Relevant bibliographies by topics / Microbial antagonists

Academic literature on the topic 'Microbial antagonists'

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Published: 18 May 2024

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Journal articles on the topic "Microbial antagonists"

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Trisawa, I. M., Dyah Manohara, Deciyanto Soetopo, and Siswanto. "In vitro antagonistic activity of soil microbes isolated from oil palm to Ganoderma zonatum." IOP Conference Series: Earth and Environmental Science 974, no. 1 (January 1, 2022): 012052. http://dx.doi.org/10.1088/1755-1315/974/1/012052.

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Abstract Ganoderma zonatum is the causal agent of basal stem rot of oil palm (Elaeis guineensis Jacq) in Riau. The research objective was to explore and select soil microbial antagonists to Ganoderma zonatum. Soil samples were taken from the non/rhizosphere of 27 oil palm plants in Kampar and Siak Regency, Riau Province, Indonesia, in 2018-2019. The soil microbes were grown on Potatoes Dextrose Agar for fungus and Tryptic Soy Agar for the bacterium. The antagonist was measured by a dual culture method. The colony diameter of G. zonatum the (dual) culture was measured to assess the inhibition potency of the potential microbial antagonists. The soil microbial collected was 138 isolates, including 58 of Trichoderma spp. and 80 of bacteria. The inhibition against the isolated soil microbes to G. zonatum growth ranged from 46-74% for Trichoderma spp. and 0-86% for the bacterium. Seven isolates of Trichoderma spp and 13 of bacterial inhibited G. zonatum growth >70%, have potential as biocontrol agents. Two isolates that showed the most potential as antagonists, i.e Trichoderma harzianum (AC2, rhizosphere) and Burkholderia gladioli (N1, non-rhizosphere) could be developed for further as microbial antagonists.
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Kurdish, I. K. "PROSPECTS FOR MICROBIAL ANTAGONISTS USE IN PROTECTION OF AGROECOSYSTEMS FROM PHYTOPATHOGENES." Agriciltural microbiology 13 (August 19, 2011): 23–41. http://dx.doi.org/10.35868/1997-3004.13.23-41.

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Thepapercoverstheanalysisoftherelationshipofmicroorganisms – antagonists and pathogens in agroecosystems which is an important factor of plant diseases prevalence control. Among the studied microorganisms the most important antagonist of phytopathogenic bacteria and fungi in agricoenosis were the representatives of the genera Pseudomonas, Bacillus, Trichoderma, Chaetomium and some other microorganisms. Several studied strains-antagonists were selected as the basis or as the perspective ones for the production of microbial preparations for pathogens control in agroecosystems and improvement of plants productivity.
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HAYASHI, KENICHI, MOTOAKI NISHIKAWA, ICHIRO ARAMORI, SUMIO KIYOTO, and MASAKUNI OKUHARA. "Tachykinin Antagonists Screening from Microbial Origin." Journal of Antibiotics 49, no. 1 (1996): 110–12. http://dx.doi.org/10.7164/antibiotics.49.110.

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Almuslimawi, Alaa, Borbála Kuchár, Susana Navas, György Turóczi, and Katalin Posta. "The Effect of Combined Application of Biocontrol Microorganisms and Arbuscular Mycorrhizal Fungi on Plant Growth and Yield of Tomato (Solanum lycopersicum L.)." Agriculture 14, no. 5 (May 16, 2024): 768. http://dx.doi.org/10.3390/agriculture14050768.

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Sustainable plant production requires less use of synthetic chemicals in plant nutrition and protection. Microbial products are among the most promising substitutes for chemicals. With the increasing popularity and availability of such products, it has become obligatory to use different microbes together. The effect of this has been tested in several studies, but their results have sometimes been contradictory depending on the microbial strains tested and the mode of application. We tested the effect of two commercially available antagonists and Funneliformis mosseae alone and in combination on tomato. Mycorrhizal treatment increased plant growth and yield, both alone and combined with the antagonists; however, mycorrhizal root colonization was not influenced by the antagonist. This treatment also led to a slight decrease in the occurrence of Trichoderma spp. on tomato roots but did not impede the colonization of roots by the applied Trichoderma strain. Our result confirmed that Trichoderma asperellum (T34) and Streptomyces griseoviridis (K61) can be safely combined with arbuscular mycorrhizal fungi (AMF), namely with F. mosseae.
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Pusey, P. L., and E. A. Curry. "Temperature and Pomaceous Flower Age Related to Colonization by Erwinia amylovora and Antagonists." Phytopathology® 94, no. 8 (August 2004): 901–11. http://dx.doi.org/10.1094/phyto.2004.94.8.901.

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Fire blight of apple and pear is initiated by epiphytic populations of Erwinia amylovora on flower stigmas. Predicting this disease and managing it with microbial antagonists depends on an understanding of bacterial colonization on stigmas. Detached ‘Manchurian’ crab apple flowers were inoculated with E. amylovora and subjected to a range of constant temperatures or various fluctuating temperature regimes. Results may have application to disease risk assessment systems such as the Cougarblight model, which now are based on in vitro growth of the pathogen. In other experiments, detached crab apple flowers and attached ‘Gala’ apple flowers were maintained at different temperatures for various periods before inoculation with E. amylovora or antagonists (Pseudomonas fluorescens strain A506 and Pantoea agglomerans strains C9-1 and E325). Maximum stigma age supporting bacterial multiplication decreased as temperature increased, and was reduced by pollination. Stigmas were receptive to bacteria at ages older than previously reported, probably due to less interference from indigenous organisms. The study revealed antagonist limitations that possibly affect field performance (e.g., the inability of strain A506 to grow on relatively old stigmas conducive to the pathogen). Such deficiencies could be overcome by selecting other antagonists or using antagonist mixtures in the orchard.
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陈, 嘉敏. "Research Development of Microbial Antagonists against Plant Disease." Advances in Microbiology 06, no. 02 (2017): 35–43. http://dx.doi.org/10.12677/amb.2017.62005.

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Gálvez, Antonio, Hikmate Abriouel, Nabil Benomar, and Rosario Lucas. "Microbial antagonists to food-borne pathogens and biocontrol." Current Opinion in Biotechnology 21, no. 2 (April 2010): 142–48. http://dx.doi.org/10.1016/j.copbio.2010.01.005.

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Rohrlack, Thomas. "Low temperatures can promote cyanobacterial bloom formation by providing refuge from microbial antagonists." AIMS Microbiology 4, no. 2 (2018): 304–18. http://dx.doi.org/10.3934/microbiol.2018.2.304.

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BORA, POPY, and L. C. BORA. "Revisiting non-chemical modes of diseases and pests management in tea (Camellia sinensis): A review." Indian Journal of Agricultural Sciences 92, no. 1 (January 31, 2022): 3–9. http://dx.doi.org/10.56093/ijas.v92i1.120819.

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Tea [Camellia sinensis (L) O. Kuntze] like any other perennial plantation crop is subjected to loss in biomass yield and functional quality, once exposed to beyond economic thresholds of diseases and pests load. A battery of diseases and pests are reported to badly affect the tea industry of India. Microbial antagonists and botanicals emerged as two most vibrant via-media of addressing tea diseases and pests amongst non-chemical modes, in a manner, closest to residue free production system. Authors revisited the use of microbial antagonists and botanicals through comprehensive updated analysis of breakthroughs recorded in the success of microbial antagonists-and botanicals mediated diseases and pests management in tea. Our efforts also portrays the futuristic viewpoints in terms of developments of commercial formulations of botanicals using their bioactive compounds, consortium of bioagents and fortification of botanicals with bioagents through area wide field response studies in the back drop of growing demand of organic tea, the most pressing developmental issue of tea industry.
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Pajcin, Ivana, Vanja Vlajkov, Dragoljub Cvetkovic, Maja Ignjatov, Mila Grahovac, Damjan Vucurovic, and Jovana Grahovac. "Selection of antagonists for biocontrol of Xanthomonas euvesicatoria." Acta Periodica Technologica, no. 51 (2020): 181–89. http://dx.doi.org/10.2298/apt2051181p.

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Xanthomonas euvesicatoria is a worldwide causer of pepper bacterial spot, a bacterial plant disease responsible for massive losses of fresh pepper fruits. Considering the current problems in management of bacterial plant diseases, biological control using antagonistic microbial strains with high potential for plant pathogens suppression emerges as a possible solution. The aim of this study was to select suitable antagonists for suppression of X. euvesicatoria among the bacteria, yeast and fungi from the genera Pseudomonas, Lactobacillus, Saccharomyces and Trichoderma, based on in vitro antimicrobial activity testing using the diffusion disc method. The results of this study have revealed that cultivation broth samples of the antagonists Lactobacillus MK3 and Trichoderma reseii QM 9414, as well as supernatant samples of the antagonist Pseudomonas aeruginosa I128, have showed significant potential to be applied in biological control of X. euvesicatoria. Further research would be required to formulate suitable cultivation medium and optimize bioprocess conditions for production of the proposed pepper bacterial spot biocontrol agents.
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Dissertations / Theses on the topic "Microbial antagonists"

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Ghosh, Sankar. "Studies on post harvest diseases of tomato pineapple and orange and their control by microbial antagonists and botanicals." Thesis, University of North Bengal, 2010. http://hdl.handle.net/123456789/1417.

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Mendoza, Luna Alexander Rafael. "Interrelationships between microbial antagonists having divergent modes-of-action and their influence on biological control of plant-parasitic nematodes." Göttingen Cuvillier, 2008. http://d-nb.info/989139182/04.

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Hollywood, Jane Constance. "Biological control of late blight of potatoes : in vivo and in vitro evaluation of microbial antagonists against tuber blight." Thesis, University College London (University of London), 2004. http://discovery.ucl.ac.uk/1446592/.

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The cost of losses and control measures attributed to late blight of potatoes caused by Phytophthora infestans, are estimated to exceed $5 billion annually. Breeding for resistance is difficult owing to the tetraploid genotype of potato and current strains of the pathogen have developed resistance to chemical control. Consequently the search for biological control has assumed greater importance. In this investigation an in vivo bioassay was used to select soils antagonistic to late blight of potatoes, caused by Phytophthora infestans. Four out of eight samples demonstrated reproducible antagonism as determined by a reduction in the volume of tuber tissue rotted. A total of 292 bacterial and yeast samples and 20 fungal samples were recovered from suppressive soils using a variety of non-selective and selective media. When these organisms were tested individually against P. infestans in the assay, 15 isolates suppressed tuber rotting by >85% in at least three out of four assays. The antagonists were characterised as Pseudomonas spp. (3 strains), Enterobacter spp. (4 strains), Bacillus spp. (1 strain), Pantoea spp. (2 strains), Citrobacter spp. (1 strain), Buttiauxella spp. (1 strain), Trichosporon spp. (2 strains) and Geotrichum spp. (1 strain) by routine bacteriological tests, fatty acid profiling and partial sequencing of the gene encoding 16S or 18S (where appropriate) ribosomal RNA. Subsequently the possible mechanisms by which the potential biocontrol agents inhibited the disease were examined. Nine isolates showed some evidence of antibiotic production with a Pantoea spp. producing a compound that caused the hyphae of P. infestans to kink and permanently cease growth. Three isolates colonised hyphae of the pathogen and eleven produced siderophores in liquid culture. Hydrogen cyanide, proteolytic, cellulolytic and beta-1,3-glucanase activity was also evident in some species. Significant promotion of axenically grown tomato seedlings, as determined by increased stem and main root elongation, was achieved by ten of the isolates. Three population levels of the isolates were retested for disease inhibition at the end of the investigation. Isolates 3, 7 and 14 exhibited the highest levels of consistent inhibition at the lowest population levels and were therefore tested in combination. This achieved disease suppression that, at an antagonist concentration of 25 cfu/nL, was more consistent than isolate 3 alone and was over 30% greater than either isolate 7 or 14.
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Nascimento, Mariela Otoni do. "Interação entre fungos de solos e a formiga-cortadeira Atta sexdens (Linnaeus, 1758)." Universidade Federal do Tocantins, 2015. http://hdl.handle.net/11612/374.

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As formigas-cortadeiras (Hymenoptera: Formicidae), gêneros Atta e Acromyrmex, são as pragas mais importantes da silvicultura, encontradas exclusivamente nas Américas. Sua importância econômica se deve ao seu hábito alimentar de cortar material vegetal fresco – sendo algumas importantes espécies cultivadas - que serve de substrato para o fungo simbionte mutualista Leucoagaricus gongylophorus (Basidiomycota: Agaricales) o qual é cultivado em câmaras subterrâneas. As fêmeas fecundadas são responsáveis pela fundação de uma nova colônia e sofrem influência direta de microrganismos presentes no solo, assim existem evidências que fêmeas de Atta spp. recém-fecundadas evitam solos férteis, com alta carga microbiana e mesmo as áreas de matas para fundação dos seus ninhos. Os fungos entomopatogênicos e fungos antagonistas de L. gongylophorus, presentes naturalmente no solo, podem ser usados no controle biológico de formigas-cortadeiras. Os objetivos deste trabalho foram avaliar em laboratório o desenvolvendo de colônias jovens de Atta sexdens em contato com solos de área de mata e de área desnuda, realizar a bioprospecção de isolados de fungos antagonistas de L. gongylophorus (Trichoderma spp.), em solos da região de Gurupi - TO, e testar o efeito antagônico desses fungos contra L. gongylophorus. Após 106 dias da revoada, as operárias de A. sexdens das 36 colônias, logo que iniciado o experimento, removeram o solo em todos os tratamentos, e esse comportamento favoreceu a sobrevivência das colônias, apresentando uma taxa de sobrevivência de 91,67% durante as 13 semanas. Verificou-se que, após as colônias terem passado pelo período crítico de fundação, o tipo de solo parece exercer pouca influência na sobrevivência das operárias e das colônias. O solo de área de mata apresenta maior quantidade e diversidade de fungos filamentosos que o solo de área desnuda; A utilização de Tenebrio molitor como isca-viva é eficiente para bioprospecção por fungos entomopatogênicos. Todos os isolados de Trichoderma foram capazes de inibir o crescimento in vitro de L. gongylophorus; Trichoderma spirale isolado 2 apresentou crescimento micelial lento em placa de Petri e inibição contra L. gongylophorus, podendo este ser um isolado promissor em testes em campo.
The leaf-cutting ants (Hymenoptera: Formicidae), Atta and Acromyrmex genera, are the most important forest pests. They are found exclusively in Americas. Its economic importance is due to behavior to cut fresh plant material that serves as a substrate for the mutualistic symbiotic fungus Leucoagaricus gongylophorus (Basidiomycota: Agaricales) that are grown in underground chambers. Fertilized females are responsible for the founding of a new colony and they suffer direct influence of soil microorganisms. Therefore, newly fertilized females of Atta spp. should avoid fertile soils with high microbial load and even forested areas to found their nests. Entomopathogenic fungi and antagonists of L. gongylophorus are naturally present in the soil and they could be used in biological control of leaf-cutting ants. The objectives of this study were to evaluate and to compare the developing of young colonies of Atta sexdens in contact with soil from forested area and in contact with bare soils. Also, this and others procedures served to bioprospect antagonistic fungi of L. gongylophorus (Trichoderma spp.) from Gurupi region soil, and test the antagonistic effect of Trichoderma spp. against L. gongylophorus. In the first hours of start of experiments, Atta workers removed soil from colony recipients. This behavior could have favored colony survival, with a survival rate of 91,67 % during the 13 weeks. It was found that after the colonies have passed the critical period of foundation, the soil appears to exert little influence on the survival of workers and colonies. The soil from forested area had greater quantity and diversity of filamentous fungi than that from bare soil. The use of Tenebrio molitor as bait alive is efficient for bioprospecting by entomopathogenic fungi. All isolates of Trichoderma were able to inhibit in vitro growth of L. gongylophorus. Trichoderma spirale isolated 2 showed slow mycelial growth in Petri dish and strong level of inhibition against L. gongylophorus in vitro. So, this isolate is promising and should be tested in field.
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Rodrigues, André [UNESP]. "O papel dos microfungos associados aos jardins das formigas Attini (Hymenoptera: Formicidae)." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/103936.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
As formigas da tribo Attini são conhecidas pela complexa simbiose que mantêm com fungos, os quais cultivam como alimento. É sabido que além desse fungo, outros microrganismos podem ser encontrados nos ninhos desses insetos e estudos prévios apontaram que alguns microfungos (i.e. leveduras e fungos filamentosos) podem ser importantes nessa simbiose. O objetivo do presente trabalho foi avaliar o papel desses microfungos associados aos jardins dessas formigas. Analisando várias espécies do gênero Acromyrmex do sul do Brasil, demonstrou-se que as formigas importam uma comunidade diversa de microfungos para seus ninhos, provavelmente provenientes do solo e do substrato vegetal que as formigas utilizam para cultivar seu fungo. Num segundo estudo, avaliando formigas Attini da América do Norte (Atta texana, Trachymyrmex septentrionalis e Cyphomyrmex wheeleri) observou-se que a estrutura das comunidades de microfungos nos jardins desses insetos não se correlaciona com a variação sazonal, sugerindo que não existam relações espécie-específicas entre as formigas e os microfungos. Apesar de tais microrganismos não serem especialistas dos jardins desses insetos, é sugerido que os microfungos atuem como antagonistas do fungo simbionte. Ainda, descobriu-se que o parasita especializado Escovopsis spp. parece ser menos freqüente nas populações de formigas da América do Sul em relação as Attini da América Central, porém estudos adicionais são necessários para estabelecer a epidemiologia desse parasita nos ninhos das Attini. Num terceiro estudo, demonstrou-se que leveduras presentes nos jardins de fungos da formiga cortadeira A. texana inibem o crescimento de Escovopsis spp., sugerindo que esses insetos utilizam outros microrganismos, além das bactérias presentes em suas cutículas (Pseudonocardia spp.), para inibir esse parasita. Esse achado traz importantes implicações para essa...
Ants in the tribe Attini are well-known social insects that maintain a symbiotic relationship with fungi which they cultivate as food. Besides of the cultivated fungi, fungus gardens contain several other microorganisms considered to be potential players in this symbiosis. The aim of the present study was to evaluate the possible roles of microfungi (i.e. yeasts and filamentous fungi) in attine gardens. Our microbial profiling of gardens from several species in the genus Acromyrmex from South Brazil revealed that ants can harbor a diverse community of microfungi that probably originated from the surrounding soil or from the substrate used to manure the cultivated fungus. In this sense, additional studies of North American attine species (Atta texana, Trachymyrmex septentrionalis and Cyphomyrmex wheeleri) demonstrated that the structure of microfungal communities in gardens of these ants did not correlate with seasonal changes over a one year period, again suggesting there are no species-specific relationships among ants and microfungi species. Although, the microfungi are not specialized parasites of the attine ant-fungus symbiosis we suggest they can be considered antagonists to the cultivated fungus. Moreover, we demonstrated that the specialized parasite Escovopsis spp. is probably less frequent in South America than in Central America and we reinforce that additional studies are necessary to unravel the epidemiology of this parasite in attine gardens. In another study, we showed that yeasts isolated from gardens of the leafcutter ant A. texana can significantly inhibit the growth of Escovopsis sp. This interesting finding suggests that attine ants may use additional microbes to protect their gardens against Escovopsis spp. and not only actinomycete bacteria (Pseudonocardia spp.) found in their cuticles. Finally, we studied microfungi relationships with female alates (gynes) in two... (Complete abstract click electronic access below)
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Carder, Phyllis. "Microbial Communities of Spinach at Various Stages of Plant Growth From Seed to Maturity." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/34104.

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Little is known about how the leaf bacterial community is affected by the seed microbiota at different stages of plant development. The bacterial populations of spinach seed and leaves after germination were compared using DGGE, to assess bacterial community richness, and real-time PCR to compare the abundance of select phyla (total bacteria, Actinobacteria, Bacteroidetes, Firmicutes, α-Proteobacteria and β- Proteobacteria). To determine the effect of environment, the plants were grown in the field and growth chambers. Vertical transmission of bacterial community members was evident; the developmental stage of the plant affected the richness and abundance of select bacterial phyla. The bacterial richness of plants grown in the two environments was not affected. However, overall numbers of bacteria increased in field grown samples in comparison to those produced in growth chambers during development. A statistically significant interaction was seen between growth stage and environment with each of the selected phyla. Populations on cotyledons were smaller than mature leaves, but were not significantly different than the 3-4 leaf stage plants. The culturable populations of bacteria on seeds (~5 log CFU/g) were significantly smaller than determined using real time PCR (~7 log copies). Of these bacteria cultured from spinach seeds, isolates belonging to the genera Pantoea were found to inhibit growth of E. coli O157:H7 in vitro. This study highlights the importance of vertical transmission on the bacterial community of plants and suggests the importance of developing strategies to influence these communities on seed to control human and plant pathogens on the leaf surface.


Master of Science in Life Sciences
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Travaglini, Raphael Vacchi. "Bases para o controle microbiano de formigas cortadeiras." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/152256.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O controle biológico tem recebido atenção dos pesquisadores, principalmente devido aos movimentos, de preservação do ambiente. Têm sido amplamente aplicado em espécies consideradas importantes pragas agrícolas, porém não indicado para as formigas cortadeiras. Tais formigas apresentam um conjunto de estratégias físicas, químicas e comportamentais que as operárias realizam a fim de evitar a própria contaminação e da colônia. Entretanto alguns microorganismos conseguem causar mortalidade de alguns membros da colônia, como os fungos entomopatogênicos. Pretende-se fornecer conhecimentos básicos para desenvolvimento de novas estratégias de controle microbiano das formigas cortadeiras em um futuro próximo. Para tanto estudamos quatro fungos com grande potencial patogênico, Metarhizium anisopliae, Beauveria bassiana, Aspergillus flavus e Trichoderma asperellus. Primeiramente foram estudados a patogenicidade dos fungos (entomopatogeno e oportunista) em operarias isoladas da colônia. Estudou-se a susceptibilidade de larvas e adultos de formigas cortadeiras Atta sexdens rubropilosa a conídios de B. bassiana, por meio de técnicas histológicas e de microscopia. Finalmente encapsulados com conídios foram veiculados para o jardim de fungo simbionte visando o controle de mini colônias em laboratório. Propomos a elaboração de novas alternativas aos manejos existentes.
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REVETTA, RANDY PRIMO. "ISOLATION AND IDENTIFICATION OF FRESHWATER BACTERIA ANTAGONISTIC TO GIARDIA INTESTINALIS." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1141305893.

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Tydings, Heather Anne. "Identification and Optimization of the Antagonistic Potential of Native Spinach Microbiota towards Escherichia coli O157:H7." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/43364.

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Leafy greens such as spinach have been the object of several recent food-borne pathogen outbreaks. The purpose of this study was to isolate bacteria spinach epiphytic bacteria that inhibit growth of E. coli O157:H7, which we describe as antagonism. The mechanism of antagonism was investigated and we attempted to improve the antagonistic potential in vitro and on spinach leaves when cellobiose, a carbon source utilized by the antagonists but not E. coli O157:H7, was added. There were larger culturable populations of bacteria on the leaves of savoyed cultivars compared to flat. From the isolated colonies, 47 displayed antagonism towards E.coli O157:H7, and were identified as members of 11 different genera and sixteen species. A representative isolate from each species was evaluated for three possible mechanisms of antagonism: acid production, secretion of an inhibitory compounds or secreted protease. The majority (14/16) produced at least a moderate level of acid. Two of these strains, Paenibacillus polymyxa and Pseudomonas espejiana, were found to secrete a non- protease antagonistic compound. These antagonists varied in their reduction of E.coli O157:H7 numbers in vitro, but all significantly reduced numbers in 48 hours of co-culturing in nutrient rich media. Five antagonists resulted in a significant reduction in E.coli O157:H7 populations when co-cultured on spinach leaves. Application of cellobiose did not improve the amount of antagonism in vitro or on the leaf surface after 24 hours.
Master of Science
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Lima, José Vinícius Leite. "Populações microbianas e antagonismo de actinobactérias sobre rizóbios em solos do semiárido." reponame:Repositório Institucional da UFC, 2017. http://www.repositorio.ufc.br/handle/riufc/26028.

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LIMA, José Vinícius Leite. Populações microbianas e antagonismo de actinobactérias sobre rizóbios em solos do semiárido. 2017. 81 f. Tese (Doutorado em Ecologia e Recursos Naturais)-Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2017.
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The structure of the communities living in the soil is driven by various mechanisms and the ecological interactions established between the living organisms. In the same way, the components of the microbiota present harmonic or non-harmonic relationships, for example, between actinobacteria and rhizobia. Interspecific competition among microorganisms occurs when many species require the same resources, and the negative effect on the availability of common resources adversely affects the others. In this context, the objective of this study was to quantify the microbial population in the soil and leaf litter in the vegetation of the caatinga and carrasco in the Brazilian semiarid region (Chapter I) and to characterize and evaluate the antagonistic effect of actinobacteria on rhizobia (Chapter II). The soil samples were collected at the Ecological Station of Aiuaba (Aiuaba, Ceará), characterized by the vegetation of caatinga and carrasco. In chapter I, the population density of the microbial community was evaluated by sampling of soil and litter in the vegetation of caatinga and carrasco at the Aiuaba Ecological Station. The microorganisms were isolated from the soil samples in flasks containing 0.8% saline solution and cultured, after consecutive dilutions, in culturing media specific to cultivable populations of total bacteria, actinobacteria, cellulolytic bacteria, phosphate solubilizing bacteria and fungi. Population estimation was then performed by standard counting on plates and the values were expressed in CFU.g-1. The microbial populations from the soil and leaf litter differed each other quantitatively and in the two vegetations, but in general were greater in the leaf litter. Thus, the knowledge of the population structure of the microbial community can be extended to the semiarid soils. In Chapter II, the strains of actinobacteria isolated in the first study were characterized and tested for “in vitro” inhibitory effect on strains of rhizobia also isolated from semiarid soils. The actinobacteria were purified in their respective culture medium (CDA medium). The strains were characterized for their color and morphology of the colonies, tolerance to pH levels, production of melanin and use of carbon sources. The “in vitro” antagonism of actinobacteria on rhizobia was evaluated in Petri dish containing yeast mannitol agar (YMA) medium by the formation of inhibition zone. The actinobacteria and rhizobia that had greater antagonistic effect or did not presented inhibition zones were molecularly identified. Sixty strains were identified in seven genera of actinobacteria in which had tolerance to variations in pH, low melanin production and generalist use of carbon sources. It was also observed “in vitro” antagonism of actinobacteria species, standing out the genus Streptomyces, on strains of Rhizobium tropici, Bradyrhizobium yuanmingense and two other rhizobia strains not identified. This is the first work that addresses this ecological interaction between microorganisms of the Brazilian semiarid region and reveals the occurrence of new species related to this negative interaction. Thus, the presence of antagonism among these organisms may lead to “in vivo” studies, contributing to future agricultural and/or ecological uses.
A estrutura das comunidades que vivem no solo é direcionada por vários mecanismos e as interações ecológicas estabelecidas entre os organismos. Da mesma forma, os componentes da microbiota apresentam relações harmônicas ou não entre si, como por exemplo, entre actinobactérias e rizóbios. A competição interespecífica entre os micro-organismos acontece quando muitas espécies procuram pelos mesmos recursos, e o efeito depressor que cada uma tem na disponibilidade dos recursos comuns afeta adversamente os outros. Neste contexto, teve-se como objetivo neste estudo quantificar em região semiárida a população microbiana no solo e serrapilheira nas fisionomias vegetais de caatinga e carrasco (Capítulo I) e caracterizar e avaliar o efeito antagônico de actinobactérias sobre rizóbios do semiárido (Capítulo II). O estudo foi realizado na Estação Ecológica de Aiuaba (Aiuaba, Ceará) caracterizada pelas fisionomias de caatinga e carrasco. No capítulo I, avaliou-se a densidade populacional da comunidade microbiana por meio de coleta de amostras do solo e serrapilheira nas fisionomias vegetais de caatinga e carrasco na Estação Ecológica de Aiuaba. Os micro-organismos foram isolados das amostras em solução salina 0,8% e cultivados, após diluições seriadas, em meios de cultura específicos para populações cultiváveis de bactérias totais, actinobactérias, bactérias celulolíticas, bactérias solubilizadoras de fosfato e fungos. Em seguida foi realizada a contagem das populações pela contagem padrão em placas usando a técnica de espalhamento em superfície, e os valores foram expressos em UFC.g-1. As populações microbianas oriundas do solo e serrapilheira diferiram quantitativamente entre elas e nas duas fisionomias vegetais, mas no geral foram maiores na serrapilheira. Dessa forma, pode-se ampliar o conhecimento da estrutura populacional da comunidade microbiana em solos de clima semiárido. No capítulo II, caracterizaram-se as cepas de actinobactérias isoladas das populações obtidas do primeiro estudo e testou-as para efeito inibidor in vitro sobre estirpes de rizóbios também oriundas de solos semiáridos. As actinobactérias foram purificadas no seu respectivo meio de cultura (meio CDA). As cepas foram caracterizadas quanto a atributos cromogênicos e morfológicos, para tolerância a níveis de pH, na produção de melanina e uso de fontes de carbono. O antagonismo das actinobactérias in vitro sobre rizóbios foi avaliado em meio de cultura ágar manitol levedura (YMA) pela formação de halo de inibição em placa de Petri. Em seguida, as actinobactérias e rizóbios que tiveram maior efeito antagônico ou que não formaram halo inibidor foram caracterizadas molecularmente. Foram obtidas 60 cepas identificados em sete gêneros de actinobactérias que tiveram tolerância a variações de pH, baixa produção de melanina e uso generalista de fontes de carbono. Foi observado antagonismo in vitro com formação de halo inibidor de espécies de actinobactérias, com destaque para o gênero Streptomyces, sobre os rizóbios Rhizobium tropici, Bradyrhizobium yuanmingense e outras duas estirpes não identificadas. Este é o primeiro trabalho que aborda essa relação ecológica em micro-organismos do semiárido e revela a ocorrência de novas espécies relacionados com essa interação negativa. Com isso, confirma-se a presença de antagonismo entre esses organismos que pode direcionar estudos de certificação in vivo, contribuindo para futuros usos agrícolas e/ou ecológicos.
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Books on the topic "Microbial antagonists"

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C, Moellering Robert, ed. Therapeutic implications of treatment with beta-lactamase inhibitor combinations. Montreal: PharmaLibri Publishers, 1994.

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Enzyme-mediated resistance to antibiotics: Mechanisms, dissemination, and prospects for inhibition. Washington, DC: ASM Press, 2007.

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Bonomo, Robert A., and Marcelo E. Tolmasky. Enzyme-Mediated Resistance to Antibiotics: Mechanisms, Dissemination, and Prospects for Inhibition. Wiley & Sons, Limited, John, 2014.

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(Editor), Robert A. Bonomo, and Marcelo E. Tolmasky (Editor), eds. Enzyme-Mediated Resistance to Antibiotics: Mechanisms, Dissemination, and Prospects for Inhibition. ASM Press, 2007.

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Book chapters on the topic "Microbial antagonists"

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Srivastava, Atul Kumar, Ashish Kumar Nayak, Arvind Saroj, and Pooja Misra. "Antagonists and Antibiosis: Game Changer of Agriculture and Health Sector." In Microbes in Microbial Communities, 215–38. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-5617-0_10.

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Di Francesco, Alessandra, and Elena Baraldi. "Biological Control of Postharvest Diseases by Microbial Antagonists." In Progress in Biological Control, 243–61. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-51034-3_10.

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Klose, Viviana, Markus Neureiter, Michaela Mohnl, Herbert Danner, and Christina Donat. "Microbial Antagonists in Animal Health Promotion and Plant Protection." In Microbes at Work, 193–211. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-04043-6_10.

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Rodriguez-Kabana, R., G. Morgan-Jones, and I. Chet. "Biological control of nematodes: Soil amendments and microbial antagonists." In Plant and Soil Interfaces and Interactions, 237–47. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3627-0_17.

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Droby, S., R. R. Gonzalez-Estrada, G. Avila-Quezada, P. Durán, G. Manzo-Sánchez, and L. G. Hernandez-Montiel. "Microbial Antagonists from Different Environments Used in the Biocontrol of Plant Pathogens." In Microbial Biocontrol: Food Security and Post Harvest Management, 227–44. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-87289-2_9.

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Elena, Georgina, and Jürgen Köhl. "Screening Strategies for Selection of New Microbial Antagonists of Plant Pathogens." In Progress in Biological Control, 165–81. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-53238-3_11.

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Singh, Monika, Kapil Deo Pandey, A. C. Rathore, Shailendra Pratap Sharma, and Rajendra Kumar. "Bacterial Antagonists: Effective Tools for the Management of Postharvest Diseases in Fruits, Vegetables, and Food Grains." In Microbial Biocontrol: Food Security and Post Harvest Management, 295–309. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-87289-2_13.

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Gooch, Jan W. "Microbial Antagonism." In Encyclopedic Dictionary of Polymers, 907. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_14217.

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Gooch, Jan W. "Microbial Antagonism." In Encyclopedic Dictionary of Polymers, 907. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_14218.

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Stouvenakers, Gilles, Peter Dapprich, Sebastien Massart, and M. Haïssam Jijakli. "Plant Pathogens and Control Strategies in Aquaponics." In Aquaponics Food Production Systems, 353–78. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-15943-6_14.

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AbstractAmong the diversity of plant diseases occurring in aquaponics, soil-borne pathogens, such as Fusarium spp., Phytophthora spp. and Pythium spp., are the most problematic due to their preference for humid/aquatic environment conditions. Phytophthora spp. and Pythium spp. which belong to the Oomycetes pseudo-fungi require special attention because of their mobile form of dispersion, the so-called zoospores that can move freely and actively in liquid water. In coupled aquaponics, curative methods are still limited because of the possible toxicity of pesticides and chemical agents for fish and beneficial bacteria (e.g. nitrifying bacteria of the biofilter). Furthermore, the development of biocontrol agents for aquaponic use is still at its beginning. Consequently, ways to control the initial infection and the progression of a disease are mainly based on preventive actions and water physical treatments. However, suppressive action (suppression) could happen in aquaponic environment considering recent papers and the suppressive activity already highlighted in hydroponics. In addition, aquaponic water contains organic matter that could promote establishment and growth of heterotrophic bacteria in the system or even improve plant growth and viability directly. With regards to organic hydroponics (i.e. use of organic fertilisation and organic plant media), these bacteria could act as antagonist agents or as plant defence elicitors to protect plants from diseases. In the future, research on the disease suppressive ability of the aquaponic biotope must be increased, as well as isolation, characterisation and formulation of microbial plant pathogen antagonists. Finally, a good knowledge in the rapid identification of pathogens, combined with control methods and diseases monitoring, as recommended in integrated plant pest management, is the key to an efficient control of plant diseases in aquaponics.
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Conference papers on the topic "Microbial antagonists"

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Polivtseva, Valentina N., Tatiana N. Abashina, Alexander E. Noskov, Nataliya E. Suzina, Gholam Khodakaramian, and Inna P. Solyanikova. "New Strains of Streptomyces as Perspective Antagonists of Microbial Phytopathogens †." In ECP 2023. Basel Switzerland: MDPI, 2023. http://dx.doi.org/10.3390/ecp2023-14727.

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Yin, Chuntao. "Disease-induced changes in the rhizosphere microbiome reduced root disease." In IS-MPMI Congress. IS-MPMI, 2023. http://dx.doi.org/10.1094/ismpmi-2023-5r.

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Rhizosphere microbiota, referred to as the second genome of plants, are crucial to plant health. Increasing evidence reveals that plants can change their rhizosphere microbiome and promote microbial activity to reduce plant disease. However, how plant and phytopathogens factor in combination to structure the rhizosphere microbiome and govern microbial selection for adaptation to disease stress remains incompletely understood. In this study, rhizosphere microbiota from successive wheat plantings under the pressure of the soilborne pathogen Rhizoctonia solani AG8 were characterized. Amplicon sequence analyses revealed that bacterial and fungal communities clustered by planting cycles. The addition of AG8 enhanced the separation of the rhizosphere microbiota. The alpha diversity of bacteria and fungi significantly decreased over planting cycles. Compared with rhizosphere bacterial communities, AG8 was a major driver structuring fungal communities. Pathogen-infected monocultures enriched a group of bacterial genera with potential antagonistic activities or abilities for plant growth promotion or nitrogen fixation. Further, eleven bacterial species exhibited antagonistic activities toward Rhizoctonia spp., and four of them displayed broad antagonism against multiple soilborne fungal pathogens. These findings support the potential to improve plant health through manipulating rhizosphere microbiota.
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Loban, Liudmyla, Nina Pyliak, and Vladislav Yaroshevsky. "Gene resource of industrially important microbial culture collection for agriculture biologization." In Scientific International Symposium "Plant Protection – Achievements and Perspectives". Institute of Genetics, Physiology and Plant Protection, Republic of Moldova, 2023. http://dx.doi.org/10.53040/ppap2023.26.

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The article is dedicated to describing the gene resource of Industrially Important Microbial Culture Collection for Agriculture Biologization of Engineering and Technological Institute "Biotekhnika" of the National Academy of Agrarian Sciences of Ukraine, which holds the status of the Ukrainian National Asset. The Collection includes known industrial microbial strains with antagonistic, entomocidal, rodenticidal, nematocidal, and cellulosolytic properties. There are natural isolates that can transform insoluble phosphorus and ones are phytohormones producers in the Collection. The Collection can serve as a ground of experience exchange for scientists and specialists working in the field of plant protection, as well as for educating students’ biologists, biotechnologists, and agronomists.
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Mikhailouskaya, N. A., D. V. Voitka, E. K. Yuzefovich, and T. B. Barashenko. "Effect of three-component microbial inoculant on winter rye and spring barley yields." In РАЦИОНАЛЬНОЕ ИСПОЛЬЗОВАНИЕ ПРИРОДНЫХ РЕСУРСОВ В АГРОЦЕНОЗАХ. Federal State Budget Scientific Institution “Research Institute of Agriculture of Crimea”, 2020. http://dx.doi.org/10.33952/2542-0720-15.05.2020.17.

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One of the modern techniques of improving microbial preparations efficiency is a combination of several microorganisms with different beneficial properties in one inoculant. Taking into account the role of nitrogen and potassium nutrition and their synergism, it is essential to develop preparations of N2-fixing and K-mobilizing rhizobacteria, especially Azospirillum sp. and Bacillus sp. Effective biological control of root infections is of great importance in order to prevent crop yield losses. Among soil antagonistic fungi, Trichoderma sp. is the most promising one. Microbial inoculant includes three components: Azospirillum brasilеnse 2(b)3 + Bacillus circulans K-81 + Trichoderma longibrachiatum L-7 (1:1:1). Combined application of rhizobacteria A. brasilense + B. сirculans induced significant hormonal effect. Roots dry mass increased by 28%, roots length per plant – by 25%, stem dry mass – by 33%. In the field experiment, the treatment of barley by microbial inoculant provided the reduction of root rot incidence by 52.0–58.0%, disease development (waxy ripeness) – by 2.6–2.9 times, biological efficiency was 66.3–69.5%. Treatment of winter rye resulted in the reduction of disease incidence by 42.4–45.0%, disease development (milky ripeness) – by 2.0–2.6 times, biological efficiency – 50.2–61.2% according to soil-erosion catena. Beneficial influence of inoculation on plant development and nutrition, as well as effective biological control of plant diseases, provided significant crop responses: for winter rye – 3.8-4.5 c ha-1 or 7.0% - 9.8%, for spring barley – 5,2 – 4.9 c ha-1 or 9.3% – 9.2% according to soil-erosion catena. Microbial inoculant exhibits the properties of plant growth promoter, biological fertilizer, and biological fungicide.
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Waluyo, Lud. "Antagonism of Microbial Consortium Decomposers in Deadly Water-borne Pathogens in Domestic Wastewater." In 2018 3rd International Conference on Education, Sports, Arts and Management Engineering (ICESAME 2018). Paris, France: Atlantis Press, 2018. http://dx.doi.org/10.2991/amca-18.2018.168.

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Klimenko, N. N. "Estimation of the state of microbocenosis of the peach rhizosphere during the biologization of its cultivation." In CURRENT STATE, PROBLEMS AND PROSPECTS OF THE DEVELOPMENT OF AGRARIAN SCIENCE. Federal State Budget Scientific Institution “Research Institute of Agriculture of Crimea”, 2020. http://dx.doi.org/10.33952/2542-0720-2020-5-9-10-113.

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Our research has shown that the use of biologization techniques for growing peaches positively affected the number of bacteria of the main ecological and trophic groups involved in the transformation of soil organic matter: ammonifying bacteria ‒ by 26-47 %; amylolytic bacteria – by 48-103 %; phosphate mobilizing bacteria – by 32-72 %; oligonitrophilic bacteria – by 24-49 %; oligotrophic bacteria – by 57-59 %; cellulolytic bacteria – by 25-39 % in the soil layer of 0-30 and 30-60 cm compared to the control, respectively. There was a decrease in the number of micromycetes, which, in our opinion, is associated with the antagonistic effect of microbial preparations. The use of biologization techniques did not significantly affect the oligotrophy index: its values remained at the control level and fluctuated between 0.6 and 0.8, depending on the experiment variant. The values of the pedotrophy index of the soil of the experimental site on both backgrounds of grassing did not differ and amounted to 1.1 when using Azotobacterin and 1.0 – when bacterizing with CMP. Increasing values of this index indicate the transition of the studied biocenosis to a stable state.
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Al-Attiya, Wadha Ahmed Khalifa, Zahoor UI Hassan, Roda Al-Thani, and Samir Jaoua. "Prevalence of Toxigenic Fungi and Mycotoxins in Arabic Coffee: Protective Effect of Traditional Coffee Roasting, Brewing and Microbial Volatiles." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2021. http://dx.doi.org/10.29117/quarfe.2021.0067.

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Like other agricultural crops, fungal infection and synthesis of mycotoxins in coffee leads to significant economic losses. This study is aimed at investigating the prevalence of toxigenic fungi, their metabolites, and the effect of traditional roasting and brewing on ochratoxin A (OTA) and aflatoxins (AFs) contents of naturally contaminated coffee samples. In addition, in vivo biocontrol assays were performed to explore the antagonistic activities of Bacillus simplex 350-3 (BS350-3) on the growth and mycotoxins synthesis potential of Aspergillus ochraceus and A. flavus. The relative density of A. niger, A. flavus, Penicillium verrucosum and A. carbonarius on green coffee bean was 60.82%, 7.21%, 3.09% and 1.03%, respectively. OTA contents were lowest in green coffee beans (2.15 µg/kg), followed by roasted (2.76 µg/kg) and soluble coffee (8.95 µg/kg). Likewise, AFs levels were highest in soluble coffee (90.58 µg/kg) followed by roasted (33.61 µg/kg) and green coffee (9.07 µg/kg). Roasting naturally contaminated coffee beans by three traditional styles; low, medium and high, followed by brewing resulted in reduction of 58.74%, 60.88% and 64.70% in OTA and 40.18%, 47.86% and 62.38% AFs contents, respectively. BS350-3 volatiles resulted in significant inhibition in AFs and OTA synthesis by A. flavus and A. carbonarius on infected coffee beans, respectively. Gas chromatography mass spectrochemistry (GC-MS/MS) analysis of headspace BS350-3 volatiles showed quinoline, benzenemethanamine and 1-Octadecene as bioactive antifungal molecules. These findings suggest that marketed coffee samples are generally contaminated with OTA and AFs; with a significant number of roasted and soluble coffee contaminated at the levels above EU permissible limits for OTA. Further, along with coffee roasting and brewing; microbial volatiles possess a promising potential, which can be optimized to minimize the dietary exposure to mycotoxins.
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Reports on the topic "Microbial antagonists"

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Droby, Samir, Joseph W. Eckert, Shulamit Manulis, and Rajesh K. Mehra. Ecology, Population Dynamics and Genetic Diversity of Epiphytic Yeast Antagonists of Postharvest Diseases of Fruits. United States Department of Agriculture, October 1994. http://dx.doi.org/10.32747/1994.7568777.bard.

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One of the emerging technologies is the use of microbial agents for the control of postharvest diseases of fruits and vegetables. A number of antagonistic microorganisms have been discovered which have the potential to effectively control postharvest diseases. Some of this technology has been patented and commercial products such as AspireTM (Ecogen Corporatin, Langhorne, PA, USA), Biosave 10TM and Biosave 11TM (Ecoscience Inc., Worchester, MA, USA) have been registered for commercial use. The principal investigator of this project was involved in developing the yeast-based biofungicide-AspireTM and testing its efficacy under commercial conditions. This research project was initiated to fill the gap between the knowledge available on development and commercial implementation of yeast biocontrol agents and basic understanding of various aspects related to introducing yeast antagonists to fruit surfaces, along with verification of population genetics. The main objectives of this study were: Study ecology, population dynamics and genetic diversity of the yeast antagonists Candida guilliermondii, C. oleophila, and Debaryomyces hansenii, and study the effect of preharvest application of the yeast antagonist C. oleophila naturally occurring epiphytic microbial population and on the development of postharvest diseases of citrus fruit during storage. Our findings, which were detailed in several publications, have shown that an epiphytic yeast population of grapefruit able to grow under high osmotic conditions and a wide range of temperatures was isolated and characterized for its biocontrol activity against green mold decay caused by Penicillium digitatum. Techniques based on random amplified polymorphic DNA (RAPD) and arbitrary primed polymerase chain reaction (ap-PCR), as well as homologies between sequences of the rDNA internal transcribed spacers (ITS) and 5.8S gene, were used to characterize the composition of the yeast population and to determine the genetic relationship among predominant yeast species. Epiphytic yeasts exhibiting the highest biocontrol activity against P. digitatum on grapefruit were identified as Candida guilliermondii, C. oleophila, C. sake, and Debaryomyces hansenii, while C. guilliermondii was the most predominant species. RAPD and ap-PCR analysis of the osmotolerant yeast population showed two different, major groups. The sequences of the ITS regions and the 5.8S gene of the yeast isolates, previously identified as belonging to different species, were found to be identical. Following the need to develop a genetically marked strain of the yeast C. oleophila, to be used in population dynamics studies, a transformation system for the yeast was developed. Histidine auxotrophy of C. oloephila produced using ethyl methanesulfonate were transformed with plasmids containing HIS3, HIS4 and HIS5 genes from Saccharomyces cerevisiae. In one mutant histidin auxotrophy was complemented by the HIS5 gene of S. cerevisiae is functionally homologous to the HIS5 gene in V. oleophila. Southern blot analysis showed that the plasmid containing the S. cerevisiae HIS5 gene was integrated at a different location every C. oleophila HIS+ transformant. There were no detectable physiological differences between C. oleophila strain I-182 and the transformants. The biological control ability of C. oleophila was not affected by the transformation. A genetically marked (with b-glucuronidase gene) transformant of C. oleophila colonized wounds on orange fruits and its population increased under field conditions. Effect of preharvest application of the yeast C. oleophila on population dynamics of epiphytic microbial population on wounded and unwounded grapefruit surface in the orchard and after harvest was also studied. In addition, the effect of preharvest application of the yeast C. oleophila on the development of postharvest decay was evaluated. Population studies conducted in the orchard showed that in control, non-treated fruit, colonization of wounded and unwounded grapefruit surface by naturally occurring filamentous fungi did not vary throughout the incubation period on the tree. On the other hand, colonization of intact and wounded fruit surface by naturally occurring yeasts was different. Yeasts colonized wounded surface rapidly and increased in numbers to about two orders of magnitude as compared to unwounded surface. On fruit treated with the yeast and kept on the tree, a different picture of fungal and yeast population had emerged. The detected fungal population on the yeast-treated intact surface was dramatically reduced and in treated wounds no fungi was detected. Yeast population on intact surface was relatively high immediately after the application of AspireTM and decreased to than 70% of that detected initially. In wounds, yeast population increased from 2.5 x 104 to about 4x106 after 72 hours of incubation at 20oC. Results of tests conducted to evaluate the effect of preharvest application of AspireTM on the development of postharvest decay indicated the validity of the approach.
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Droby, S., J. L. Norelli, M. E. Wisniewski, S. Freilich, A. Faigenboim, and C. Dardick. Microbial networks on harvested apples and the design of antagonistic consortia to control postharvest pathogens. Israel: United States-Israel Binational Agricultural Research and Development Fund, 2020. http://dx.doi.org/10.32747/2020.8134164.bard.

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We have demonstrated, at a global level, the existence of spatial variation in the fungal and bacterial composition of different fruit tissues. The composition, diversity and abundance varied in fruit harvested in different geographical locations and suggests a potential link between location and the type and rate of postharvest diseases that develop in each country. The global core microbiome of apple fruit was determined and found to be represented by several beneficial microbial taxa and accounted for a large fraction of the fruit microbial community. To further characterize apple fruit the microbiome after harvest, a detailed study was performed to evaluate effects of postharvest practices on the composition of the fruit peel. Microbiota. Results of this work conformed our findings that tissue-type is the main factor driving fungal and bacterial diversity and community composition on apple fruit. Both postharvest treatments and low temperature storage had a great impact on the fungal and bacterial diversity and community composition of these tissue types. Distinct spatial and temporal changes in the composition and diversity of the microbiota were observed in response to various postharvest management practices. Our results clearly indicated that apple fruit has a unique core microbiome that is universal. Analysis of the microbiome across Malus species indicates that the microbiome of domesticated apple has a higher diversity and abundance and is an admixture of the microbiome present in its wild progenitors, with clear evidence for introgression. These findings support the existence of co-evolution between Malus species and their microbiome during domestication. A network analysis of the metagenomics data was used to further elucidate functional differences between the microbiome of organic vs. conventional fruit. Our analysis predicted a link between Capnodiales and the degradation of aromatic compounds. Alternaria, a genus in the Capnodiales genus, is one of the main pathogens of stored apple fruit and was also abundant in our samples. The potential role of Alternaria in the degradation of aromatic compounds is in agreement with previous studies indicating a link between Alternaria and the metabolism of the aromatic compound, alphafarnesene38, a key volatile secreted by the fruit during maturation. A greater number of metabolic pathways related to plant defense substances (e.g. terpenoids and alkaloids) were identified in the microbiome of organic fruit samples, while more antibiotic-related metabolic pathways for compounds such as Erythromycin, Avermectin, Ansamycin, and Penicillin were present in the microbiome of apple fruit samples grown using conventional management practices.
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