scholarly journals A Potent Burkholderia Endophyte against Boxwood Blight Caused by Calonectria pseudonaviculata

2020 ◽  
Vol 8 (2) ◽  
pp. 310 ◽  
Author(s):  
Ping Kong ◽  
Chuanxue Hong
Keyword(s):  
Burkholderia Cepacia ◽  
Lead Time ◽  
Biocontrol Agent ◽  
Burkholderia Cepacia Complex ◽  
Broth Culture ◽  
Great Promise ◽  
Bacterial Concentration ◽  
Control Efficacy ◽  
Landscape Plant ◽  
Blight Disease

Calonectria pseudonaviculata (Cps) poses an increasing threat to boxwood, a major nursery crop and iconic landscape plant worldwide. Here, we report on a potent biocontrol agent that produces small sage green (SSG) colonies on potato dextrose agar. SSG is a bacterial strain recovered from Justin Brouwers boxwood leaves with unusual response to Cps inoculation. Water-soaked symptoms developed on leaves 2 days after inoculation then disappeared a few days later. This endophyte affected several major steps of the boxwood blight disease cycle. SSG at 107 cfu/mL lysed all conidia in mixed broth culture. SSG at 108 cfu/mL reduced blight incidence by >98% when applied one day before or 3 h after boxwood were inoculated with Cps. Its control efficacy decreased with decreasing bacterial concentration to 103 cfu/mL and increasing lead time up to 20 days. When applied on diseased leaf litter under boxwood plants, SSG reduced Cps sporulation and consequently mitigated blight incidence by 90%. SSG was identified as a new member of the Burkholderia cepacia complex with distinct characters from known clinical strains. With these protective, curative, and sanitizing properties, this Burkholderia endophyte offers great promise for sustainable blight management at production and in the landscape.

scholarly journals Survival of SSG, an Endophytic Burkholderia Biocontrol Agent, on the Boxwood Leaf Surface

2021 ◽  
Vol 39 (4) ◽  
pp. 138-142
Author(s):  
Ping Kong
Keyword(s):  
Burkholderia Cepacia ◽  
Biocontrol Agent ◽  
Field Performance ◽  
Time Factors ◽  
Burkholderia Cepacia Complex ◽  
Factors Affecting ◽  
Buxus Sempervirens ◽  
Plant Foliage ◽  
Wet Condition ◽  
C 50

Abstract Survival of Burkholderia cepacia complex (Bcc)-based biocontrol agents (BCA) has been associated with their field performance for foliage disease control. SSG, a strain of boxwood endophytic Bcc, suppresses a broad spectrum of plant foliage diseases, including boxwood blight, but the control efficacy declines over time. Factors affecting SSG survival on leaf surfaces were investigated to promote the application of the BCA for boxwood blight management. ‘Justin Brouwers' boxwood plants were treated with SSG cells at 107 to 108 colony-forming unit (CFU)·ml−1, maintained in a moist chamber at 10, 20, or 30 C (50, 68, 86 F), and sampled after the inoculum was blow-dried at 0, 3, 6, 12, and 24 h after treatment. The retained cells per leaf at 0 hours was 105 to 106 CFU, but only less than 10% of the cells survived 24 h after application, irrespective of the wet period and temperature. A wet condition of 12 and 24 h at 20 and 30 C facilitated SSG survival on the second day. Further survival of SSG was affected by temperature but not wetness. Damp conditions and pleasant temperatures can improve bacteria survival and stability and are keys to promoting BCA field applications. Index words: Biocontrol agent, endophyte, survival on plant surfaces, temperature, wetness. Species used in this study: Bacterium strain, SSG (Burkholderia sp);Plant species: Buxus sempervirens L. ‘Justin Brouwers'.

scholarly journals Evaluation of a novel endophytic Pseudomonas lactis strain for control of boxwood blight1

2019 ◽  
Vol 37 (2) ◽  
pp. 39-43 ◽  
Author(s):  
Ping Kong
Keyword(s):  
Biocontrol Agent ◽  
Disease Suppression ◽  
Lead Times ◽  
Bacterial Strains ◽  
Control Efficacy ◽  
Public Gardens ◽  
Buxus Sempervirens ◽  
Private And Public ◽  
Culture Growth ◽  
Blight Disease

Abstract Boxwood blight, caused by Calonectria pseudonaviculata (Cps) (Synonyms: Cylindrocladium buxicola, Cylindrocladium pseudonaviculatum), is a devastating disease which affects boxwood (Buxus) in private and public gardens worldwide. SW, an endophyte identified as a strain of Pseudomonas lactis, was isolated along with seven other bacterial strains from symptom-reversed boxwood leaves infected by Cps. SW had the largest population among the 8 isolates. SW inhibited Cps culture growth similar to three other antagonistic isolates but was the strongest suppressor of Cps conidial germination and germling development. When the cell-free supernatant (CFS) from SW liquid cultures was used to treat boxwood plants 48 h prior to inoculation with Cps, it resulted in a 69.4% disease reduction; suggesting involvement of its metabolites in disease suppression. Boxwood blight control efficacy was further evaluated with resuspended SW cell at 108-9 cfu.ml−1 at different treatment lead times. When SW was applied 2 or 10 days before inoculation with Cps, boxwood blight disease decreased by 72% and 67%, respectively. Further extending the lead time to 20 and 30 days, the efficacy was reduced to 26-27%. However, with its features of moderate control efficacy, high population in plant tissue and safety towards humans, SW shows great potential as a biocontrol agent for boxwood blight. Index words: Biocontrol agent, endophyte, plant pretreatment, Calonectria pseudonaviculata suppression. Species used in this study: Bacterium strain SW (Pseudomonas lactis). Plant species: Buxus sempervirens ‘Justin Brouwers'.

scholarly journals Effect of a bacteriophage T5virus on growth of Shiga toxigenic Escherichia coli and Salmonella strains in individual and mixed cultures

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Yan D. Niu ◽  
Hui Liu ◽  
Roger P. Johnson ◽  
Tim A. McAllister ◽  
Kim Stanford
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Biocontrol Agent ◽  
Sampling Time ◽  
Mixed Cultures ◽  
Broth Culture ◽  
Great Promise ◽  
Multiplicity Of Infection ◽  
Post Harvest ◽  
Zoonotic Pathogens

AbstractA previously isolated a bacteriophage, vB_EcoS_AKFV33 of T5virus, demonstrated great potential in biocontrol of Shiga toxigenic Escherichia coli (STEC) O157. This study further evaluated its potential as a biocontrol agent in broth culture against other important non-O157 serogroups of STEC and Salmonella. AKFV33 was capable of lysing isolates of STEC serogroups O26 (n = 1), O145 (n = 1) and Salmonella enterica serovars (n = 6). In a broth culture microplate system, efficacy of AKFV33 for killing STEC O26:H11, O145:NM and Salmonella was improved (P < 0.05) at a lower multiplicity of infection and sampling time (6–10 h), when STEC O157:H7 was also included in the culture. This phage was able to simultaneously reduce numbers of STEC and Salmonella in mixtures with enhanced activity (P < 0.05) against O157:H7 and O26:H11, offering great promise for control of multiple zoonotic pathogens at both pre and post-harvest.

scholarly journals Comparison of Microbiological Characteristics and Genetic Diversity between Burkholderia cepacia Complex Isolates from Vascular Access and Other Clinical Infections

2020 ◽  
Vol 9 (1) ◽  
pp. 51
Author(s):  
Min Yi Wong ◽  
Yuan-Hsi Tseng ◽  
Tsung-Yu Huang ◽  
Bor-Shyh Lin ◽  
Chun-Wu Tung ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Vascular Access ◽  
Burkholderia Cepacia ◽  
Bacterial Species ◽  
Diversity Indices ◽  
Burkholderia Cepacia Complex ◽  
Reca Gene ◽  
Clinical Effects ◽  
Environmental Distribution ◽  
Microbiological Characteristics

Burkholderia cepacia complex (BCC) is a group of closely related bacteria with widespread environmental distribution. BCC bacteria are opportunistic pathogens that cause nosocomial infections in patients, especially cystic fibrosis (CF). Multilocus sequence typing (MLST) is used nowadays to differentiate species within the BCC complex. This study collected 41 BCC isolates from vascular access infections (VAIs) and other clinical infections between 2014 and 2020. We preliminarily identified bacterial isolates using standard biochemical procedures and further conducted recA gene sequencing and MLST for species identification. We determined genetic diversity indices using bioinformatics software. We studied 14 isolates retrieved from patients with VAIs and observed that Burkholderia cepacia was the predominant bacterial species, and B. contaminans followed by B. cenocepacia were mainly retrieved from patients with other infections. According to MLST data, we identified that all B. contaminans isolates belonged to ST102, while a wide variety of sequence types (STs) were found in B. cenocepacia isolates. In summary, the high diversity and easy transmission of BCC increase BCC infections, which provides insights into their potential clinical effects in non-CF infections.

Multi-institutional outbreak of Burkholderia cepacia complex associated with contaminated mannitol solution prepared in compounding pharmacy

2013 ◽  
Vol 41 (11) ◽  
pp. 1038-1042 ◽  
Author(s):  
Maria Beatriz Souza Dias ◽  
Larissa G.T. Cavassin ◽  
Valeska Stempliuk ◽  
Luciene S. Xavier ◽  
Renata D. Lobo ◽  
...  
Keyword(s):  
Burkholderia Cepacia ◽  
Burkholderia Cepacia Complex ◽  
Mannitol Solution

scholarly journals Synergistic Effect of Combined Application of a New Fungicide Fluopimomide with a Biocontrol Agent Bacillus methylotrophicus TA-1 for Management of Gray Mold in Tomato

Plant Disease ◽  
2019 ◽  
Vol 103 (8) ◽  
pp. 1991-1997 ◽  
Author(s):  
Xiaoxue Ji ◽  
Jingjing Li ◽  
Zhen Meng ◽  
Shouan Zhang ◽  
Bei Dong ◽  
...  
Keyword(s):  
Field Experiments ◽  
Biocontrol Agent ◽  
Severe Disease ◽  
Combined Treatment ◽  
Field Trials ◽  
Antimicrobial Activities ◽  
Gray Mold ◽  
Control Efficacy ◽  
Bacillus Methylotrophicus

Gray mold caused by Botrytis cinerea can be a severe disease of tomato infecting leaves and fruits of tomato plants. Chemical control is currently the most effective and reliable method; however, application of fungicides has many drawbacks. The combination of biological control agents with newly developed fungicides may be a practicable method to control B. cinerea. Fluopimomide is a newly developed fungicide with a novel mode of action. Bacillus methylotrophicus TA-1, isolated from rhizosphere soil of tomato, is a bacterial strain with a broad spectrum of antimicrobial activities. Little information is currently available about the effect of fluopimomide and its integrated effect on B. cinerea. Therefore, laboratory, pot, and field experiments were carried out to determine the effects of fluopimomide alone and in combination with B. methylotrophicus TA-1 against gray mold on tomato. The in vitro growth of B. methylotrophicus TA-1 was unaffected by 100 mg liter−1 fluopimomide. Inhibition of B. cinerea mycelial growth was significantly increased under combined treatment of fluopimomide and B. methylotrophicus TA-1. In greenhouse experiments, efficacy against gray mold was significantly greater by an integration of fluopimomide and B. methylotrophicus TA-1 than by either alone; control efficacy of fluopimomide at 50 and 100 g ha−1 in combination with B. methylotrophicus TA-1 at 108 colony-forming units (cfu) ml−1 reached 70.16 and 69.32%, respectively, compared with the untreated control. In both field trials during 2017 and 2018, control efficacy was significantly higher for the combination of fluopimomide at 50 and 100 g ha−1 in combination with B. methylotrophicus TA-1 than for either treatment alone. The results from this study indicated that integration of the new fungicide fluopimomide with the biocontrol agent B. methylotrophicus TA-1 synergistically increased control efficacy of the fungicide against gray mold of tomato.

Clonal diversity among Burkholderia cepacia complex isolates from cystic fibrosis patients in a reference unit

2013 ◽  
Vol 31 (10) ◽  
pp. 665-668 ◽  
Author(s):  
Laura Barrado ◽  
M. Teresa Martinez ◽  
Jennifer Villa ◽  
M. Ángeles Orellana ◽  
Esther Viedma ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Burkholderia Cepacia ◽  
Clonal Diversity ◽  
Burkholderia Cepacia Complex

scholarly journals Differential Persistence among Genomovars of the Burkholderia cepacia Complex in a Murine Model of Pulmonary Infection

2002 ◽  
Vol 70 (5) ◽  
pp. 2715-2720 ◽  
Author(s):  
Karen K. Chu ◽  
Donald J. Davidson ◽  
T. Keith Halsey ◽  
Jacqueline W. Chung ◽  
David P. Speert
Keyword(s):  
Cystic Fibrosis ◽  
Clinical Outcomes ◽  
Murine Model ◽  
Burkholderia Cepacia ◽  
Pulmonary Infection ◽  
Burkholderia Cepacia Complex ◽  
Clinical Infection ◽  
Minimal Toxicity

ABSTRACT Cystic fibrosis patients infected with strains from different genomovars of the Burkholderia cepacia complex can experience diverse clinical outcomes. To identify genomovar-specific determinants that might be responsible for these differences, we developed a pulmonary model of infection in BALB/c mice. Mice were rendered leukopenic by administration of cyclophosphamide prior to intranasal challenge with 1.6 × 104 bacteria. Five of six genomovar II strains persisted at stable numbers in the lungs until day 16 with minimal toxicity, whereas zero of seven genomovar III strains persisted but resulted in variable toxicity. We have developed a chronic pulmonary model of B. cepacia infection which reveals differences among genomovars in terms of clinical infection outcome.

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