Bacteria Associated with Onion Foliage in Michigan and Their Copper Sensitivity

Bacterial stalk and leaf necrosis of onion, Allium cepa L., is a concern of Michigan producers. Plants with symptoms of bacterial stalk and leaf necrosis were collected in 2013 and 2014 from 17 fields in six Michigan counties. Bacterial isolates were identified using Biolog and confirmed by sequencing the 16s rDNA gene. From a total of 414 isolates, 10 bacterial species were identified. Pantoea agglomerans (42.5%), Pantoea ananatis (17.4%), and Enterobacter cowanii (7.5%) were most prevalent and were tested for pathogenicity on onion foliage and bulbs. More P. ananatis isolates (92%) were pathogenic on seedlings than P. agglomerans or E. cowanii isolates (approximately 50%). When 197 bacterial isolates were tested for sensitivity to copper hydroxide (200 µg/ml), 41% of P. agglomerans isolates were found to be tolerant to copper hydroxide, whereas 19 and 22% of P. ananatis and E. cowanii isolates were tolerant, respectively. Identifying the bacterial species associated with foliar disease symptoms on onions in Michigan, their pathogenicity and tolerance to copper is an important step in developing improved disease management strategies.

Download Full-text

Screening and Isolation of Polyhydroxyalkanoates (PHA)-Producing Bacteria from Landfill by using Cocoa Pod Husks as Carbon Source

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i4.14.27470 ◽

2019 ◽

Vol 7 (4.14) ◽

pp. 51

Author(s):

W R Wan Abdul Razak ◽

N J Mohamad Yusuf ◽

A Abdul-Aziz ◽

S K Navaratnam ◽

I Zubir ◽

...

Keyword(s):

Carbon Source ◽

16S Rdna ◽

Bacterial Species ◽

Gene Sequencing ◽

Morphological Identification ◽

Bacterial Isolates ◽

16S Rdna Gene ◽

Rdna Gene ◽

Cocoa Pod Husks ◽

16S Rdna Gene Sequencing

Polyhydroxyalkanoates (PHA) are bioplastics, produced by various bacteria as food and energy reservoir. PHA is an alternative for synthetic plastic because they are environmentally friendly and can be degraded naturally by microorganisms. One of the important factors for the growth of PHA producing bacteria is an excess of carbon supply. In order to reduce the overall cost of PHA production, a low cost pure substrate, which is cocoa pod husks (CPH) was used as a carbon source. The objectives of this study were to isolate and screen PHA producing bacteria from landfill samples which are leachate and soil, to identify the PHA producing bacteria by using morphological characterization and 16s rDNA gene sequencing and to determine the best percentage of CPH that can be used as a carbon source for PHA producing bacteria. PHA producing bacteria from leachate and soil from landfill in Jeram, Selangor were screened by using Nile Blue A staining method. Two potential PHA producers with the brightest fluorescence under UV light from each samples were isolated and characterized by using morphological and molecular identification. Results of morphological identification shows all bacterial isolates have a rod shape and have a capsule, three bacterial isolates (L4, S3, S5) have an endospore while the remaining does not have endospore (L1). Three out of four were Gram positive bacteria (L4, S3, S5) and the remaining was Gram negative bacteria (L1). These isolates were confirmed of their identity as K. pneumoniae (L1), B. cereus (L4 & S3) and B. toyonensis (S5) using 16s rDNA gene sequencing. Different concentration of CPH, which are 2% (w/v), 5% (w/v), 7% (w/v) and 10% (w/v) were used to study the best percentage of CPH that can be used as carbon source. PHA accumulation was the highest at 7% (w/v) for all bacterial species tested and lowest at 10% (w/v) CPH except for B. toyonensis. Therefore, K. pneumoniae, B. cereus and B. toyonensis which isolated from landfill show the ability to produce PHA and the used of 7% (w/v) cocoa pod husks as carbon source give the highest PHA accumulation.

Download Full-text

DIVERSITY OF CULTURABLE BACTERIAL MICROBIOTA OF THE Eisenia foetida DIGESTIVE TRACT

Revista Fitotecnia Mexicana ◽

10.35196/rfm.2018.3.255-264 ◽

2018 ◽

Vol 41 (3) ◽

pp. 255-264 ◽

Cited By ~ 1

Author(s):

J. Abraham Pérez-Pérez ◽

David Espinosa-Victoria ◽

Hilda V. Silva-Rojas ◽

Lucía López-Reyes

Keyword(s):

Bacterial Diversity ◽

Digestive Tract ◽

Bacterial Species ◽

Brain Heart Infusion ◽

Rrna Gene ◽

Eisenia Foetida ◽

Bacterial Isolates ◽

Bacterial Microbiota ◽

Decomposition Of Organic Matter ◽

Earthworm Gut

Bacteria are an unavoidable component of the natural earthworm diet; thus, bacterial diversity in the earthworm gut is directly linked to decomposition of organic matter and development of the surrounding plants. The aim of this research was to isolate and to identify biochemically and molecularly the culturable bacterial microbiota of the digestive tract of Eisenia foetida. Earthworms were sourced from Instituto de Reconversión Productiva y Bioenergética (IRBIO) and Colegio de Postgraduados (COLPOS), México. Bacterial isolation was carried out on plates of Brain Heart Infusion (BHI) culture medium. Fifty six and 44 bacterial isolates were obtained from IRBIO and COLPOS, respectively. The population was composed of 44 Gram-negative and 56 Gram-positive isolates. Over 50 % of the bacterial isolates were rod-shaped cells. The 16S rRNA gene was sequenced and nine genera were identified in worms from IRBIO (Bacillus, Paenibacillus, Solibacillus, Staphylococcus, Arthrobacter, Pantoea, Stenotrophomonas, Acinetobacter and Aeromonas) and six in worms from COLPOS (Bacillus, Paenibacillus, Stenotrophomonas, Staphylococcus, Acinetobacter and Aeromonas). Bacillus was the predominant genus, with eight and six species in the oligochaetes from IRBIO and COLPOS, respectively. The most represented bacteria in the worms from both sites were Bacillus sp. and B. subtilis. The predominance of Bacillus was probably due to spore formation, a reproductive strategy that ensures survival and dispersion in the soil and oligochaetes digestive tract. The gut of E. foetida not only harbored bacterial species of agronomic importance but also species potentially pathogenic for humans (Staphylococcus warneri, Pantoea agglomerans and Stentrophomonas sp.). The larger bacterial diversity in worms from IRBIO could be due to their feeding on cattle manure, which is a rich source of bacteria.

Download Full-text

Trends in Molecular Diagnosis and Diversity Studies for Phytosanitary Regulated Xanthomonas

Microorganisms ◽

10.3390/microorganisms9040862 ◽

2021 ◽

Vol 9 (4) ◽

pp. 862

Author(s):

Vittoria Catara ◽

Jaime Cubero ◽

Joël F. Pothier ◽

Eran Bosis ◽

Claude Bragard ◽

...

Keyword(s):

Molecular Diagnosis ◽

Bacterial Species ◽

Management Strategies ◽

Diagnostic Methods ◽

Plant Diseases ◽

Wild Plants ◽

Future Climate Change ◽

Climate Change Scenarios ◽

Wide Range ◽

Diversity Studies

Bacteria in the genus Xanthomonas infect a wide range of crops and wild plants, with most species responsible for plant diseases that have a global economic and environmental impact on the seed, plant, and food trade. Infections by Xanthomonas spp. cause a wide variety of non-specific symptoms, making their identification difficult. The coexistence of phylogenetically close strains, but drastically different in their phenotype, poses an added challenge to diagnosis. Data on future climate change scenarios predict an increase in the severity of epidemics and a geographical expansion of pathogens, increasing pressure on plant health services. In this context, the effectiveness of integrated disease management strategies strongly depends on the availability of rapid, sensitive, and specific diagnostic methods. The accumulation of genomic information in recent years has facilitated the identification of new DNA markers, a cornerstone for the development of more sensitive and specific methods. Nevertheless, the challenges that the taxonomic complexity of this genus represents in terms of diagnosis together with the fact that within the same bacterial species, groups of strains may interact with distinct host species demonstrate that there is still a long way to go. In this review, we describe and discuss the current molecular-based methods for the diagnosis and detection of regulated Xanthomonas, taxonomic and diversity studies in Xanthomonas and genomic approaches for molecular diagnosis.

Download Full-text

Bacterial Inhibition on Beauveria bassiana Contributes to Microbiota Stability in Delia antiqua

Frontiers in Microbiology ◽

10.3389/fmicb.2021.710800 ◽

2021 ◽

Vol 12 ◽

Author(s):

Fangyuan Zhou ◽

Yunxiao Gao ◽

Mei Liu ◽

Letian Xu ◽

Xiaoqing Wu ◽

...

Keyword(s):

Beauveria Bassiana ◽

Mycelial Growth ◽

Bacterial Species ◽

Management Strategies ◽

Underlying Mechanism ◽

Conidial Germination ◽

Delia Antiqua ◽

Bacterial Microbiota ◽

Fungal Microbiota ◽

Microbial Environment

Given the multiple roles of associated microbiota in improving animal host fitness in a microbial environment, increasing numbers of researchers have focused on how the associated microbiota keeps stable under complex environmental factors, especially some biological ones. Recent studies show that associated microbiota interacts with pathogenic microbes. However, whether and how the interaction would influence microbiota stability is limitedly investigated. Based on the interaction among Delia antiqua, its associated microbiota, and one pathogen Beauveria bassiana, the associated microbiota's response to the pathogen was determined in this study. Besides, the underlying mechanism for the response was also preliminarily investigated. Results showed that B. bassiana neither infect D. antiqua larvae nor did it colonize inside the associated microbiota, and both the bacterial and fungal microbiota kept stable during the interaction. Further experiments showed that bacterial microbiota almost completely inhibited conidial germination and mycelial growth of B. bassiana during its invasion, while fungal microbiota did not inhibit conidial germination and mycelial growth of B. bassiana. According to the above results, individual dominant bacterial species were isolated, and their inhibition on conidial germination and mycelial growth of B. bassiana was reconfirmed. Thus, these results indicated that bacterial instead of fungal microbiota blocked B. bassiana conidia and stabilized the associated microbiota of D. antiqua larvae during B. bassiana invasion. The findings deepened the understanding of the role of associated microbiota–pathogen microbe interaction in maintaining microbiota stability. They may also contribute to the development of novel biological control agents and pest management strategies.

Download Full-text

Virulent secondary metabolites of entomopathogenic bacteria genera, Xenorhabdus and Photorhabdus, inhibit phospholipase A2 to suppress host insect immunity

10.21203/rs.3.rs-63434/v2 ◽

2020 ◽

Author(s):

Md. Mahi Imam Mollah ◽

Yonggyun Kim

Keyword(s):

Secondary Metabolites ◽

Bacterial Culture ◽

Bacterial Species ◽

Culture Broth ◽

Insect Immunity ◽

Bacterial Isolates ◽

Bacterial Pathogenicity ◽

Entomopathogenic Bacteria ◽

Organic Extracts ◽

Insecticidal Activities

Abstract Background: Xenorhabdus and Photorhabdus are entomopathogenic bacteria that cause septicemia and toxemia in insects. They produce secondary metabolites to induce host immunosuppression. Their metabolite compositions vary among bacterial species. Little is known about the relationship between metabolite compositions and the bacterial pathogenicity. The objective of this study was to compare pathogenicity and production of secondary metabolites of 14 bacterial isolates (species or strains) of Xenorhabdus and Photorhabdus. Results: All bacterial isolates exhibited insecticidal activities after hemocoelic injection to Spodoptera exigua (a lepidopteran insect) larvae, with median lethal doses ranging from 168.8 to 641.3 CFU per larva. Bacterial infection also led to immunosuppression by inhibiting eicosanoid biosynthesis. Bacterial culture broth was fractionated into four different organic extracts. All four organic extracts of each bacterial species exhibited insecticidal activities and resulted in immunosuppression. These organic extracts were subjected to GC-MS analysis which predicted 182 compounds, showing differential compositions for 14 bacteria isolates. There were positive correlations between total number of secondary metabolites produced by each bacterial culture broth and its bacterial pathogenicity based on immunosuppression and insecticidal activity. From these correlation results, 70 virulent compounds were selected from secondary metabolites of high virulent bacterial isolates by deducting those of low virulent bacterial isolates. These selected virulent compounds exhibited significant immunosuppressive activities by inhibiting eicosanoid biosynthesis. They also exhibited relatively high insecticidal activities. Conclusion: Virulence variation between Xenorhabdus and Photorhabdus is determined by their different compositions of secondary metabolites, of which PLA2 inhibitors play a crucial role.

Download Full-text

Isolation, Characterization, and Identification of Bacterial Population from Textile and Tannery Effluents of Bangladesh

Bangladesh Journal of Microbiology ◽

10.3329/bjm.v29i2.28441 ◽

2016 ◽

Vol 29 (2) ◽

pp. 84-88

Author(s):

A Hakim ◽

S Hoque ◽

SM Ullah

Keyword(s):

Bacterial Population ◽

Bacterial Species ◽

Bacterial Count ◽

Rrna Gene ◽

Bacterial Isolates ◽

Tannery Effluents ◽

Bacterial Composition ◽

Degrading Bacteria ◽

Diagnostic Characteristics ◽

Metal Treatment

Ten effluent samples from two different sites located at Hazaribagh tannery belt and Dhaka EPZ, Savar were collected. This study aimed to compare the bacterial composition isolated from tannery and textile effluents and to investigate the occurrence of metal toxicity tolerant and dye degrading bacteria and to select the potential strains for the use in bioremediation. The average bacterial count of HT and DETDE varied in between 3.35×106 and 5.45×106 cfu/mL and 4.8×106 and 7.75×106cfu/mL, respectively. A total of 12 bacterial isolates were characterized as strains of Bacillus, Staphylococcus, and Pseudomonas. A few, however, were re-cultured on other recommended media for verification of diagnostic characteristics. Maximum numbers of bacterial species were isolated from textile effluent. The results showed that a Gram-positive bacillus with a yellow pigment was considered as a major group of the population. Among them three isolates were identified based on alignments of partial sequence of 16S rRNA gene. These are also being used in different wastewater and metal treatment plants all over the world.Bangladesh J Microbiol, Volume 29, Number 2, Dec 2012, pp 84-88

Download Full-text

Influence of inoculated gut bacteria on the development of Bactrocera dorsalis and on its susceptibility to the entomopathogenic fungus, Metarhizium anisopliae

BMC Microbiology ◽

10.1186/s12866-020-02015-y ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Joseph Gichuhi ◽

Fathiya Khamis ◽

Johnnie Van den Berg ◽

Samira Mohamed ◽

Sunday Ekesi ◽

...

Keyword(s):

Gut Microbiome ◽

Metarhizium Anisopliae ◽

Entomopathogenic Fungus ◽

Management Strategies ◽

Gut Bacteria ◽

Bactrocera Dorsalis ◽

Bacterial Isolates ◽

Standard Dosage ◽

Germ Free ◽

Wide Range

Abstract Background Symbiotic interactions between insects and bacteria have been associated with a vast variety of physiological, ecological and evolutionary consequences for the host. A wide range of bacterial communities have been found in association with the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), an important pest of cultivated fruit in most regions of the world. We evaluated the diversity of gut bacteria in B. dorsalis specimens from several populations in Kenya and investigated the roles of individual bacterial isolates in the development of axenic (germ-free) B. dorsalis fly lines and their responses to the entomopathogenic fungus, Metarhizium anisopliae. Results We sequenced 16S rRNA to evaluate microbiomes and coupled this with bacterial culturing. Bacterial isolates were mono-associated with axenic B. dorsalis embryos. The shortest embryonic development period was recorded in flies with an intact gut microbiome while the longest period was recorded in axenic fly lines. Similarly, larval development was shortest in flies with an intact gut microbiome, in addition to flies inoculated with Providencia alcalifaciens. Adult B. dorsalis flies emerging from embryos that had been mono-associated with a strain of Lactococcus lactis had decreased survival when challenged with a standard dosage of M. anisopliae ICIPE69 conidia. However, there were no differences in survival between the germ-free lines and flies with an intact microbiome. Conclusions These findings will contribute to the selection of probiotics used in artificial diets for B. dorsalis rearing and the development of improved integrated pest management strategies based on entomopathogenic fungi.

Download Full-text

Pantoea spp. Associated with Smooth Crabgrass (Digitaria ischaemum) Seed Inhibit Competitor Plant Species

Microorganisms ◽

10.3390/microorganisms7050143 ◽

2019 ◽

Vol 7 (5) ◽

pp. 143 ◽

Cited By ~ 1

Author(s):

Matthew T. Elmore ◽

James F. White ◽

Kathryn L. Kingsley ◽

Katherine H. Diehl ◽

Satish K. Verma

Keyword(s):

Trifolium Repens ◽

Bacterial Isolate ◽

Axenic Culture ◽

Taraxacum Officinale ◽

Bacterial Isolates ◽

Seedling Mortality ◽

Pantoea Ananatis ◽

Fungal Isolates ◽

Successional Species ◽

Bacteria And Fungi

Digitaria ischaemum (Schreb.) Schreb. ex Muhl. and Poa annua L. are competitive, early successional species which are usually considered weeds in agricultural and turfgrass systems. Bacteria and fungi associated with D. ischaemum and P. annua seed may contribute to their competitiveness by antagonizing competitor forbs, and were studied in axenic culture. Pantoea spp. were the most common bacterial isolate of D. ischaemum seed, while Epicoccum and Curvularia spp. were common fungal isolates. A variety of species were collected from non-surface sterilized P. annua. Certain Pantoea spp. isolates were antagonistic to competitor forbs Taraxacum officinale, Trifolium repens. All bacterial isolates that affected T. officinale mortality were isolated from D. ischaemum seed while none of the P. annua isolates affected mortality. Two selected bacterial isolates identified as Pantoea ananatis were evaluated further on D. ischaemum, T. repens (a competitor forb) and P. annua (a competitor grass) alone and in combination with a Curvularia sp. fungus. These bacteria alone caused >65% T. repens seedling mortality but did not affect P. annua seedling mortality. These experiments demonstrate that Pantoea ananatis associated with D. ischaemum seeds is antagonistic to competitor forbs in axenic culture. The weedy character of D. ischaemum could at least in part stem from the possession of bacteria that are antagonistic to competitor species.

Download Full-text

Effects of Temperature, Relative Humidity, and Plant Age on Bacterial Disease of Onion Plants

Plant Health Progress ◽

10.1094/php-05-19-0038-rs ◽

2019 ◽

Vol 20 (4) ◽

pp. 200-206

Author(s):

Kim E. Tho ◽

Elizabeth Brisco-McCann ◽

Prissana Wiriyajitsomboon ◽

Mary K. Hausbeck

Keyword(s):

Relative Humidity ◽

Management Strategies ◽

Bacterial Pathogen ◽

Plant Age ◽

Effect Of Temperature ◽

Bacterial Disease ◽

Disease Symptoms ◽

Foliar Disease ◽

Progress Curve ◽

Effects Of Temperature

Foliar disease of onion in Michigan, caused by Pantoea agglomerans, Pantoea ananatis, or Enterobacter cowanii, has recently become a concern to producers. The objective of this study was to determine the effect of temperature, relative humidity (RH), and plant age in growth chamber and greenhouse experiments on onion plants inoculated with each pathogen. A significant level of disease resulted from each pathogen at 25 to 30°C, with strong positive associations detected using regression analysis between the area under the disease progress curve (AUDPC) and temperature. RH also significantly influenced symptom development. Foliar disease symptoms developed sooner and were more severe when RH was high (80 to 100%) but was limited at RH < 60%. Significant positive associations between RH and AUDPC, as described by linear regression, were also detected. When 6- to 14-week-old plants were inoculated with each bacterial pathogen, susceptibility increased significantly with age. These results provide insight into the epidemiology of P. agglomerans, P. ananatis, and E. cowanii bacterial pathogens of onions in Michigan and can assist in the development and timing of management strategies.

Download Full-text

Influence of the Diversity of Bacterial Isolates from Drinking Water on Resistance of Biofilms to Disinfection

Applied and Environmental Microbiology ◽

10.1128/aem.00872-10 ◽

2010 ◽

Vol 76 (19) ◽

pp. 6673-6679 ◽

Cited By ~ 100

Author(s):

Lúcia Chaves Simões ◽

Manuel Simões ◽

Maria João Vieira

Keyword(s):

Drinking Water ◽

Sodium Hypochlorite ◽

Bacterial Species ◽

Acinetobacter Calcoaceticus ◽

Single Species ◽

Bacterial Isolates ◽

Multispecies Biofilms

ABSTRACT Single- and multispecies biofilms formed by six drinking water-isolated bacterial species were used to assess their susceptibilities to sodium hypochlorite (SHC). In general, multispecies biofilms were more resistant to inactivation and removal than single biofilms. Total biofilm inactivation was achieved only for Acinetobacter calcoaceticus single-species biofilms and for those multispecies biofilms without A. calcoaceticus. Biofilms with all bacteria had the highest resistance to SHC, while those without A. calcoaceticus were the most susceptible. A. calcoaceticus formed single biofilms susceptible to SHC; however, its presence in multispecies biofilms increased their resistance to disinfection.

Download Full-text