sustainable management of plant health. We describe the contextual background of, justification for and specific research questions with regard to the following challenges:
Development of terminology to describe plant–bacterial relationships in terms of bacterial fitness. Definition of the full scope of the environments in which plant‐pathogenic bacteria reside or survive. Delineation of pertinent phylogenetic contours of plant‐pathogenic bacteria and naming of strains independent of their presumed life style. Assessment of how traits of plant‐pathogenic bacteria evolve within the overall framework of their life history. Exploration of possible beneficial ecosystem services contributed to by plant‐pathogenic bacteria.
Collapse
Affiliation(s)
- Cindy E. Morris
- INRA, UR0407 Plant Pathology Research UnitMontfavet84143France
| | - Marie‐Anne Barny
- Sorbonne Universités, UMR1392 INRA, UPMC Université Paris 06, CNRS, IRDDiderot Université Paris 07, UPEC Université Paris 12, Institut d'Ecologie et des Sciences de l'Environnement de Paris, Case 237, 4 place Jussieu75252ParisFrance
| | - Odile Berge
- INRA, UR0407 Plant Pathology Research UnitMontfavet84143France
| | - Linda L. Kinkel
- University of Minnesota1991 Upper Buford Circle, 495 Borlaug HallSt PaulMN55108‐0010USA
| | | |
Collapse
|
10
|
Baltrus DA, McCann HC, Guttman DS. Evolution, genomics and epidemiology of Pseudomonas syringae: Challenges in Bacterial Molecular Plant Pathology. MOLECULAR PLANT PATHOLOGY 2017; 18:152-168. [PMID: 27798954 PMCID: PMC6638251 DOI: 10.1111/mpp.12506] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 05/12/2023]
Abstract
A remarkable shift in our understanding of plant-pathogenic bacteria is underway. Until recently, nearly all research on phytopathogenic bacteria was focused on a small number of model strains, which provided a deep, but narrow, perspective on plant-microbe interactions. Advances in genome sequencing technologies have changed this by enabling the incorporation of much greater diversity into comparative and functional research. We are now moving beyond a typological understanding of a select collection of strains to a more generalized appreciation of the breadth and scope of plant-microbe interactions. The study of natural populations and evolution has particularly benefited from the expansion of genomic data. We are beginning to have a much deeper understanding of the natural genetic diversity, niche breadth, ecological constraints and defining characteristics of phytopathogenic species. Given this expanding genomic and ecological knowledge, we believe the time is ripe to evaluate what we know about the evolutionary dynamics of plant pathogens.
Collapse
Affiliation(s)
| | - Honour C. McCann
- New Zealand Institute for Advanced StudyMassey UniversityAuckland 0632New Zealand
| | - David S. Guttman
- Department of Cell and Systems BiologyUniversity of TorontoTorontoON M5S 3B2Canada
- Centre for the Analysis of Genome Evolution and FunctionUniversity of TorontoTorontoON M5S 3B2Canada
| |
Collapse
|
11
|
de Boer W, Hundscheid MPJ, Klein Gunnewiek PJA, de Ridder-Duine AS, Thion C, van Veen JA, van der Wal A. Antifungal Rhizosphere Bacteria Can increase as Response to the Presence of Saprotrophic Fungi. PLoS One 2015; 10:e0137988. [PMID: 26393509 PMCID: PMC4578881 DOI: 10.1371/journal.pone.0137988] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 08/24/2015] [Indexed: 01/26/2023] Open
Abstract
Knowledge on the factors that determine the composition of bacterial communities in the vicinity of roots (rhizosphere) is essential to understand plant-soil interactions. Plant species identity, plant growth stage and soil properties have been indicated as major determinants of rhizosphere bacterial community composition. Here we show that the presence of saprotrophic fungi can be an additional factor steering rhizosphere bacterial community composition and functioning. We studied the impact of presence of two common fungal rhizosphere inhabitants (Mucor hiemalis and Trichoderma harzianum) on the composition of cultivable bacterial communities developing in the rhizosphere of Carex arenaria (sand sedge) in sand microcosms. Identification and phenotypic characterization of bacterial isolates revealed clear shifts in the rhizosphere bacterial community composition by the presence of two fungal strains (M. hiemalis BHB1 and T. harzianum PvdG2), whereas another M. hiemalis strain did not show this effect. Presence of both M. hiemalis BHB1 and T. harzianum PvdG2 resulted in a significant increase of chitinolytic and (in vitro) antifungal bacteria. The latter was most pronounced for M. hiemalis BHB1, an isolate from Carex roots, which stimulated the development of the bacterial genera Achromobacter and Stenotrophomonas. In vitro tests showed that these genera were strongly antagonistic against M. hiemalis but also against the plant-pathogenic fungus Rhizoctonia solani. The most likely explanation for fungal-induced shifts in the composition of rhizosphere bacteria is that bacteria are being selected which are successful in competing with fungi for root exudates. Based on the results we propose that measures increasing saprotrophic fungi in agricultural soils should be explored as an alternative approach to enhance natural biocontrol against soil-borne plant-pathogenic fungi, namely by stimulating indigenous antifungal rhizosphere bacteria.
Collapse
Affiliation(s)
- Wietse de Boer
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, 6708 PB, the Netherlands
- Department of Soil Quality, Wageningen University, Wageningen, 6708 PB, the Netherlands
| | - Maria P. J. Hundscheid
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, 6708 PB, the Netherlands
| | | | - Annelies S. de Ridder-Duine
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, 6708 PB, the Netherlands
| | - Cecile Thion
- School of Biological Science, University of Aberdeen, Aberdeen, AB24 3UU, United Kingdom
| | - Johannes A. van Veen
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, 6708 PB, the Netherlands
- Insititute of Biology, Leiden University, Leiden, 2333 BE, the Netherlands
| | - Annemieke van der Wal
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, 6708 PB, the Netherlands
- * E-mail:
| |
Collapse
|
12
|
Minimal genomes of mycoplasma-related endobacteria are plastic and contain host-derived genes for sustained life within Glomeromycota. Proc Natl Acad Sci U S A 2015; 112:7791-6. [PMID: 25964324 DOI: 10.1073/pnas.1501676112] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Arbuscular mycorrhizal fungi (AMF, Glomeromycota) colonize roots of the majority of terrestrial plants. They provide essential minerals to their plant hosts and receive photosynthates in return. All major lineages of AMF harbor endobacteria classified as Mollicutes, and known as mycoplasma-related endobacteria (MRE). Except for their substantial intrahost genetic diversity and ability to transmit vertically, virtually nothing is known about the life history of these endobacteria. To understand MRE biology, we sequenced metagenomes of three MRE populations, each associated with divergent AMF hosts. We found that each AMF species harbored a genetically distinct group of MRE. Despite vertical transmission, all MRE populations showed extensive chromosomal rearrangements, which we attributed to genetic recombination, activity of mobile elements, and a history of plectroviral invasion. The MRE genomes are characterized by a highly reduced gene content, indicating metabolic dependence on the fungal host, with the mechanism of energy production remaining unclear. Several MRE genes encode proteins with domains involved in protein-protein interactions with eukaryotic hosts. In addition, the MRE genomes harbor genes horizontally acquired from AMF. Some of these genes encode small ubiquitin-like modifier (SUMO) proteases specific to the SUMOylation systems of eukaryotes, which MRE likely use to manipulate their fungal host. The extent of MRE genome plasticity and reduction, along with the large number of horizontally acquired host genes, suggests a high degree of adaptation to the fungal host. These features, together with the ubiquity of the MRE-Glomeromycota associations, emphasize the significance of MRE in the biology of Glomeromycota.
Collapse
|
13
|
Patel HK, Matiuzzo M, Bertani I, Bigirimana VDP, Ash GJ, Höfte M, Venturi V. Identification of virulence associated loci in the emerging broad host range plant pathogen Pseudomonas fuscovaginae. BMC Microbiol 2014; 14:274. [PMID: 25394860 PMCID: PMC4237756 DOI: 10.1186/s12866-014-0274-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 10/23/2014] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Pseudomonas fuscovaginae (Pfv) is an emerging plant pathogen of rice and also of other gramineae plants. It causes sheath brown rot disease in rice with symptoms that are characterized by brown lesions on the flag leaf sheath, grain discoloration and sterility. It was first isolated as a high altitude pathogen in Japan and has since been reported in several countries throughout the world. Pfv is a broad host range pathogen and very little is known about its virulence mechanisms. RESULTS An in planta screen of 1000 random independent Tn5 genomic mutants resulted in the isolation of nine mutants which showed altered virulence. Some of these isolates are mutated for functions which are known to be virulence associated factors in other phytopathogenic bacteria (eg. pil gene, phytotoxins and T6SS) and others might represent novel virulence loci. CONCLUSIONS Being an emerging pathogen worldwide, the broad host range pathogen Pfv has not yet been studied for its virulence functions. The roles of the nine loci identified in the in planta screen are discussed in relation to pathogenicity of Pfv. In summary, this article reports a first study on the virulence of this pathogen involving in planta screening studies and suggests the presence of several virulence features with known and novel functions in the Pseudomonas group of bacteria.
Collapse
Affiliation(s)
| | - Maura Matiuzzo
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
| | - Iris Bertani
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
| | | | - Gavin J Ash
- Graham Centre for Agricultural Innovation, School of Agricultural and Wine Sciences, Charles Sturt University, Wagga Wagga, NSW, 2650, Australia.
| | - Monica Höfte
- Department of Crop Protection, Laboratory of Phytopathology, Ghent University, Coupure, Links 653, 9000, Ghent, Belgium.
| | - Vittorio Venturi
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
| |
Collapse
|
14
|
Stanley CE, Stöckli M, van Swaay D, Sabotič J, Kallio PT, Künzler M, deMello AJ, Aebi M. Probing bacterial–fungal interactions at the single cell level. Integr Biol (Camb) 2014; 6:935-45. [DOI: 10.1039/c4ib00154k] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
|
15
|
CZT-1 is a novel transcription factor controlling cell death and natural drug resistance in Neurospora crassa. G3-GENES GENOMES GENETICS 2014; 4:1091-102. [PMID: 24717808 PMCID: PMC4065252 DOI: 10.1534/g3.114.011312] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We pinpoint CZT-1 (cell death–activated zinc cluster transcription factor) as a novel transcription factor involved in tolerance to cell death induced by the protein kinase inhibitor staurosporine in Neurospora crassa. Transcriptional profiling of staurosporine-treated wild-type cells by RNA-sequencing showed that genes encoding the machinery for protein synthesis are enriched among the genes repressed by the drug. Functional category enrichment analyses also show that genes encoding components of the mitochondrial respiratory chain are downregulated by staurosporine, whereas genes involved in endoplasmic reticulum activities are upregulated. In contrast, a staurosporine-treated Δczt-1 deletion strain is unable to repress the genes for the respiratory chain and to induce the genes related to the endoplasmic reticulum, indicating a role for CZT-1 in the regulation of activity of these organelles. The Δczt-1 mutant strain displays increased reactive oxygen species accumulation on insult with staurosporine. A genome-wide association study of a wild population of N. crassa isolates pointed out genes associated with a cell death role of CZT-1, including catalase-1 (cat-1) and apoptosis-inducing factor–homologous mitochondrion-associated inducer of death 2 (amid-2). Importantly, differences in the expression of czt-1 correlates with resistance to staurosporine among wild isolate strains. Our results reveal a novel transcription factor that regulates drug resistance and cell death in response to staurosporine in laboratory strains as well as in wild isolates of N. crassa.
Collapse
|
16
|
Van der Nest MA, Olson A, Lind M, Vélëz H, Dalman K, Brandström Durling M, Karlsson M, Stenlid J. Distribution and evolution of het gene homologs in the basidiomycota. Fungal Genet Biol 2013; 64:45-57. [PMID: 24380733 DOI: 10.1016/j.fgb.2013.12.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 12/04/2013] [Accepted: 12/20/2013] [Indexed: 12/24/2022]
Abstract
In filamentous fungi a system known as somatic incompatibility (SI) governs self/non-self recognition. SI is controlled by a regulatory signaling network involving proteins encoded at the het (heterokaryon incompatible) loci. Despite the wide occurrence of SI, the molecular identity and structure of only a small number of het genes and their products have been characterized in the model fungi Neurospora crassa and Podospora anserina. Our aim was to identify and study the distribution and evolution of putative het gene homologs in the Basidiomycota. For this purpose we used the information available for the model fungi to identify homologs of het genes in other fungi, especially the Basidiomycota. Putative het-c, het-c2 and un-24 homologs, as well as sequences containing the NACHT, HET or WD40 domains present in the het-e, het-r, het-6 and het-d genes were identified in certain members of the Ascomycota and Basidiomycota. The widespread phylogenetic distribution of certain het genes may reflect the fact that the encoded proteins are involved in fundamental cellular processes other than SI. Although homologs of het-S were previously known only from the Sordariomycetes (Ascomycota), we also identified a putative homolog of this gene in Gymnopus luxurians (Basidiomycota, class Agaricomycetes). Furthermore, with the exception of un-24, all of the putative het genes identified occurred mostly in a multi-copy fashion, some with lineage and species-specific expansions. Overall our results indicated that gene duplication followed by gene loss and/or gene family expansion, as well as multiple events of domain fusion and shuffling played an important role in the evolution of het gene homologs of Basidiomycota and other filamentous fungi.
Collapse
Affiliation(s)
- M A Van der Nest
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden.
| | - A Olson
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
| | - M Lind
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
| | - H Vélëz
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
| | - K Dalman
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
| | - M Brandström Durling
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
| | - M Karlsson
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
| | - J Stenlid
- Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala SE-750 07, Sweden
| |
Collapse
|
17
|
Morris CE, Monteil CL, Berge O. The life history of Pseudomonas syringae: linking agriculture to earth system processes. ANNUAL REVIEW OF PHYTOPATHOLOGY 2013; 51:85-104. [PMID: 23663005 DOI: 10.1146/annurev-phyto-082712-102402] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The description of the ecology of Pseudomonas syringae is moving away from that of a ubiquitous epiphytic plant pathogen to one of a multifaceted bacterium sans frontières in fresh water and other ecosystems linked to the water cycle. Discovery of the aquatic facet of its ecology has led to a vision of its life history that integrates spatial and temporal scales spanning billions of years and traversing catchment basins, continents, and the planet and that confronts the implication of roles that are potentially conflicting for agriculture (as a plant pathogen and as an actor in processes leading to rain and snowfall). This new ecological perspective has also yielded insight into epidemiological phenomena linked to disease emergence. Overall, it sets the stage for the integration of more comprehensive contexts of ecology and evolutionary history into comparative genomic analyses to elucidate how P. syringae subverts the attack and defense responses of the cohabitants of the diverse environments it occupies.
Collapse
Affiliation(s)
- Cindy E Morris
- INRA, UR0407 Pathologie Végétale, 84143 Montfavet Cedex, France.
| | | | | |
Collapse
|
18
|
Zhang D, de Souza RF, Anantharaman V, Iyer LM, Aravind L. Polymorphic toxin systems: Comprehensive characterization of trafficking modes, processing, mechanisms of action, immunity and ecology using comparative genomics. Biol Direct 2012; 7:18. [PMID: 22731697 PMCID: PMC3482391 DOI: 10.1186/1745-6150-7-18] [Citation(s) in RCA: 358] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 05/31/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Proteinaceous toxins are observed across all levels of inter-organismal and intra-genomic conflicts. These include recently discovered prokaryotic polymorphic toxin systems implicated in intra-specific conflicts. They are characterized by a remarkable diversity of C-terminal toxin domains generated by recombination with standalone toxin-coding cassettes. Prior analysis revealed a striking diversity of nuclease and deaminase domains among the toxin modules. We systematically investigated polymorphic toxin systems using comparative genomics, sequence and structure analysis. RESULTS Polymorphic toxin systems are distributed across all major bacterial lineages and are delivered by at least eight distinct secretory systems. In addition to type-II, these include type-V, VI, VII (ESX), and the poorly characterized "Photorhabdus virulence cassettes (PVC)", PrsW-dependent and MuF phage-capsid-like systems. We present evidence that trafficking of these toxins is often accompanied by autoproteolytic processing catalyzed by HINT, ZU5, PrsW, caspase-like, papain-like, and a novel metallopeptidase associated with the PVC system. We identified over 150 distinct toxin domains in these systems. These span an extraordinary catalytic spectrum to include 23 distinct clades of peptidases, numerous previously unrecognized versions of nucleases and deaminases, ADP-ribosyltransferases, ADP ribosyl cyclases, RelA/SpoT-like nucleotidyltransferases, glycosyltranferases and other enzymes predicted to modify lipids and carbohydrates, and a pore-forming toxin domain. Several of these toxin domains are shared with host-directed effectors of pathogenic bacteria. Over 90 families of immunity proteins might neutralize anywhere between a single to at least 27 distinct types of toxin domains. In some organisms multiple tandem immunity genes or immunity protein domains are organized into polyimmunity loci or polyimmunity proteins. Gene-neighborhood-analysis of polymorphic toxin systems predicts the presence of novel trafficking-related components, and also the organizational logic that allows toxin diversification through recombination. Domain architecture and protein-length analysis revealed that these toxins might be deployed as secreted factors, through directed injection, or via inter-cellular contact facilitated by filamentous structures formed by RHS/YD, filamentous hemagglutinin and other repeats. Phyletic pattern and life-style analysis indicate that polymorphic toxins and polyimmunity loci participate in cooperative behavior and facultative 'cheating' in several ecosystems such as the human oral cavity and soil. Multiple domains from these systems have also been repeatedly transferred to eukaryotes and their viruses, such as the nucleo-cytoplasmic large DNA viruses. CONCLUSIONS Along with a comprehensive inventory of toxins and immunity proteins, we present several testable predictions regarding active sites and catalytic mechanisms of toxins, their processing and trafficking and their role in intra-specific and inter-specific interactions between bacteria. These systems provide insights regarding the emergence of key systems at different points in eukaryotic evolution, such as ADP ribosylation, interaction of myosin VI with cargo proteins, mediation of apoptosis, hyphal heteroincompatibility, hedgehog signaling, arthropod toxins, cell-cell interaction molecules like teneurins and different signaling messengers.
Collapse
Affiliation(s)
- Dapeng Zhang
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | | | | | | | | |
Collapse
|
19
|
Frey-Klett P, Burlinson P, Deveau A, Barret M, Tarkka M, Sarniguet A. Bacterial-fungal interactions: hyphens between agricultural, clinical, environmental, and food microbiologists. Microbiol Mol Biol Rev 2011; 75:583-609. [PMID: 22126995 PMCID: PMC3232736 DOI: 10.1128/mmbr.00020-11] [Citation(s) in RCA: 461] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Bacteria and fungi can form a range of physical associations that depend on various modes of molecular communication for their development and functioning. These bacterial-fungal interactions often result in changes to the pathogenicity or the nutritional influence of one or both partners toward plants or animals (including humans). They can also result in unique contributions to biogeochemical cycles and biotechnological processes. Thus, the interactions between bacteria and fungi are of central importance to numerous biological questions in agriculture, forestry, environmental science, food production, and medicine. Here we present a structured review of bacterial-fungal interactions, illustrated by examples sourced from many diverse scientific fields. We consider the general and specific properties of these interactions, providing a global perspective across this emerging multidisciplinary research area. We show that in many cases, parallels can be drawn between different scenarios in which bacterial-fungal interactions are important. Finally, we discuss how new avenues of investigation may enhance our ability to combat, manipulate, or exploit bacterial-fungal complexes for the economic and practical benefit of humanity as well as reshape our current understanding of bacterial and fungal ecology.
Collapse
Affiliation(s)
- P Frey-Klett
- INRA, UMR1136 Interactions Arbres-Microorganismes, 54280 Champenoux, France.
| | | | | | | | | | | |
Collapse
|
20
|
Records AR. The type VI secretion system: a multipurpose delivery system with a phage-like machinery. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:751-757. [PMID: 21361789 DOI: 10.1094/mpmi-11-10-0262] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Whether they live in the soil, drift in the ocean, survive in the lungs of human hosts or reside on the surfaces of leaves, all bacteria must cope with an array of environmental stressors. Bacteria have evolved an impressive suite of protein secretion systems that enable their survival in hostile environments and facilitate colonization of eukaryotic hosts. Collectively, gram-negative bacteria produce six distinct secretion systems that deliver proteins to the extracellular milieu or directly into the cytosol of host cells. The type VI secretion system (T6SS) was discovered recently and is encoded in at least one fourth of all sequenced gram-negative bacterial genomes. T6SS proteins are evolutionarily and structurally related to phage proteins, and it is likely that the T6SS apparatus is reminiscent of phage injection machinery. Most studies of T6SS function have been conducted in the context of host-pathogen interactions. However, the totality of data suggests that the T6SS is a versatile tool with roles in virulence, symbiosis, interbacterial interactions, and antipathogenesis. This review gives a brief history of T6SS discovery and an overview of the pathway's predicted structure and function. Special attention is paid to research addressing the T6SS of plant-associated bacteria, including pathogens, symbionts and plant growth-promoting rhizobacteria.
Collapse
Affiliation(s)
- Angela R Records
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA.
| |
Collapse
|
21
|
Fatal attraction: bacteria exploit fungal heterokaryon incompatibility to obtain nutrients. J Biosci 2010; 35:329-30. [PMID: 20826941 DOI: 10.1007/s12038-010-0037-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
22
|
Sensor kinases RetS and LadS regulate Pseudomonas syringae type VI secretion and virulence factors. J Bacteriol 2010; 192:3584-96. [PMID: 20472799 DOI: 10.1128/jb.00114-10] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas syringae pv. syringae B728a is a resident on leaves of common bean, where it utilizes several well-studied virulence factors, including secreted effectors and toxins, to develop a pathogenic interaction with its host. The B728a genome was recently sequenced, revealing the presence of 1,297 genes with unknown function. This study demonstrates that a 29.9-kb cluster of genes in the B728a genome shares homology to the novel type VI secretion system (T6SS) locus recently described for other gram-negative bacteria. Western blot analyses showed that B728a secretes Hcp, a T6SS protein, in culture and that this secretion is dependent on clpV, a gene that likely encodes an AAA(+) ATPase. In addition, we have identified two B728a sensor kinases that have homology to the P. aeruginosa proteins RetS and LadS. We demonstrate that B728a RetS and LadS reciprocally regulate the T6SS and collectively modulate several virulence-related activities. Quantitative PCR analyses indicated that RetS and LadS regulate genes associated with the type III secretion system and that LadS controls the expression of genes involved in the production of the exopolysaccharides alginate and levan. These analyses also revealed that LadS and the hybrid sensor kinase GacS positively regulate the expression of a putative novel exopolysaccharide called Psl. Plate assays demonstrated that RetS negatively controls mucoidy, while LadS negatively regulates swarming motility. A mutation in retS affected B728a population levels on the surfaces of bean leaves. A model for the LadS and RetS control of B728a virulence activities is proposed.
Collapse
|
23
|
Abstract
In fungi, cell fusion between genetically unlike individuals triggers a cell death reaction known as the incompatibility reaction. In Podospora anserina, the genes controlling this process belong to a gene family encoding STAND proteins with an N-terminal cell death effector domain, a central NACHT domain and a C-terminal WD-repeat domain. These incompatibility genes are extremely polymorphic, subject to positive Darwinian selection and display a remarkable genetic plasticity allowing for constant diversification of the WD-repeat domain responsible for recognition of non-self. Remarkably, the architecture of these proteins is related to pathogen-recognition receptors ensuring innate immunity in plants and animals. Here, we hypothesize that these P. anserina incompatibility genes could be components of a yet-unidentified innate immune system of fungi. As already proposed in the case of plant hybrid necrosis or graft rejection in mammals, incompatibility could be a by-product of pathogen-driven divergence in host defense genes.
Collapse
Affiliation(s)
- Mathieu Paoletti
- Laboratoire de Génétique Moléculaire des Champignons, Institut de Biochimie et de Génétique Cellulaires, UMR 5095 CNRS-Université de Bordeaux 2, 1 rue Camille St Saëns, 33077 Bordeaux Cedex, France
| | | |
Collapse
|
24
|
Tarkka MT, Sarniguet A, Frey-Klett P. Inter-kingdom encounters: recent advances in molecular bacterium-fungus interactions. Curr Genet 2009; 55:233-43. [PMID: 19337734 DOI: 10.1007/s00294-009-0241-2] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 03/04/2009] [Accepted: 03/16/2009] [Indexed: 01/20/2023]
Abstract
Interactions between bacteria and fungi are well known, but it is often underestimated how intimate and decisive such associations can be with respect to behaviour and survival of each participating organism. In this article we review recent advances in molecular bacterium-fungus interactions, combining the data of different model systems. Emphasis is given to the positive or negative consequences these interactions have on the microbe accommodating plants and animals. Intricate mechanisms of antagonism and tolerance have emerged, being as important for the biological control of plants against fungal diseases as for the human body against fungal infections. Bacterial growth promoters of fungal mycelium have been characterized, and these may as well assist plant-fungus mutualism as disease development in animals. Some of the toxins that have been previously associated with fungi are actually produced by endobacteria, and the mechanisms that lie behind the maintenance of such exquisite endosymbioses are fascinating. Bacteria do cause diseases in fungi, and a synergistic action between bacterial toxins and extracellular enzymes is the hallmark of such diseases. The molecular study of bacterium-fungus associations has expanded our view on microbial communication, and this promising field shows now great potentials in medicinal, agricultural and biotechnological applications.
Collapse
Affiliation(s)
- Mika T Tarkka
- UFZ, Department of Soil Ecology, Helmholtz Centre for Environmental Research, Halle, Germany.
| | | | | |
Collapse
|
25
|
Aanen DK, Debets AJM, de Visser JAGM, Hoekstra RF. The social evolution of somatic fusion. Bioessays 2008; 30:1193-203. [PMID: 18937373 DOI: 10.1002/bies.20840] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The widespread potential for somatic fusion among different conspecific multicellular individuals suggests that such fusion is adaptive. However, because recognition of non-kin (allorecognition) usually leads to a rejection response, successful somatic fusion is limited to close kin. This is consistent with kin-selection theory, which predicts that the potential cost of fusion and the potential for somatic parasitism decrease with increasing relatedness. Paradoxically, however, Crozier found that, in the short term, positive-frequency-dependent selection eliminates the required genetic polymorphism at allorecognition loci. The 'Crozier paradox' may be solved if allorecognition is based on extrinsically balanced polymorphisms, for example at immune loci. Alternatively, the assumption of most models that self fusion is mutually beneficial is wrong. If fusion is on average harmful, selection will promote unconditional rejection. However, we propose that fusion within individuals is beneficial, selecting for the ability to fuse, but fusion between individuals on average costly, selecting for non-self recognition (rather than non-kin recognition). We discuss experimental data on fungi that are consistent with this hypothesis.
Collapse
Affiliation(s)
- Duur K Aanen
- Plant Sciences, Laboratory of genetics, Wageningen University, Netherlands.
| | | | | | | |
Collapse
|
26
|
van Diepeningen AD, Pál K, van der Lee TAJ, Hoekstra RF, Debets AJM. The het-c heterokaryon incompatibility gene in Aspergillus niger. ACTA ACUST UNITED AC 2008; 113:222-9. [PMID: 19015029 DOI: 10.1016/j.mycres.2008.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Revised: 09/22/2008] [Accepted: 10/13/2008] [Indexed: 11/15/2022]
Abstract
Heterokaryon incompatibility among Aspergillus niger strains is a widespread phenomenon that is observed as the inability to form stable heterokaryons. The genetic basis of heterokaryon incompatibility reactions is well established in some sexual filamentous fungi but largely unknown in presumed asexual species, such as A. niger. To test whether the genes that determine heterokaryon incompatibility in Neurospora crassa, such as het-c, vib-1 and pin-c, have a similar function in A. niger, we performed a short in silico search for homologues of these genes in the A. niger and several related genomes. For het-c, pin-c and vib-1 we did indeed identify putative orthologues. We then screened a genetically diverse worldwide collection of incompatible black Aspergilli for polymorphisms in the het-c orthologue. No size variation was observed in the variable het-c indel region that determines the specificity in N. crassa. Sequence comparison showed only minor variation in the number of glutamine coding triplets. However, introduction of one of the three N. crassa alleles (het-c2) in A. niger by transformation resulted in an abortive phenotype, reminiscent of the heterokaryon incompatibility in N. crassa. We conclude that although the genes required are present and the het-c homologue could potentially function as a heterokaryon incompatibility gene, het-c has no direct function in heterokaryon incompatibility in A. niger because the necessary allelic variation is absent.
Collapse
Affiliation(s)
- Anne D van Diepeningen
- Laboratory of Genetics, Department of Plant Sciences, Wageningen University, Arboretumlaan 4, 6703 BD Wageningen, The Netherlands.
| | | | | | | | | |
Collapse
|