Use Of Native Strains Research Articles

Characterization of novel strains of <i>Trichoderma</i> spp. and their utilization in management of damping off disease in tomato

Chemical fungicides used in plant disease management may have deteriorative effects on humans, animals, and the environment. The use of native strains of Trichoderma spp. against plant diseases may help to reduce the dependence on chemical fungicides. In this study, eleven novel isolates of Trichoderma spp. from virgin forest soils of different agro-climatic zones of Kerala were characterized and evaluated for their efficacy against damping off disease of tomato caused by Pythium aphanidermatum under in vitro and in vivo; and also, against wilt pathogen, Fusarium oxysporum under in vitro conditions. Dual culture assay showed that all the Trichoderma isolates were found to inhibit the growth of P. aphanidermatum and F. oxysporum under in vitro conditions with multiple modes of action. The mycelial colour, texture, and conidial characters varied among all the isolates. The volatile metabolites by isolates of Trichoderma spp. also showed in vitro inhibition of the pathogens. Seed treatment (20 g kg-1) and potting medium addition @ 2 % (w/w) of isolates TRMW-2, TRKR-2, TRPN-3, TRPN-11 and TRPN-17 could effectively reduce pre- and post-emergence damping off of tomato. Among them, isolates TRMW-2, TRKR-2, and TRPN-11 were the most effective ones in reducing pre- and post-emergence damping off to about 72 and 90 percent respectively. Molecular identification of the isolates of Trichoderma spp. using ITS universal primers revealed similarity with certain reference strains of the NCBI Genbank database.

Peruvian Native Bacterial Strains as Potential Bioremediation Agents in Hg-Polluted Soils by Artisanal Mining Activities in Southern Peru

Bioremediation of soils and waters due to mercury (Hg) contamination represents one of the most critical environmental challenges. In addition, this challenge is even greater in arid soils due to the low economic interest in these regions. Such is the case of the Secocha Annex, located in the Arequipa province of Camaná in Southern Peru. In this region, the excessive use of Hg in artisanal and small-scale gold mining (ASGM) activities has seriously endangered the health of its inhabitants. Unfortunately, there are few projects aimed at improving the environmental and sanitary conditions of this locality. An alternative to conventional cleaning technology is the use of native microorganisms that allow the recovery of ecological environments with low-cost and low-tech techniques. This work aims to present two new Hg-resistant bacterial strains obtained from Hg-polluted soils of the Secocha Annex as potential bioremediation agents. Both strains showed growth capacity on Hg substrates and their adsorption behaviors and Hg removal capacities were evaluated. By deoxyribonucleic acid (DNA) analysis, both Gram-positive strains were identified as Kocuria sp. (99.35% similarity) and Zhihengliuella sp. (99.78% similarity). Spectrometry results showed elimination capacities with values close to 28.4 and 33.3 % in an incubation time period of 45 days, with the maximum elimination efficiency in the first 24 h. These results are encouraging and offer new possibilities for the use of native strains in the bioremediation of arid soils contaminated with Hg in the Secocha Annex. Furthermore, due to the low cost and minimization of negative impacts, this technique and our bacterial strains could be used in other regions of Peru.

Production of tubers from buds present in potato peel with fertilization of Trichoderma sp.

Potato consumption occurs throughout the Altiplano of Puno and among the organic wastes produced daily at home is potato peelings. The objective of this research is the production of tubers from buds present in potato peels with four strains of Trichoderma sp. The study was carried out under an experimental design with four strains of Trichoderma sp, in a randomized way with a total of 5 treatments that were distributed with two repetitions with a total of 12 experimental units, the potato peels with buds were selected, including a fertilization with four native and commercial strains of Trichoderma, some of them were codified since the species has not yet been identified, to support the growth of seedlings so, in this way, it gives value to the "organic production". The results found evidenced that the greater quantity of tubers was obtained with the strain of Trichoderma sp. 3 with 121.50 tubers/2.4m2 (10.13 tubers/plant). Followed by the strain of Trichoderma sp. 5 with 107.50 tubers/2.4m2 (8.96 tubers/plant), which statistically were similar and superior to the other treatments, while the control had less quantity of tubers with 18.50 tubers/2.4m2 (1.54 tubers/plant). Therefore, in the millenary practice of Andean wisdom, we rescued the use of native strains of Trichoderma sp. in order to contribute to the solution of human-environmental problems and the sustainable use of potato peelings in the region.

Evaluation of a native isolate of Metarhizium anisopliae (Metschn.) Sorokin TMBMA1 against tea mosquito bug, Helopeltis theivora infesting cocoa (Theobroma cacao L.)

The tea mosquito bug, Helopeltis spp. is a destructive pest of cocoa across the globe. In the climate change scenario, the tea mosquito bug species complex, viz. Helopeltis theivora Waterhouse, 1886, H. bradyi Waterhouse, 1886, and H. antonii V. Signoret, 1858, poses a serious threat to cocoa cultivation in India. Presently, systemic and/or broad-spectrum insecticides are used for mirid management by cocoa growers. However, concerns about their adverse effects on human health and the environment prompted us to search for alternative eco-friendly options for their management. Entomopathogenic fungi (EPF) are an effective and eco-friendly alternative to chemical insecticides for the management of cocoa mirids. The use of native strains of biological control agents improves their success rate. Hence, the present investigation was conducted to isolate, characterize and evaluate an indigenous insect-pathogenic isolate of EPF Metarhizium anisopliae against the mirid H. theivora. An extensive survey was conducted in the Dakshina Kannada district of Karnataka, India, to collect the adults of H. theivora naturally infected with entomopathogenic fungi. A pure culture of the EPF named as TMBMA1 was isolated from the infected adults. Based on the detailed morphological and molecular characterization, the isolate TMBMA1 was identified as Metarhizium anisopliae (Metsch.) Sorokin. The isolate TMBMA1 was found to be highly effective against H. theivora in an in-vitro bioassay and caused 100% insect mortality at 1 × 108 and 1 × 109 conidial suspensions 6 days post inoculation. Similarly, TMBMA1 was found effective in significantly reducing the incidence of mirids in field evaluations conducted for two consecutive years. TMBMA1 was found better than other commercial biopesticides and was comparable with the recommended chemical insecticide Lambda-cyhalothrin. In conclusion, our results reveal that the native EPF, M. anisopliae isolate TMBMA1 has great potential against the mirid H. theivora and can serve as an eco-friendly and sustainable alternative for mirid management in cocoa and other plantations in India.

First report of three species of Trichoderma isolated from the rhizosphere in Algeria and the high antagonistic effect of Trichoderma brevicompactum to control grey mould disease of tomato

BackgroundGrey mould caused by Botrytis cinerea Pers. (teleomorph Botryotinia fuckeliana (de Bary) Whetzel) is one of the most destructive fungal diseases of Mediterranean crops. In Algeria, few studies have been made on the economic impact of this disease. Nevertheless, it is practically present in all tomato and strawberry greenhouses, as well as in prospected vineyards in the north and south of the country. The complexity of chemical control of this disease has led to search for Trichoderma strains that are effective in biological control.ResultsFifteen isolates of Trichoderma spp. were obtained from vigorous and healthy plants (tomatoes, strawberries, and vines) rhizosphere, and from a commercial bio-compost (Bio-composte®), then identified as T. afroharzianum (four isolates), T. gamsii (four isolates), T. longibrachiatum (three isolates), T. atroviride (one isolate), T. brevicompactum (one isolate), T. breve (one isolate), and T. lixii (one isolate) on the basis of DNA sequence analysis of four genes (ITS, tef1, rpb2, and acl1). In vitro biocontrol tests revealed that four Algerian isolates of Trichoderma spp. (TAtC11, TGS7, TGS10, and TBS1) had a high antagonistic activity against B. cinerea, the mycelial growth has been reduced by 62 to 65% in dual-culture technique, by 62.31 to 64.49% in volatile compounds test, and a high inhibition of germling growth was recorded by TBS1 isolate with 90.68% in Culture filtrates test. Biocontrol tests carried out on tomato plants with T. brevicompactum (TBS1), T. atroviride (TAtC11), and T. lixii (TLiC8) against B. cinerea (BCT04) showed that TBS1 inoculation significantly reduced the incidence of disease by 64.43 and 51.35% in preventive and curative treatment, respectively.ConclusionThe present study revealed the first report of T. brevicompactum, T. breve, and T. lixii in Algeria, and it also contributes to the promotion of the use of native strains of Trichoderma in biological control leading to a better preservation of soil microbial diversity.

Trichoderma as biological control agent: scope and prospects to improve efficacy.

A major current challenge is to increase the food production while preserving natural resources. Agricultural practices that enhance the productivity and progressively improve the soil quality are relevant to face this challenge. Trichoderma species are widely used in agriculture to stimulate the plant growth and to control different pathogens affecting crops, representing useful tools for sustainable food production. This mini-review summarizes applications of Trichoderma strains in agriculture to control fungal pathogens, nematodes and insects, the involved biocontrol mechanisms, efficacy and inoculation forms in greenhouse, field and post-harvest conditions. Aspects of Trichoderma handling that influence on biocontrol efficacy such as preventive treatments, frequency of applications and delivery methods are discussed. Strategies useful to improve the antagonistic performance such as the use of native strains, protoplast fusion, formulation, growth on pathogen cell wall medium and combination with other antagonists in integrated treatments are discussed. This mini-review provides practical knowledge to design safe and optimal biocontrol strategies based on Trichoderma and pose challenges to expand its antagonist performance.

Impact of the Physicochemical Composition and Microbial Diversity in Apple Juice Fermentation Process: A Review.

Fermented apple beverages are produced all over the world with diverse characteristics associated with each country. Despite the diversifications, cider producers are confronted with similar issues and risks. The nature of the raw material, also known as the fermentation medium, plays a key role in fermentation. A well-defined composition of apples is, therefore, required to produce cider with good quality. In addition, ferment and its metabolism are important factors in the fermentation process. The producers of cider and other alcoholic beverages are looking in general for novel yeast strains or for the use of native strains to produce “authentic” and diversified beverages that are distinct from each other, and that attract more and more consumers. Research articles on cider production are infrequent compared to wine production, especially on the impact of the chemical composition and microbial diversity of apples on fermentation. Even though the processing of fermented beverages is close in terms of microbial interactions and production, the study of the specific properties of apples and the production challenges of cider production is advantageous and meaningful for cider producers. This review summarizes the current knowledge on apple composition and the impact of the must composition on fermentation and yeast growth. In addition, the microbial diversity of cider, activities, and its influence on fermentation are reviewed.

Effect of Colombian Strains ofSteinernema colombiense(Rhabditida: Steinernematidae) andHeterorhabditis bacteriophora(Rhabditida: Heterorhabditidae) AgainstEurhizococcus colombianus(Hemiptera: Margarodidae) andAeneolamiasp. (Hemiptera: Cercopidae)

Summary Two entomopathogenic nematodes, Steinernema colombiense sp. nov. (strain SNIO198) (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora Poinar (strain Fresno HNI0100) (Rhabditida: Heterorhabditidae), were isolated from the Colombian Andes and cultured in the laboratory. In semi-field tests against the ground pearl Eurhizococcus colombianus Jakubski (Hemiptera: Margarodidae) on blackberry, neither species was pathogenic to crawlers and only S. colombiense was moderately infective against adults at 105 IJ/ml. Higher activity for both nematodes was observed against immature spittlebugs Aeneolamia sp. (Hemiptera: Cercopidae) infesting kikuyu grass, with H. bacteriophora and S. colombiense killing 100% and 75% of insects, respectively, in our tests. Our results demonstrate the potential use of native strains of entomopathogenic nematodes as biological control agents in Colombia.

Characterization of a phenol-degrading bacterium isolated from an industrial effluent and its potential application for bioremediation

The use of native microorganisms is a useful strategy for phenol bioremediation. In the present work, a bacterial strain, named RTE1.4, was isolated from effluents of a chemical industry. The strain was able to grow at high concentrations of phenol and its derivatives, such as guaiacol, 2,4-dichlorophenol and pentachlorophenol, as well as in a medium containing industrial effluents. This bacterium was identified as Acinetobacter sp. using morphological, physiological, biochemical and 16S rRNA gene analysis. Acinetobacter sp. RTE1.4 degraded phenol (200 to 600 mg/L) at wide pH range and temperature (5–9 and 25–37°C, respectively) demonstrating high adaptation ability to different conditions. The strain would metabolize phenol by the ortho-pathway since catechol 1,2-dioxygenase activity was detected. When bacteria were grown in medium containing phenol, an altered whole-cell protein pattern was observed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), with the lack of some low-molecular mass polypeptides and an increase in the relative abundance of high-molecular mass proteins after treatment. Considering that the use of native strains in bioremediation studies shows several ecological advantages and that the studied bacterium showed high tolerance and biodegradation capabilities, Acinetobacter sp. RTE1.4 could be an appropriate microorganism for improving bioremediation and biotreatment of areas polluted with phenol and/or some of its derivatives. Moreover, the establishment of the optimal growth conditions (pH, temperature, concentration of the pollutant) would provide baseline data for bulk production of the strain and its use in bioremediation processes.

Heavy metal tolerance of microorganisms isolated from wastewaters: Identification and evaluation of its potential for biosorption

The aim of this study was to select autochthonous microorganisms that are able to biosorb heavy metals in aqueous systems. Forty-eight strains, included fungi, yeasts and bacteria, were isolated from water and sludge samples from urban and industrial wastewater treatment plants in the province of Jaén, southern Spain. Purified isolates were screened on the basis of their resistance to Pb(II), Zn(II) and Ag(I). Ten strains were selected and identified by molecular techniques. Tolerance index and minimum inhibitory concentration (MIC) for the three metals were also determined. It can be noted that tolerance of the strains appears to be associated with the sites of their isolation. The best results were obtained for the yeast Trichosporon sp. 4S3 which showed the following MICs: 32–35mM for lead, 16–18mM for zinc and 3–5mM for silver. The use of native strains can be an interesting alternative for bioremediation processes of heavy metals. This study increases the number of microbial strains that have the ability to resist relatively higher concentrations of metals, which may make them recommendable as potentially low-cost biosorbents. The nucleotide sequences of all the selected isolates were deposited in GenBank, which could be of great interest for other investigators as reference strains in bioremediation processes of heavy metals.