Evaluation of Endophytic Bacterial Isolates against Root Knot Nematode, Meloidogyne incognita in Tomato under Glasshouse Condition

A field survey was conducted in 12 districts of Assam viz., Jorhat, Golaghat, Nagaon, Marigaon, Goalpara, Dibrugarh, Tinsukia, Lakhimpur, Dhemaji, Sivsagar, Kamrup and Barpeta. A total of 92 root samples were collected and 37 bacterial isolates were isolated from commercial banana cultivars. The culture filtrates extracted from 37 endophytic bacterial isolates, were screened against southern root-knot nematode, Meloidogyne incognita in vitro and under pot culture studies. The five bacterial isolates viz., EB4, EB8, BC1, BC11 and BC12 showed 100% inhibition of egg hatching and juvenile mortality of M. incognita with an exposure period of 48 and 72h. On seed bacterization, with these five promising isolates, two isolates viz.EB4, BC1 significantly enhanced germination percentage (33.33, 25.31%) and vigour index (75.5, 64.39%) of paddy, receptively. The potential bacterial isolates viz., BC1 and EB4 were identified as Lysinibacillus sp. and Pseudomonas sp., respectively , based on the morphological phenotypic and biochemical characterization. The pot culture experiment revealed that the bacterial endophytes viz., Lysinibacillus sp. (BC1) Pseudomonas sp. (EB4) significantly reduced the soil (61.64, 56.71%) and root nematode population (77.29, 68.87%), number of adult females (73.97, 69.89%), egg masses (85.63, 80.11%) and root-knot index (1.33, 1.67) of M. incognita compared to untreated control. The bacterial endophytes viz., Pseudomonas sp. (EB4), Lysinibacillus sp. (BC1) were also significantly increased the growth parameters viz., shoot length (43.33, 39.18%), and root length (78.24, 59.26%) and pesudostem girth (58.38, 52.13%).

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Potential of some endophytic bacteria in biological control of root-knot nematode Meloidogyne incognita

Egyptian Journal of Biological Pest Control ◽

10.1186/s41938-021-00396-4 ◽

2021 ◽

Vol 31 (1) ◽

Author(s):

Shalaleh Moslehi ◽

Salar Pourmehr ◽

Akbar Shirzad ◽

Reza Khakvar

Keyword(s):

Biological Control ◽

Meloidogyne Incognita ◽

Endophytic Bacteria ◽

Plant Pathogens ◽

Bacterial Isolates ◽

Inhibitory Effects ◽

Root Knot Nematode ◽

Isolation And Identification ◽

Root Knot Nematodes ◽

Biocontrol Potential

Abstract Background Root-knot nematodes (Meloidogyne spp.) are among the most important plant pathogens. Biological control is one of the safety and effective methods for control of these nematodes. The aim of the present study was the isolation and identification of endophytic bacteria from tomato fields in some areas of Iran in order to evaluate their biocontrol potential against root-knot nematode. In the present study, the population of Meloidogyne was collected from infected cucumber roots of a greenhouse, and the bacteria were isolated from tomato samples collected from the fields in West-Azarbaijan province of Iran. The effects of the bacterial isolates on hatching and mortality of nematode second-stage juveniles were evaluated, and the effects of six selected isolates on infection of a susceptible cultivar of tomato with nematode were evaluated under greenhouse conditions. Results The root-knot nematode was identified as Meloidogyne incognita. Results showed that the all isolates exhibited considerable inhibitory effects on nematode hatching. The bacterial isolates also caused the mortality of juveniles. Six bacterial isolates with notable biocontrol potential were selected, and supplementary experiments and molecular identification of selected bacterial isolates were performed. Isolates 1, 2, 5, 7, 10, and 11 were identified as follows: Bacillus wiedmannii (MW405861), Pseudoxantomonas mexicana (MW405860), Pseudomonas thivervalensis (MW405862), Serratia liquefaciens (MW405864), Pseudomonas chlororaphis (MW405863), and P. fluorescens (MW405825), respectively. Based on the results of the greenhouse experiment, the selected isolates exhibited good results in terms of reduction of galls and egg masses of nematode. However, B. wiedmannii and S. liquefaciens had the best results in reduction of all investigated factors compared to other isolates. P. mexicana, P. chlororaphis, and P. fluorescens resulted moderate effects. P. thivervalensis was less effective than the others and in some cases had no effect on nematode reduction. Conclusions The results showed that endophytic bacteria are good candidates for management of root-knot nematodes. The use of such agents instead of chemicals will be very valuable to the control of nematodes.

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Endophytic Bacterial Consortium Originated from Forestry Plant Roots and Their Nematicidal Activity against Meloidogyne incognita Infestation in Greenhouse

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis ◽

10.11118/actaun201967051171 ◽

2019 ◽

Vol 67 (5) ◽

pp. 1171-1182

Author(s):

Abdul Munif ◽

Supramana ◽

Elis Nina Herliyana ◽

Ankardiansyah Pandu Pradana

Keyword(s):

Meloidogyne Incognita ◽

Volatile Compound ◽

Bacterial Consortium ◽

Physiological Characteristics ◽

Phenotypic Characterization ◽

Bacterial Isolates ◽

Root Knot Nematode ◽

Egg Hatching ◽

Protease Enzyme

Yield loss due to root-knot nematode Meloidogyne incognita infection is reported to reach 35%, depends on factors contributing to infection. Application of several endophytic bacterial isolates (bacterial consortium) to control pathogenic infection is reported to be more effective compared to the application of single bacterial isolate. This study was aimed to obtain endophytic bacterial consortium originated from forestry plant that is effective to control root-knot nematode. The study was conducted through bacterial isolation followed by biosafety test. Bacterial isolates that were found to be safe for plants and mammals and compatible with each other were further grouped as the endophytic bacterial consortium. Phenotypic characterization and physiological characteristics including Gram type, ability to produce protease, chitinase, and lipase enzymes as well as HCN volatile compound were also tested. Moreover, the ability to fix nitrogen and dissolve phosphate were also examined. The endophytic bacterial consortium consisted of several bacterial isolates was further tested for its ability to inhibit M. incognita egg hatching and increase J2 of M. incognita mortality in vitro. Furthermore, test on tomato plants infested with 500 J2 of M. incognita was also performed in the greenhouse. Test results showed that 70 bacterial isolates were successfully isolated from Shorea sp., Swietenia sp., Albizia falcataria, Anthocephalus cadamba, and Juglans nigra. However, 34 bacterial isolates were observed to be safe (did not cause hypersensitivity reaction and did not produce hemolytic toxin). According to physiological characteristics, it was found that 25 isolates were able to produce protease enzyme, 26 isolates were able to produce chitinase enzyme, and 14 isolates were able to produce lipase enzyme. Moreover, it was also detected that 11 isolates were able to produce HCN volatile compound, 23 isolates were able to fix nitrogen (N), and 24 isolates were able to dissolve phosphate (P). Endophytic bacterial consortium obtained in this study was also observed to be able to inhibit M. incognita egg hatching up to 81.33% and increase J2 of M. incognita mortality up to 85% compared to control. In addition, the application of endophytic bacterial consortium was also able to increase the growth of tomato plant infected with M. incognita, and suppress the severity of the root-knot disease. This study provided information that endophytic bacterial consortium originated from forestry plants has the potential as a biocontrol agent of M. incognita.

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Resistance mechanisms ofPrunusrootstocks to root-knot nematode,Meloidogyne incognita

Fruits ◽

10.1051/fruits/2009024 ◽

2009 ◽

Vol 64 (5) ◽

pp. 295-303 ◽

Cited By ~ 1

Author(s):

Hang Ye ◽

Wen-jun Wang ◽

Guo-jie Liu ◽

Li-xin Zhu ◽

Ke-gong Jia

Keyword(s):

Meloidogyne Incognita ◽

Resistance Mechanisms ◽

Root Knot Nematode

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dl-β-Amino butyric acid induced resistance in tomato against root-knot nematode Meloidogyne incognita under salt stress condition

Indian Phytopathology ◽

10.1007/s42360-021-00320-8 ◽

2021 ◽

Author(s):

Mohd Asif ◽

Faryad Khan ◽

Taruba Ansari ◽

Faheem Ahmad ◽

Moh Tariq ◽

...

Keyword(s):

Salt Stress ◽

Induced Resistance ◽

Butyric Acid ◽

Meloidogyne Incognita ◽

Stress Condition ◽

Root Knot Nematode ◽

Salt Stress Condition ◽

Amino Butyric Acid

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Genetic Diversity, Virulence, and Meloidogyne incognita Interactions of Fusarium oxysporum Isolates Causing Cotton Wilt in Georgia

Plant Disease ◽

10.1094/pdis-09-16-1382-re ◽

2017 ◽

Vol 101 (6) ◽

pp. 948-956 ◽

Cited By ~ 9

Author(s):

Alois A. Bell ◽

Robert C. Kemerait ◽

Carlos S. Ortiz ◽

Sandria Prom ◽

Jose Quintana ◽

...

Keyword(s):

Genetic Diversity ◽

Fusarium Oxysporum ◽

Meloidogyne Incognita ◽

Root Knot Nematode ◽

Soil Infestation ◽

Causal Pathogen ◽

Complementation Groups ◽

Shoot Weight ◽

Cotton Wilt ◽

Significant Disease

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.

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The role of Caenorhabditis elegans sex-determination homologs, Mi-sdc-1 and Mi-tra-1 in Meloidogyne incognita

European Journal of Plant Pathology ◽

10.1007/s10658-021-02335-3 ◽

2021 ◽

Author(s):

Anil Baniya ◽

Soumi Joseph ◽

Larry Duncan ◽

William Crow ◽

Tesfamariam Mengistu

Keyword(s):

Caenorhabditis Elegans ◽

Sex Determination ◽

Meloidogyne Incognita ◽

Egg Production ◽

Target Genes ◽

Parasitic Nematode ◽

Plant Parasitic Nematode ◽

Root Knot Nematode ◽

Model Free ◽

Plant Parasitic

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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