scholarly journals Suppression of Meloidogyne incognita by the Entomopathogenic Fungus Lecanicillium muscarium

Plant Disease ◽  
2018 ◽  
Vol 102 (5) ◽  
pp. 977-982 ◽  
Author(s):  
Manzoor Hussain ◽  
Miloslav Zouhar ◽  
Pavel Ryšánek

The entomopathogenic fungus Lecanicillium muscarium (Petch) Zare and Gams is currently being developed as a biocontrol agent against insect pests, as well as some plant-pathogenic fungi and bacteria. Data about its activity against plant-parasitic nematodes exist, but are relatively limited. To expand this understanding, we investigated the biocontrol efficiency of three isolates of L. muscarium (Lm) against the root knot nematode, Meloidogyne incognita, in both in vitro and in vivo conditions. In our experiments, the maximum number of nematode eggs, juveniles (J2s), females, and egg masses that were parasitized were quantified after a 72-h exposure to the fungus. The isolate Lm1 was designated as the best biocontrol agent against nematode eggs as well as J2s. It showed the highest colonization of eggs and significantly decreased egg hatching events. The results from two additional isolates, Lm2 and Lm3, were also significant (P = 0.05) but less pronounced than those observed with Lm1. L. muscarium treatments had significant (P = 0.05) positive effects on plant shoot and root growth compared with the growth of control plants. These results suggest the effectiveness of the fungus may be due to either the infection of eggs and J2s, or the production of secondary metabolites that induced plant defense mechanisms and lead to systemic resistance. Our study demonstrates that L. muscarium could be used as a potential biocontrol agent against root knot nematodes.

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1222
Author(s):  
Qiong He ◽  
Dongya Wang ◽  
Bingxue Li ◽  
Ambreen Maqsood ◽  
Haiyan Wu

The root-knot nematode is one of the most damaging plant-parasitic nematodes worldwide, and the ecofriendly alternative approach of biological control has been used to suppress nematode populations. Here the nematicidal activity of Aspergillus japonicus ZW1 fermentation filtrate against Meloidogyne incognita was evaluated in vitro and in greenhouse, and the effects of A. japonicus ZW1 fermentation filtrate on seed germination and the active compound of A. japonicus ZW1 fermentation filtrate were determined. The 2-week fermentation filtrate (2-WF) of A. japonicus ZW1 exhibited markedly inhibitory effects on egg hatching, and 5% 2-WF showed potential nematicidal activities on second-stage juveniles (J2s); the mortality of J2s was 100% after 24 h exposure. The internal contents of nematodes were degraded and remarkable protruded wrinkles were present on the body surface of J2s. The nematicidal activity of the fermentation was stable after boiling and was not affected by storage time. A germination assay revealed that 2-WF did not have a negative effect on the viability and germination of corn, wheat, rice, cowpeas, cucumbers, soybeans, or tomato seeds. The pot-grown study confirmed that a 20% fermentation broth solution significantly reduced root galls and egg numbers on tomatoes, and decreased galls and eggs by 47.3% and 51.8% respectively, over Czapek medium and water controls. The active compound from the A. japonicus ZW1 fermentation filtrate was isolated and identified as 1,5-Dimethyl Citrate hydrochloride ester on the basis of nuclear magnetic resonance (NMR) and LC-MS (liquid chromatograph-mass spectrometer) techniques. Thus, fermentation of A. japonicus ZW1 could be considered a potential new biological nematicide for the control of M. incognita.


Nematology ◽  
2001 ◽  
Vol 3 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Jaap Bakker ◽  
Fred Gommers ◽  
Geert Smant ◽  
Pierre Abad ◽  
Marie-Noëlle Rosso ◽  
...  

AbstractExpressed sequence tags (EST) have been widely used to assist in gene discovery in various organisms (e.g., Arabidopsis thaliana, Caenorhabditis elegans, Mus musculus, and Homo sapiens). In this paper we describe an EST project, which aims to investigate gene expression in Meloidogyne incognita at the onset of parasitism. Approximately 1000 5′-end sequence tags were produced from a cDNA library made of freshly hatched preparasitic second stage juveniles (J2). The EST were identified in the primary transformants of the cDNA library, and assigned to nine different functional groups, including (candidate) parasitism genes. A large fraction of the EST (45%) did not have a putative homologue in public databases. Sixty five percent of the EST that could be clustered into a functional group had putative homologues in other nematode species. EST were found for virtually all parasitism related genes that have been cloned from M. incognita to date. In addition, several novel genes were tagged, including a xylanase and a chitinase gene. The efficiency of EST projects, which produce sequence data for thousands of genes in months time without any difficult pre-selections of mRNA pools, makes random sequencing cDNA libraries a superior method to identify candidates for parasitism related genes in plant-parasitic nematodes. The sequences in this paper are retrievable from Genbank with the accession numbers BE191640 to BE191741, BE217592 to BE217720, BE225324 to BE225598, BE238852 to BE239221, and BE240829 to BE240865.


2019 ◽  
Vol 12 (1) ◽  
pp. 24-37
Author(s):  
M.A. Radwan ◽  
A.S.A. Saad ◽  
H.A. Mesbah ◽  
H.S. Ibrahim ◽  
M.S. Khalil

Summary Avermectins and spinosyns are structurally related natural products of microbial origin and belong to a new family of macrolides which are active against a vast array of invertebrate pests. In the present study, the effects of four members of macrolides; abamectin (ABM), emamectin benzoate (EMB), spinosad (SPI) and spinetoram (SPIT), on Meloidogyne incognita were investigated under in vitro and in vivo conditions. All compounds reduced egg hatching and led to high mortality of the nematode second-stage juveniles (J2). ABM showed the maximum rate of egg hatching inhibition and J2 mortality while SPIT recorded the minimum. All treatments reduced the number of galls, egg masses, eggs/egg mass in roots and J2 in the soil when compared to the control. Based on the 10 folds of the 24 h-LC50 values of J2 mortality in vitro, EMB and ABM exhibited higher percent reduction in galls (79.68 and 71.45%), egg masses (75.19 and 70.54%), eggs/egg mass (60.49 and 40.91%) and J2 in the soil (90.31 and 86.54%), respectively, compared to SPI and SPIT. Significant increase in tomato shoot height occurred in all biopesticides (10 folds) and SPIT (20 folds). SPI at 10 folds of the 24 h-LC50 values of J2 mortality in vitro, significantly increased root length while ABM at 50 folds and SPIT at 20 folds decreased root length by 5.15% and 5.88%, respectively, compared to the untreated inoculated plants. In all treatments, the dry shoot and root weights increased, compared to the untreated control. Our findings suggest that these macrolides have the ability to regulate nematode population densities and may be an alternative to classical nematicides.


2017 ◽  
Vol 9 (2) ◽  
pp. 1090-1096
Author(s):  
Ramandeep Kaur ◽  
K. K. Chahal ◽  
N. K. Dhillon ◽  
Urvashi Bhardwaj

Nematicidal potential of chloroform root extract of Inula racemosa and its fractions was investigated on egg hatching and mortality of root knot nematode Meloidogyne incognita. Egg masses and second stage juveniles (J2) of M. incognita were exposed to different concentrations (0.1-8.0 mg ml-1) of I. racemosa root extract and its fractions. Observations on egg hatch were recorded on 1st, 3rd, 5th, 7th and 9th day and those of mortality studies were recorded on 2nd, 4th, 6th, 8th and 10th day, respectively. Significant mortality as well as egg hatch inhibition was observed for all the tested components at 5 %. The root extract was found to be most effective in controlling egg hatching as complete inhibition was observed at 8.0 mg ml-1 concentration on 1stday of treatment and nonpolar fraction was most effective in causing mortality of J2 of M. incognita as 100 % inhibition was observed at 6.0 and 8.0 mg ml-1 concentration on 2nd day of treatment. Maximum inhibition of egg hatching was observed for root extract at 8.0 mg ml-1 concentration and 100 % mortality was observed for root extract as well as nonpolar fraction at the same concentration. The nonpolar fraction was most effective in causing mortality as maximum mortality was observed at 6.0 and 8.0 mg ml-1 concentration throughout the exposure time. Polar fraction was least effective among all the components both in egg hatch inhibition and J2 mortality of M. incognita. Both the activities showed concentrations as well as time dependence. Results show different role of tested components on egg hatching and mortality of root knot nematode. The root extract of I. racemosa and its fractions showed a potential to develop new nematicide.


2019 ◽  
Vol 18 (4) ◽  
pp. 62-69
Author(s):  
Phong V. Nguyen

Effectors have been identified to play a very important role in the parasitism of plant-parasitic nematode. To cope with this type of pathogen, many approaches of silencing genes encoding for effectors have been studied and promise to be an effective tool to create plant varieties resistant to plant-parasitic nematodes. In this study, the Minc16281 gene encoding a pioneer effector with unknown function was determined and cloned from a Meloidogyne incognita population isolated from soybean field (ID: MH315945.1). The nucleotide sequence of this gene showed 97% identity to its homolog in GenBank (ID: JK287445.1) used as the control strain in our research. To generate host-induced gene silencing constructs which can potentially silence the expression of Minc16281 gene, two artificial microRNAs were synthesized based on the miR319a structure of Arabidopsis thaliana and inserted into an expression vector in soybean. These microRNAs can be introduced into soybean to investigate the function of Minc16281 on parasitism of root-knot nematode.


2021 ◽  
Vol 108 (Special) ◽  
Author(s):  
Ganeshan k ◽  
◽  
Vetrivelkalai p ◽  
Bhagawati B ◽  
Nibha G ◽  
...  

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%).


2020 ◽  
Vol 17 (3) ◽  
pp. 118 ◽  
Author(s):  
RITA HARNI ◽  
MEYNARTI SARI DEWI IBRAHIM

<p>ABSTRAK</p><p>Meloidogyne incognita, merupakan salah satu organisme peng-ganggu (OPT) penyebab penyakit kuning pada tanaman lada dan dapatmengakibatkan penurunan hasil sampai 32%. Beberapa teknik untukmengendalikan patogen ini telah dilakukan tetapi belum memberikan hasilyang memuaskan. Pengendalian biologi dengan menggunakan bakteriendofit merupakan salah satu alternatif pengendalian yang cukup men-janjikan untuk dapat mengatasi permasalahan nematoda penyakit tanaman.Penelitian ini telah dilakukan di Laboratorium Bakteriologi danNematologi Departemen Proteksi Tanaman Institut Pertanian Bogor, danRumah Kaca Balai Penelitian Tanaman Rempah dan Aneka TanamanIndustri Pakuwon Sukabumi dari bulan Mei sampai November 2009.Kegiatan yang dilakukan adalah: 1) Seleksi beberapa isolat bakteri endofituntuk mengendalikan nematoda M. incognita pada tanaman lada dan 2)Potensi induced systemic resistance (ISR) dan analisis asam salisilat sertaperoksidase. Isolat bakteri endofit yang digunakan adalah isolat bakteriendofit potensial yang diisolasi dari akar nilam. Akar tanaman ladadirendam dalam suspensi bakteri endofit, selanjutnya diinokulasi dengan500 ekor larva 2 M. incognita. Sebulan setelah inokulasi tanamandibongkar diamati populasi nematoda dan pertumbuhan tanaman. AnalisisISR dilakukan dengan metode split root system dilanjutkan dengananalisis kadar asam salisilat dan peroksidase. Penelitian mengunakanRancangan Acak Lengkap. Hasil penelitian menunjukkan bahwa bakteriendofit dapat menekan jumlah puru dan populasi nematoda di dalam akar.Penekanan tertinggi pada isolat MSK (97,93%) tidak berbeda nyatadengan isolat BAS, TT2, dan NJ46 yaitu 97,35; 95,22; dan 92,14%.Berdasarkan analisis split root system, ke 4 isolat tersebut dapat meng-induksi ketahanan tanaman lada secara sistemik dengan mekanismepeningkatan kandungan asam salisilat dan peroksidase di dalam akar.</p><p>Kata kunci : Bakteri endofit, penyakit kuning, Piper nigrum L.,Meloidogyne incognita, induksi ketahanan</p><p>ABSTRACT</p><p>The use of endophytic bacteria to induce plant resistanceagainst infection of root-knot nematode (Meloidogyneincognita) on black pepper</p><p>Root-knot nematode (Meloidogyne incognita) is one of important patho-gens causing yellow disease on black pepper. As a result of this pathogenattack can lower the results up to 32%. Several control methods have beendone successful to control pathogen. Biological control using endophyticbacteria is one of prospective alternative control methods to overcomenematode problem. The research had been conducted in the Laboratory ofBacteriology and Nematology Department of Plant Protection, BogorAgricultural University (IPB) and in greenhouse of Indonesian Spices andIndustrial Crops Research Institute (ISICRI) Sukabumi. The objectives ofthis study were : 1) Selection of endophytic bacteria to control M.incognita nematodes on black pepper and 2) Potential of induced systemicresistance (ISR) and analysis of salicylic acid and peroxidase. Endophyticbacterial isolates used were endophytic potential bacterial isolates isolatedfrom the roots of patchouli. Pepper plant roots were soaked in anendophytic bacterial suspension, then inoculated with 500 larvae of 2 M.incognita. A month after inoculation, the plants were dismantled andobserved population of nematodes and plant growth. ISR analysis wasperformed by the method of split root system followed by analysis ofsalicylic acid and peroxidase contents. The research was arranged usingCompletely Randomized Design. The results showed that endophyticbacteria were able to suppress the amount of gall and nematode populationin roots. The highest suppression was on MSK isolate (97.93%) which wasnot significantly different from BAS, TT2, and NJ46 isolates, namely97.35, 95.22, and 92.14%, respectively. The analysis of split root systemshowed that the 4 isolates were able to induce systemic resistance of blackpepper with a mechanism of increase in salicylic acid and peroxidasecontents in roots.</p><p>Key words : Endophytic bacteria, yellow disease, Piper nigrum L.,Meloidogyne incognita, induce systemic resistance</p>


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