scholarly journals Selecting Antagonistic Yeast for Postharvest Biocontrol of Colletotrichum gloeosporioides in Papaya Fruit and Possible Mechanisms Involved

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 760
Author(s):  
Hamizah Hassan ◽  
Mahmud Tengku Muda Mohamed ◽  
Siti Fairuz Yusoff ◽  
Erneeza Mohd Hata ◽  
Nor Elliza Tajidin

Colletotrichum gloeosporioides causes anthracnose disease in papaya fruit resulting in tremendous economic loss due to its latent infection. This study aimed to evaluate the biocontrol activity of antagonistic yeasts against C. gloeosporioides in papaya and determine the possible mechanism involved. One hundred and ten yeast strains were isolated from different parts of the papaya plant. Among them, only five strains, namely F001, F006, L003, FL013 and LP010, showed more than 55% radial growth inhibition of C. gloeosporioides. These five potent yeast strains were further evaluated in vitro and in vivo. The results indicated that strain F001 had the strongest biocontrol activity based on spore germination and fungal growth inhibition. In vivo, the strain F001 caused 66.7% and 25% reductions in disease incidence and severity, respectively. Based on molecular identification, the strain F001 was confirmed as Trichosporon asahii. Despite there was no significant induction of defense enzyme activities found on the treated fruits, SEM observation showed direct attachment of T. asahii with the fungal hyphae and interfere in their establishment to the fruit surface. Based on these findings, the antagonistic yeast T. asahii strain F001 may be used as a potential natural biological control agent against anthracnose disease in papaya fruit.

2018 ◽  
Vol 13 (2) ◽  
pp. 111 ◽  
Author(s):  
Yadi Suryadi ◽  
Tri Puji Priyatno ◽  
I Made Samudra ◽  
Dwi Ningsih Susilowati ◽  
Tuti Septi Sriharyani ◽  
...  

<p>Anthracnose (Colletotrichum gloeosporioides) is one of the important diseases of fruit crops that need to be controlled. This study was aimed to obtain the best formula of hydrolyzed nano chitosan and its potensial in controlling anthracnose. The hydrolyzed chitosan was prepared using chitinase enzyme extracted from Burkholderia cepacia isolate E76. Chitosan nanoparticles were synthesized using ionic gelation method by reacting hydrolyzed chitosan (0.2%) with Sodium tripolyphosphate (STPP) (0.1%) as cross-linking agent using 30&amp;ndash;60 minutes stirring condition. The bioactivity of the nano chitosan formula was tested to C. gloeosporioides under in vitro and in vivo assays. The specific enzymatic activity of the purified chitinase was higher (0.19 U/mg) than that of crude enzyme (supernatant) with the purity increased by 3.8 times. Of the four formula tested, Formula A (hydrolyzed chitosan to STPP volume ratio of 5 : 1 with 60 minutes stirring condition) was found good in terms of physical characteristic of the particle. The formula nano chitosan particle had the spherical-like shape with an average particle size of 126.2+3.8 nm, polydispersity index (PI) of 0.4+0.02, and zeta potential (ZP) value of 27.8+0.2 mV. Nano chitosan had an inhibitory activity to C. gloeosporioides in vitro up to 85.7%. Moreover, it could inhibit 61.2% of C. gloeosporioides spores germination. It was shown that nano chitosan was also effective to reduce anthracnose disease severity in vivo when applied as a preventive measure on chili and papaya fruits. This study could be used as a reference for further fruit coating application using nano chitosan as a promising postharvest biocontrol agent to C. gloeosporioides.</p>


Author(s):  
Ngoh Dooh Jules Patrice ◽  
Deurnaye Placide ◽  
Abdoul Madjerembe ◽  
Mbou T. Pavel Rony ◽  
Djongnang Gabriel ◽  
...  

Aims: The aim of this work was to evaluate effect of Mancozeb 80 WP against Colletotrichum gloeosporioides, the agent responsible of anthracnose of cashew tree (Anacardium occidentale  L.). Study Design: The experimental design was in completely randomized blocks with three replications. Place and Duration of Study: in vitro and in vivo experiments were performed in Laboratory of  Department of Biological Sciences, University of Maroua during six months. Field trial was carried out in Kelo, Chad during three months. Methodology: Isolates were obtained from diseased organs (leaves and fruits) from Kélo in Chad and Maroua in Cameroon. The concentrations used in the laboratory were C1 (5 mg/ml), C2 (0.5 mg/ml), C3 (0.05 mg/ml), C4 (0.005 mg/ml), C5 (0.0 mg/ml). Radial growth, sporulation, conidial germination and pathogenicity were used to characterize and evaluate the effect of Mancozeb on the isolates in vitro. The preventive test was performed on three-month-old plants previously treated with Mancozeb. The concentration of 5 g/l was applied to the field and the incidence and severity were used to calculate the AUIPC (Area Under Disease Incidence Progress Curve) and AUSiPC (Area Under Disease Severity Index Progress Curve) curves. Results: Mancozeb reduced radial growth of all isolates at concentrations C1 (5 mg/ml), C2 (0.5 mg/ml) and C3 (0.05 mg/ml). The percentages of inhibition ranged from 50 to 100%. Mancozeb 80 WP completely (100%) inhibited the germination of C. gloeosporioides conidia in vitro. Mancozeb has protected cashew plants in vivo at the concentration C1 (5 mg/ml). AUIPC and AUSiPC were higher on control plants and lower on Mancozeb-treated plants. Conclusion: Mancozeb 80 WP may be associated in integrated pest management strategy against anthracnose.


Author(s):  
Sudiono . ◽  
Efri . ◽  
Muhammad Asep Awaludin

Aims: The objective of this research was to find out the influence of papaya leaf extract to the in-vitro growth of Colletotrichum gloeosporioides and in-vivo anthracnose disease occurrence at papaya fruit. Methodology: This research used completely randomized design with seven treatments and four replications. Obtained data were analyzed by using analysis of variance and mean scores were compared and tested with least significance difference (LSD) at 5% and polynomial test at 5%. Results: The research result showed the significant influence of papaya leaf extract and synthetic fungicide in inhibiting the growth of Colletotrichum gloeosporioides colony and the disease occurrence at papaya fruit. The polynomial test result of papaya leaf extract showed linier pattern of C. Gloeosporioides colony diameter and disease course progression. Conclusion: The papaya leaf extract inhibited C. Gloeosporioides colony growth at 2 up to 7 days after inoculation, but it did not inhibit spore germination and its density. The papaya leaf extract also inhibit the disease occurrence at 5 and 6 days after application.


el–Hayah ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 104-111
Author(s):  
Zahroul Afifah ◽  
Ulfah Utami

Background: An anthracnose disease caused by pathogenic fungal Colletotrichum capsici has been attacking the cayenne plants either harvested or has not been harvested. This disease must be handled appropriately and quickly because it can reduce the production of chili up to 90%. Recently, anthracnose disease prevention still use chemical fungicide that if applied for long time will cause new impact for environment. Objective: Trichoderma and Bacillus cereus endophytes may be used as antagonistic agents for C. capsici pathogens because they have various antibiotic compounds. Methods: This research uses experimental method. The stages of this study include sterilization of tools and materials, preparation of culture media of fungal and bacteria, rejuvenation of endophytic microbe culture Trichoderma sp. and Bacillus cereus, rejuvenation of  C. capsici pathogen, antagonistic test in vitro using dual culture method. Result and conclusion: The results of in vitro antagonistic tests showed that inhibition percentage of Trichoderma treatment (96%) and combination treatment Trichoderma and B. cereus (97%) is not significantly different. While in B. cereus treatment (11, 88%) significantly different with all of treatments. Endophytes are shown by its dominating growth in petri dishes than C. capsici pathogen or B. cereus endophytes. Furthermore,for endophytes Trichoderma sp continued on in vivo test because it was most effective.The result for incubation period is 3 days after inoculation compared with negative control 2 days. For disease incidence 100%, and for disease intensity that is 61,25% compared with negative control equal to 88,75%.


Antioxidants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 580 ◽  
Author(s):  
Roberto G. Chiquito-Contreras ◽  
Bernardo Murillo-Amador ◽  
Saul Carmona-Hernandez ◽  
Cesar J. Chiquito-Contreras ◽  
Luis G. Hernandez-Montiel

Anthracnose, caused by Colletotrichum gloeosporioides, is one of the most important diseases in papaya fruit. Its control has been achieved with synthetic fungicides, but the application of marine bacteria and the sulphated polysaccharide ulvan (structural description: β[1,4]-D-GlcA-α[1,4]-L-Rha 3 sulfate, β[1,4]-L-IdoA-α[1,4]-L-Rha 3 sulfate, β[1,4]-D-Xyl-α[1,4]-L-Rha 3 sulfate, and β[1,4]-D-Xyl 2-sulfate-α[1,4]-L-Rha 3 sulfate) from Ulva sp. can be an alternative in the use of agrochemicals. Thus, the objective of this study was to assess the effect in vitro and in vivo of two marine bacteria, Stenotrophomonas rhizophila and Bacillus amyloliquefaciens, and ulvan in papaya fruit’s bio-protection against C. gloeosporioides. The capacity of marine bacteria to inhibit mycelial growth and phytopathogen spore germination in vitro through volatile organic compounds (VOCs) and carbohydrate competition was evaluated. Fruit was inoculated with bacteria, ulvan, and C. gloeosporioides and incubated at 25 °C and 90% of relative humidity (RH) for seven days. Disease incidence (%), lesion diameter (mm), and antioxidant defense enzyme activity (such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were quantified. In vitro, C. gloeosporioides was inhibited by S. rhizophila and B. amyloliquefaciens. In vivo, disease incidence and the lesion diameter of anthracnose on papaya fruit were significantly reduced by marine bacteria and ulvan. Antioxidant defense enzyme activity played an important role in fruit bio-protection against C. gloeosporioides. The application of marine bacteria and ulvan can be an alternative in the sustainable postharvest management of papaya.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shanu Magotra ◽  
Nancy Bhagat ◽  
Sheetal Ambardar ◽  
Tahir Ali ◽  
Barbara Reinhold Hurek ◽  
...  

AbstractNative Bacillus sp. strain D5 coded as (Bar D5) has been isolated from the saffron corm that showed plant growth promotion (PGP) properties and also inhibits the growth of corm rot causing Fusarium oxysporum R1 (Fox R1) in-vitro. Bar D5 was more efficient PGP bacterium in comparison to earlier reported native bio-formulations by our group. Pot assays and field evaluation of Bar D5 confirmed its in-vivo efficacy for PGP traits and biocontrol activity as well. Pot trials were followed by field trials at traditional (Kishtwar) and non-traditional (R.S Pura) saffron cultivation areas in Jammu and Kashmir. At both places, Bar D5 bio-formulation treatment led to the increase in root number & length, shoot number & length, flower number and number & weight of daughter corms. Additionally, it also decreased the corm rot disease incidence significantly. Priming of corms with bio-formulation resulted in the reduction of pathogenic fungal load by three fold at the depth of corm sowing from ground level. The shelf life/viability of Bar D5 based bio-formulation was found to be 52% (viable spores) for one year at room temperature. Draft genome sequence of Bar D5 revealed the presence of genes necessary for PGP and biocontrol activity. Further, confirmation of gene sequences and annotation was done by amplification, re-sequencing and mapping of PGP and biocontrol genes on draft genome. Bar D5 based bio-formulation can be provided to companies/researchers interested in saffron cultivation or bio-formulation production for commercial exploitation, since saffron is grown as revenue crop across continents. The present study bridges the gap between genomics and its field application.


Blood ◽  
1990 ◽  
Vol 76 (6) ◽  
pp. 1250-1255 ◽  
Author(s):  
S Whitehead ◽  
TE Peto

Abstract Deferoxamine (DF) has antimalarial activity that can be demonstrated in vitro and in vivo. This study is designed to examine the speed of onset and stage dependency of growth inhibition by DF and to determine whether its antimalarial activity is cytostatic or cytocidal. Growth inhibition was assessed by suppression of hypoxanthine incorporation and differences in morphologic appearance between treated and control parasites. Using synchronized in vitro cultures of Plasmodium falciparum, growth inhibition by DF was detected within a single parasite cycle. Ring and nonpigmented trophozoite stages were sensitive to the inhibitory effect of DF but cytostatic antimalarial activity was suggested by evidence of parasite recovery in later cycles. However, profound growth inhibition, with no evidence of subsequent recovery, occurred when pigmented trophozoites and early schizonts were exposed to DF. At this stage in parasite development, the activity of DF was cytocidal and furthermore, the critical period of exposure may be as short as 6 hours. These observations suggest that iron chelators may have a role in the treatment of clinical malaria.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Siamak Salehi ◽  
Oliver D. Tavabie ◽  
Augusto Villanueva ◽  
Julie Watson ◽  
David Darling ◽  
...  

AbstractRegulated cell proliferation is an effector mechanism of regeneration, whilst dysregulated cell proliferation is a feature of cancer. We have previously identified microRNA (miRNA) that regulate successful and failed human liver regeneration. We hypothesized that these regulators may directly modify tumor behavior. Here we show that inhibition of miRNAs -503 and -23a, alone or in combination, enhances tumor proliferation in hepatocyte and non-hepatocyte derived cancers in vitro, driving more aggressive tumor behavior in vivo. Inhibition of miRNA-152 caused induction of DNMT1, site-specific methylation with associated changes in gene expression and in vitro and in vivo growth inhibition. Enforced changes in expression of two miRNA recapitulating changes observed in failed regeneration led to complete growth inhibition of multi-lineage cancers in vivo. Our results indicate that regulation of regeneration and tumor aggressiveness are concordant and that miRNA-based inhibitors of regeneration may constitute a novel treatment strategy for human cancers.


2021 ◽  
Vol 9 (2) ◽  
pp. 379
Author(s):  
Breanne M. Head ◽  
Christopher I. Graham ◽  
Teassa MacMartin ◽  
Yoav Keynan ◽  
Ann Karen C. Brassinga

Legionnaires’ disease incidence is on the rise, with the majority of cases attributed to the intracellular pathogen, Legionella pneumophila. Nominally a parasite of protozoa, L. pneumophila can also infect alveolar macrophages when bacteria-laden aerosols enter the lungs of immunocompromised individuals. L. pneumophila pathogenesis has been well characterized; however, little is known about the >25 different Legionella spp. that can cause disease in humans. Here, we report for the first time a study demonstrating the intracellular infection of an L. bozemanae clinical isolate using approaches previously established for L. pneumophila investigations. Specifically, we report on the modification and use of a green fluorescent protein (GFP)-expressing plasmid as a tool to monitor the L. bozemanae presence in the Acanthamoeba castellanii protozoan infection model. As comparative controls, L. pneumophila strains were also transformed with the GFP-expressing plasmid. In vitro and in vivo growth kinetics of the Legionella parental and GFP-expressing strains were conducted followed by confocal microscopy. Results suggest that the metabolic burden imposed by GFP expression did not impact cell viability, as growth kinetics were similar between the GFP-expressing Legionella spp. and their parental strains. This study demonstrates that the use of a GFP-expressing plasmid can serve as a viable approach for investigating Legionella non-pneumophila spp. in real time.


Author(s):  
Letizia Mondani ◽  
Giorgio Chiusa ◽  
Paola Battilani

AbstractThe aim of the study was to test in vitro and in vivo the efficacy of triazoles and biocontrol agents (BCAs) against Fusarium proliferatum and F. oxysporum, the former signaled as the main causal agent of garlic dry rot and the latter also involved. In vitro trials were organized using potato dextrose agar with added chemicals or BCAs inoculated with selected F. proliferatum and F. oxysporum. Garlic cloves were dipped before sowing in suspensions prepared with the fungicides showing the best performances in vitro; then they were dipped in Fusaria suspension before sowing. In in vitro trials, the maximum Fusaria growth inhibition was performed by Propiconazole + Prochloraz (100%), followed by Tebuconazole (88.9%). BCAs showed great capacity to control Fusaria, with a maximum growth inhibition of 80% (Trichoderma harzianum + T. gamsii). In vivo bacterial BCAs showed a similar capacity to control F. proliferatum and F. oxysporum compared to chemical products (mean of severity index 18.6% and 11.7%, respectively). In vivo results confirmed the in vitro performances, except for Trichoderma, which had the worst performances in vivo. Therefore, the results are preliminary but promising for future field application.


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