scholarly journals Identification and characterization of Pseudomonas fluorescensstrains effective against Xanthomonasoryzaepv. oryzae causing bacterial blight of rice in Punjab, India

2017 ◽  
Vol 9 (1) ◽  
pp. 253-261
Author(s):  
Mandeep Singh Hunjan ◽  
Anjali Thakur ◽  
Pushpinder Paul Singh

For the control of bacterial blight of rice caused by Xanthomonasoryzaepv. oryzae, sixty four Pseudomonas fluorescens strains were recovered from rice and wheat rhizosphere. These strains were identified on the basis of internal transcribed spacer (ITS) region. It was observed that the strains showing fluorescence in the selective media showed the amplification of the targeted P. fluorescens specific ITS region. The strains were also characterized for the production of the antibiotic 2, 4-diacetylphloroglucinol (DAPG) using phlDlocus. The characteristic 750bp region was amplified in all the DAPG producing strains. These strains were evaluated against X. oryzae in vitro by dual culture method. The P. fluorescens strains found effective in vitro were further tested in field for their antagonistic potentiality and disease suppression ability. P. fluorescens strain number Pf-4-R showed maximum inhibition i.e. of 5.5 mm against the test pathogen X. oryzaepv. oryzae. Talc based powder formulation of the effective strain Pf-4-R used for field evaluation, showed that pre-inoculation foliar sprays were effective in controlling bacterial blight of rice with disease suppression efficiency ranging from 29.6 to 65.6 percent in different treatments.

Author(s):  
Jaygendra Kumar ◽  
Mukesh Kumar ◽  
Akash Tomar ◽  
. Vaishali ◽  
Pushpendra Kumar ◽  
...  

Trichoderma species are well known for their biocontrol activity which colonize many soil and tuber-borne and foliage plant pathogens. In this study, 12 native isolates of Trichiderma spp were collected from various crop rhizosphere soil samples and characterized them phenotypically based on morphological and cultural features and genotypically based on sequence analysis of internal transcribed spacer (ITS) region-PCR amplification. The results obtained from phenotypic and genotypic observation revealed that isolates were belonged to five different species namely T. asperellum, T. harzianum, T. longibrachiatum, T. koningii and T. koningiopsis. All Trichoderma isolates produced ~600 bp amplicon and phylogenetic analysis revealed that all isolates were grouped with respective species. Further, the antagonistic potential of all the isolates was evaluated against Fusarium spp. following in vitro dual culture method. The results showed that isolates of T. harzianum exhibited maximum growth inhibition activity. The highest rate of inhibition was recorded with T. harzianum isolate TBT6 (87.1%) followed by TBT7 (82.2%), while the least inhibition was observed in T. longibrachiatum isolate TBT10 (59.7%) after 7 days of incubation. The antagonistic T. harzianum isolate TBT6 can be used for development of Trichoderma based bio-formulation and served as bio-control agent against Fusaium spp. under field conditions.


2020 ◽  
Vol 18 (1) ◽  
pp. 103-112
Author(s):  
R. A. OLOYEDE ◽  
A. A. ILUPEJU ◽  
O. O. OYELAKIN ◽  
W. R. AJIJOLA

Fusarium wilt is one of the important diseases of cucumber and causes economic loss to farmers. The present study was undertaken to evaluate the potential of rhizosphere lactic acid bacteria as biocontrol agents of Fusarium wilt of cucumber. Lactic acid bacteria (LAB) were isolated and identified from the rhizosphere of five medicinal plants. The in-vitro antagonistic activity of LAB strains on F. oxysporum f.sp. cucumerinum was evaluated by dual culture method. The screen house experiment was then conducted to assess the effect of antagonistic LAB isolates on Fusarium wilt disease incidence in cucumber plants. The antagonistic LAB strains were further characterized using 16S rRNA gene sequencing technique. The total LAB counts of rhizospheric soil samples ranged from 7.0×105 cfu/g to 15.0×105 cfu/g. The LAB isolates were identified as strains of Lactobacillus acidophilus (21.4%), L. plantarum (35.7%), L. fermentum (28.6%), L. alimentarius (7.1%) and L. brevis (7.1%). Treatment of cucumber seeds with antagonistic LAB strains significantly reduced Fusarium wilt of cucumber incidence from 95% to 48%. Lactobacillus fermentum isolated from the rhizosphere of A. indica exhibited strong disease suppression (49.5%). The study therefore revealed that the rhizospheric-LAB could be applied to reduce the manifestation of Fusarium wilt in cucumber.    


2021 ◽  
Vol 13 (1) ◽  
pp. 69-80
Author(s):  
Majida Hadi Mahdi Alsaady ◽  
Hussein Ali Salim ◽  
Rakib A. Al-ani ◽  
Hadi M. Aboud ◽  
Jamal Talib M Al Roubaie

In this study, the antagonistic effect of five bacteria genera namely Bacillus, Pseudomonas, Azotobacter, Azospirillum, and Streptomyces isolated from rhizosphere of wheat were evaluated against Fusarium graminearum as potential biocontrol agents in vitro. F. graminearum was molecularly diagnosed using the Polymerase chain reaction (PCR) technique. Each bacteria were tested for the production of catalase enzyme, oxidase enzyme, analysis of starch, analyze of gelatin, and the motility, where Azotobacter, Azospirillum, and Bacillus subtilis were positive for all tested. Fungal inhibition tests were performed by using the dual culture method and agar well diffusion technique. Among them, Streptomyces and Azospirillum exhibited potent inhibition to the growth of F. graminearum (72.14% and 66.42%) respectively, followed by B.pumillus, P.fluorescens, B. subtilis and Azotobacter ( 58.28%, 43.23%, 39.71% and 35.71%) respectively as compared with the control treatment (0.0%).The dry weight of the fungus biomass was decreased with bacteria P. fluorescens, Streptomyces sp, Azotobacter sp, Azospirillum sp, B. subtilis, and B. pumillus which reached (0.114, 0.103, 0.147, 0.101, 0.143, and 0.107 g) respectively compared to the control treatment that was 0. 665 g.


2020 ◽  
Vol 4 (2) ◽  
Author(s):  
Nana Ariska ◽  
Lola Adres Yanti ◽  
Chairudin Chairudin

Nutmeg (Myristica fragrans Houtt) is a multipurpose plantation commodity crop that almost all parts of the plant have strategic economic value to be cultivated. In Indonesia there are the largest nutmeg commodity centers, including the Maluku islands, North Sulawesi and Aceh. The biggest problem with nutmeg plants is the attack of pests and diseases. One of the most severe diseases in nutmeg is white root mushroom (Rigidoporus lignosus). This study aims to 1) determine the fungus of white root fungus antagonists (Rigodoporus lignosus) from the Aceh nutmeg rhizosphere (Myristica fragrans Houtt), 2) identify the content of antibiotic fungus JAP antagonist compounds in Aceh nutmeg plants. The study was conducted by taking soil samples from nutmeg plants at three nutmeg plantations in South Aceh. The antagonist fungus isolation activity uses a dilution method. Isolation of JAP from infected roots using direct planting method. Furthermore, it is identified macroscopically and microscopically. The antagonist test was carried out using the dual culture method with RAL. From the rhizosphere in the nutmeg area, 5 candidate antagonist isolates were obtained, having high in vitro antagonism ability to the pathogen R. lignosus. Identification results showed that isolates 1, 2 and 3 were Trichoderma spp, and isolates 4 and 5 were Gliocladium virens. Keywords: In vitro, the content of antibiotic compounds, Aceh nutmeg, Rigidoporus lignosus, antagonistic test


2020 ◽  
Vol 14 (2) ◽  
pp. 178-186
Author(s):  
Lisa Novita Arios ◽  
Dwi Suryanto . ◽  
Kiki Nurtjahja . ◽  
Erman Munir .

Assay on ability of endophytic bacteria isolated from peanut to inhibit Sclerotium sp. growth in peanut seedlings.   A study on assay of ability of endophytic bacteria to inhibit Sclerotium sp. in peanut seedling has been done. The bacteria were isolated from peanut healthy plants, while Sclerotium sp. was isolated from infected peanaut plant. Antagonistic assay was conducted by dual culture method.  In vivo assay of inhibiting Sclerotium sp. was conducted by dipping peanut seed in bacterial solution, and planting the seed in soil:compost (3:1) growing media. Six endophytic bacterial isolates showed to inhibit the growth of Sclerotium sp. in vitro. LN1 seemed to inhibit more of Sclerotium sp., while LN5 showed to inhibit less. Two potential isolates LN1 of gram-negative and LN2 of gram-positive using for further study showed to decrease more of dumping off. It also seemed that the isolates increased the seedling height, number of leaves, and dry weight.


2021 ◽  
Vol 24 (2) ◽  
pp. 107-120
Author(s):  
SMN Islam ◽  
SS Siddique ◽  
MZH Chowdhury ◽  
NJ Mishu

A native Trichoderma isolate was collected from the agricultural soil of Gazipur. This isolate was identified as a Trichoderma asperellum through morphology and analysis of internal transcribed spacer (ITS) region of ribosomal RNA gene sequence and reconstruction of the phylogenetic tree. The antagonistic effects of the newly identified T. asperellum isolate were assessed against brinjal bacterial wilt caused by Ralstonia solanacearum both in vitro and in planta. Both qualitative and quantitative bioassays were conducted in vitro. For qualitative tests, dual culture and antibacterial activity were carried out, and pathogen growth was observed visually. The antagonism of T. asperellum cell free culture filtrate on the growth of R. solanacearum was conducted in a quantitative test. Successful antagonism was recorded after both in vitro qualitative tests. In addition, the lowest colony forming unit was recorded in 100% of CFC (2.4±0.51 ×103 cfu/ml) in quantitative test. The T. asperellum inoculated plant showed low disease incidence (13.33%) when seedlings were challenged with R. solanacearum in planta experiment. Disease incidence was 100% for seedlings when treated with only R. solanacearum. The results showed that the isolated and identified T. asperellum isolate suppressed R. solanacearum growth in vitro and protected the seedling from wilting in planta. Therefore, this isolate could be considered as a potential isolate. Ann. Bangladesh Agric. (2020) 24(2) : 107-120


2020 ◽  
Vol 4 (2) ◽  
pp. 109-117
Author(s):  
Priyo Adi Nugroho ◽  
Cici Indriani Dalimunthe

The concern of oil palm empty fruit bunches (OPEFB) utilization in the rubber field that potential to be a host of white root disease needs to be deeply investigated. The objective of this study was to assess the bacteria on the surface of OPEFB that able to inhibit the growth of R. microporus fungi. The antagonistic assay of eight isolates of bacteria against R. microporus fungi was conducted in the Plant Protection Laboratory of Sungei Putih Research Centre. The isolates were isolated from the surface of OPEFB applied in the rubber field. Nutrient agar (NA) was employed in the isolation and purification of bacteria. The antagonistic assay was carried out in vitro using the dual culture method. The observation was performed on 2, 4, 6, and 8 days after incubation (DAI). The result indicated that the eight isolates have varied in inhibition ability of R. Microporus fungi. The initial inhibition was started since 2 DAI particularly in the isolates B2, B3, B4, and B7. The percentage of inhibition were 30%, 60%, 65% dan 69% respectively. Until 8 HSI, the isolates B2, B3, B4, B6, B7, and B8 were still inhibiting the growth of R. microporus fungi > 80%. The isolates B3 and B4 showed the best performance in fungi inhibition with the percentage > 95%. Whereas, the ability of inhibition of the isolates B1 and B5 were very low as < 50%. The existence of such antagonistic bacteria perhaps led to OPEB was not role as the host of white root disease while applied in the rubber field


2015 ◽  
Vol 15 (1) ◽  
pp. 72
Author(s):  
Susanti Tasik ◽  
Siti Muslimah Widyastuti ◽  
Harjono .

Mechanism of parasitism of Trichoderma harzianum on Fusarium oxysporum on Acacia mangium seedlings. Fusarium oxysporum is one of the most important soil-borne fungi the causal agent of damping-off disease. Detailed information it needed to know how the pathogen can be inhibited by Trichoderma harzianum. The objective of this research was to investigate the inhibition mechanism of T. harzianum on F. oxysporum in vitro and in planta. Green Flourescent Protein (GFP) T. harzianum was used as biocontrol agent of F. oxysporum. An in vitro inhibition test of T. harzianum was performed using dual culture method. In the in planta inhibition tests, seedlings of A. mangium were applied with GFP T. harzianum two days before inoculation of F. oxysporum; GFP T. harzianum was simultaneously applied with F. oxysporum and GFP T. harzianum was applied two days after inoculation of F. oxysporum. The inhibition effect of T. harzianum GFP was observed at seven days incubation, indicated by attachment of T. harzianum to F. oxysporum hyphae. GFP T. harzianum hyphae covered the colonies of F. oxysporum at 12 days after incubation. The highest life percentage of A. mangium seedlings was found on the treatment of GFP T. harzianum two days before inoculation of F. oxysporum (82.22%), whereas the lowest life percentage was found on seedling applied with GFP T. harzianum two days after inoculation of F. oxysporum (64.44%).


2020 ◽  
Vol 4 (1) ◽  
pp. 47
Author(s):  
Fauziyyah Nahdah ◽  
Noorkomala Sari ◽  
Akhmad Rizali ◽  
Rabiatul Wahdah

<p class="Abstract">Basal plate rot is a major disease on shallot caused by <em>Fusarium oxysporum</em>. Endophytic fungi is promising to use as antagonist agent to the pathogen. Endophyte is microbes that are living in plant cells and have an asymptomatic characteristic. Nowadays, fungal endophyte is believed to produce antimicrobial substances similar with their plant host's natural product. <em>Jatropha curcas</em> is one of the plants containing secondary metabolites that have antifungal activities. The research aimed to study the ability of endophyte from <em>Jatropha curcas</em> to inhibit the growth of <em>Fusarium oxysporum</em>. The dual culture method was used in this research and the data were analyzed by SPSS software. This antagonism test was conducted by 9 isolates endophyte and each plate consisted of 3 replicates. The result revealed endophyte fungal obtaining 9 isolates with the radial growth of 4,5 cm/2 days. Endophytes of <em>Jatropha curcas</em> L. were able to inhibit the growth of <em>Fusarium oxysporum</em> C2. The percentage of inhibition of <em>Fusarium oxysporum </em>causing of root blight diseases was controlled by up 38.27 - 74.48%. The highest percentage of inhibition is gained by B4b and the lowest of it is A2b. Our observations showed that each endophyte has a consistent linear trend. B4b still leaded as the highest strength to inhibit the growth of pathogen on the monitoring of 3, 5, and 7 days. Moreover, the ability of fungi endophyte from <em>Jatropha curcas</em> as antagonist agent to <em>Fusarium oxysporum</em> needs to be further examined by the in vivo method.</p>


2016 ◽  
Vol 12 (3) ◽  
pp. 96
Author(s):  
Susiana Purwantisari ◽  
Achmadi Priyatmojo ◽  
Retno Peni Sancayaningsih ◽  
Rina Sri Kasiamdari

Late blight disease on potato caused by a plant pathogenic fungus (Phytophthora infestans)  is the most important disease in Indonesia.  The use of antagonist fungi Trichoderma is an environmentally friendly technology to control the potato disease. The purpose of this study was to determine the ability of Trichoderma spp. to control P. infestans in vitro. Trichoderma spp. have been isolated from suppressive soil at central potato areas in district of Lembang, Bandung, West Java Province. To determine the inhibition ability of Trichoderma spp against P. infestans, a dual culture method was performed.  Variable observed was inhibition zone of Trichoderma spp. against P. infestans. The results showed that 9 isolates of Trichoderma were successfuly isolated from suppressive soil, i.e. T. viride (2 isolates), T. atroviride (1 isolate), T. harzianum (1 isolate) and T. aureoviride (5 isolates). All the Trichoderma isolates revealed growth inhibition abality against P. infestans and. The highest growth inhibition (68.6%) was observed by T. viride isolate ( Ti 9).


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