Screening supplements to enhance the biological control activity of HR42 against Colletotrichum acutatum

Ten compounds were evaluated for their effects on the efficacy of the bacterial biological control agent (BCA) HR42 against the avocado postharvest rot fungus Colletotrichum acutatum The effects of the 10 compounds (chitin Dglucose glycol chitosan Lserine Laspartic acid calcium chloride calcium carbonate potassium chloride ammonium molybdate and sodium carbonate) at four different concentrations (1 10 100 and 1000 mM) were tested separately on bacterial and fungal growth Lserine Laspartic acid and calcium chloride all stimulated growth of HR42 and suppressed mycelial growth of C acutatum The BCA and these compounds were then tested in combination on detached avocado fruit for their ability to inhibit lesion development following woundinoculation A high concentration of HR42 (107 cfu/ml) significantly inhibited the development of lesions caused by 105 and 107 conidia/ml of C acutatum There was no improvement of control by the addition of any of the three compounds These results show that HR42 has biocontrol activity against C acutatum in a detached fruit test but there was no enhancement of control by the addition of supplements

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Mechanistically Compatible Mixtures of Bacterial Antagonists Improve Biological Control of Fire Blight of Pear

Phytopathology ◽

10.1094/phyto-03-10-0098 ◽

2011 ◽

Vol 101 (1) ◽

pp. 113-123 ◽

Cited By ~ 54

Author(s):

V. O. Stockwell ◽

K. B. Johnson ◽

D. Sugar ◽

J. E. Loper

Keyword(s):

Biological Control ◽

Plant Disease ◽

Fire Blight ◽

Biological Control Agent ◽

Field Trials ◽

Control Agent ◽

Extracellular Protease ◽

Peptide Antibiotics ◽

Biological Control Agents ◽

Control Activity

Mixtures of biological control agents can be superior to individual agents in suppressing plant disease, providing enhanced efficacy and reliability from field to field relative to single biocontrol strains. Nonetheless, the efficacy of combinations of Pseudomonas fluorescens A506, a commercial biological control agent for fire blight of pear, and Pantoea vagans strain C9-1 or Pantoea agglomerans strain Eh252 rarely exceeds that of individual strains. A506 suppresses growth of the pathogen on floral colonization and infection sites through preemptive exclusion. C9-1 and Eh252 produce peptide antibiotics that contribute to disease control. In culture, A506 produces an extracellular protease that degrades the peptide antibiotics of C9-1 and Eh252. We hypothesized that strain A506 diminishes the biological control activity of C9-1 and Eh252, thereby reducing the efficacy of biocontrol mixtures. This hypothesis was tested in five replicated field trials comparing biological control of fire blight using strain A506 and A506 aprX::Tn5, an extracellular protease-deficient mutant, as individuals and combined with C9-1 or Eh252. On average, mixtures containing A506 aprX::Tn5 were superior to those containing the wild-type strain, confirming that the extracellular protease of A506 diminished the biological control activity of C9-1 and Eh252 in situ. Mixtures of A506 aprX::Tn5 and C9-1 or Eh252 were superior to oxytetracycline or single biocontrol strains in suppressing fire blight of pear. These experiments demonstrate that certain biological control agents are mechanistically incompatible, in that one strain interferes with the mechanism by which a second strain suppresses plant disease. Mixtures composed of mechanistically compatible strains of biological control agents can suppress disease more effectively than individual biological control agents.

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Saccharomyces cerevisiae: A novel and efficient biological control agent for Colletotrichum acutatum during pre-harvest

Microbiological Research ◽

10.1016/j.micres.2015.04.003 ◽

2015 ◽

Vol 175 ◽

pp. 93-99 ◽

Cited By ~ 29

Author(s):

Marcos Roberto Lopes ◽

Mariana Nadjara Klein ◽

Luriany Pompeo Ferraz ◽

Aline Caroline da Silva ◽

Katia Cristina Kupper

Keyword(s):

Saccharomyces Cerevisiae ◽

Biological Control ◽

Biological Control Agent ◽

Control Agent ◽

Colletotrichum Acutatum

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Biological control of symphylid pests in a commercial chrysanthemum (Dendranthema grandiflora) crop using the fungus Purpureocillium lilacinum, strain UdeA0106

Revista Facultad Nacional de Agronomía Medellín ◽

10.15446/rfnam.v73n1.76027 ◽

2020 ◽

Vol 73 (1) ◽

pp. 9057-9064

Author(s):

Diego Alberto Salazar-Moncada ◽

Julián Morales-Muñoz ◽

Nadya Cardona-Bustos

Keyword(s):

Biological Control ◽

Biological Control Agent ◽

Control Agent ◽

High Concentration ◽

Dendranthema Grandiflora ◽

Purpureocillium Lilacinum

The symphylids, also known as garden centipedes or pseudocentipedes, are soil-dwelling arthropods of the class Symphyla. They affect diverse crops worldwide due to the consumption of young roots and seedlings. This study presents the effectiveness of the fungus Purpureocillium lilacinum (strain UdeA0106) to reduce the symphylid population under commercial greenhouse conditions. The results showed that this fungus strain could reduce symphylid density by 70.6%. It also demonstrated that a high concentration of strain UdeA0106 helped to recover chrysanthemum (Dendranthema grandifIora) crops infested with symphylid. The results shown in this paper are the first evidence of effective biological control of symphylids pest in a commercial fIower plantation, representing the potential of P. lilacinum strain UdeA0106 as a biological control agent.

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Generation of Trichoderma harzianum with pyr4 auxotrophic marker by using the CRISPR/Cas9 system

Scientific Reports ◽

10.1038/s41598-020-80186-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Amanda A. Vieira ◽

Giovanni R. Vianna ◽

Jessica Carrijo ◽

Francisco J. L. Aragão ◽

Pabline M. Vieira

Keyword(s):

Biological Control ◽

Trichoderma Harzianum ◽

Biological Control Agent ◽

Control Agent ◽

Phenotypic Characterization ◽

Agricultural Pests ◽

Control Activity ◽

Guide Rna ◽

Endogenous Expression ◽

Auxotrophic Marker

AbstractTrichoderma harzianum is a filamentous fungus used as a biological control agent for agricultural pests. Genes of this microorganism have been studied, and their applications are patented for use in biofungicides and plant breeding strategies. Gene editing technologies would be of great importance for genetic characterization of this species, but have not yet been reported. This work describes mutants obtained with an auxotrophic marker in this species using the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)/ Cas (CRISPR-associated) system. For this, sequences for a guide RNA and Cas9 overexpression were inserted via biolistics, and the sequencing approach confirmed deletions and insertions at the pyr4 gene. Phenotypic characterization demonstrated a reduction in the growth of mutants in the absence of uridine, as well as resistance to 5-fluorotic acid. In addition, the gene disruption did not reduce mycoparasitc activity against phytopathogens. Thus, target disruption of the pyr4 gene in T. harzianum using the CRISPR/Cas9 system was demonstrated, and it was also shown that endogenous expression of the system did not interfere with the biological control activity of pathogens. This work is the first report of CRISPR Cas9-based editing in this biocontrol species, and the mutants expressing Cas9 have potential for the generation of useful technologies in agricultural biotechnology.

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