scholarly journals Isolation and Identification of Chitinolytic Bacteria as Biocontrol Agent of Pathogenic Fungi on Gold Silkworm Cocoon Cricula trifenestrata

Author(s):  
Yunita, M. ◽  
Mubarik, N. R. ◽  
Solihin, D. D.
1998 ◽  
Vol 44 (2) ◽  
pp. 121-127 ◽  
Author(s):  
Emma Frändberg ◽  
Johan Schnürer

Chitinolytic bacteria are used as biocontrol agents of plant pathogenic fungi. They might also potentially inhibit growth of molds, e.g., Aspergillus spp. and Penicillium spp., in stored plant material. We isolated chitinolytic bacteria from airtight stored cereal grain and evaluated their antifungal capacity. Between 0.01 and 0.5% of the total aerobic counts were chitinolytic bacteria. Gram-negative bacteria, mainly Pseudomonadaceae, constituted approximately 80% of the chitinolytic population. Gram-positive isolates belonged predominantly to the Corynebacterium-Arthrobacter group, Streptomyces, and Bacillus. Chitinolytic activity was evaluated using culture filtrates from chitin-grown isolates as the release of p-nitrophenol from p-nitrophenyl N,N'-diacetylchitobiose and as the formation of clearing zones on chitin agar. No correlation between chitinolytic activity and antifungal effects was found when challenging Penicillium roqueforti Dierckx with bacterial isolates on chitin agar in a dual culture bioassay. Fungal hyphae frequently grew seemingly unaffected through the bacterial colony of a high chitinase producer on colloidal chitin. Only 4% of the chitinolytic isolates had strong effects on fungal growth. Among these, Streptomyces halstedii (K122) and Streptomyces coelicolor (K139) inhibited growth of a broad range of fungi. Streptomyces halstedii affected hyphal morphology and decreased the radial growth rate of all fungi investigated. These effects were not caused by volatile metabolites, polyenes, or N-carbamoyl-D-glucosamine.Key words: antifungal, chitinase, Streptomyces halstedii, Streptomyces coelicolor.


2011 ◽  
Vol 343-344 ◽  
pp. 1212-1216 ◽  
Author(s):  
Cun Kun Chen ◽  
Wen Sheng Wang ◽  
Jia Ning ◽  
Yuan Hui Gao

In order to investigate the reasons for the occurrence of melon disease, according to Koch’s postulates, the pathogenic fungi which caused the disease of postharvest melon“86-1”has been isolated and three kinds of bacterial strain has been identified. By identifying the pathogenicity, results revealed that they are Alternaria sp., Fusarium sp. and Penicillium sp.. They are the major pathogenic fungi which caused the decay of the postharvest Hami melon.


2019 ◽  
Vol 8 (1) ◽  
pp. 16
Author(s):  
Hari Suprapto ◽  
Sudarno Sudarno ◽  
Istikhara Mentari Tito

AbstrakIndonesia memiliki potensi perikanan yang sangat tinggi, salah satunya adalah lobster. Ekspor lobster air tawar cenderung meningkat tiap tahun. Total ekspor hasil lobster budidaya mencapai 94.511 ton/tahun. Pangsa pasar lobster air tawar tidak hanya terbatas di dalam negeri saja tetapi juga ke luar negeri. Penelitian ini bertujuan untuk mengetahui adanya bakteri kitinolitik dan juga jenis-jenis bakteri kitinolitik yang terdapat pada cangkang lobster air tawar. Penelitian ini menggunakan Penelitian ini menggunakan metode observasi untuk mengetahui adanya bakteri kitinolitik yang ada pada cangkang lobster air tawar. Data yang digunakan dalam penelitian ini adalah secara deskriptif. Data yang diperoleh dianalisis secara deskriptif yaitu penyajian data tentang morfologi dan karakteristik dari bakteri kitinolitik yang diisolasi dari cangkang lobser air tawar (Cherax quadricarinatus) dan dibandingkan dengan morfologi dan karakteristik bakteri kitinolitik dengan literatur yang sesuai. Hasil penelitian ini adalah diperoleh bahwa bakteri yang diisolasi dari cangkang lobster air tawar (Cherax quadricarinatus) dapat tumbuh dan berkembang pada media uji. Kemudian hasil uji hidrolisis bakteri kitinolitik ditandai dengan adanya zona bening yang dihasilkan dari bakteri tersebut. Dari hasil pengujian tersebut didapatkan jenis – jenis bakteri yaitu Aeromonas sp., Bacillus sp. dan Pseudomonas sp. AbstractIndonesia have highest potential of fishery. One of them is Lobster. It has increasing slightly, approximately 94.511 ton/years. The aims this research to determine the presence of chitinolytic bacteria and identify its species in crayfish shells. This research was performed via observation method to determine the presence of chitinolytic bacteria, which are exist in crayfish (cherax quadricarinatus) shell. The data used in this research is descriptive. The data descriptively analyzed represented the morphology and characteristics of chitinolytic bacteria isolated from crayfish (Cherax quadricarinatus) and comparison the morphology and characteristics of chitinolytic bacteria with appropriate literature. These results obtained that the bacteria isolated from crayfish (Cherax quadricarinatus) shell can grow and develop in the test medium. Then, chitinolytic activity was signed by the formation of clear zone on the test medium. The results obtained several bacterium species including Aeromonas sp., Bacillus sp. and Pseudomonas sp. 


2018 ◽  
Vol 14 (4) ◽  
pp. 120
Author(s):  
Dian Syahfitri ◽  
Nisa Rachmania Mubarik ◽  
Lisdar A Manaf

Use of Chitinolytic Bacteria as Biological Control of Colletotrichum capsici on Chili PlantsColletotrichum capsici is known as the causal agent of anthracnose disease in chili plant and may cause reduction of crop yield. Chitinolytic bacteria, namely Serratia marcescens KAHN 15.12, Bacillus thuringiensis SAHA 12.12, and BAE 36 were reported to have antagonistic activity against C. capsici. Therefore, a study was conducted to determine the potential of chitinolytic bacteria on controlling C. capsici on chili plants in greenhouse experiment. Three bacterial isolates used as biocontrol agent was formulated by using talcum as carrier materials. The methodologies consisted of characterization of bacterial isolates, formulation of biocontrol agent, viability test of bacterial isolate, efficacy of biocontrol agents in the laboratory and in the greenhouse.  Disease severity in the laboratory reached 64% when chili treated with isolate formulation of BAE 36.  In the greenhouse, BAE 36 isolate formulation and consortium formulation were able to suppress infection of C. capsici; each was indicated by disease incidence of 25% and 50%, respectively. These results indicated that chitinolytic bacterial formulations could be potencial as biocontrol agents of C. capsici.


2019 ◽  
Vol 25 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Babak Elyasifar ◽  
Sevda Jafari ◽  
Somayeh Hallaj-Nezhadi ◽  
Florence Chapeland-leclerc ◽  
Gwenaël Ruprich-Robert ◽  
...  

Background: Halophilic bacteria are potent organisms in production of novel bioactive antimicrobial compounds which might be considered in drug innovation and control of plant pathogens. Salt deserts in Semnan province are of the most permanent hypersaline areas in the North of Iran. Despite the importance of these areas, there is no scientific report regarding the biodiversity and potency of their halophilic bacteria. Thus, aforementioned areas were selected to detect the halophilic bacteria. Methods: Here, seven strains were isolated and cultured on their molecular and biochemical properties were characterized. To determine the antibiotic potency of the isolates, agar well diffusion method was conducted. Phylogenetic analysis was done to reveal the isolates relationship with previously known strains. Results: As a result, growth of the strains in the medium containing 5 to 20% (w/v) NaCl determined that the majority of the isolates were moderately halophile. Catalase activity of all strains was positive. The results represented that D6A, Dar and D8B have antimicrobial effects against different plant and human pathogens. Phylogenic tree analysis also showed that two strains of D6A and Dar are belonged to Bacillus subtilis and D8B is belonged to Virgibacillus olivae. The bacteria extracts were evaluated for their antifungal and antibacterial activities on human and Plant pathogenic strains. The MIC of the extract B. subtilis against was found active against human pathogenic fungi and Plant pathogenic bacteria and fungi, ranging from 12.5 to 25 µg/mL. Conclusion: This study highlights the therapeutic and prophylactic potential of B. subtilis extracts as antibacterial and antifungal agents.


Diversity ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 55 ◽  
Author(s):  
Héctor Herrera ◽  
Tedy Sanhueza ◽  
Alžběta Novotná ◽  
Trevor C. Charles ◽  
Cesar Arriagada

Endophytic bacteria are relevant symbionts that contribute to plant growth and development. However, the diversity of bacteria associated with the roots of terrestrial orchids colonizing Andean ecosystems is limited. This study identifies and examines the capabilities of endophytic bacteria associated with peloton-containing roots of six terrestrial orchid species from southern Chile. To achieve our goals, we placed superficially disinfected root fragments harboring pelotons on oatmeal agar (OMA) with no antibiotic addition and cultured them until the bacteria appeared. Subsequently, they were purified and identified using molecular tools and examined for plant growth metabolites production and antifungal activity. In total, 168 bacterial strains were isolated and assigned to 8 OTUs. The orders Pseudomonadales, Burkholderiales, and Xanthomonadales of phylum Proteobacteria were the most frequent. The orders Bacillales and Flavobacteriales of the phylla Firmicutes and Bacteroidetes were also obtained. Phosphate solubilization was detected in majority of isolates; however, it was significantly higher in Collimonas pratensis and Chryseobacterium sp. (PSI = 1.505 ± 0.09 and 1.405 ± 0.24, respectively). Siderophore production was recorded only for C. pratensis (0.657 ± 0.14 mm day−1), Dyella marensis (0.131 ± 0.02 mm day−1), and Luteibacter rhizovicinus (0.343 ± 0.12 mm day−1). Indole acetic acid production was highly influenced by the isolate identity; however, the significantly higher activity was recorded for Pseudomonas spp. (ranging from 5.507 ± 1.57 µg mL−1 to 7.437 ± 0.99 µg mL−1). Additionally, six bacterial isolates were able to inhibit the growth of some potential plant pathogenic fungi. Our findings demonstrate the potential for plant growth promoting capabilities and some antifungal activities of endophytic bacteria inhabiting the mycorrhizal tissue of terrestrial orchids, which may contribute especially at early developmental stages of orchid seedlings.


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