scholarly journals Rapd-Pcr of Trichoderma Isolates and In Vitro Antagonism Against Fusarium Wilt Pathogens of Psidium Guajaval.

Author(s):  
Vijai Gupta ◽  
Ashok Misra ◽  
Arti Gupta ◽  
Brajesh Pandey ◽  
Rajarshi Gaur
2019 ◽  
Vol 9 (2) ◽  
pp. 91
Author(s):  
Ghea Dotulong ◽  
Stella Umboh ◽  
Johanis Pelealu

Uji Toksisitas Beberapa Fungisida Nabati terhadap Penyakit Layu Fusarium (Fusarium oxysporum) pada Tanaman Kentang (Solanum tuberosum L.) secara In Vitro (Toxicity Test of several Biofungicides in controlling Fusarium wilt (Fusarium oxysporum) in Potato Plants (Solanum tuberosum L.) by In Vitro) Ghea Dotulong1*), Stella Umboh1), Johanis Pelealu1), 1) Program Studi Biologi, FMIPA Universitas Sam Ratulangi, Manado 95115*Email korespondensi: [email protected] Diterima 9 Juli 2019, diterima untuk dipublikasi 10 Agustus 2019 Abstrak Tanaman kentang (Solanum tuberosum L.) adalah salah satu tanaman hortikultura yang sering mengalami penurunan dari segi produksi dan produktivitasnya, akibat adanya serangan penyakit layu yang salah satunya disebabkan oleh Fusarium oxysporum. Tujuan penelitian ini adalah mengidentifikasi toksisitas beberapa fungisida nabati dalam mengendalikan penyakit Layu Fusarium (F. oxysporum) pada tanaman kentang (Solanum tuberosum L.) secara In Vitro. Metode Penelitian yang digunakan yaitu metode umpan beracun. Data dianalisis dengan Rancangan Acak Lengkap (RAL) dengan Analisis Varian (ANAVA) yang dilanjutkan dengan menggunakan metode BNT (Beda Nyata Terkecil). Hasil Penelitian, diperoleh nilai toksisitas fungisida nabati tertinggi yaitu pada ekstrak daun sirsak dengan nilai HR (69,44%), kategori berpengaruh, ditandai dengan diameter koloni 2,75 cm (100ppm) dan yang terendah toksisitasnya yaitu pada ekstrak daun jeruk purut dengan nilai HR (49,81%), kategori cukup berpengaruh ditandai dengan diameter koloni 3,75 cm (25ppm). Semakin tinggi konsentrasi yang diujikan maka semakin tinggi toksisitas dari fungisida nabati yang diberikan.Kata Kunci: fungisida nabati, Fusarium oxysporum, tanaman kentang, In Vitro Abstract Potato plants (Solanum tuberosum L.) is one of the horticulture plants which often decreases in terms of production and productivity, due to the attack of wilt, one of which is caused by Fusarium oxysporum. The purpose of this study was to determine the toxicity of several biofungicides in controlling Fusarium wilt (F. oxysporum) in potato plants (Solanum tuberosum L.) in Vitro. The research method used was the In Vitro method with the poison bait method. Data were analyzed by Completely Randomized Design with Variant Analysis (ANAVA), followed by the BNT method. The results showed that the highest biofungicide toxicity value was soursop leaf extract with HR values (69.44%), influential categories, characterized by colony diameter 2.75 cm (100ppm) and the lowest toxicity, namely in kaffir lime leaf extract with a value of HR (49.81%), quite influential category was characterized by colony diameter of 3.75 cm (25ppm). The higher the concentration tested, the higher the toxicity of the biofungicide given.Keywords: biofungicides, Fusarium oxysporum, Potato Plants, In Vitro.


2017 ◽  
Vol 53 (No. 2) ◽  
pp. 78-84 ◽  
Author(s):  
Boukerma Lamia ◽  
Benchabane Messaoud ◽  
Charif Ahmed ◽  
Khélif Lakhdar

The potential of Pseudomonas fluorescens PF15 and Pseudomonas putida PP27 to protect tomato plants against Fusarium wilt under greenhouse conditions was evaluated. In vitro antagonism showed a significant inhibition of the pathogen growth (47%) revealed by PF15. However, PP27 presented a 10% rate of the mycelium inhibition. An in situ experiment was conducted with split-root design for induced systemic resistance (ISR) and without split-root design to measure both ISR and antagonistic activities. Fluorescent Pseudomonas revealed a delay in the onset of symptoms and slower kinetics of disease progression compared to the pathogen control. McKinney’s index, which measures the severity of the disease, was reduced by 37–72%, and the levels of infection (incidence) by 7–36%.


2014 ◽  
Vol 40 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Zayame Vegette Pinto ◽  
Matheus Aparecido Pereira Cipriano ◽  
Amaury da Silva dos Santos ◽  
Ludwig Heinrich Pfenning ◽  
Flávia Rodrigues Alves Patrício

Bottom rot, caused by Rhizoctonia solani AG 1-IB, is an important disease affecting lettuce in Brazil, where its biological control with Trichoderma was not developed yet. The present study was carried out with the aim of selecting Trichoderma isolates to be used in the control of lettuce bottom rot. Forty-six Trichoderma isolates, obtained with baits containing mycelia of the pathogen, were evaluated in experiments carried out in vitro and in vivo in a greenhouse in two steps. In the laboratory, the isolates were evaluated for their capabilities of parasitizing and producing toxic metabolic substances that could inhibit the pathogen mycelial growth. In the first step of the in vivo experiments, the number and the dry weight of lettuce seedlings of the cultivar White Boston were evaluated. In the second step, 12 isolates that were efficient in the first step and showed rapid growth and abundant sporulation in the laboratory were tested for their capability of controlling bottom rot in two repeated experiments, and had their species identified. The majority of the isolates of Trichoderma spp. (76%) showed high capacity for parasitism and 50% of them produced toxic metabolites capable of inhibiting 60-100% of R. solani AG1-IB mycelial growth. Twenty-four isolates increased the number and 23 isolates increased the dry weight of lettuce seedlings inoculated with the pathogen in the first step of the in vivo experiments.In both experiments of the second step, two isolates of T. virens, IBLF 04 and IBLF 50, reduced the severity of bottom rot and increased the number and the dry weight of lettuce seedlings inoculated with R. solani AG1-IB. These isolates had shown a high capacity for parasitism and production of toxic metabolic substances, indicating that the in vitro and in vivo steps employed in the present study were efficient in selecting antagonists to be used for the control of lettuce bottom rot.


2016 ◽  
Vol 9 (2) ◽  
pp. 66
Author(s):  
Deden Sukmadjaja ◽  
Ragapadmi Purnamaningsih ◽  
Tri P. Priyatno

<p>Fusarium wilt of banana (Musa spp.) caused by<br />Fusarium oxysporum f. sp. cubense (Foc) is the most serious<br />problem faced in banana cultivation in terms of plant<br />productivity and fruit quality. Mutation breeding is one of the<br />alternative method that can be applied in producing new<br />banana cultivar. Mutants can be induced by chemical<br />mutagen such as ethyl methane sulfonate (EMS) followed by<br />in vitro selection and then evaluation of the mutants to<br />fusarium wilt disease in glasshouse and Foc infected field.<br />The aim of this research was obtained EMS induced and in<br />vitro selected mutants of banana var. Ambon Kuning and<br />evaluated Foc disease resistant clones in glasshouse and<br />Foc infected field. The first step to obtain the explants for<br />this research was initiation and formation of multiple bud<br />clumps (MBC) using MS basal media supplemented with 5,<br />10, and 20 mg/l of benzyladenin. Plant regeneration of MBC<br />was also studied by using MS media containing 0, 0.2, and 1<br />mg/l of benzyladenin. To induce mutagenesis, MBC was<br />soaked in 0.1, 0.3, and 0.5% (v/v) EMS for 1, 2, and 3 hours.<br />The assesment of resistant MBC mutants to Fusarium<br />phytotoxin was conducted by using fusaric acid (FA) as<br />selection agent in concentration of 30, 45, and 60 ppm.<br />Putative mutant plants produced by in vitro selection were<br />further tested using spore solution of Foc race 4 in<br />glasshouse. Meanwhile, Foc resistance assesment in the<br />infected field was conducted in Pasirkuda Experimental<br />Station, Bogor Agricultural University. The results showed<br />that MBC can be formed in MS basal media supplemented<br />with 10 or 20 mg/l benzyladenin. The EMS played a role in<br />obtaining mutants by producing 68 MBC putative mutants<br />tolerant to Foc based on FA selection. Further evaluation in<br />the glasshouse was obtained 64 Foc resistant plants from<br />391 putative mutants produced by in vitro selection.<br />Evaluation in the Foc infected field showed six clones<br />survived until generative phase (12 month of age).</p>


2019 ◽  
Vol 5 ◽  
pp. 68-72
Author(s):  
Shrinkhala Manandhar ◽  
Bimala Pant ◽  
Chetana Manandhar ◽  
Suraj Baidya

Biocontrol is an important aspect of disease management for plant pathogens, especially for the soil borne fungi. Trichoderma species is the most exploited biocontrol agent in recent years. The soil specific nature of Trichoderma species is a well-known fact and hence native Trichoderma isolates should be more emphasized for control of plant pathogens. Fifty soil samples from rhizosphere of various agricultural crops were collected for isolation of Trichoderma sp. Ten isolates of Trichoderma were tested in dual culture with soil borne pathogens Fusarium solani, Rhizoctonia solani and Sclerotinia sclerotiorum in an in vitro assay. All of the test isolates were found to be significant in terms of mycelial inhibition growth as compared to control. However, varying degrees of antagonism by different Trichoderma isolates were observed for above mentioned soil borne pathogens. The isolate (T363) was found to exhibit more than 80% inhibition of S. sclerotiorum while the isolate T357 was found to control F. solani by more than 80%.  For the control of R. solani, six of the tested Trichoderma isolates showed more than 80% inhibition of its radial colony growth. The Trichoderma isolates seen effective in this study need to be tested in pot and field experiments for exploiting the use and benefits of biocontrol.


1976 ◽  
Vol 54 (8) ◽  
pp. 752-757 ◽  
Author(s):  
Frank L. Caruso ◽  
Terry A. Tattar ◽  
Mark S. Mount ◽  
Margaret E. Malia

Decreases in electrical resistance (ER) of tomato taproots were correlated with the progression of Fusarium wilt disease. Production of polygalacturonase (PG) from four isolates of Fusarium oxysporum f. sp. lycopersici, as determined from ammonium sulfate fractions, was correlated with the degree of virulence of each isolate. A drop in ER in tomato plant taproots at 6 cm below the soil level was noticed within 2 h after separate inoculation with all strains. These drops in ER preceded foliar symptom development by 20 h. Measurement of ER in the stems of inoculated tomato plants, however, was found to be no different from that of uninoculated plants. The rate of ER decrease was correlated with the in vitro production of PG by these isolates; the higher the PG activity, the greater the decrease in ER.


Plant Disease ◽  
2016 ◽  
Vol 100 (9) ◽  
pp. 1910-1920 ◽  
Author(s):  
J. Himmelstein ◽  
J. E. Maul ◽  
Y. Balci ◽  
K. L. Everts

Fall-planted Vicia villosa or Trifolium incarnatum cover crops, incorporated in spring as a green manure, can suppress Fusarium wilt (Fusarium oxysporum f. sp. niveum) of watermelon. During cover crop growth, termination, and incorporation into the soil, many factors such as arbuscular mycorrhizae colonization, leachate, and soil respiration differ. How these cover-crop-associated factors affect Fusarium wilt suppression is not fully understood. Experiments were conducted to evaluate how leachate, soil respiration, and other green-manure-associated changes affected Fusarium wilt suppression, and to evaluate the efficacy of the biocontrol product Actinovate AG (Streptomyces lydicus WYEC 108). General and specific suppression was examined in the field by assessing the effects of cover crop green manures (V. villosa, T. incarnatum, Secale cereale, and Brassica juncea) on soil respiration, presence of F. oxysporum spp., and arbuscular mycorrhizal colonization of watermelon. Cover crop treatments V. villosa, T. incarnatum, and S. cereale and no cover crop were evaluated both alone and in combination with Actinovate AG in the greenhouse. Additionally, in vitro experiments were conducted to measure the effects of cover crop leachate on the mycelial growth rates of F. oxysporum f. sp. niveum race 1 and Trichoderma harzianum. Soil microbial respiration was significantly elevated in V. villosa and Trifolium incarnatum treatments both preceding and following green manure incorporation, and was significantly negatively correlated with Fusarium wilt, suggesting that microbial activity was higher under the legumes, indicative of general suppression. Parallel to this, in vitro growth rates of F. oxysporum f. sp. niveum and Trichoderma harzianum on V. villosa leachate amended media were 66 and 213% greater, respectively, than on nonamended plates. The F. oxysporum spp. population (based on CFU and not differentiated into formae specialis or races) significantly increased in V. villosa-amended field plots. Additionally, the percentage of watermelon roots colonized by arbuscular mycorrhizae following V. villosa and Trifolium incarnatum green manures was significantly higher than in watermelon following bare ground (58 and 44% higher, respectively). In greenhouse trials where cover crops were amended to soil, Actinovate AG did not consistently reduce Fusarium wilt. Both general and specific disease suppression play a role in reducing Fusarium wilt on watermelon.


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