scholarly journals The carB Gene of Escherichia coli BL21(DE3) is Associated with Nematicidal Activity against the Root-Knot Nematode Meloidogyne javanica

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 222
Author(s):  
Yanfei Xia ◽  
Shen Li ◽  
Guohui Xu ◽  
Shanshan Xie ◽  
Xueting Liu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Culture Filtrate ◽  
Ph Value ◽  
Meloidogyne Javanica ◽  
Nematicidal Activity ◽  
Dependent Manner ◽  
Root Knot Nematode ◽  
Juvenile Mortality ◽  
Escherichia Coli Bl21 ◽  
Culture Filtrates

Biological nematicides have been widely used to lower the losses generated by phytoparasitic nematodes. The purpose of this study was to evaluate the nematicidal effects of Escherichia coli BL21(DE3) against Meloidogyne javanica and to identify nematicide-related genes. Culture filtrates of BL21(DE3) caused juvenile mortality and inhibited egg hatching in a dose-dependent manner. In the greenhouse, treatment of tomato seedlings with BL21(DE3) culture filtrates at 50 and 100% concentrations not only reduced the amount of M. javanica egg masses and galls, but improved plant root and shoot fresh weight. Culture filtrate analysis indicated that the nematicidal active ingredients of strain BL21(DE3) were non-proteinaceous, heat and cold resistant, sensitive to pH and volatile. To identify the genes associated with nematicidal activity, a BL21(DE3) library of 5000 mutants was produced using Tn5 transposase insertion. The culture filtrate of the MB12 mutant showed no nematicidal activity after 72 h of treatment and thermal asymmetrical interlaced PCR demonstrated that the carB gene was disrupted. Nematicidal activity was restored when the pH of the MB12 culture filtrate was adjusted to the original pH value (4.15) or following MB12 complementation with the carB gene, confirming a role for carB in mediating pH value and nematicidal activity. The outcomes of this pilot study indicate that BL21(DE3) is a potential microorganism for the continuable biological control of root-knot nematode in tomato and that carB affects the nematicidal activity of BL21(DE3) by modulating the pH environment.

Suppressive effects of composts against the root-knot nematode Meloidogyne javanica on tomato

Nematology ◽  
2002 ◽  
Vol 4 (8) ◽  
pp. 891-898 ◽  
Author(s):  
Yuji Oka ◽  
Uri Yermiyahu
Keyword(s):  
Water Extract ◽  
Meloidogyne Javanica ◽  
Suppressive Effect ◽  
Cattle Manure ◽  
Nematicidal Activity ◽  
Root Knot Nematode ◽  
Grape Marc ◽  
Manure Compost ◽  
Cattle Manure Compost

AbstractSuppressive effects of two composts, from cattle manure and grape marc, on the root-knot nematode Meloidogyne javanica were tested in pot and in vitro experiments. No root galls were found on tomato roots grown in soils containing 10 or 25% (v/v) cattle manure compost, and very few on those grown in 50% grape marc compost. Significant reductions in galling index were also found on tomato plants grown in soils containing lower concentrations of this compost. Chemical analysis of the composts and leachates from the soils showed that the cattle manure compost had higher electrical conductivity (EC) and higher concentrations of nitrogen, especially N–NH4, than the grape marc compost. Water extract of the cattle manure compost showed high nematicidal activity to the nematode juveniles and less activity toward the eggs in vitro. Water extract of the grape marc compost showed weaker nematicidal activity to the juveniles and eggs. Washing composted soils with excess water before nematode inoculation and tomato planting led to better plant growth, but the nematode-suppressive effect was decreased. These results suggest that high nitrogen concentrations, especially N–NH4, and high EC values contribute to the nematode suppressiveness of the composts.

Nematicidal activity of essential oil components against the root-knot nematode Meloidogyne javanica

Nematology ◽  
2001 ◽  
Vol 3 (2) ◽  
pp. 159-164 ◽  
Author(s):  
Yuji Oka
Keyword(s):  
Essential Oil ◽  
Meloidogyne Javanica ◽  
Nematicidal Activity ◽  
Root Knot Nematode ◽  
Tomato Plants ◽  
Pot Experiments ◽  
Application Methods ◽  
Oil Components ◽  
Shoot Weight

AbstractNematicidal activity of eight essential oil components; trans -anethole, anis alcohol, p-anisaldehyde, benzaldehyde, 4-methoxyphenol, trans-cinnamaldehyde, (R)-(+)-pulegone, 2-furaldehyde, and a non-essential oil component anisole, was tested against the root-knot nematode Meloidogyne javanica in solutions in 200-ml and 3-l pots and in microplots. Among the anisole derivatives, p-anisaldehyde showed the highest nematicidal activity in solutions and in soil. However, trans-cinnamaldehyde, 2-furaldehyde and benzaldehyde showed higher nematicidal activity than p-anisaldehyde in the 3-l pot experiments. EC50 values of trans-cinnamaldehyde for juvenile immobilisation and hatching inhibition in vitro were as low as 15 and 11.3 μl/l, respectively. In the 3-l pot experiments, trans-cinnamaldehyde, 2-furaldehyde, benzaldehyde and carvacrol at a concentration of 100 mg/kg greatly reduced the root galling of tomato, whereas trans-anethole was not effective. In a microplot experiment, soil treatment with trans-cinnamaldehyde (50 ml/m2) reduced the galling index and increased the shoot weight of tomato plants. Although further experiments, such as development of formulations and application methods, are needed, some essential oil components, especially aldehydes, can be developed into lowtoxicity nematicides.

scholarly journals Inhibitory effects of salicylic acid on Meloidogyne javanica reproduction in tomato plants

2016 ◽  
Vol 14 (1) ◽  
pp. e1001 ◽  
Author(s):  
Fatemeh Moslemi ◽  
Seddigheh Fatemy ◽  
Françoise Bernard
Keyword(s):  
Salicylic Acid ◽  
Seed Treatment ◽  
Growth Parameters ◽  
Seed Priming ◽  
Meloidogyne Javanica ◽  
Root Knot Nematode ◽  
Nematode Reproduction ◽  
Tomato Plants ◽  
Juvenile Mortality ◽  
Soil Drench

<p>Root-knot nematodes (<em>Meloidogyne</em> spp.), play a major role in loss of agricultural production<strong>. </strong>Natural substances<strong>,</strong> such as salicylic acid (SA) could possibly be involved in inducing host plant resistance against nematodes. The present study is concerned with exploring the effects of varying concentrations of SA as seed priming and soil drench on tomato growth parameters and the reproduction of the root-knot nematode <em>Meloidogyne javanica</em>. SA at 50 μM concentration caused only 2% of juvenile mortality under in vitro conditions. SA applied as 50 μM seed treatment caused 95% and, as a soil drench, 78% reduction in the number of egg masses that formed on tomato plants. The numbers of galls were reduced to a lesser extent. Final nematode density per gram of soil was reduced to less than 1 by the 50 μM SA seed treatment, and in other treatments decreased by between 70 and 88% compared with control plants. Our results indicate SA has potential to lower root knot nematode reproduction in tomato, and seed priming is a fairly easy method to work with.</p>

scholarly journals Evaluation of Streptomyces saraciticas as Soil Amendments for Controlling Soil-Borne Plant Pathogens

2021 ◽  
Vol 37 (6) ◽  
pp. 596-606
Author(s):  
Pei-Hsuan Wu ◽  
Tung-Tsuan Tsay ◽  
Peichen Chen
Keyword(s):  
Plant Pathogens ◽  
Ph Value ◽  
Soil Amendments ◽  
Organic Amendments ◽  
Root Knot Nematode ◽  
Egg Hatching ◽  
Juvenile Mortality ◽  
Nematode Eggs ◽  
Greenhouse Tests

Soil-borne diseases are the major problems in mono cropping. A mixture (designated LTM-m) composed of agricultural wastes and a beneficial microorganism Streptomyces saraceticus SS31 was used as soil amendments to evaluate its efficacy for managing Rhizoctonia solani and root knot nematode (Meloidogyne incognita). In vitro antagonistic assays revealed that SS31 spore suspensions and culture broths effectively suppressed the growth of R. solani, reduced nematode egg hatching, and increased juvenile mortality. Assays using two Petri dishes revealed that LTM-m produced volatile compounds to inhibit the growth of R. solani and cause mortality to the root knot nematode eggs and juveniles. Pot and greenhouse tests showed that application of 0.08% LTM-m could achieve a great reduction of both diseases and significantly increase plant fresh weight. Greenhouse trials revealed that application of LTM-m could change soil properties, including soil pH value, electric conductivity, and soil organic matter. Our results indicate that application of LTM-m bio-organic amendments could effectively manage soil-borne pathogens.

scholarly journals Trigonella foenum-graecum (fenugreek)-mediated suppression of Meloidogyne javanica in mungbean

2013 ◽  
Vol 55 (2) ◽  
pp. 121-132 ◽  
Author(s):  
Tayyaba Zia ◽  
Imran A. Siddiqui ◽  
Syed S. Shaukat ◽  
Syed Nazaru-Hasnai
Keyword(s):  
Meloidogyne Javanica ◽  
Macrophomina Phaseolina ◽  
Fungal Communities ◽  
Root Knot Nematode ◽  
Egg Hatch ◽  
Soil Suppressiveness ◽  
Juvenile Mortality ◽  
Trigonella Foenum Graecum ◽  
Root Tissues ◽  
Population Numbers

Soil amendments with powdered seeds of <i>Trigonella foenum - graecum</i> (fenugreek) caused soil suppressiveness against <i>Meloidogyne javanica</i>. Decomposed seeds of fenugreek caused marked reduction in nematode population densities and subsequent root-knot development as compared to the aqueous extract of the seeds indicating that some indirect factors are involved in the suppression of root-knot nematode. Both decomposed seeds and aqueous extracts enhanced plant height and fresh weights of shoot whereas root growth remained uninfluenced. Changes in fungal communities associated with nematode control were studied by comparing population numbers of fungi in the soil and in internal root tissues (endorhiza) in non-amended and fenugreekamended soils. <i>Acremonium</i> sp., <i>Chaetomium globosum, Fusarium solani, Macrophomina phaseolina</i> and <i>Rhizoctonia solani</i> were found to colonize inner root tissues of mungbean. <i>Acremonium</i> sp., <i>C. globosum</i> and <i>F.solani</i> were isolated in a relatively higher frequency from roots growing in the amended soils while <i>M. phaseolina</i> and <i>R. solani</i> colonized greatly in roots growing in non-amended soil. Of the fungi isolated from soils, <i>Penicillium brefaldianum</i> caused maximum juvenile mortality of <i>M.javanica</i> whereas <i>F.solani</i> caused greatest inhibition of egg hatch.

scholarly journals Endophytic Fungi as Potential Bio-Control Agents against Root Knot Nematode, Meloidogyne incognita in Banana

2021 ◽  
pp. 7-18
Author(s):  
K. Ganeshan ◽  
P. Vetrivelkalai ◽  
B. Bhagawati ◽  
Nibha Gupta ◽  
K. Devrajan ◽  
...  
Keyword(s):  
Endophytic Fungi ◽  
Meloidogyne Incognita ◽  
Growth Parameters ◽  
Root Knot Nematode ◽  
Egg Hatching ◽  
Population Number ◽  
Juvenile Mortality ◽  
Fungal Isolates ◽  
Culture Filtrates ◽  
Pot Culture

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.

scholarly journals Mineral composition of beetroot treated with potential elicitors and inoculated with Meloidogyne javanica

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Paula Juliana Grotto Débia ◽  
Beatriz Cervejeira Bolanho ◽  
Claudia Regina Dias-Arieira
Keyword(s):  
Population Density ◽  
Mineral Composition ◽  
Integrated Management ◽  
Meloidogyne Javanica ◽  
Nematode Population ◽  
Root Knot Nematode ◽  
Cu Content ◽  
Manganese Zinc ◽  
Nematode Population Density ◽  
Elicitor Treatments

Abstract Background The root-knot nematode Meloidogyne javanica can infect beetroots, causing extensive damage to this food crop. As chemical and genetic control tactics have shown limited efficacy, new strategies are needed to improve the integrated management of this parasite. This study assessed the influence of potential defence elicitors and M. javanica infection on the mineral composition of beetroot. Plants were treated with acibenzolar-S-methyl (ASM), citrus biomass, or a mannanoligosaccharide-based product (MOS) and inoculated with 1000 eggs and second-stage juveniles of M. javanica. At 60 days after inoculation, beetroot plants were harvested and evaluated for nematode population density, vegetative growth, and mineral content. Results All potential elicitors reduced nematode population density in beetroots (p ≤ 0.10) and improved the vegetative parameters of inoculated plants (p ≤ 0.05), except shoot fresh weight. Some minerals were found to be negatively affected by treatments, particularly calcium, whose levels were consistently lower in treated plants. On the other hand, M. javanica inoculation increased magnesium, iron, manganese, zinc, and copper contents in beetroots. However, the latter mineral (Cu content) of inoculated plants was positively influenced by MOS and ASM. Conclusion Potential elicitor treatments did not improve the mineral composition of beetroot, but were effective in reducing nematode population density. Plants inoculated with M. javanica had higher mineral levels. However, gall formation decreases the commercial value of the crop and might render it unsuitable for commercialisation. M. javanica-infected beetroots may be used for nutrient extraction or sold to food processing industries.

Enhanced accumulation of pinosylvin stilbenes and related gene expression in Pinus strobus after infection of pine wood nematode

2021 ◽  
Author(s):  
Hwan-Su Hwang ◽  
Jung Yeon Han ◽  
Yong Eui Choi
Keyword(s):  
Transcription Factors ◽  
Defense Mechanisms ◽  
De Novo ◽  
Pinus Strobus ◽  
Pine Wilt Disease ◽  
Monomethyl Ether ◽  
Bursaphelenchus Xylophilus ◽  
Nematicidal Activity ◽  
Dependent Manner ◽  
Pine Wood

Abstract Pine wood nematodes (PWNs: Bursaphelenchus xylophilus) infect pine trees and cause serious pine wilt disease. Eastern white pine (Pinus strobus) has resistance to PWN. However, the detailed defense mechanisms of P. strobus against PWN are not well known. When P. strobus plants were infected with PWNs, the accumulation of stilbenoids, dihydropinosylvin monomethyl ether (DPME) and pinosylvin monomethyl ether (PME), were increased remarkably. DPME and PME had the high nematicidal activity. Interestingly, the nematicidal activity of the two compounds was resulted in a developmental stage-dependent manner. PME was more toxic to adult PWNs than juveniles, whereas DPME was found more toxic to juvenile PWNs than the adults. The genes involved in PME and DPME biosynthesis such as phenylalanine ammonia-lyase (PAL), 4-coumarate-CoA ligase (4CL), pinosylvin synthase (STS), and pinosylvin O-methyltransferase (PMT) were isolated using de novo sequencing of the transcriptome in P. strobus. In addition, transcription factors (bHLH, MYB and WRKY) related to stilbene biosynthesis were isolated. qPCR analyses of the selected genes (PAL, 4CL, STS, and PMT) including transcription factors (bHLH, MYB and WRKY) revealed that the expression level of the selected genes highly enhanced after PWN infection. Our results suggest that pinosylvin-type stilbenoid biosynthesis is highly responsive to PWN infection and plays an important role in PWN resistance of P. strobus trees.

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