Control Of Plant Parasitic Nematodes Research Articles

Control of the plant-parasitic nematode Meloidogyne incognita in soil and on tomato roots by Clonostachys rosea.

Clonostachys rosea is a well-known mycoparasite that has recently been investigated as a bio-based alternative to chemical nematicides for the control of plant-parasitic nematodes. In the search for a promising biocontrol agent, the ability of the C. rosea strain PHP1701 to control the southern root-knot nematode Meloidogyne incognita was tested. Control of M. incognita in vitro and in soil by C. rosea strain PHP1701 was significant and concentration dependent. Small pot greenhouse trials confirmed a significant reduction in tomato root galling compared to the untreated control. In a large greenhouse trial, the control effect was confirmed in early and mid-season. Tomato yield was higher when the strain PHP1701 was applied compared to the untreated M. incognita-infected control. However, the yield of non-M. incognita-infected tomato plants was not reached. A similar reduction in root galling was also observed in a field trial. The results highlight the potential of this fungal strain as a promising biocontrol agent for root-knot nematode control in greenhouses, especially as part of an integrated pest management approach. We recommend the use of C. rosea strain PHP1701 for short-season crops and/or to reduce M. incognita populations on fallow land before planting the next crop.

Nematicidal Activity of Phytochemicals against the Root-Lesion Nematode Pratylenchus penetrans.

Plant-parasitic nematodes (PPNs) are highly damaging pests responsible for heavy losses in worldwide productivity in a significant number of important plant crops. Common pest management strategies rely on the use of synthetic chemical nematicides, which have led to serious concerns regarding their impacts on human health and the environment. Plant natural products, or phytochemicals, can provide a good source of agents for sustainable control of PPNs, due to their intrinsic characteristics such as higher biodegradability, generally low toxicity for mammals, and lower bioaccumulation in the environment. In this work, the nematicidal activity of 39 phytochemicals was determined against the root-lesion nematode (RLN) Pratylenchus penetrans using standard direct and indirect contact methodologies. Overall, the RLN was tolerant to the tested phytochemicals at the highest concentration, 2 mg/mL, seldom reaching full mortality. However, high activities were obtained for benzaldehyde, carvacrol, 3-octanol, and thymol, in comparison to other phytochemicals or the synthetic nematicide oxamyl. These phytochemicals were seen to damage nematode internal tissues but not its cuticle shape. Also, the environmental and (eco)toxicological parameters reported for these compounds suggest lower toxicity and higher safety of use than oxamyl. These compounds appear to be good candidates for the development of biopesticides for a more sustainable pest management strategy.

Depth distribution of plant-parasitic nematodes on bentgrass golf greens in Missouri and Indiana.

Control of plant-parasitic nematodes (PPNs) on golf putting greens with nematicides is dependent on the seasonal occurrence and depth distribution of target PPN populations. This study aimed to determine if plant-parasitic nematode populations on golf course putting greens in Missouri and Indiana peaked at a targetable depth at a specific time in the year, focusing primarily on lance (Hoplolaimus spp.) and root-knot (Meloidogyne spp.) nematodes. To elucidate species diversity in the region, rDNA from a subset of lance and root-knot nematodes was sequenced and analyzed, with additional micromorphology of a lance nematode assessed in scanning electron micrographs (SEM). Soil samples were taken to a depth of 25 cm and stratified into 5 cm increments during April, June, August and October at seven sites across Missouri, three in the Kansas City metro of Kansas in 2021 and in ten sites across Indiana in 2022. Samples were stratified in five-centimeter increments and aggregated for a total of 100 cm3 of soil at each depth for each sampling. Samples were processed using a semi-automatic elutriator followed by the sucrose-flotation method, and populations were counted using a hemocytometer and recorded. For molecular characterization, rDNA was extracted and analyzed from 31 individual lance nematodes from one site in Missouri and eight sites in Indiana, and 13 root-knot nematodes from nine sites across Indiana. A significant interaction occurred between sampling month and depth for lance and ring nematodes Missouri/KS, with both PPN populations peaking at the 0-5 cm depth during October, which is well after most targeted nematicide applications are applied. Ring nematodes in Indiana did not follow this trend and were most abundant in August at a depth of 0-5 cm. No significant interaction between depth and month occurred for lance or root-knot nematodes in Indiana, or root-knot nematodes in Missouri/KS. Hoplolaimus stephanus and H. magnistylus were the lance species identified on golf greens, and Meloidogyne naasi, M. graminicola and M. marylandi were the root-knot species identified. Scanning-electron micrographs confirmed morphological characteristics unique to H. stephanus.

Testing the viability of poultry droppings as an option in the management of soil nematodes on <i>Capsicum annuum</i> plant

A survey to evaluate the viability of poultry droppings as a management option for the control of plant parasitic nematodes was tested on Capsicum annuum. Bell pepper monoculture farms cultivated conventionally and another with poultry droppings as fertilizer were surveyed. Soil samples were collected using a hand trowel while roots were collected by means of kitchen knife. Plant parasitic nematodes extraction was done by using sieve plate method. Nematodes were identified using the light microscope of x4 and x10 objectives, and identification was done using a pictorial key. Roots assay from the conventional far revealed a total of 175 endophytic nematodes from 10 genera while 56 nematodes from 6 genera were extracted from the farm with poultry droppings. Nematode dynamics in diversity was observed such that certain nematode genera such as Meliodogyne, Radopholus, Pratylenchus, Ditylenchus, Hoplolaimus, Rhaditis were reported in both plots. Phyto-parasitic species were predominant at the conventional farm plot whereas nematodes predatory species recorded higher populations in the farm plot with poultry droppings, an observation which depict that parasitic nematodes could be inhibited by the presence of free living species. This observation further suggests that poultry droppings can adequately fit in as a management of nematodes management if properly harmonised.

Control of Root-knot Nematodes (Meloidogyne spp.) on Tomato (Lycopersicum esculentum Mill.) using Antagonist Fungi

Nematodes Meloidogyne spp. is the most important phytonematode in the world, especially in agriculture in tropical areas. The level of root damage to tomato plants caused by the nematode Meloidogyne spp. can reach 68.3%. In general, control of plant parasitic nematodes is still carried out using pesticides in the form of insecticides which can also be used as nematicides. Continuous use of chemicals to control nematodes can cause environmental pollution, resurgence and nematode resistance to chemicals. One alternative control is biological. One of the biological agents that can be used to control Meloidogyne nematodes is the endophytic fungus Beauveria bassiana and Trichoderma asperellum. The research aims to obtain the best isolates of endophytic fungi for controlling rootknot nematodes (Meloidogyne spp.). The isolates tested were 2 Beauveria bassiana isolates and 2 Trichoderma asperellum isolates. The results showed that the fungus isolate Beauveria bassiana isolate TD312 had a higher ability to control Meloidogyne spp on tomatoes.

Biomolecule repository of endophytic bacteria from guava serves as a key player in suppressing root- knot nematode, Meloidogyne enterolobii

Guava production in India is hampered by invasion of guava root knot nematode, Meloidogyne enterolobii. Biological control of plant parasitic nematodes is the best strategy to quench the soil and root population of nematodes. Hence the attempts were made to dissect the endophytic bacteria from various niche of guava plants. Amongst the various endophytic bacteria's, Klebsiella quasivaricola inhibited the egg hatching (100%) and moratlity of juveniles (100%). Exploration of non-volatile organic compounds of K. quasivaricola exhibited the presence of 2″-terthiophene, 9′spirobifluorenone, 4-Cyanophenyl 4-butylbenzoate, Benzoic acid, Benzoyl chloride, 3-phenyl-1, 2, 4-triazolin-5-one, Ethanone, 2,3-dihydro-5‑methoxy-, Ethanone, Trifluoroacetophenone, 6,12-dinaphthylindolo[3,2-b] carbazole having anti-microbial activities. Considering this, molecular docking experiments were carried out with important proteins of M. enterolobii such as Translationally Controlled Tumour Proteins, pectate lyase, phospholipase, hexokinase and Sphingomyelinase to understand the effect of biomolecules from K. quasivaricola. The results indicated that all biomolecules had prominent effect on different protein targets and in specific binding affinity with amino acid residues of protein targets benzoic acid, 4-Cyanophenyl 4-butylbenzoate, Trifluoroacetophenone, 6,12-dinaphthylindolo[3,2-b]carbazole, 3-phenyl-1,2,4-triazolin-5-one had significant effect on aforementioned protein targets of M. enterolobii. In addition, bio-hardened guava plants with the effective bacterial endophytes were challenged with M. enterolobii showcased 80% increase on plant growth parameters and 70% reduction of egg mass over control. Hence the present study gave limelight to explore the novel biomolecules from endophytic bacterium which could serve as an alternative synthetic nematicides for the management of M. enterolobii.

Nematodes associated with saffron II: Bioindication for soil health assessment and impact of agricultural practices

BackgroundSaffron cultivation is vital in the Taliouine-Taznakht regions, but the influence of agricultural practices on soil nematode communities, critical for soil health and plant productivity, is not well understood.This study characterizes nematode communities in saffron fields of the Taliouine-Taznakht regions, assessing the impact of various agricultural practices on these communities, with a focus on their diversity, functional roles, and potential as bio-indicators of soil health.A total of 163 soil samples were collected from saffron fields in Taliouine-Taznakht. Nematode communities were identified, quantified, and their functional diversity analyzed. Principal Component Analysis (PCA) was used to visualize relationships between nematode communities and sampling sites. Co-inertia analysis assessed the impact of agricultural practices on nematode diversity.The nematode communities were diverse and varied across regions. PCA identified unique nematode community compositions in different saffron fields. Omnivorous nematodes were strongly linked with Taouyalte (TA), and herbivorous ones were prevalent at Agadir Melloul (AM) and Sidi Hssaine (SH). Modern crop types, high-frequency irrigation, and alfalfa-barley rotation were positively correlated with predator nematode abundance, potentially controlling plant parasitic nematodes and encouraging nutrient cycling. Conversely, monocropping, traditional irrigation, and long plantation age correlated with reduced structure and maturity indices, suggesting a less stable ecosystem.This study unveils the intricate relationships between nematode communities in Taliouine-Taznakht saffron fields and agricultural practices. Findings indicate that specific practices, such as crop rotation and modern irrigation techniques, can foster beneficial nematode groups that improve soil health and potentially regulate harmful plant parasitic nematodes. This knowledge is crucial for crafting sustainable and effective saffron cultivation strategies.

Isolation, Identification and Molecular Mechanism Analysis of the Nematicidal Compound Spectinabilin from Newly Isolated Streptomyces sp. DT10.

Plant parasitic nematodes (PPNs) are highly destructive and difficult to control, while conventional chemical nematicides are highly toxic and cause serious environmental pollution. Additionally, resistance to existing pesticides is becoming increasingly common. Biological control is the most promising method for the controlling of PPNs. Therefore, the screening of nematicidal microbial resources and the identification of natural products are of great significance and urgency for the environmentally friendly control of PPNs. In this study, the DT10 strain was isolated from wild moss samples and identified as Streptomyces sp. by morphological and molecular analysis. Using Caenorhabditis elegans as a model, the extract of DT10 was screened for nematicidal activity, which elicited 100% lethality. The active compound was isolated from the extracts of strain DT10 using silica gel column chromatography and semipreparative high-performance liquid chromatography (HPLC). The compound was identified as spectinabilin (chemical formula C28H31O6N) using liquid chromatography mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR). Spectinabilin exhibited a good nematicidal activity on C. elegans L1 worms, with a half-maximal inhibitory concentration (IC50) of 2.948 μg/mL at 24 h. The locomotive ability of C. elegans L4 worms was significantly reduced when treated with 40 μg/mL spectinabilin. Further analysis of spectinabilin against known nematicidal drug target genes in C. elegans showed that it acts via target(s) different from those of some currently used nematicidal drugs such as avermectin and phosphine thiazole. This is the first report on the nematicidal activity of spectinabilin on C. elegans and the southern root-knot nematode Meloidogyne incognita. These findings may pave the way for further research and application of spectinabilin as a potential biological nematicide.

Nematostatic activity of isoprenylated guanidine alkaloids from Pterogyne nitens and their interaction with acetylcholinesterase

Although new nematicides have appeared, the demand for new products less toxic and more efficient for the control of plant-parasitic nematodes are still high. Consequently, studies on natural secondary metabolites from plants, to develop new nematicides, have increased. In this work, nineteen extracts from eleven Brazilian plant species were screened for activity against Meloidogyne incognita. Among them, the extracts of Piterogyne nitens showed a potent nematostatic activity. The alkaloid fraction obtained from the ethanol extract of leaves of P. nitens was more active than the coming extract. Due to the promising activity from the alkaloid fraction, three isoprenylated guanidine alkaloids isolated from this fraction, galegine (1), pterogynidine (2), and pterogynine (3) were tested, showing similar activity to the alkaloid fraction, which was comparable to that of the positive control Temik at 250 μg/mL. At lower concentrations (125−50 μg/mL), compound 2 showed to be the most active one. As several nematicides act through inhibition of acetylcholinesterase (AChE), the guanidine alkaloids were also employed in two in vitro AChE assays. In both cases, compound 2 was more active than compounds 1 and 3. Its activity was considered moderated compared to the control (physostigmine). Compound 2 was selected for an in silico study with the electric eel (Electrophorus electricus) AChE, showing to bind mostly to the same site of physostigmine in the AChEs, pointing out that this could be the mechanism of action for this compound. These results suggested that the guanidine alkaloids 1,2 and 3 from P. nitens are promising for the development of new products to control M. incognita, especially guanidine 2, and encourage new investigations to confirm the mechanism of action, as well as to determine the structure-activity relationship of the guanidine alkaloids.

Roles of the Fungal-Specific Lysine Biosynthetic Pathway in the Nematode-Trapping Fungus Arthrobotrys oligospora Identified through Metabolomics Analyses.

In higher fungi, lysine is biosynthesized via the α-aminoadipate (AAA) pathway, which differs from plants, bacteria, and lower fungi. The differences offer a unique opportunity to develop a molecular regulatory strategy for the biological control of plant parasitic nematodes, based on nematode-trapping fungi. In this study, in the nematode-trapping fungus model Arthrobotrys oligospora, we characterized the core gene in the AAA pathway, encoding α-aminoadipate reductase (Aoaar), via sequence analyses and through comparing the growth, and biochemical and global metabolic profiles of the wild-type and Aoaar knockout strains. Aoaar not only has α-aminoadipic acid reductase activity, which serves fungal L-lysine biosynthesis, but it also is a core gene of the non-ribosomal peptides biosynthetic gene cluster. Compared with WT, the growth rate, conidial production, number of predation rings formed, and nematode feeding rate of the ΔAoaar strain were decreased by 40-60%, 36%, 32%, and 52%, respectively. Amino acid metabolism, the biosynthesis of peptides and analogues, phenylpropanoid and polyketide biosynthesis, and lipid metabolism and carbon metabolism were metabolically reprogrammed in the ΔAoaar strains. The disruption of Aoaar perturbed the biosynthesis of intermediates in the lysine metabolism pathway, then reprogrammed amino acid and amino acid-related secondary metabolism, and finally, it impeded the growth and nematocidal ability of A. oligospora. This study provides an important reference for uncovering the role of amino acid-related primary and secondary metabolism in nematode capture by nematode-trapping fungi, and confirms the feasibility of Aoarr as a molecular target to regulate nematode-trapping fungi to biocontrol nematodes.

Properties of Nano-Amendments and Their Effect on Some Soil Properties and Root-Knot Nematode and Yield Attributes of Tomato Plant

The use of green nano-amendments is a promising approach for improving soil health and providing sustainable options to reduce root-knot nematodes (RKN) and thus increase yields. Therefore, the purpose of this research was to identify the characteristics of nano-amendments such as nanobiochar (nB), green nanobiochar (GnB), and magnetic nanobiochar (MnB) and their effect on the root-knot nematodes and tomato yield at levels of 3 and 6 mg kg−1 in sandy loam soil. The results showed that the GnB and MnB contain many functional groups (such as O-H, C=C, S-H, H-C=O, C-O, and H–O–H) and minerals (such as magnetite, ferrous sulfate monohydrate, and quartz), and they also had an elevated specific surface area. The application of the investigated soil nano-amendments significantly increased soil organic matter (OM) and microbial biomass carbon (MBC) and decreased the root-knot nematodes, playing a major role in increasing tomato growth. The highest significant values of OM and MBC were found in the soil amended by GnB at 6 mg kg−1, with increases of 84.7% and 71.5% as compared to the control, respectively. GnB6 significantly decreased the number of root galls, the egg mass, and number of nematodes per 250 cm3 soil by 77.67, 88.65, and 74.46%, respectively, compared to the control. Green nanobiochar was more efficient in accelerating the growth and yield components of the tomato plant. The addition of GnB is an effective strategy and an environmentally friendly technology to control plant parasitic nematodes and increase tomato yield. Therefore, the results recommend adding GnB at a rate of 6 mg kg−1 in sandy loam soil.

GABA Immunoreactivity and Pharmacological Effects vary Among Stylet-Bearing Nematodes.

Plant-parasitic nematodes conduct a series of sophisticated behaviors to complete their life cycles. Among these, locomotion behaviors, including finding the host and migrating to the feeding site, directly affect the success of parasitism. Thus, disrupting locomotion behaviors has the potential to control these parasites. γ-Aminobutyric acid (GABA) is the prominent inhibitory neurotransmitter in nematodes. GABA-immunoreactive neurons are mostly found in motor neurons, where they regulate behaviors in the model nematode C. elegans. However, the GABA system in most stylet-bearing nematodes has received little attention. Using immunohistochemistry, we found variation in the pattern of GABA-immunoreactivity among two major plant-parasites and a fungal feeder. Some of these GABA-immunoreactive neurons lack clear homologs to C. elegans. Pharmaceutical assays showed that applying GABA, its agonist, and its antagonist, can disrupt the locomotion behaviors of these nematodes, although sensitivity to a given compound varied between species. Our data suggest that the GABA system is a potential target for the control of plant-parasitic nematodes.

Suppression of Meloiodogyne incognita (Tylenchida: Heteroderidae) and Tylenchulus semipenterans (Tylenchida: Tylenchulidae) using Tilapia fish powder and plant growth promoting rhizobacteria in vivo and in vitro

Plant-parasitic nematodes (PPNs) in particular those belonging to the genera Meloidogyne and Tylenchulus are a limiting factor in the production of many plants. In this research, we investigate a strategy for the control of PPNs in vivo and in vitro. The purpose of this research is to evaluate different concentrations of Tilapia fish powder (TFP) and of (in the form of BECTO Grow Roots®) against egg hatching and second-stage juveniles of Meloiodogyne incognita (Tylenchida: Heteroderidae) under laboratory condition. We also assessed the effect of TFP and on M. incognita and Tylenchulus semipenterans (Tylenchida: Tylenchulidae) reproduction. Our data showed that the percentage of egg hatching inhibition ranged from 8.03 to 53.21% and 42.25 to 75.12% after five days of treatment at different concentrations of TFP and PGPR, respectively compared with the control. The percentage of M. incognita J2 mortality increase significantly (p ≤ 0.05) from 52.1 to 86.7 and 44.6 to 92.3% after seven days of treatment at different concentrations of TFP and PGPR, respectively compared with control. Under greenhouse conditions, a remarkable (p ≤ 0.05) increase in plant growth parameters was observed in cucumber plants that received TFP and In the field experiment, the highest reduction of T. semipeneterans density was TFP + PGPR This holds both for healthy and infected trees. Healthy navel orange (HNO) + PGPR + TFP achieved maximum enhancement in orange weight/tree compared to other treatments. Our study recommended TFP and PGPR not only because of their potential against nematodes, but also because of their safety for humans, mammals and non-target organisms.

Natural nematicidal metabolites and advances in their biocontrol capacity on plant parasitic nematodes.

Covering: 2010 to 2021Natural nematicidal metabolites are important sources of nematode control. This review covers the isolation and structural determination of nematicidal metabolites from 2010 to 2021. We summarise chemical structures, bioactivity, metabolic regulation and biosynthesis of potential nematocides, and structure-activity relationship and application potentiality of natural metabolites in plant parasitic nematodes' biocontrol. In doing so, we aim to provide a comprehensive overview of the potential roles that natural metabolites can play in anti-nematode strategies.

Soil Nematodes as a Means of Conservation of Soil Predatory Mites for Biocontrol

Numerous lab and field studies have reported the potential of soil predatory mites for the biological control of plant-parasitic nematodes and arthropods pests. Most of these studies have utilized biocontrol agents in augmentative releases, essentially controlling the pest with the released predators. While this may be a valid approach, we hypothesize that conservation of soil mite predators with available, suitable, and accessible free-living nematodes as prey, will provide better agricultural ecosystem performance and long-range sustainability. In this manuscript, we review the relevant studies on soil predatory mite–nematode interactions and highlight their potential for conservation biological control of soil-borne pests. Additionally, we emphasize the importance of implementing environmentally sound soil management practices for the sustainability and conservation of functional soil food webs.

Nonefficacy of Postplant Nematicides in Vitis vinifera Wine Grapes in Georgia, U.S.A.

Plant parasitic nematodes (PPNs) are known to cause significant yield loss in vineyards across the world. Methods for PPN control are limited, and there is a need for development of treatments that provide long-term efficacy. Preplant fumigants provide ephemeral effects, so growers are searching for alternative, postplant nematicides to combat these pests. Two postplant nematicides, fluensulfone and spirotetramat, were evaluated for their efficacy on the three most abundant ectoparasitic PPN genera ( Helicotylenchus, Mesocriconema, Xiphinema) in a northern Georgia vineyard over a 2-year period. Nematode densities following treatment with either nematicide did not differ statistically from the untreated control. This strongly suggests that fluensulfone and spirotetramat are highly unlikely to provide useful levels of ectoparasitic PPN control on wine grapes in comparable Georgia soils.

Exploiting Plant-Phytonematode Interactions to Upgrade Safe and Effective Nematode Control.

Plant-parasitic nematodes (PPNs) bring about substantial losses of economic crops globally. With the environmental and health issues facing the use of chemical nematicides, research efforts should focus on providing economically effective and safe control methods. The sound exploitation of plant-PPN interactions is fundamental to such efforts. Initially, proper sampling and extraction techniques should be followed to avoid misleading nematode data. Recent evolutions in plant-PPN interactions can make use of diverse non-molecular and molecular approaches to boost plant defenses. Therefore, PPN control and increasing crop yields through single, sequential, dual-purpose, and simultaneous applications of agricultural inputs, including biocontrol agents, should be seriously attempted, especially within IPM schemes. The use of biologicals would ideally be facilitated by production practices to solve related issues. The full investment of such interactions should employ new views of interdisciplinary specialties in the relevant modern disciplines to optimize the PPN management. Having an accurate grasp of the related molecular events will help in developing tools for PPN control. Nonetheless, the currently investigated molecular plant-PPN interactions favoring plant responses, e.g., resistance genes, RNA interference, marker-assisted selection, proteinase inhibitors, chemo-disruptive peptides, and plant-incorporated protectants, are key factors to expanding reliable management. They may be applied on broader scales for a substantial improvement in crop yields.

Biocontrol of plant-parasitic nematodes by soil in soybean cultivation

Soybean is a commodity widely cultivated in Brazil and represents one of the main export products. Several biotic and abiotic factors have limited the productivity growth of this oilseed, one of them are the nematodes associated with the monoculture. Therefore, the objective of this study was to evaluate the effect of different bioagents in control of plant-parasitic nematodes in soybean, via soil. The experiment was carried in Gurupi-TO in a randomized complete block design, with four repetitions and 14 treatments, including the witness. The treatments consisted of biocontrol agents: Paecilomyces sp., Trichoderma asperirellum, Bacillus subtilis and Pochonia sp., evaluated singly and in combinations. The treatments with Paecilomyces sp. + Bacillus subtilis and the combination of all the microorganisms results in higher averages for most traits when compared to the control treatment. The treatments Paecilomyces spp. + Bacillus subtilis and Paecilomyces sp. + Trichoderma asperellum + Bacillus subtilis + Pochonia sp., were also the most efficient in reduction of the population of nematodes evaluated. For this reason, the combination of biological control agents can reduce the population of phytonematodes.

Trichoderma harzianum and Trichoderma asperellum are potential biocontrol agents of Meloidogyne javanica in banana cv. Grande Naine

Biological control of plant-parasitic nematodes by Trichoderma has been widely studied, especially in annual crops such as soybean and cotton, but scarcely explored in the banana crop. Phytonematodes often attack banana plantations, and the species of Meloidogyne typically are the most frequent. Depending on the nematode population, they lead to yield losses or even plant death. Despite several Trichoderma commercial products registered in Brazil as biofungicides or bionematicides, there is a single one recommended to manage Meloidogyne incognita, with no approvals for M. javanica. The objective of this study was to evaluate two Trichoderma harzianum isolates (ALL42 and IBLF006) and the T. asperellum T00 strain as antagonists of M. javanica and as inducers of systemic resistance on bananas. Greenhouse experiments were conducted by treating seedlings of the Grande Naine susceptible cultivar with conidia suspension of the isolates. The enzymatic activity of CHId and GLUeon banana leaves was evaluated at 7, 14, and 21 days after inoculation (DAI). Plant growth and nematode population were evaluated at 60 DAI. T. harzianum ALL42 and T. harzianum IBFL006 reduced the M. javanica population on banana roots by up to 55.2 % and 67.9 %, respectively, in contrast to T. asperellum T00 that was inefficient. Enzymatic activity of CHI in plants non-inoculated with the nematode was higher at 14 DAI and decreased afterward. CHI and GLU activity were higher at 21 DAI in plants treated with isolate IBFL006 and grown in infested soil. The treatments did not promote plant growth. The effect of T. harzianum isolates was tested “in vitro” as filtrate or conidia suspension on mortality of J2 individuals. ALL42 and IFBL006 non-autoclaved filtrates promoted the highest M. javanica mortality rates of 59.6 %, and 68.8 % respectively.

Understanding Molecular Plant-Nematode Interactions to Develop Alternative Approaches for Nematode Control.

Developing control measures of plant-parasitic nematodes (PPNs) rank high as they cause big crop losses globally. The growing awareness of numerous unsafe chemical nematicides and the defects found in their alternatives are calling for rational molecular control of the nematodes. This control focuses on using genetically based plant resistance and exploiting molecular mechanisms underlying plant–nematode interactions. Rapid and significant advances in molecular techniques such as high-quality genome sequencing, interfering RNA (RNAi) and gene editing can offer a better grasp of these interactions. Efficient tools and resources emanating from such interactions are highlighted herein while issues in using them are summarized. Their revision clearly indicates the dire need to further upgrade knowledge about the mechanisms involved in host-specific susceptibility/resistance mediated by PPN effectors, resistance genes, or quantitative trait loci to boost their effective and sustainable use in economically important plant species. Therefore, it is suggested herein to employ the impacts of these techniques on a case-by-case basis. This will allow us to track and optimize PPN control according to the actual variables. It would enable us to precisely fix the factors governing the gene functions and expressions and combine them with other PPN control tactics into integrated management.