scholarly journals Morphological and molecular characterisation of Streptomyces spp. which suppress pathogenic fungi

2020 ◽  
Vol 28 (4) ◽  
pp. 555-566
Author(s):  
N. Goredema ◽  
T. Ndowora ◽  
R. Shoko ◽  
E. Ngadze
Keyword(s):  
Antimicrobial Activity ◽  
Fusarium Oxysporum ◽  
Aspergillus Flavus ◽  
Plant Pathogens ◽  
Morphological Characteristics ◽  
Molecular Characteristics ◽  
Penicillium Italicum ◽  
Streptomyces Species ◽  
Genus Streptomyces ◽  
Wide Range

Streptomyces species are aerobes and chemoorganotrophic bacteria. These microorganisms produce a wide range of industrially significant compounds, specifically antibiotics and anti fungal substances. The objective of this study was to characterise soil-borne Streptomyces isolates using morphological and molecular traits in order to identify them to species level, and leverage from their potential to suppress the growth of Aspergillus flavus, Fusarium oxysporum and Penicillium italicum. Twenty-seven soil-borne putative Streptomyces, which elicited comprehensive antimicrobial activity against Aspergillus flavus, Fusarium oxysporum and Penicillium italicum, in a previous study, were evaluated. On the basis of morphology, the bacteria resembled the genus Streptomyces. Initially, colonies phenotypically appeared to have a relatively smooth surface but as growth progressed the bacteria developed a weft of aerial mycelium granular, powdery or velvety in appearance. Bacteria produced a wide variety of pigments which in turn were responsible for the colour of the vegetative and aerial mycelia, colour ranged from white to cream or buff shades and yellow to orange or brown. Microscopic analyses and morphological characteristics generated sub-groups of the isolates and clustered them according to their similarities. One bacterial strain was randomly selected from each cluster and investigated using molecular characteristics. Partial 16S rDNAs from the selected representative isolates from each subgroup, were sequenced and phylogenetic analysis performed. The 16S rDNA sequences of the isolates indicated that they were related to  Streptomyces species: S. bungoensis, S. thermocarboxydus, S. corchorusii and S. lasaliensis, that are known secondary metabolite producers possessing antimicrobial activity against plant pathogens.

scholarly journals In vitro suppression of pathogenic fungi by Streptomyces spp.

2020 ◽  
Vol 28 (2) ◽  
pp. 141-149
Author(s):  
N. Goredema ◽  
T. Ndowora ◽  
R. Shoko ◽  
E. Ngadze
Keyword(s):  
Antimicrobial Activity ◽  
Fusarium Oxysporum ◽  
Aspergillus Flavus ◽  
Pathogenic Fungi ◽  
Penicillium Italicum ◽  
Natural Form ◽  
Multiple Test ◽  
Streptomyces Spp ◽  
Living Organisms

The use of living organisms or natural enemies of pathogens to control their populations is called biological disease control. It involves harnessing and introduction of exotic species of microorganism in a natural form, with the intention of controlling pathogens that may exist naturally in the same ecosystem. Prospects for biological control of Aspergillus flavus, Fusarium oxysporum and Penicillium italicum were investigated using Streptomyces spp. isolated from Chinhoyi University of Technology Farm soils in Mashonaland West, Zimbabwe. Twenty seven Streptomyces spp were obtained from the soil, and screened for antimicrobial activity and antagonism in in vitro pathogen inhibition assays, replicated thrice. Although majority of the isolates tested elicited no effect on test pathogens, 22% of the Streptomyces isolates were able to effectively suppress A. flavus, F. oxysporum and P. italicum by at least 55%. There was a significant interaction between Streptomyces isolates and pathogen (A. flavus, F. oxysporum and P. italicum) (P<0.05) on fungal radial growth at days 7, 10 and 14 after pathogen-Streptomyces incubation. Antimicrobial potential against individual and multiple test pathogens was observed, with CUT-Streptomyces 4, CUT-Streptomyces 10, CUT-Streptomyces 11, CUT-Streptomyces 20 and CUT-Streptomyces 23 showing the greatest antimicrobial activity. CUT-Streptomyces isolates have the potential to suppress A. flavus, F. oxysporum and P. italicum in vitro. Key words:  Aspergillus flavus, Fusarium oxysporum, Penicillium italicum

scholarly journals The Potential of New Streptomyces Isolates as Biocontrol Agents Against Fusarium Spp

2018 ◽  
Vol 1 (1) ◽  
pp. 594-600
Author(s):  
Mihaela Ursan ◽  
Oana Alina Boiu-Sicuia ◽  
Cătălina Voaides ◽  
Vasilica Stan ◽  
Corina Bubueanu ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Plant Protection ◽  
Screening Method ◽  
Biocontrol Agents ◽  
Fungal Resistance ◽  
Bacterial Strains ◽  
Fusarium Spp ◽  
Streptomyces Species ◽  
Streptomyces Spp ◽  
Wide Range

Abstract The excessive use of synthetic pesticides for plant pathogens control could cause possible harmful side-effects to humans and animals, environmental pollution, residual toxicity, affects soil characteristics or induce the development of fungal resistance. Alternative ways for fungal contamination control involve natural products, based on microorganisms, many of them being already available for use. The selection and characterization of new biological agents useful for plant pathogens control are permanent goals for plant protection researches. In the last decade, several studies revealed that Streptomyces species are promising biocontrol agents against a wide range of phytopathogenic fungi, including Fusarium spp., one of the most important wheat pathogens. In our study, 60 strains of Streptomyces spp. were isolated from soil or compost and evaluated for in vitro antifungal abilities by dual confrontation method. At least 30% of the isolates presented inhibitory activity against F. culmorum and F. graminearum. The bacterial strains were also tested for their ability to produce various bioactive compounds, possible involved in fungal inhibition. The capacity of some of the bacterial isolates to produce cellulases, amylases, lipases and volatile metabolites was proved. In addition, a new screening method for chitinases production was developed, based on the use of a combination of Congo red and Lugol solutions, which allowed the detection of chitinases in several Streptomyces spp. strains. Moreover, the reduction of the level of some Fusarium mycotoxins was detected by HPTLC analysis. As a conclusion, antagonistic interactions between Streptomyces isolates and fusaria could involve antibiosis, competition and parasitism and suggested that at least some of the selected isolates could be used in obtaining biological control products.

scholarly journals Inventarisasi dan Identifikasi Patogen Tular-tanah pada Pertanaman Kentang di Kabupaten Purbalingga

2016 ◽  
Vol 21 (3) ◽  
pp. 254
Author(s):  
Lukassus Soesanto ◽  
E Mugiastuti ◽  
R F Rahayuniati
Keyword(s):  
Phytophthora Infestans ◽  
Fusarium Oxysporum ◽  
Ralstonia Solanacearum ◽  
Plant Pathogens ◽  
Morphological Characteristics ◽  
Soil Bioremediation ◽  
Fluorescent Pseudomonad ◽  
Purposive Sampling ◽  
Growth Production ◽  
Yield Quality

atogen tular-tanah di lahan kentang merupakan salah satu faktor penting yang berpengaruh terhadap pertumbuhan, produksi, dan kualitas hasil tanaman. Inventarisasi dan identifikasi patogen tular-tanah di lahan kentang dengan metode purposive sampling telah dilakukan di Kabupaten Purbalingga, yang meliputi Dusun Gunung Malang di Desa Serang dan Dusun Bambangan dan Kutabawa di Desa Kutabawa Kecamatan Karangreja dari bulan November 2008 sampai Januari 2009. Penelitian bertujuan untuk mengetahui jenis dan virulensi patogen tular-tanah di lahan kentang di lokasi tersebut. Isolasi dan uji virulensi dilaksanakan di Laboratorium Mikrobiologi, Fakultas Pertanian, Universitas Jenderal Soedirman, Purwokerto. Peubah yang diamati yaitu karakter morfologi mikrobe patogen, kepadatan di dalam tanah, dan reaksi hipersensitif. Hasil penelitian menunjukkan bahwa tujuh spesies patogen ditemukan di lahan kentang, yaitu Fusarium oxysporum, F. solani, Ralstonia solanacearum, Curvularia sp., Phytophthora infestans, Helminthosporium purpureum, dan Pseudomonas kelompok berpendar. Populasi mikrobe di lahan kentang yang paling dominan ialah R. solanacearum, yaitu 71,6%, disusul oleh F. oxysporum sebesar 16,87%. Sebaran mikrobe di masing-masing lahan kentang berbeda. Semua lahan kentang di Kabupaten Purbalingga sudah terkontaminasi patogen tular-tanah penting sehingga perlu disehatkan kembali secara hayati.<br /><br /><br /><br />Soilborne plant pathogens in potato land are one of important factors influencing plant growth, production and yield quality. Inventarization and identification of soilborne diseases using purposive sampling method  were conducted at potato land in Purbalingga Regency consisted of Guning Malang location at Serang Village and Bambangan and Kutabawa locations at Kutabawa Village, Karangreja District from November 2008 to January 2009.  The study aimed to determine type and virulence of soilborne pathogens at the locations.  Isolation and virulence test were carried out at the Laboratory of Microbiology, Faculty of Agriculture, Jenderal Soedirman University, Purwokerto. Variable observed in the research was morphological characteristics of pathogenic microbes, their density in soils, and response of hypersensitive test. Result of the research showed that seven pathogenic species were found at the land, i.e., Fusarium oxysporum, F. solani, Ralstonia solanacearum, Curvularia sp., Phytophthora infestans, Helminthosporium purpureum, and fluorescent Pseudomonad. The dominant microbe population in potato land was R. solanacearum with 71.6% followed by F. oxysporum with 16.87%. The microbes were spread differently in every potato land. All potato lands in Purbalingga Regency have been contaminated by the important potato pathogens so that soil bioremediation is needed.

scholarly journals De Novo Design of Antimicrobial Peptides With a Special Charge Pattern and Their Application in Combating Plant Pathogens

2021 ◽  
Vol 12 ◽  
Author(s):  
Eric H. -L. Chen ◽  
Cheng-Wei Weng ◽  
Yi-Min Li ◽  
Ming-Chin Wu ◽  
Chien-Chih Yang ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
Plant Pathogens ◽  
De Novo ◽  
Plant Protection ◽  
Acyl Chain ◽  
Fatty Acyl ◽  
Plant Diseases ◽  
Basic Residue ◽  
Wide Range

Plant diseases are important issues in agriculture, and the development of effective and environment-friendly means of disease control is crucial and highly desired. Antimicrobial peptides (AMPs) are known as potential alternatives to chemical pesticides because of their potent broad-spectrum antimicrobial activity and because they have no risk, or have only a low risk, of developing chemical-resistant pathogens. In this study, we designed a series of amphipathic helical peptides with different spatial distributions of positive charges and found that the peptides that had a special sequence pattern “BBHBBHHBBH” (“B” for basic residue and “H” for hydrophobic residue) displayed excellent bactericidal and fungicidal activities in a wide range of economically important plant pathogens. The peptides with higher helical propensity had lower antimicrobial activity. When we modified the peptides with a long acyl chain at their N-terminus, their plant protection effect improved. Our application of the fatty acyl-modified peptides on the leaves of tomato and Arabidopsis plants lessened the infection caused by Pectobacterium carotovorum subsp. carotovorum and Botrytis cinerea. Our study provides important insights on the development of more potent novel AMPs for plant protection.

Additions to Karst Fungi 4: Botryosphaeria spp. associated with woody hosts in Guizhou province, China including B. guttulata sp. nov.

Phytotaxa ◽  
2020 ◽  
Vol 454 (3) ◽  
pp. 186-202
Author(s):  
YA-YA CHEN ◽  
ASHA J. DISSANAYAKE ◽  
ZUO-YI LIU ◽  
JIAN-KUI (JACK) LIU
Keyword(s):  
Plant Pathogens ◽  
Sequence Data ◽  
Morphological Characteristics ◽  
Abundant Species ◽  
Molecular Data ◽  
Nature Reserves ◽  
Guizhou Province ◽  
Botryosphaeria Dothidea ◽  
Wide Range ◽  
One New Species

Members of Botryosphaeria encompass important plant pathogens, saprobes and endophytes on a wide range of woody hosts worldwide. Botryosphaeria species are difficult to differentiate due to the overlapping morphological characteristics and the molecular data analyses are necessary recently when species identification is carried out. In this study, 28 Botryosphaeria isolates were obtained from decaying woody hosts in six nature reserves in Guizhou province, China. Based on both morphological characteristics and molecular analysis of combined ITS and tef1-α sequence data, four known species (Botryosphaeria dothidea, B. minutispermatia, B. sinensia and B. wangensis) are identified and one new species B. guttulata is introduced. Botryosphaeria sinensia (32% of the isolates obtained from various hosts) is the abundant species, followed by B. dothidea (28.5% of the isolates), B. guttulata (28.5% of the isolates), B. minutispermatia (7% of the isolates) and B. wangensis (4% of the isolates). These results represent the first study of Botryosphaeria species associated with woody hosts from nature reserves in Guizhou province, China. Our findings indicate that there is a potential of Botryosphaeria species remain to be discovered in this unique landform (Karst formations) in Guizhou province, China.

scholarly journals Etiology and Symptoms of Maize Leaf Spot Caused by Bipolaris spp. in Sichuan, China

Pathogens ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 229 ◽  
Author(s):  
Xiaofang Sun ◽  
Xiaobo Qi ◽  
Wei Wang ◽  
Xuan Liu ◽  
Henan Zhao ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Plant Pathogens ◽  
Morphological Characteristics ◽  
Disease Diagnosis ◽  
Sichuan Province ◽  
Population Diversity ◽  
Seedling Blight ◽  
Maize Leaf ◽  
Linear Lesions ◽  
Wide Range

Many species of the genus Bipolaris are important plant pathogens and often cause leaf spot, root rot, and seedling blight in an extremely wide range of hosts around the world. In recent years, maize leaf spot caused by Bipolaris species has frequently occurred with complex symptoms and is becoming increasingly serious in Sichuan Province of China. To investigate the population diversity of Bipolaris spp. and their corresponding symptoms in maize, 747 samples of maize leaf spot were collected from 132 sampling sites in 19 administrative districts of Sichuan Province from 2011 to 2018. Based on morphological characteristics, pathogenicity testing, and phylogenetic analysis of the rDNA internal transcribed spacer (ITS) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes, a total of 1186 Bipolaris isolates were identified as B. maydis, B. zeicola, B. cynodontis, B. oryzae, B. setariae, and B. saccharicola, among which B. maydis and B. zeicola were the dominant pathogenic species, accounting for 57.34% and 42.07% of the isolates, respectively. We found that B. zeicola isolates were mainly distributed in high altitude and cool mountainous areas, while B. maydis was more widely distributed in Sichuan Province. The typical symptoms caused by the Bipolaris species were clearly distinct in maize. The typical symptoms caused by B. maydis were elongated strip lesions, or fusiform, elliptical lesions, and those caused by B. zeicola were narrow linear lesions. Herein, B. saccharicola was first reported on maize and caused subrotund lesions. This study provides useful information for disease diagnosis and management for Bipolaris leaf spot in maize.

scholarly journals SURVEY ON THE INCIDENCE OF FUSARIUM WILT OF TOMATO INCITED BY FUSARIUM OXYSPORUM F.SP. LYCOPERSICI (FOL) IN MAJOR TOMATO GROWING AREAS OF KRISHNAGIRI DISTRICT

2020 ◽  
Vol 21 (supplemenet 1) ◽  
Author(s):  
K. Vignesh ◽  
K. Rajamohan ◽  
P. Balabaskar ◽  
R. Anandan ◽  
R. Udhayakumar
Keyword(s):  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Fungal Pathogen ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Wilt Disease ◽  
Tomato Seedlings ◽  
Collar Region ◽  
Wide Range ◽  
Wilt Incidence

Tomato is one of the most important, commercial and widely grown vegetable crop in the world. It is affected by several fungal, bacterial and viral diseases. Among these Fusarium wilt caused by the fungus Fusarium oxysporum f.sp. lycopersici causes 30-40% yield loss. A survey was conducted to investigate the incidence and severity of Fusarium wilt incited by Fusarium oxysporum f.sp. lycopersici in ten major tomato growing areas of Krishnagiri district. The occurrence of wilt disease incidence ranged from 18 % to 49% was noticed. Plant showing typical symptoms were taken from 10 fields and identified based on symptom appearance as well as morphological characteristics. The result of the survey revealed that wide range of infection and severity of wilt disease were occurred in the major tomato growing areas in Krishnagiri district. Isolation of the pathogen associated with tomato wilt was made from the diseased tissues in roots and collar region of the plant on the Potato dextrose agar (PDA) medium. Fol3 recorded the maximum wilt incidence followed by Fol4 and the minimum wilt incidence was recorded by Fol6 . The pathogenicity of the fungal pathogen was also proved after artificial inoculation of the tomato seedlings

scholarly journals Metrodorea flavida (K. Krause) Extracts in Pathogen Control of Senegalia polliphyla (Dc.) Seeds

2020 ◽  
pp. 1-7
Author(s):  
Eloisa Salvador Mascarini ◽  
Juliana Garlet ◽  
Muriel Da Silva Folli-Pereira
Keyword(s):  
Fusarium Oxysporum ◽  
Aspergillus Flavus ◽  
Morphological Characteristics ◽  
Promising Alternative ◽  
Ethanolic Extracts ◽  
Pathogen Control ◽  
Forest Seeds

This study aimed to determine the main pathogens present in Senegalia polliphyla (DC.) seeds and to evaluate the fungicidal potential of Metrodorea flavida (K. Krause) extracts. For this purpose, concentrations of 0.5, 1.0, 1.5 and 2.0% of the extract of Metrodorea flavida leaves were used, in an ethanolic or aqueous form. The experiment was carried out using the Blottertest method to assess the incidence of pathogens in seeds and after application of treatments. Thus, the effect of extracts on the incidence of pathogens and the effects of the extracts on the germination and morphological characteristics of the seedlings was analyzed. The main pathogens found in Senegalia polliphyla seeds were Aspergillus flavus and Fusarium oxysporum. The aqueous and ethanolic extracts reduced the infestation of pathogens associated with Senegalia polliphyla seeds, as well as the main fungus found: Aspergillus flavus Link. It was also found that the extracts did not influence the germination and morphological characteristics of Senegalia polliphyla seedlings in all concentrations evaluated, thus being a promising alternative for pathogen control in forest seeds.

scholarly journals Isolation, Screening and Time Course Study of Amylase-producing Fungi from Garri Processing Environment

2020 ◽  
Vol 1 (3) ◽  
pp. 68-75
Author(s):  
Francis Ire ◽  
Sotonye Ipalibo Wokoma ◽  
Augustine Okoli
Keyword(s):  
Waste Water ◽  
Aspergillus Flavus ◽  
Enzyme Production ◽  
Time Course ◽  
Morphological Characteristics ◽  
Industrial Applications ◽  
Molecular Characteristics ◽  
Amylase Secretion ◽  
Southern Nigeria ◽  
Time Course Study

Amylases (E.C.3.2.1.1) are enzymes which catalyze the breakdown of -1,4 glycosidic linkages of starch to simple sugars and different monomeric products. Microbial amylases are essential enzymes compared with animals and plants amylases in industrial applications. Thus, in southern Nigeria, garri processing waste-water from mills poses a serious environmental challenge and this situation could be exploited by utilizing microorganisms colonizing the area to manufacture microbial products. This present study was aimed at evaluating the potential of fungi isolated from garri processing environment for amylase secretion and conduct a time course study of the enzyme production. Fungi were isolated from the soil and waste water from garri processing sites using Standard Microbiological Procedures. The five fungi isolated from garri processing environmental samples were screened using Lugols iodine. Three fungal isolates were then selected on the hydrolysis of starch in qualitative zonation agar plates but one isolate named B among them was better in starch hydrolysis related to highest clear zone plates. After qualitative screening, the three hyper production amylase extracted fungi were identified according to the morphological characteristics. The hyper producing amylase isolate B was then identified as Aspergillus flavus (RCBBR_AEAFUN2) and recorded as a novel strain in southern Nigeria according to molecular characteristics, which was selected for further studies. The current results of time course study showed that the maximum growth (2.453 g) occurred after 24 h of incubation at pH 4.5 while maximum enzyme production (2.3 U/ml/min) was obtained after 96 h of incubation at pH 3.5. Therefore, the hyper producing amylase from garri processing sites, Aspergillus flavus (RCBBR_AEAFUN2) novel strain has great prospects for future biotechnological and industrial applications and help in ameliorating the environmental pollution posed by the waste-water.

scholarly journals Identification of Botryosphaeriaceae Species Causing Kiwifruit Rot in Sichuan Province, China

Plant Disease ◽  
2015 ◽  
Vol 99 (5) ◽  
pp. 699-708 ◽  
Author(s):  
You Zhou ◽  
Guoshu Gong ◽  
Yongliang Cui ◽  
Daixi Zhang ◽  
Xiaoli Chang ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Plant Pathogens ◽  
Elongation Factor ◽  
Morphological Characteristics ◽  
Sichuan Province ◽  
Fruit Rot ◽  
First Report ◽  
Primary Inoculum ◽  
Tubulin Genes ◽  
Wide Range

Species of Botryosphaeriaceae fungi are important plant pathogens causing cankers, blight, and fruit rot in an extremely wide range of host. In recent years, kiwifruit rot has been a serious problem in Sichuan Province, one of the important kiwifruit production areas of China. Botryosphaeria dothidea has previously been associated with kiwifruit rot but little is known regarding whether other Botryosphaeriaceae genera also constitute kiwifruit rot pathogens in China. Accordingly, diseased fruit were collected from six different areas of Sichuan Province. Based on morphological characteristics, pathogenicity testing, and comparisons of DNA sequences of the internal transcribed spacer, transcription elongation factor 1-α, and β-tubulin genes, 135 isolates of Botryosphaeriaceae were identified as B. dothidea, Lasiodiplodia theobromae, and Neofusicoccum parvum. All of these species were found to cause kiwifruit rot. To understand the infection cycle of kiwifruit rot pathogens, these three species were used to inoculate leaves and shoots of kiwifruit. The results showed that these species could cause spots on leaves and lesions on shoots, producing abundant pycnidia on leaves and shoots surfaces. Moreover, B. dothidea conidia and ascospores from overwintered pycnidia and pseudothecia in kiwifruit orchards in April and August could cause fruit rot and spots on leaves of kiwifruit. Therefore, we concluded that overwintered pycnidia and pseudothecia of B. dothidea in kiwifruit orchards are the primary inoculum for kiwifruit rot, with new pycnidia that develop during the growing season serving as a secondary inoculum. This is the first report of N. parvum and L. theobromae causing kiwifruit rot in China and is also the first report that B. dothidea is able to overwinter as pycnidia and pseudothecia in kiwifruit orchards and serve as the primary inoculum for kiwifruit rot.

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