Effect of pure culture and culture filtrates of Trichoderma species on root-knot nematode, Meloidogyne incognita infesting tomato

2018 ◽  
Vol 71 (2) ◽  
pp. 265-274 ◽  
Author(s):  
Mujeebur Rahman Khan ◽  
Irfan Ahmad ◽  
Faheem Ahamad
Author(s):  
Wafaa M. A. El-Nagdi ◽  
Mahmoud M. A. Youssef ◽  
Hassan Abd El-Khair ◽  
Mahfouz M. M. Abd-Elgawad

AbstractThis study was conducted to evaluate the effects of three fungal species, Trichoderma harzianum (Th), T. viride (Tv), and T. vierns (Tvi), and ground seeds of fennel (Foeniculum vierns) and caraway (Carum carvi), and powdered leaves of basil (Ocimum basilicum) as soil amendments against the root-knot nematode, Meloidogyne incognita on pea root, Pisum sativum under screen house conditions. The treatments were compared to a nematicide, carbofuran 10G, and untreated check. The tested materials significantly (P ≤ 0.05) reduced M. incognita on pea as indicated by the numbers of galls, egg masses, and J2 per root system in pots, either as single or combined treatments. The combined treatments caused higher average total percentages of nematode reduction than those achieved by single ones. The single treatments recorded the averages total percentages of nematode reduction ranged from 72.4 to 82.0%. Basil waste as single was superior in reducing nematode numbers of J2 and egg masses in root system per plant, as it achieved the highest average total percentages of nematode reduction (77.9%) than 73. 9 and 72.4% caused by fennel and caraway, respectively. In combined treatments, the average total percentages of nematode reduction ranged from 72.4 to 86.4%. Basil + (Th) caused the highest reduction (86.4%), followed by caraway+Tvi (86.3%) and caraway+Th (86.2%). The nematicide, carbofuran was as effective as most as the treatments in reducing nematode parameters. Also, the treatments highly increased growth and yield criteria of pea infected with M. incognita as indicated by shoot length and fresh and dry weights and root fresh weight, number and fresh and dry weights of pods.


Nematology ◽  
2000 ◽  
Vol 2 (8) ◽  
pp. 871-879 ◽  
Author(s):  
Samia Massoud ◽  
Susan L.F. Meyer ◽  
Daniel Roberts ◽  
David Chitwood

AbstractThe bacterium Burkholderia cepacia (strain Bc-2) and the fungus Trichoderma virens (strain Gl-3) were investigated for activity against the nematode Meloidogyne incognita. Culture filtrates from Bc-2 and Gl-3 contained extracellular factors that inhibited egg hatch and second-stage juvenile (J2) mobility. Size fractionation results and lack of detectable chitinase or protease activities from Bc-2 and Gl-3 culture filtrates suggested that the inhibitory factors in the in vitro assays were non-enzymic. Tomato root explant cultures of M. incognita treated with T.virens culture filtrate had 42% fewer eggs and J2 per g of roots than cultures treated with control medium that had not been inoculated with T. virens. In glasshouse tests with tomato, Bc-2 and Gl-3 were applied individually as seed coatings and as root drenches in both viable and non-viable formulations. At the 65-day harvest, non-viable B. cepacia was the only treatment that suppressed eggs and J2 per g of roots (29% suppression) compared to water controls. Evaluation de l'activité antagoniste de Trichoderma virens et Burkholderia cepacia envers le nématode Meloidogyne incognita - La bactérie Burkholderia cepacia (souche Bc-2) et le champignon Trichoderma virens (souche G1-3) ont été étudiés dans l'optique de leur action envers le nématode Meloidogyne incognita. Les filtrats de culture de Bc-2 et de G1-3 contiennent des facteurs extracellulaires inhibant l'éclosion et la motilité des juvéniles de deuxième stade (J2) du nématode. Les résultats de fractionnements relatifs à la taille et la nondétection d'une activité chitinasique ou protéasique dans les filtrats de culture de Bc-2 et G1-3 suggèrent que les facteurs inhibant présents lors des expériences in vitro ne sont pas de nature enzymatique. Des élevages de M. incognita sur explants de racines de tomate traités avec des filtrats de culture de T. virens produisent des oeufs et des J2 en nombre inférieur de 42% à celui d'élevages traités par un milieu témoin, non inoculé avec T. virens. Lors d'essais en serre sur tomate, Bc-2 et G1-3 ont été appliqués séparément, soit en pralinage des semences, soit sur la tranchée, et en formulation vivante ou non-vivante. A la récolte, après 65 jours, la formulation non-vivante de B. cepacia s'est révélée le seul traitement diminuant le nombre d'oeufs et de J2 par g de racines: moins 29% par rapport au témoin ne contenant que de l'eau.


Author(s):  
K. Ganeshan ◽  
P. Vetrivelkalai ◽  
B. Bhagawati ◽  
Nibha Gupta ◽  
K. Devrajan ◽  
...  

A Survey was conducted in 12 districts of Assam to collect 92 healthy banana root samples. A total of 55 fungal isolates were successfully isolated from commercial banana cultivars. The culture filtrates were extracted from 55 endophytic fungal isolates and screened against root knot nematode, Meloidogyne incognita in vitro and pot culture studies. Among them, five fungal isolates viz., EF4, BF7, BF27, BF28 and BF35 showed 100% inhibition of egg hatching and 96.33 to 81.33% juvenile mortality of M. incognita with an exposure period of 72h when compared to other isolates and control. On paddy seed treatment with endophytic fungi of five promising isolates, two isolates viz., BF7 and BF28 significantly enhanced germination percentage (82.67%, 73.33%) and vigour index (62.91, 47.24%), respectively. The selected five endophytic fungal isolates were evaluated for their efficacy against M. incognita in banana under pot culture conditions. The study revealed that culture filtrates of BF7 and BF28 significantly reduced the soil and root nematode population, number of adult females, egg masses and root gall index of M.incognita compared to untreated control. The isolates BF7 and BF28 also significantly increased the growth parameters viz., pseudostem height, root length and pseudostem girth. These promising endophytic fungal isolates viz., BF7 and BF28 were identified as non-pathogenic Fusarium oxysporum strains (Accession no. MN567668) and (Accession no. MN567710), respectively by PCR -18S rRNA of ITS region of gene sequence and phylogenetic tree construction.


Fruits ◽  
2009 ◽  
Vol 64 (5) ◽  
pp. 295-303 ◽  
Author(s):  
Hang Ye ◽  
Wen-jun Wang ◽  
Guo-jie Liu ◽  
Li-xin Zhu ◽  
Ke-gong Jia

Plant Disease ◽  
2017 ◽  
Vol 101 (6) ◽  
pp. 948-956 ◽  
Author(s):  
Alois A. Bell ◽  
Robert C. Kemerait ◽  
Carlos S. Ortiz ◽  
Sandria Prom ◽  
Jose Quintana ◽  
...  

Locally severe outbreaks of Fusarium wilt of cotton (Gossypium spp.) in South Georgia raised concerns about the genotypes of the causal pathogen, Fusarium oxysporum f. sp. vasinfectum. Vegetative complementation tests and DNA sequence analysis were used to determine genetic diversity among 492 F. oxysporum f. sp. vasinfectum isolates obtained from 107 wilted plants collected from seven fields in five counties. Eight vegetative complementation groups (VCG) were found, with VCG 01117B and VCG 01121 occurring in 66% of the infected plants. The newly recognized VCG 01121 was the major VCG in Berrien County, the center of the outbreaks. All eight VCG resulted in significant increases in the percentages of wilted leaves (27 to 53%) and significant reductions in leaf weight (40 to 67%) and shoot weight (33 to 60%) after being stem punctured into Gossypium hirsutum ‘Rowden’. They caused little or no significant reductions in shoot weight and height or increases in foliar symptoms and vascular browning in a soil-infestation assay. Soil infestation with Meloidogyne incognita race 3 (root-knot nematode) alone also failed to cause significant disease. When coinoculated with M. incognita race 3, all VCG caused moderate to severe wilt. Therefore, the VCG identified in this study belong to the vascular-competent pathotype, and should pose similar threats to cotton cultivars in the presence of the root-knot nematode. Use of nematode-resistant cultivars, therefore, is probably the best approach to control the disease in Georgia.


Author(s):  
Anil Baniya ◽  
Soumi Joseph ◽  
Larry Duncan ◽  
William Crow ◽  
Tesfamariam Mengistu

AbstractSex determination is a key developmental event in all organisms. The pathway that regulates sexual fate has been well characterized at the molecular level in the model free-living nematode Caenorhabditis elegans. This study aims to gain a preliminary understanding of sex-determining pathways in a plant-parasitic nematode Meloidogyne incognita, and the extent to which the roles of the sex determination genes are conserved in a hermaphrodite species, C. elegans, and plant-parasitic nematode species, M. incognita. In this study, we targeted two sex-determining orthologues, sdc-1 and tra-1 from M. incognita using RNA interference (RNAi). RNAi was performed by soaking second-stage juveniles of M. incognita in a solution containing dsRNA of either Mi-tra-1or Mi-sdc-1 or both. To determine the effect of RNAi of the target genes, the juveniles treated with the dsRNA were inoculated onto a susceptible cultivar of cowpea grown in a nutrient pouch at 28 °C for 5 weeks. The development of the nematodes was analyzed at different time points during the growth period and compared to untreated controls. Our results showed that neither Mi-sdc-1 nor Mi-tra-1 have a significant role in regulating sexual fate in M. incognita. However, the silencing of Mi-sdc-1 significantly delayed maturity to adult females but did not affect egg production in mature females. In contrast, the downregulation of Mi-tra-1 transcript resulted in a significant reduction in egg production in both single and combinatorial RNAi-treated nematodes. Our results indicate that M. incognita may have adopted a divergent function for Mi-sdc-1 and Mi-tra-1distinct from Caenorhabditis spp. However, Mi-tra-1 might have an essential role in female fecundity in M. incognita and is a promising dsRNA target for root-knot nematode (RKN) management using host-delivered RNAi.


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