scholarly journals The biological control of the grapevine downy mildew disease using Ochrobactrum sp.

2019 ◽  
Vol 56 (No. 1) ◽  
pp. 52-61 ◽  
Author(s):  
Chaoqun Zang ◽  
Qiujun Lin ◽  
Jinhui Xie ◽  
Ying Lin ◽  
Shuyi Yu ◽  
...  
Keyword(s):  
Biological Control ◽  
Downy Mildew ◽  
Phytophthora Capsici ◽  
Morphological Characteristics ◽  
Good Control ◽  
Plasmopara Viticola ◽  
Antagonistic Activity ◽  
Bacterial Strains ◽  
Grapevine Downy Mildew

Grape downy mildew, caused by Plasmopara viticola (Berk. & M.A. Curtis) Berl. & De Toni 1888, is a widespread fungal disease that causes serious harm to the grape production. The long-term continuous use of chemical pesticides has caused issues with the resistance, residues and resurgence, as well as creating environmental pollution and the declining quality of the products. A biological control offers a safe and effective method to control diseases. We determined the in vitro antagonistic activity of 303 bacterial strains from infected grapevine leaves, and 12 isolates showed some level of antagonism in a detached leaf assay. Isolate SY286 reduced the disease severity in the detached leaves by 93.18%, and showed good control effects in a field assay. The scanning electron microscopy showed the damaged P. viticola cell walls when the mycelia and sporangia were treated with the fermentation liquor of isolate SY286. Furthermore, it showed an antagonistic activity against Phytophthora capsici, Phytophthora infestans, Botrytis cinerea, Fusarium oxysporum, Colletotrichum orbiculare, Trichothecium roseum, and Botryosphaeria berengeriana. The isolate was identified as Ochrobactrum sp. combined with its morphological characteristics, physiological and biochemical reactions and 16S rDNA sequence analysis, and it has the potential to control the grapevine downy mildew.

scholarly journals Antagonistic Effect of Gut Bacteria in the Hybrid Carniolan Honey Bee, Apis Mellifera Carnica, Against Ascosphaera Apis, the Causal Organism of Chalkbrood Disease

2014 ◽  
Vol 58 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Mohamed O. M. Omar ◽  
Adhm M. Moustafa ◽  
Mohammad J. Ansari ◽  
Abdelsalam M. Anwar ◽  
Bassam F. Fahmy ◽  
...  
Keyword(s):  
Biological Control ◽  
Apis Mellifera ◽  
Honey Bee ◽  
Antagonistic Activity ◽  
Bacterial Strains ◽  
Ascosphaera Apis ◽  
Causal Organism ◽  
Apis Mellifera Carnica

Abstract The objective of this study was to isolate and characterize bacterial strains associated with the gut of the hybrid Carniolan honey bee, Apis mellifera carnica, and to determine their in vitro and in vivo potential against Ascosphaera apis, the causal organism of chalkbrood disease, with the purpose of exploring feasible biological control. Six bacterial strains were isolated from healthy worker honey bees by culture-dependent methods. Six fungal strains (A3, A4, A7, A8, A9, and A15) of A. apis were isolated from larvae suffering from chalkbrood disease on Yeast-Glucose-Starch agar (YGPSA) medium. All bacteria were identified by a combination of morphology, Gram stain, and 16S rRNA sequence analysis, and fungal strains were identified by morphology and 5.8S rRNA. In vitro and in vivo inhibition assays were carried out to determine the ability of bacterial isolates to inhibit A. apis, the causal agent of chalkbrood disease. The analysis of 16S rRNA sequences revealed that four bacterial strains (B2, B4, B10, and B100) belong to Bacillus subtilis species, and two strains (P1 and P5) belong to Pseudomonas fluorescence. Significant differences in antagonistic activity of all bacterial strains were observed. B. subtilis isolate B2 showed the highest antagonistic activity, as measured by the inhibition zone against A. apis, followed by the P1 strain of P. fluorescence. SEM analysis also supports the antagonistic activity of these bacteria against A. apis. This study provides a theoretical basis for biological control of honey bee chalkbrood disease.

scholarly journals Characterization of CRN-Like Genes From Plasmopara viticola: Searching for the Most Virulent Ones

2021 ◽  
Vol 12 ◽  
Author(s):  
Gaoqing Xiang ◽  
Xiao Yin ◽  
Weili Niu ◽  
Tingting Chen ◽  
Ruiqi Liu ◽  
...  
Keyword(s):  
Cell Death ◽  
Downy Mildew ◽  
Molecular Mechanisms ◽  
Phytophthora Capsici ◽  
Sequence Divergence ◽  
Plasmopara Viticola ◽  
Wine Industry ◽  
In Planta ◽  
Vitis Riparia ◽  
Grapevine Downy Mildew

Grapevine downy mildew is an insurmountable disease that endangers grapevine production and the wine industry worldwide. The causal agent of the disease is the obligate biotrophic oomycete Plasmopara viticola, for which the pathogenic mechanism remains largely unknown. Crinkling and necrosis proteins (CRN) are an ancient class of effectors utilized by pathogens, including oomycetes, that interfere with host plant defense reactions. In this study, 27 CRN-like genes were cloned from the P. viticola isolate YL genome, hereafter referred to as PvCRN genes, and characterized in silico and in planta. PvCRN genes in ‘YL’ share high sequence identities with their ortholog genes in the other three previously sequenced P. viticola isolates. Sequence divergence among the genes in the PvCRN family indicates that different PvCRN genes have different roles. Phylogenetic analysis of the PvCRN and the CRN proteins encoded by genes in the P. halstedii genome suggests that various functions might have been acquired by the CRN superfamily through independent evolution of Plasmopara species. When transiently expressed in plant cells, the PvCRN protein family shows multiple subcellular localizations. None of the cloned PvCRN proteins induced hypersensitive response (HR)-like cell death on the downy mildew-resistant grapevine Vitis riparia. This was in accordance with the result that most PvCRN proteins, except PvCRN11, failed to induce necrosis in Nicotiana benthamiana. Pattern-triggered immunity (PTI) induced by INF1 was hampered by several PvCRN proteins. In addition, 15 PvCRN proteins prevented Bax-induced plant programmed cell death. Among the cell death-suppressing members, PvCRN17, PvCRN20, and PvCRN23 were found to promote the susceptibility of N. benthamiana to Phytophthora capsici, which is a semi-biotrophic oomycete. Moreover, the nucleus-targeting member, PvCRN19, promoted the susceptibility of N. benthamiana to P. capsici. Therefore, these PvCRN proteins were estimated to be virulent effectors involved in the pathogenicity of P. viticola YL. Collectively, this study provides comprehensive insight into the CRN effector repertoire of P. viticola YL, which will help further elucidate the molecular mechanisms of the pathogenesis of grapevine downy mildew.

scholarly journals A High-Quality Grapevine Downy Mildew Genome Assembly Reveals Rapidly Evolving and Lineage-Specific Putative Host Adaptation Genes

2019 ◽  
Vol 11 (3) ◽  
pp. 954-969 ◽  
Author(s):  
Yann Dussert ◽  
Isabelle D Mazet ◽  
Carole Couture ◽  
Jérôme Gouzy ◽  
Marie-Christine Piron ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Genome Assembly ◽  
Population Genomics ◽  
Plasmopara Viticola ◽  
Plant Diseases ◽  
Host Specialization ◽  
Grapevine Downy Mildew ◽  
Downy Mildews ◽  
Genes Encoding ◽  
High Level

Abstract Downy mildews are obligate biotrophic oomycete pathogens that cause devastating plant diseases on economically important crops. Plasmopara viticola is the causal agent of grapevine downy mildew, a major disease in vineyards worldwide. We sequenced the genome of Pl. viticola with PacBio long reads and obtained a new 92.94 Mb assembly with high contiguity (359 scaffolds for a N50 of 706.5 kb) due to a better resolution of repeat regions. This assembly presented a high level of gene completeness, recovering 1,592 genes encoding secreted proteins involved in plant–pathogen interactions. Plasmopara viticola had a two-speed genome architecture, with secreted protein-encoding genes preferentially located in gene-sparse, repeat-rich regions and evolving rapidly, as indicated by pairwise dN/dS values. We also used short reads to assemble the genome of Plasmopara muralis, a closely related species infecting grape ivy (Parthenocissus tricuspidata). The lineage-specific proteins identified by comparative genomics analysis included a large proportion of RxLR cytoplasmic effectors and, more generally, genes with high dN/dS values. We identified 270 candidate genes under positive selection, including several genes encoding transporters and components of the RNA machinery potentially involved in host specialization. Finally, the Pl. viticola genome assembly generated here will allow the development of robust population genomics approaches for investigating the mechanisms involved in adaptation to biotic and abiotic selective pressures in this species.

scholarly journals Isolation, Characterization, and Identification of Biological Control Agent for Potato Soft Rot in Bangladesh

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
M. M. Rahman ◽  
M. E. Ali ◽  
A. A. Khan ◽  
A. M. Akanda ◽  
Md. Kamal Uddin ◽  
...  
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Control Agent ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
Antagonistic Bacteria ◽  
And Storage

A total of 91 isolates of probable antagonistic bacteria of potato soft rot bacteriumErwinia carotovorasubsp.carotovora(Ecc) were extracted from rhizospheres and endophytes of various crop plants, different soil varieties, and atmospheres in the potato farming areas of Bangladesh. Antibacterial activity of the isolated probable antagonistic bacteria was testedin vitroagainst the previously identified most common and most virulent soft rot causing bacterial strain Ecc P-138. Only two isolates E-45 and E-65 significantly inhibited thein vitrogrowth of Ecc P-138. Physiological, biochemical, and carbon source utilization tests identified isolate E-65 as a member of the genusBacillusand the isolate E-45 asLactobacillussp. The stronger antagonistic activity against Ecc P-138 was found in E-65in vitroscreening and storage potatoes. E-65 reduced the soft rot infection to 22-week storage potatoes of different varieties by 32.5–62.5% in model experiment, demonstrating its strong potential to be used as an effective biological control agent for the major pectolytic bacteria Ecc. The highest (62.5%) antagonistic effect of E-65 was observed in the Granola and the lowest (32.7%) of that was found in the Cardinal varieties of the Bangladeshi potatoes. The findings suggest that isolate E-65 could be exploited as a biocontrol agent for potato tubers.

scholarly journals Evaluation of in vitro antagonistic activity of fungi from peatlands against Ganoderma species under acidic condition

2020 ◽  
Vol 21 (7) ◽  
Author(s):  
SUPRIYANTO ◽  
PURWANTO ◽  
S.H. POROMARTO ◽  
SUPYANI
Keyword(s):  
Biological Control ◽  
Antagonistic Activity ◽  
Biological Control Agents ◽  
Antagonistic Fungi ◽  
High Incidence ◽  
Acidic Conditions ◽  
Mineral Soils ◽  
Ph Range ◽  
Biological Methods

Abstract. Supriyanto, Purwanto, Poromarto SH, Supyani. 2020. Evaluation of in vitro antagonistic activity of fungi from peatlands against Ganoderma species under acidic conditions. Biodiversitas 21: 2935-2945. The use of peatlands is a significant contributor to the world’s palm oil production. A serious problem of oil palm plantations in peatlands is the high incidence of basal stem rot (BSR) disease caused by Ganoderma, which has a higher attack rate than on mineral soils. There is no effective way to control Ganoderma in peatlands. At present, the effort for the same focuses on environment-friendly biological methods; however, this is constrained by the unavailability of appropriate biological agents for peatlands. The development of biological control agents for peatlands is hampered by limited data on biological control of Ganoderma in peatlands. This research was conducted to evaluate the in vitro antagonistic activity of fungi isolated from a peatland in acidic pH conditions. Twenty-seven Ganoderma-antagonistic fungi from peatland were evaluated for their activity and their ability to antagonism in vitro within a pH range of 2-7. The results show that most antagonistic fungi from peatland, based on biomass weight, the sporulation ability, and germination of conidium, were able to grow optimally at pH 3.0-4.0, indicating that most of the Ganoderma-antagonistic fungi from peatland can be used as biological control agents for BSR on oil palms in peatlands.

scholarly journals Isolation of Plasmopara viticola from Grapevine Leaves

Proceedings ◽  
2019 ◽  
Vol 29 (1) ◽  
pp. 34
Author(s):  
Camelia Ungureanu ◽  
Liliana Cristina Soare ◽  
Diana Vizitiu ◽  
Mirela Calinescu ◽  
Irina Fierascu ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Plasmopara Viticola ◽  
Grapevine Downy Mildew ◽  
Grapevine Leaves ◽  
Downy Mildew Disease

In order to test some biofungicides, the isolation of Plasmopara viticola was carried out.Plasmopara viticola is a fungus that causes the grapevine downy mildew disease [...]

scholarly journals Identification of the First Oomycete Mating-type Locus Sequence in the Grapevine Downy Mildew Pathogen, Plasmopara viticola

2020 ◽  
Vol 30 (20) ◽  
pp. 3897-3907.e4 ◽  
Author(s):  
Yann Dussert ◽  
Ludovic Legrand ◽  
Isabelle D. Mazet ◽  
Carole Couture ◽  
Marie-Christine Piron ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Mating Type ◽  
Plasmopara Viticola ◽  
Type Locus ◽  
Grapevine Downy Mildew ◽  
Mating Type Locus

scholarly journals Draft Genome Sequence of Plasmopara viticola , the Grapevine Downy Mildew Pathogen

2016 ◽  
Vol 4 (5) ◽  
Author(s):  
Yann Dussert ◽  
Jérôme Gouzy ◽  
Sylvie Richart-Cervera ◽  
Isabelle D. Mazet ◽  
Laurent Delière ◽  
...  
Keyword(s):  
Downy Mildew ◽  
Genome Sequence ◽  
Genome Analysis ◽  
Plant Pathogen ◽  
Host Resistance ◽  
Draft Genome ◽  
Plasmopara Viticola ◽  
Host Specialization ◽  
Grapevine Downy Mildew ◽  
Plant Pathogen Interactions

Plasmopara viticola is a biotrophic pathogenic oomycete responsible for grapevine downy mildew. We present here the first draft of the P. viticola genome. Analysis of this sequence will help in understanding plant-pathogen interactions in oomycetes, especially pathogen host specialization and adaptation to host resistance.

scholarly journals Constituents and antimicrobial activity of the essential oils of six Himalayan Nepeta species

2010 ◽  
Vol 75 (6) ◽  
pp. 739-747 ◽  
Author(s):  
Dinesh Bisht ◽  
Rajendra Padalia ◽  
Lalit Singh ◽  
Veena Pande ◽  
Priyanka Lal ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Essential Oil ◽  
Essential Oils ◽  
Antagonistic Activity ◽  
Significant Activity ◽  
Variable Degree ◽  
Bacterial Strains ◽  
Fungal Strains ◽  
Microbial Strains

The essential oils from six Himalayan Nepeta species, viz. Nepeta leucophylla Benth., Nepeta discolor Royle ex Benth., Nepeta govaniana Benth., Nepeta clarkei Hook f., Nepeta elliptica Royle ex Benth. and Nepeta erecta Benth., were tested for their in vitro antimicrobial activity against six pathogenic bacterial and two fungal strains. The results showed that Pseudomonas aeruginosa was the most sensitive strain tested to the essential oils of Nepeta species. The essential oils of N. elliptica and N. erecta exhibited the highest activity against P. aeruginosa, followed by the essential oils of N. leucophylla and N. clarkei. The essential oils from N. elliptica and N. erecta were also found to be very effective against Serratia marcescens; while the essential oil from N. leucophylla displayed significant activity against Proteus vulgaris and Staphylococcus aureus. Other bacterial strains displayed variable degree of susceptibility against one or more of the tested essential oils. The essential oil from N. leucophylla also showed the highest antifungal activity against both tested fungal strains, viz. Candida albicans and Trichophyton rubrum, followed by the essential oils from N. clarkei, N. govaniana and N. erecta. Iridodial derivatives, viz. iridodial ?-monoenol acetate (25.4 %), dihydroiridodial diacetate (18.2 %) and iridodial dienol diacetate (7.8 %) were identified as the major constituents of N. leucophylla, while the essential oils from N. elliptica and N. erecta were dominated by (7R)-trans, trans nepetalactone (83.4 %) and isoiridomyrmecin (66.7 %), respectively. The essential oil of N. discolor was characterized by 1,8-cineole (25.5 %) and ?-caryophyllene (18.6 %), while N. clarkei was dominated by ?-sesquiphellandrene (22.0 %) and germacrene D (13.0 %). Isoiridomyrmecin (35.2 %) and pregeijerene (20.7 %) were identified as the major constituents of N. govaniana. In general the Nepeta species containing constituents with an iridoid or lactone skeleton were found to have the greater antagonistic activity against most of the microbial strains as compared to those containing regular terpene constituents.

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