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Moallem M, Hamidizade M, Taghavi SM, Aeini M, Abachi H, Haghighi S, Soleimani A, Hockett K, Bull CT, Osdaghi E. Rarity of Pseudomonas agarici on Edible Mushrooms Associated with Susceptibility to Biological Competition. Plant Dis 2024. [PMID: 38679595 DOI: 10.1094/pdis-02-24-0374-re] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
Taxonomically diverse Pseudomonas species induce bacterial blotch of edible mushrooms around the world. Pseudomonas tolaasii, [Pseudomonas gingeri], and Pseudomonas agarici are dominant mycopathogenic pseudomonads in mushroom production farms. In this study, among 216 mycopathogenic bacterial strains isolated from edible mushrooms in Iran, 96 strains were identified as Pseudomonas spp., while only three strains were preliminarily identified as P. agarici. Multilocus sequence analysis showed that only one strain (FH2) authentically belonged to P. agarici, while the other two strains either belonged to [P. gingeri] or represented a unique phylogenetic clade. The three strains also differed from each other in phenotypic characteristics e.g., production of fluorescent pigment and the reaction to tolaasin produced by P. tolaasii. Pathogenicity assays under controlled environment showed that the symptoms induced by authentic P. agarici were far less severe than those caused by the predominant species P. tolaasii. Furthermore, co-inoculation of P. agarici with three bacterial pathogens that are prevalent in Iran on mushroom caps i.e., P. tolaasii, Ewingella americana and Mycetocola sp. resulted in the development of combined symptoms representing characteristics of both pathogens. Antibiosis assay showed that tolaasin-producing strains of P. tolaasii could inhibit the growth of P. agarici, while tolaasin-negative strains of the same species were unable to do so. This led us to the hypothesis that the inhibitory effect of P. tolaasii on P. agarici is driven by tolaasin production in the former species. This inhibitory effect also associated with the rarity of P. agarici in natural conditions.
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Affiliation(s)
- Mahsa Moallem
- university of tehranKaraj, Iran (the Islamic Republic of), 0;
| | | | - Seied Mohsen Taghavi
- shiraz university, plant protection, shiraz, Shiraz, Iran, Islamic Republic of, 6661874956;
| | - Milad Aeini
- University of Shiraz, Plant protection, Shahid chamran university of Ahvaz, Ahvaz, Iran, Islamic Republic of, 123456;
| | - Hamid Abachi
- University of Tehran, 48425, Plant Protection, karaj, karaj, karaj, Iran (the Islamic Republic of), 3158777871;
| | - Shahrad Haghighi
- Shiraz University of Applied Sciences and Technology, Ghasroddasht Shiraz, Shiraz, Iran (the Islamic Republic of), 7194893666;
| | - Ardavan Soleimani
- University of Tehran University College of Agriculture and Natural Resources, 48424, plant pathology, University of Tehran University College of Agriculture and Natural Resources, Karaj, Iran., Masiri, Fars, Iran (the Islamic Republic of), 7357119513;
| | - Kevin Hockett
- Pennsylvania State University, 8082, Plant Pathology and Environmental Microbiology, 316 Buckhout Lab, University Park, Pennsylvania, United States, 16802-1503;
| | - Carolee Theresa Bull
- Pennsylvania State University, 8082, Plant Pathology and Environmental Microbiology, 211 Buckhout Laboratory, University Park, PA, 16802, University Park, Pennsylvania, United States, 16802-1503;
| | - Ebrahim Osdaghi
- University of Tehran, 48425, Department of Plant Protection, University of Tehran, Tehran, Iran (the Islamic Republic of), 31587-77871;
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Hamidizade M, Taghavi SM, Soleimani A, Bouazar M, Abachi H, Portier P, Osdaghi E. Wild mushrooms as potential reservoirs of plant pathogenic bacteria: a case study on Burkholderia gladioli. Microbiol Spectr 2024; 12:e0339523. [PMID: 38380912 PMCID: PMC10986547 DOI: 10.1128/spectrum.03395-23] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 01/18/2024] [Indexed: 02/22/2024] Open
Abstract
Fruit bodies (sporocarps) of wild mushrooms growing in natural environments play a substantial role in the preservation of microbial communities, for example, clinical and food-poisoning bacteria. However, the role of wild mushrooms as natural reservoirs of plant pathogenic bacteria remains almost entirely unknown. Furthermore, bacterial transmission from a mushroom species to agricultural plants has rarely been recorded in the literature. In September 2021, a creamy-white Gram-negative bacterial strain was isolated from the sporocarp of Suillus luteus (slippery jack) growing in Bermuda grass (Cynodon dactylon) lawn in Southern Iran. A similar strain was isolated from the same fungus in the same area in September 2022. Both strains were identified as Burkholderia gladioli based on phenotypic features as well as phylogeny of 16S rRNA and three housekeeping genes. The strains were not only pathogenic on white button mushrooms (Agaricus bisporus) but also induced hypersensitive reaction (HR) on tobacco and common bean leaves and caused soft rot on a set of diverse plant species, that is, chili pepper, common bean pod, cucumber, eggplant, garlic, gladiolus, narcissus, onion, potato, spring onion, okra, kohlrabi, mango, and watermelon. Isolation of plant pathogenic B. gladioli strains from sporocarp of S. luteus in two consecutive years in the same area could be indicative of the role of this fungus in the preservation of the bacterium in the natural environment. B. gladioli associated with naturally growing S. luteus could potentially invade neighboring agricultural crops, for example, vegetables and ornamentals. The potential role of wild mushrooms as natural reservoirs of phytopathogenic bacteria is further discussed.IMPORTANCEThe bacterial genus Burkholderia contains biologically heterogeneous strains that can be isolated from diverse habitats, that is, soil, water, diseased plant material, and clinical specimens. In this study, two Gram-negative pectinolytic bacterial strains were isolated from the sporocarps of Suillus luteus in September 2021 and 2022. Molecular phylogenetic analyses revealed that both strains belonged to the complex species Burkholderia gladioli, while the pathovar status of the strains remained undetermined. Biological investigations accomplished with pathogenicity and host range assays showed that B. gladioli strains isolated from S. luteus in two consecutive years were pathogenic on a set of diverse plant species ranging from ornamentals to both monocotyledonous and dicotyledonous vegetables. Thus, B. gladioli could be considered an infectious pathogen capable of being transmitted from wild mushrooms to annual crops. Our results raise a hypothesis that wild mushrooms could be considered as potential reservoirs for phytopathogenic B. gladioli.
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Affiliation(s)
- Mozhde Hamidizade
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz, Iran
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj, Iran
| | - S. Mohsen Taghavi
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz, Iran
| | - Ardavan Soleimani
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj, Iran
| | - Mohammad Bouazar
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz, Iran
| | - Hamid Abachi
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj, Iran
| | - Perrine Portier
- Univ Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, CIRM-CFBP, Angers, France
| | - Ebrahim Osdaghi
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj, Iran
- Center for International Scientific Studies and Collaborations (CISSC) of Iran, Tehran, Iran
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Abachi H, Moallem M, Taghavi SM, Hamidizade M, Soleimani A, Fazliarab A, Portier P, Osdaghi E. Garlic Bulb Decay and Soft Rot Caused by the Cross-Kingdom Pathogen Burkholderia gladioli. Plant Dis 2024; 108:684-693. [PMID: 37775924 DOI: 10.1094/pdis-08-23-1603-re] [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] [Indexed: 10/01/2023]
Abstract
In 2021, two gram-negative bacterial strains were isolated from garlic (Allium sativum) bulbs showing decay and soft rot symptoms in Central Iran. The bacterial strains were aggressively pathogenic on cactus, garlic, gladiolus, onion, potato, and saffron plants and induced soft rot symptoms on carrot, cucumber, potato, and radish discs. Furthermore, they were pathogenic on sporophores of cultivated and wild mushrooms. Phylogenetic analyses revealed that the bacterial strains belong to Burkholderia gladioli. Garlic bulb rot caused by B. gladioli has rarely been reported in the literature. Historically, B. gladioli strains had been assigned to four pathovars, namely, B. gladioli pv. alliicola, B. gladioli pv. gladioli, B. gladioli pv. agaricicola, and B. gladioli pv. cocovenenans, infecting onion, Gladiolus sp., and mushrooms and poisoning foods, respectively. Multilocus (i.e., 16S rRNA, atpD, gyrB, and lepA genes) sequence-based phylogenetic investigations including reference strains of B. gladioli pathovars showed that the two garlic strains belong to phylogenomic clade 2 of the species, which includes the pathotype strain of B. gladioli pv. alliicola. Although the garlic strains were phylogenetically closely related to the B. gladioli pv. alliicola reference strains, they possessed pathogenicity characteristics that overlapped with three of the four historical pathovars, including the ability to rot onion (pv. alliicola), gladiolus (pv. gladioli), and mushrooms (pv. agaricicola). Furthermore, the pathotype of each pathovar could infect the hosts of other pathovars, undermining the utility of the pathovar concept in this species. Overall, using phenotypic pathovar-oriented assays to classify B. gladioli strains should be replaced by phylogenetic or phylogenomic analysis.
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Affiliation(s)
- Hamid Abachi
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj 31587-77871, Iran
| | - Mahsa Moallem
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj 31587-77871, Iran
| | - S Mohsen Taghavi
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Mozhde Hamidizade
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj 31587-77871, Iran
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Ardavan Soleimani
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj 31587-77871, Iran
| | - Amal Fazliarab
- Iranian Sugarcane Research and Training Institute (ISCRTI), Ahvaz, Khuzestan, Iran
| | - Perrine Portier
- University of Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, CIRM-CFBP, F-49000 Angers, France
| | - Ebrahim Osdaghi
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj 31587-77871, Iran
- Center for International Scientific Studies and Collaborations (CISSC), Tehran, Iran
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Osdaghi E, Taghavi SM, Hamidizade M, Kariminejhad M, Fazliarab A, Hajian Maleki H, Baeyen S, Taghouti G, Jacques MA, Van Vaerenbergh J, Portier P. Multiphasic investigations imply transfer of orange-/red-pigmented strains of the bean pathogen Curtobacterium flaccumfaciens pv. flaccumfaciens to a new species as C. aurantiacum sp. nov., elevation of the poinsettia pathogen C. flaccumfaciens pv. poinsettiae to the species level as C. Poinsettiae sp. nov., and synonymy of C. albidum with C. citreum. Syst Appl Microbiol 2024; 47:126489. [PMID: 38325043 DOI: 10.1016/j.syapm.2024.126489] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 01/17/2024] [Accepted: 01/23/2024] [Indexed: 02/09/2024]
Abstract
Curtobacterium flaccumfaciens (Microbacteriaceae), a plant-pathogenic coryneform species includes five pathovars with valid names and a number of proposed - but unvalidated - new members. In this study, phenotypic features and DNA similarity indexes were investigated among all C. flaccumfaciens members. Results showed that the C. flaccumfaciens pv. poinsettiae strains causing bacterial canker of Euphorbia pulcherrima in the USA as well as the orange-/red-pigmented strains of C. flaccumfaciens pv. flaccumfaciens pathogenic on dry beans in Iran are too distinct from each other and from the type strain of the species to be considered members of C. flaccumfaciens. Hence, the latter two groups were elevated at the species level as C. poinsettiae sp. nov. (ATCC 9682T = CFBP 2403T = ICMP 2566T = LMG 3715T = NCPPB 854T as type strain), and C. aurantiacum sp. nov. (50RT = CFBP 8819T = ICMP 22071T as type strain). Within the emended species C. flaccumfaciens comb. nov., yellow-pigmented strains causing bacterial wilt of dry beans and those causing bacterial canker of Euphorbia pulcherrima in Europe were retained as C. flaccumfaciens pv. flaccumfaciens and C. flaccumfaciens pv. poinsettiae, respectively; while taxonomic position of the sugar beet pathogen C. flaccumfaciens pv. beticola ATCC BAA144PT was confirmed. The newly described onion pathogen C. allii was also reclassified as C. flaccumfaciens pv. allii with the pathotype strain LMG 32517PT. Furthermore, C. flaccumfaciens pv. basellae causing bacterial leaf spot of malabar spinach (Basella rubra) was transferred to C. citreum pv. basellae with ATCC BAA143PT as pathotype.
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Affiliation(s)
- Ebrahim Osdaghi
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj 31587-77871, Iran.
| | - S Mohsen Taghavi
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Mozhde Hamidizade
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj 31587-77871, Iran; Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Mehdi Kariminejhad
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj 31587-77871, Iran
| | - Amal Fazliarab
- Iranian Sugarcane Research and Training Institute (ISCRTI), Ahvaz, Khuzestan, Iran
| | - Habibeh Hajian Maleki
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj 31587-77871, Iran
| | - Steve Baeyen
- Flanders' Research Institute for Agriculture, Fisheries and Food (ILVO), Unit Plant Sciences, EU Reference Laboratory for Plant Health - on bacteria, Burgemeester van Gansberghelaan 96, 9820 Merelbeke, Belgium
| | - Geraldine Taghouti
- Univ Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, CIRM-CFBP, F-49000 Angers, France
| | - Marie-Agnes Jacques
- Univ Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, CIRM-CFBP, F-49000 Angers, France
| | - Johan Van Vaerenbergh
- Flanders' Research Institute for Agriculture, Fisheries and Food (ILVO), Unit Plant Sciences, EU Reference Laboratory for Plant Health - on bacteria, Burgemeester van Gansberghelaan 96, 9820 Merelbeke, Belgium
| | - Perrine Portier
- Univ Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, CIRM-CFBP, F-49000 Angers, France.
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Osdaghi E, Taghavi SM, Hamidizade M, Fazliarab A, Hajian Maleki H, Li X, Jacques MA, Portier P. Clavibacter lycopersici sp. nov.: a peach-colored actinobacterium isolated from symptomless tomato plant. Int J Syst Evol Microbiol 2023; 73. [PMID: 37737062 DOI: 10.1099/ijsem.0.006022] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/23/2023] Open
Abstract
In 2015, Gram-positive peach-coloured actinobacterial strains were isolated from symptomless tomato phyllosphere in Iran. Biochemical and physiological characteristics, as well as 16S rRNA phylogeny showed that the strains belong to Clavibacter sp., while they were non-pathogenic on the host of isolation, and morphologically distinct from the tomato pathogen C. michiganensis and other plant-associated bacteria. Multilocus sequence analysis of five housekeeping genes showed that the two peach-coloured strains CFBP 8615T (Tom532T) and CFBP 8616 (Tom495) were phylogenetically distinct from all validly described Clavibacter species. Whole genome sequence-based indices, i.e. average nucleotide identity (orthoANI) and digital DNA-DNA hybridization (dDDH), showed that the two peach-colored strains share nearly 100 % orthoANI value with one another, while they differ from all validly described Clavibacter species with the orthoANI/dDDH values <93 % and <50 %, respectively. Thus, based on both phenotypic features and orthoANI/dDDH indices the peach-coloured strains could belong to a new species within Clavibacter. In this study, we provide a formal species description for the peach-coloured tomato-associated Clavibacter strains. Clavibacter lycopersici sp. nov. is proposed for the new species with Tom532T = CFBP 8615T = ICMP 22100T as type strain.
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Affiliation(s)
- Ebrahim Osdaghi
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj 31587-77871, Iran
| | - S Mohsen Taghavi
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Mozhde Hamidizade
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj 31587-77871, Iran
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Amal Fazliarab
- Iranian Sugarcane Research and Training Institute (ISCRTI), Ahvaz, Khuzestan, Iran
| | - Habibeh Hajian Maleki
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj 31587-77871, Iran
| | - Xiang Li
- Canadian Food Inspection Agency (CFIA), Charlottetown Laboratory, 93 Mount Edward Road, Charlottetown, PE C1A 5T1, Canada
| | - Marie-Agnes Jacques
- Univ Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, CIRM-CFBP, F-49000 Angers, France
| | - Perrine Portier
- Univ Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, CIRM-CFBP, F-49000 Angers, France
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Hamidizade M, Taghavi SM, Moallem M, Aeini M, Fazliarab A, Abachi H, Herschlag RA, Hockett KL, Bull CT, Osdaghi E. Ewingella americana: An Emerging Multifaceted Pathogen of Edible Mushrooms. Phytopathology 2023; 113:150-159. [PMID: 36131391 DOI: 10.1094/phyto-08-22-0299-r] [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] [Indexed: 06/15/2023]
Abstract
Mycopathogenic bacteria play a pivotal role in the productivity of edible mushrooms grown under controlled conditions. In this study, we carried out a comprehensive farm survey and sampling (2018 to 2021) on button mushroom (Agaricus bisporus) farms in 15 provinces in Iran to monitor the status of bacterial pathogens infecting the crop. Mycopathogenic bacterial strains were isolated from pins, stems, and caps, as well as the casing layer on 38 mushroom farms. The bacterial strains incited symptoms on mushroom caps ranging from faint discoloration to dark brown and blotch of the inoculated surfaces. Among the bacterial strains inciting disease symptoms on bottom mushroom, 40 were identified as Ewingella americana based on biochemical assays and phylogeny of 16S rRNA and the gyrB gene. E. americana strains differed in their aggressiveness on mushroom caps and stipes, where the corresponding symptoms ranged from deep yellow to dark brown. In the phylogenetic analyses, all E. americana strains isolated in this study were clustered in a monophyletic clade closely related to the nonpathogenic and environmental strains of the species. BOX-PCR-based fingerprinting revealed intraspecific diversity. Using the cutoff level of 73 to 76% similarity, the strains formed six clusters. A chronological pattern was observed, where the strains isolated in 2018 were differentiated from those isolated in 2020 and 2021. Taken together, due to the multifaceted nature of the pathogen, such a widespread occurrence of E. americana on mushroom farms in Iran could be an emerging threat for the mushroom industry in the country.
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Affiliation(s)
- Mozhde Hamidizade
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz, Iran
| | - S Mohsen Taghavi
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz, Iran
| | - Mahsa Moallem
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj, Iran
- Department of Plant Protection, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Milad Aeini
- Department of Plant Protection, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Amal Fazliarab
- Iranian Sugarcane Research and Training Institute (ISCRTI), Ahvaz, Khuzestan, Iran
| | - Hamid Abachi
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj, Iran
| | - Rachel A Herschlag
- 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
| | - Ebrahim Osdaghi
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj, Iran
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Hamidizade M, Taghavi SM, Mafakheri H, Herschlag RA, Martins SJ, Hockett KL, Bull CT, Osdaghi E. First Report of Brown Spot on White Button Mushroom ( Agaricus bisporus) Caused by Cedecea neteri in Iran. Plant Dis 2022; 106:1291. [PMID: 34597152 DOI: 10.1094/pdis-06-21-1305-pdn] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Affiliation(s)
- Mozhde Hamidizade
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - S Mohsen Taghavi
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Hamzeh Mafakheri
- Department of Plant Protection, School of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Rachel A Herschlag
- Plant Pathology & Environmental Microbiology Department, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Samuel J Martins
- 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
| | - Ebrahim Osdaghi
- Department of Plant Protection, College of Agriculture, University of Tehran, Karaj 31587-77871, Iran
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Hamidizade M, Taghavi SM, Martins SJ, Herschlag RA, Hockett KL, Bull CT, Osdaghi E. Bacterial Brown Pit, a New Disease of Edible Mushrooms Caused by Mycetocola sp. Plant Dis 2020; 104:1445-1454. [PMID: 32181723 DOI: 10.1094/pdis-10-19-2176-re] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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: 06/10/2023]
Abstract
From September to December 2018, commercial button mushroom (Agaricus bisporus) farms in central Iran were surveyed to monitor the causal agent(s) of browning and blotch symptoms on mushroom caps. In addition to dozens of pseudomonads (i.e., Pseudomonas tolaasii and Pseudomonas reactans), six slow-growing gram-positive bacterial strains were isolated from blotched mushroom caps. These bacteria presented as creamy white, circular, smooth, nonfluorescent, and shiny colonies with whole margins resembling members of Microbacteriaceae (Actinobacteria). All of the actinobacterial strains were aggressively pathogenic on cut cap surface of two edible mushrooms (i.e., A. bisporus and Pleurotus eryngii), inducing brown pit symptoms 48 h postinoculation. The strains did not induce symptoms on the vegetables tested (i.e., carrot, cucumber, and potato), and they did not affect the growth of mycelium of tested plant-pathogenic fungi (i.e., Acremonium sp., Fusarium spp., and Phytopythium sp.). Phylogeny of 16S ribosomal RNA and multilocus sequence analysis of six housekeeping genes (i.e., atpD, dnaK, gyrB, ppK, recA, and rpoB) revealed that the bacterial strains belong to the actinobacterial genus Mycetocola spp., whereas the species status of the strains remains undetermined. Mushroom-associated Mycetocola species were previously reported to be capable of detoxifying tolaasin, a toxin produced by P. tolaasii, whereas the strains isolated in this study did not show tolaasin detoxification activities. Altogether, this is the first report of a mushroom disease caused by an actinobacterial species, and "bacterial brown pit" was assigned as the common name of the disease.
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Affiliation(s)
- Mozhde Hamidizade
- Department of Plant Protection, College of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - S Mohsen Taghavi
- 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
| | - Rachel A Herschlag
- 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
| | - Ebrahim Osdaghi
- Department of Plant Protection, College of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
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Ansari M, Taghavi SM, Zarei S, Mehrb-Moghadam S, Mafakheri H, Hamidizade M, Osdaghi E. Phenotypically and Genotypically Heterogeneous Strains of Pseudomonas syringae Associated With Alfalfa Leaf Spot Disease in Iran. Plant Dis 2019; 103:3199-3208. [PMID: 31642735 DOI: 10.1094/pdis-06-19-1153-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [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: 06/10/2023]
Abstract
In this study, we provide a polyphasic characterization of 18 Pseudomonas spp. strains associated with alfalfa leaf spot symptoms in Iran. All of the strains were pathogenic on alfalfa, although the aggressiveness and symptomology varied among the strains. All strains but one were pathogenic on broad bean, cucumber, honeydew, and zucchini, whereas only a fraction of the strains were pathogenic on sugar beet, tomato, and wheat. Syringomycin biosynthesis genes (syrB1 and syrP) were detected using the corresponding PCR primers in all of the strains isolated from alfalfa. Phylogenetic analyses using the sequences of four housekeeping genes (gapA, gltA, gyrB, and rpoD) revealed that all of the strains except one (Als34) belong to phylogroup 2b of P. syringae sensu lato, whereas strain Als34 placed within phylogroup 1 close to the type strain of P. syringae pv. apii. Among the phylogroup 2b strains, nine strains were phylogenetically close to the P. syringae pv. aptata clade, whereas the remainder were scattered among P. syringae pv. atrofaciens and P. syringae pv. syringae strains. Pathogenicity and host range assays of the bacterial strains evaluated in this study on a set of taxonomically diverse plant species did not allow us to assign a "pathovar" status to the alfalfa strains. However, these results provide novel insight into the host range and phylogenetic position of the alfalfa-pathogenic members of P. syringae sensu lato, and they reveal that phenotypically and genotypically heterogeneous strains of the pathogen cause bacterial leaf spot of alfalfa.
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Affiliation(s)
- Maryam Ansari
- Department of Plant Protection, College of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - S Mohsen Taghavi
- Department of Plant Protection, College of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Sadegh Zarei
- Department of Plant Protection, College of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Soraya Mehrb-Moghadam
- Department of Plant Protection, College of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Hamzeh Mafakheri
- Department of Plant Protection, College of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Mozhde Hamidizade
- Department of Plant Protection, College of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
| | - Ebrahim Osdaghi
- Department of Plant Protection, College of Agriculture, Shiraz University, Shiraz 71441-65186, Iran
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