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Trichoderma is mainly used to control soil-borne diseases as well as some leaf and panicle diseases of various plants. Trichoderma can not only prevent diseases but also promotes plant growth, improves nutrient utilization efficiency, enhances plant resistance, and improves agrochemical pollution environment. Trichoderma spp. also behaves as a safe, low-cost, effective, eco-friendly biocontrol agent for different crop species. In this study, we introduced the biological control mechanism of Trichoderma in plant fungal and nematode disease, including competition, antibiosis, antagonism, and mycoparasitism, as well as the mechanism of promoting plant growth and inducing plant systemic resistance between Trichoderma and plants, and expounded on the application and control effects of Trichoderma in the control of various plant fungal and nematode diseases. From an applicative point of view, establishing a diversified application technology for Trichoderma is an important development direction for its role in the sustainable development of agriculture. [ABSTRACT FROM AUTHOR]

Copyright of Yuzuncu Yil Universitesi Journal of Agricultural Sciences (YYU J Agr Sci) is the property of Yuzuncu Yil University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Apple replant disease (ARD) is a severe problem in orchards and tree nurseries caused by yet unknown soil biota that accumulate over replanting cycles. This study tested the contribution of nematodes to ARD, and cultivation of Tagetes as a control option. In a pot experiment, Tagetes patula or Tagetes tenuifolia were grown in ARD soil, incorporated or removed. Nematodes extracted from untreated ARD soil and washed on 20-µm sieves induced ARD symptoms when inoculated to apple plantlets growing in a sterile substrate. In contrast, nematodes from Tagetes treated ARD soil did not reduce root growth compared to uninoculated plants, irrespective of Tagetes species and incorporation. In plots of five apple tree nurseries or orchards, either Tagetes or grass was grown on ARD soil. Nematodes extracted from the grass plots and inoculated to apple plantlets significantly reduced plant growth compared to nematodes from Tagetes plots for all five farms. Apple rootstocks showed overall a significantly higher increase in shoot base diameter when grown on Tagetes-treated plots compared to grass plots, while this effect differed among farms. Plant-parasitic nematodes were too low in abundance to explain plant damage. In conclusion, Tagetes alleviated ARD by changing the nematode community in soil. [ABSTRACT FROM AUTHOR]

The results indicated that the application of Pseudomonas fluorescens was better that minimized lesion nematode population by 73.2% and enhanced germination %, number of tillers, commercial cane sugar %, cane yield and sugar yield by 87.2, 161.5, 12.7, 121.4 and 16.4%, respectively. This field experiment was repeated once during 2016-2017 and obtained 74.0% control of lesion nematode with higher yield of 124.4 t/ha in P. fluorescens @ 2.5 kg/ha sett treatment. Simultaneously another field experiment with fungal antagonists Purpureocillium lilacinum and Trichoderma viride @ 2.5 kg/ha were conducted during 2015-2016 and 2016-2017. The P. lilacinum was better than T. viride. During 2016-2017, similar results recorded 70.5% nematode control with cane yield 124.8 t/ha. The results demonstrated that P. fluorescens in combination of neem cake was better that caused the highest reduction in lesion nematode population (74.8%) with the cane yield of 115.8 t/ha. [ABSTRACT FROM AUTHOR]

The root-knot nematode Meloidogyne incognita has a wide host range and it is one of the most economically important crop parasites worldwide. Biological control has been a good approach for reducing M. incognita infection, for which many nematophagous fungi are reportedly applicable. However, the controlling effects of Phanerochaete chrysosporium strain B-22 are still unclear. In the present study we characterized the parasitism of this strain on M. incognita eggs, second-stage juveniles (J2), and adult females. The highest corrected mortality was 71.9% at 3 × 108 colony forming units (CFU) mL-1 and the estimated median lethal concentration of the fungus was 0.96 × 108 CFU mL-1. Two days after treatment with Phanerochaete chrysosporium strain B-22 eggshells were dissolved. A strong lethal effect was noted against J2, as the fungal spores developed in their body walls, germinated, and the resulting hyphae crossed the juvenile cuticle to dissolve it, thereby causing shrinkage and deformation of the juvenile body wall. The spores and hyphae also attacked adult females, causing the shrinkage and dissolution of their bodies and leakage of contents after five days. Greenhouse experiments revealed that different concentrations of the fungal spores effectively controlled M. incognita. In the roots, the highest inhibition rate for adult females, juveniles, egg mass, and gall index was 84.61%, 78.91%, 84.25%, and 79.48%, respectively. The highest juvenile inhibition rate was 89.18% in the soil. Phanerochaete chrysosporium strain B-22 also improved tomato plant growth, therefore being safe for tomato plants while effectively parasitizing M. incognita. This strain is thus a promising biocontrol agent against M. incognita. [ABSTRACT FROM AUTHOR]

The root‐knot nematode (RKN) Meloidogyne incognita is the main nematode causing losses to the cotton crop in Brazil. In order to implement control strategies within integrated management, an accurate identification of the nematode populations prevailing in the cotton production areas is necessary. This study aimed to assess the genetic variability and aggressiveness of RKN populations from cotton production areas in Bahia state, Brazil. All populations were characterized biochemically and molecularly and identified as M. incognita. RAPD and AFLP markers detected 44% of polymorphic fragments among the 13 populations of this species. The 10 M. incognita populations collected in Bahia presented 33.7% of diversity when compared to each other, and 25% when the population from Barreiras (the most polymorphic) was excluded. This polymorphism increased when populations from other Brazilian states were included. The aggressiveness and virulence among populations from Bahia towards different cotton accessions (susceptible/resistant) was also studied. None of the populations showed virulence against the moderately resistant (Clevewilt 6, Wild Mexican Jack Jones and LA 887) and highly resistant (CIR1348 and M‐315 RNR) cultivars. Two M. incognita populations from Barreiras were the most aggressive, reaching reproduction factors of 539 and 218, respectively, in the susceptible cultivar FiberMax 966. The most aggressive population (8) was also the most genetically divergent in phylogenetic analyses. These results demonstrate that diversity of M. incognita populations from cotton farms in Bahia is not related to virulence against resistant accessions, which suggests that cultivars containing one or two resistance genes with good agronomic characteristics could be used in infested commercial areas in Bahia state, Brazil. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agriculturae Slovenica is the property of Biotechnical Faculty of the University of Ljubljana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Meloidogyne chitwoodi is a root-knot nematode that parasitizes a broad range of plants. In the Pacific Northwest (PNW) of the United States, M chitwoodi is a major potato pest. The nematodes infect roots and tubers; blemishes caused by the nematodes on the tubers significantly affect potato marketability. M. chitwoodi is a quarantine pathogen by many regulatory agencies, limiting potato trade opportunities when it is present. A loop-mediated isothermal amplification (LAMP) assay was developed to amplify the intergenic spacer (IGS2)-18S region of the ribosomal rDNA of M. chitwoodi. Using the LAMP assay, we could detect the presence of M. chitwoodi from infected Washington State soil samples. The LAMP primers showed specificity for DNA from M. chitwoodi and the closely related species M. fallax. There was no cross reaction of the LAMP primers with DNA from tropical nematodes M. incognita, M. arenaria, and M. javanica, or the Northern root-knot nematode M. hapla. The LAMP assays can be completed within 45 min, and they were 100 times more sensitive in nematode detection than conventional PCR. The LAMP assay will facilitate detection of potato nematodes M. chitwoodi and M. fallax. Knowledge of potato nematodes, particularly M. chitwoodi in PNW soils, will aid management decisions. [ABSTRACT FROM AUTHOR]

Although, breadfruit, Artocarpus altilis (Parkinson) Fosberg, is a traditional staple food crop in the Pacific Islands, the nematode community associated with a recently planted breadfruit rhizosphere is not well documented. A field at the Kaua'i Community College was therefore prepared and divided into 4 equal blocks, and 64 breadfruit saplings were planted in December 2014. Soil samples were taken from four blocks before breadfruit transplanting (year 0) and the rhizospheres of half of the plants of each block at 1, 2, and 3 years after breadfruit tree planting. Nematodes were extracted from the soil using the Baermann funnel technique and identified to genus. Frequency of occurrence (%) of each genus was determined. Each genus was grouped into a respective trophic group. Compared to year 0, 1, and 2, the greatest herbivores numbers were found in year 3 (P< 0.01). Pooled data of years 1, 2, and 3, nematode genera were observed including bacterivores, fungivores, omnivores, and predators (beneficial nematodes), and herbivores (40.0%, 17.77%, 15.55%, 15.55%, and 11.11%, respectively). Beneficial nematodes constituted 40 genera. The most frequent genus was Cephalobus (95.83% ± 02.76%) followed by other Rhabditidae (82.29% ± 04.54%). Helicotylenchus, Paratylenchus, Axonchium, Pratylenchus, and Xiphinema were observed in 71.88% ± 08.27%, 29.17% ±12.01%, 14.58% ± 06.34%, 05.21% ± 01.04% and 01.04% ± 01.04% soil samples, respectively. A positive relationship existed between the total herbivores number in breadfruit rhizosphere and year after breadfruit planting. Current findings may serve as a reference for future researchers, extension workers, and farmers. [ABSTRACT FROM AUTHOR]

TerraRossa (POR01PG20-12) is a mid-season specialty potato, released by Oregon State University, and is a product of the Northwest Potato Variety (Tri-State) Development Program. This cultivar is unique among commercially available potato cultivars in that plants produce small- to medium-sized smooth, oblong- to long-shaped tubers with red skin and red flesh. Total tuber yields of TerraRossa are similar to Dark Red Norland and less than Red La Soda. Average tuber size (136 g) is less than both of the comparison cultivars, reflecting inherent differences in tuber size distribution. TerraRossa tubers have total antioxidant levels higher than traditional white fresh varieties and comparable to the All Blue purple potato, known for its high antioxidant levels. Sensory evaluations of TerraRossa tubers indicated that it has good culinary attributes following boiling, baking, and microwaving. Potato chips made from TerraRossa tubers retained their unique red color, which represents a novelty in the chipping industry. TerraRossa could be a good candidate for the organic sector due to its tolerance to common scab (Streptomyces scabies) and tuber late blight (Phytophthora infestans) and its resistance to golden cyst nematode (Globodera rostochiensis). Due to its high yields, high chipping quality, good culinary properties, high antioxidant content and disease resistance, TerraRossa is a good candidate for opening new specialty type markets, adding diversity to the marketplace. [ABSTRACT FROM AUTHOR]

Meloidogyne incognita is the most economically important plant‐parasitic nematode. Meloidogyne incognita manipulates plant cell development and metabolism by injecting effectors from the oesophageal glands into the plant host. Chorismate mutase (CM) is one such effector that may contribute to successful parasitism by M. incognita. This investigation identified and functionally characterized a novel CM effector, Mi‐CM‐3, which is more similar to CMs from bacteria than from other phytoparasitic nematodes. Spatial and temporal expression assays showed Mi‐cm‐3 mRNA accumulates specifically in the subventral oesophageal glands and transcription is up‐regulated during the early parasitic stages of the nematode. In planta gene silencing of Mi‐cm‐3 attenuated nematode parasitism. In addition, Mi‐cm‐3 could fully restore the full virulence phenotype of the pathogenic bacterium Xanthomonas oryzae pv. oryzae by complementation when it was introduced into a mutant strain carrying a deletion in the CM gene. Transient expression of Mi‐CM‐3 caused a reduction in levels of salicylic acid (SA) and mRNA of gene PR1 in Nicotiana benthamiana in response to oomycete pathogen Phytophthora capsici infection, while confocal observations showed that Mi‐CM‐3 was localized within the cytoplasm and the nucleus, but not the plastids, of transfected N. benthamiana leaf cells. Constitutive expression of Mi‐CM‐3 in N. benthamiana plants inhibited root growth and increased susceptibility to M. incognita infection. These results provide direct experimental evidence to show that Mi‐CM‐3 may play an important role in suppressing plant immunity by regulating the SA pathway during the early parasitic stage of M. incognita so as to promote nematode parasitism. [ABSTRACT FROM AUTHOR]

Two new in vitro methods were developed to analyze plant-parasitic nematode behavior, at the population and the individual organism levels, through time-lapse image analysis. The first method employed a highresolution flatbed scanner to monitor the movement of a population of nematodes over a 24-h period at 25°C. The second method tracked multiple motion parameters of individual nematodes on a microscopic scale, using a high-speed camera. Changes in movement and motion of second-stage juveniles (J2) of the soybean cyst nematode Heterodera glycines Ichinohe were measured after exposure to a serial dilution of abamectin (0.1 to 100 μg/ml). Movement and motion of H. glycines were significantly reduced as the concentration of abamectin increased. The effective range of abamectin to inhibit movement and motion of H. glycines J2 was between 1.0 and 10 μg/ml. Proof-of-concept experiments for both methods produced one of the first in vitro sensitivity studies of H. glycines to abamectin. The two methods developed allow for higher-throughput analysis of nematode movement and motion and provide objective and data-rich measurements that are difficult to achieve from conventional microscopic laboratory methods. [ABSTRACT FROM AUTHOR]

Screening experiments were conducted during 2013 to 2015 to assess the host status of 350 accessions of cowpea (Vigna unguiculata) for resistance to Meloidogyne incognita. Based on the number of root galls induced by M. incognita among the tested accessions, six (EC0517140, EC0528391, EC0723686, EC0724523, EC0725122, and IC0253277) were resistant, and the rest were susceptible. The resistant accessions reduced root gall formation by 96-99% as compared to highly susceptible accession EC0724571. Nematode penetrations were also lower in roots of all resistant cowpea accessions compared to the susceptible accession EC0724571 (P<0.05). Similarly, egg-mass formation was retarded in the resistant accessions when observed 45 d after inoculation (P<0.05). These resistant accessions may be useful in plant breeding programs to develop nematode resistant cowpea cultivars. [ABSTRACT FROM AUTHOR]

Summary: The incompatible interaction between the rice cultivar Manikpukha and the rice stem nematode Ditylenchus angustus has been reported recently. This research focuses on the underlying mechanisms of resistance in Manikpukha. Invasion, post‐infection development and reproduction of D. angustus were compared in compatible and incompatible interactions to identify the stage in which resistance occurs. The results indicate that resistance in Manikpukha is associated with reduced development and reproduction, implying that resistance acts post‐invasion. We studied the possible involvement of three classical defence hormones, salicylic acid (SA), jasmonic acid (JA) and ethylene (ET), in response to infection in a compatible interaction using biosynthesis/signalling‐deficient transgenic rice lines. All three hormones appear to have an influence on the basal defence of Nipponbare against the stem nematode. Although hormone application increases basal defences, expression studies and hormone analyses after nematode infection in Manikpukha did not show a clear involvement of the hormone defense pathways for SA, ET and JA. However, it seems that OsPAL1 plays a pivotal role in resistance, indicating that the phenylpropanoid pathway and its products might be key players in the incompatible interaction. Lignin measurement showed that, although basal levels are similar, Manikpukha had a significantly higher lignin content on nematode infection, whereas it was decreased in the susceptible cultivar. The results presented here show that SA, ET and JA are involved in basal defences, but the resistance of Manikpukha against D. angustus probably relies on products of the phenylpropanoid pathway. [ABSTRACT FROM AUTHOR]

Aphelenchoides besseyi and A. fujianensis have been frequently found in mixed populations associated with forage grass seed in Brazil. The morphological similarity between both species has previously led A. fujianensis to be erroneously identified as A. besseyi. A. besseyi is a quarantine pest in many countries that import Brazilian forage seed; however, there is no current evidence suggesting that A. fujianensis is a plant-parasitic species. Two real-time polymerase chain reaction (qPCR) diagnostics were developed to detect each species and an operational envelope was established. A set of primers and hydrolysis probes for each species was designed targeting the large subunit (LSU) region. To assess their specificity, primers and probes sets were tested with samples of nontarget Aphelenchoides and Paraphelenchus sp. also frequently associated with forage seed. Experiments using dilutions of purified plasmid standards underpinned the sensitivity of the qPCR assays, which detected as few as 10 copies of target nematode ribosomal DNA. Thus, the developed diagnostics were sufficiently sensitive to detect DNA extracted from a fragment of a single target nematode. There was a positive correlation between copy number of the target species and nematode abundance, suggesting the potential of this method for quantification. Evidence of inUa-individual variability among cloned sequences of the LSU region in a single A. besseyi population is also reported. [ABSTRACT FROM AUTHOR]

Polyamines are ubiquitous organic polyvalent compounds involved in regulating the plant growth and development. The present study deals with the investigation of their role in plant physiology during nematode pathogenesis. Tomato seeds var. Pusa Ruby (susceptible to nematodes) were treated with different concentrations (0.5, 0.7 and 0.9 mM) of putrescine and allowed to germinate in earthen pots. Seedlings were inoculated with second stage juveniles (J2s) of Meloidogyne incognita with 130 J2s per seedling. After 45 days of nematode inoculation, various growth parameters, stress indices, photosynthetic pigments, enzymatic and non enzymatic biochemical parameters were studied in control (C), nematode inoculated (NI) and nematode inoculated plus treated plants (NI + 0.5, NI + 0.7 and 0.9 mM). Percentage germination, number of leaves, shoot/root length, fresh shoot/root weight, and dry shoot/root weight enhanced with putrescine application whereas the number of galls, average gall index, number of egg masses and root knot nematode severity level decreased. Stress indices like H 2 O 2 and MDA content decreased whereas proline content increased with putrescine treatment. Further, reduced specific activities of enzymes in putrescine treated infected plants and enhanced levels of non-enzymatic antioxidants depicted improved response of tomato plant during nematode stress. Thus, the polyamines were found to improve the physiological responses of tomato plant even during nematode pathogenesis. [ABSTRACT FROM AUTHOR]

BACKGROUND Fluensulfone is a fluoroalkenyl chemical with activity against multiple genera of plant-parasitic nematodes. The adsorption, desorption, and mobility of fluensulfone were evaluated on multiple soils from the USA in laboratory and column experiments. RESULTS Adsorption data regressed to the logarithmic Freundlich equation resulted in isotherm values of 1.24 to 3.28. Soil adsorption of fluensulfone correlated positively with organic matter (0.67) and clay (0.34), but negatively with sand (-0.54). Fluensulfone soil desorption correlated to pH (0.38) and cation exchange capacity (0.44). Fluensulfone desorption from Arredondo sand soil was 26%, and from other soils ranged from 43 to 70%. In mobility experiments, fluensulfone in the leachate peaked at 3 h, gradually declining and becoming undetectable after 9 h. Recovery from leachate was 45% of the initial fluensulfone applied to the soil surface. In separate experiments, 30-cm-long soil columns were saturated with 1 L of water, and then segregated into three 10-cm sections. Fluensulfone recovery was 41, 34, 29, and 13% in Chualar sandy loam, Arredondo sand, Greenville sandy clay loam, and Tifton loamy sand, respectively, in the top 10-cm section. CONCLUSION Data indicated that soil organic matter and clay contents will affect sorption, mobility, and dissipation of fluensulfone. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The objectives of this study were the molecular and conventional characterization of three native strains isolated from parasitic nematodes, evaluation of their potential to control Meloidogyne spp., and determination of their possible pathogenicity traits against nematodes. The identity of the strains Bacillus thuringiensis CIGBR23, Sphingobacterium sp. CIGBTb, and Stenotrophomonas maltophilia CIGBG1 was confirmed by 16S rRNA sequencing. Their effectiveness to reduce infestation of Meloidogyne spp. was evaluated in Cucurbita maxima RG-T150 as host plant growing in pot. The plant growth-promoting effects of the strains were also determined. The root-galling index, branch length, and branch and root fresh weights were determined 35 days after nematode inoculation. The three strains controlled Meloidogyne spp. The treatment with Sphingobacterium sp. CIGBTb was the most effective, reducing the infestation index from 3 to 1; whereas it was 1.6 for B. thuringiensis CIGBR23 and 1.7 for S. maltophilia CIGBG1 (Hussey and Janssen's scale 0 -5). Sphingobacterium sp. CIGBTb and S. maltophilia CIGBG1 also significantly reduced the number of root galls by C. maxima (higher than 50 %) in relation to the control (p<0.05). On the other hand, the treatment with B. thuringiensis CIGBR23 increased plant weight in 17 %. The three strains produced chitinase enzymes. Two of the strains (CIGBR23 and CIGBG1) also excreted lipases and proteases, and CIGBG1, in addition to these enzymes, also produced phospholipase and hydrogen sulfide. [ABSTRACT FROM AUTHOR]

In south Italy, tomato growers commonly face severe root-knot nematode infestations. Alternative methods of control are required because of the high toxicity of current pesticides. Therefore, the potential of an integrated pest management strategy for the control of root-knot nematodes on tomato in greenhouse was investigated. The nematode susceptible tomato cv. Ikram, non-grafted or grafted onto the tomato rootstock cv. Armstrong, with intermediate resistance to the nematode, in combination with soil applications of the nematicides fosthiazate, oxamyl, and abamectin were tested. The resistant rootstock significantly reduced nematode soil population levels and root galling index until one month after transplanting, when soil temperature was below 28°C, but not by harvest due to increased soil temperature. Fosthiazate, abamectin and oxamyl increased tomato yield and reduced root galling caused by Meloidogyne incognita. The synergistic effect of the rootstock resistant to root-knot nematodes and soil treatments of fosthiazate in combination with abamectin or oxamyl could successfully be employed in integrated pest management programs to control M. incognita in tomato. [ABSTRACT FROM AUTHOR]

Copyright of Egyptian Journal of Agronematology is the property of Egyptian Society for Agronematology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There is no known root-knot nematode (Meloidogyne spp.) resistance in caladium (Caladium×hortulanum), an ornamental foliage crop grown from tubers, but cultivars have been reported to differ in their level of susceptibility. Research was conducted to assess the relative susceptibility of seven widely grown caladium cultivars to the species of Meloidogyne which occur in the southeastern United States, where caladium cultivars are commonly planted in commercial and residential landscapes. Root-knot nematode species tested were Meloidogyne arenaria, Meloidogyne enterolobii (=M. mayaguensis), Meloidogyne floridensis, Meloidogyne incognita, and Meloidogyne javanica. All of the caladium cultivars tested were susceptible to galling by all species of Meloidogyne tested; however M. javanica caused the least severe galling. Meloidogyne enterolobii produced high numbers of eggs per gram of fresh root on all cultivars tested, with cv. Freida Hemple having the highest number (14,799 eggs/g fresh root). Meloidogyne javanica also reproduced at a high level on most cultivars tested. Overall, the number of eggs of M. arenaria, M. floridensis, and M. incognita was low on all caladium cultivars tested. Meloidogyne javanica was isolated from caladium roots in high numbers regardless of the cultivar. Meloidogyne incognita had low numbers of second stage root-knot nematode juveniles (J2) isolated from soil of all cultivars. The high level of reproduction of M. enterolobii and the high rate of isolation of M. javanica from roots, as well as the low rate of isolation of M. incognita from soil, are not reflected in gall ratings where M. javanica ratings were low but high numbers of eggs and J2 were present in roots. An increased understanding of cultivar susceptibility levels and the reproductive capacity of common root-knot nematode on caladium under various environmental conditions is needed to better manage nematode-infested planting sites and improve caladium growth. [ABSTRACT FROM AUTHOR]

Plant parasitic nematodes (PPN) are important crop pests within the global agri-sector. Critical to their success is a complex and highly sensitive chemosensory system used to locate plants by detecting host cues. In addition to this, the nematode neuronal system has evolved mechanisms to allow adaptation to a changing environment. Clearly, there is a need to better understand the host-parasite relationship and the mechanisms by which PPN successfully locate and infect host plants. Here, we demonstrate the chemotactic response of two economically important PPN species, Meloidogyne incognita and Globodera pallida to selected phytochemicals. We further reveal an adapted chemotactic response in M. incognita second-stage juveniles preexposed to ethephon (Eth), potato root diffusate (PRD), and salicylic acid (SA), and present pharmacological evidence supporting the existence of long-term habituation traits acting via serotonergic-dependent neurotransmission. [ABSTRACT FROM AUTHOR]

Gene silencing using RNAi is a powerful tool for functional analysis of nematode genes and can provide a new strategy for the management of root-knot nematodes. The transcript of the venom allergen-like protein gene ( Mhi-vap-1) of Meloidogyne hispanica is localized in the subventral oesophageal gland cells of second-stage juveniles (J2) and the gene is highly transcribed in this developmental nematode stage. The purpose of this study was to assess whether the silencing of the Mhi-vap-1 gene could affect nematode attraction to roots, penetration, development and reproduction in tomato plants. The optimum soaking time to generate silencing of this gene was determined by quantitative RT- PCR analysis of the relative expression of the Mhi-vap-1 gene in the J2 incubated with the soaking solution for 24, 32 and 48 h. At 48 h, the relative expression of Mhi-vap-1 decreased, which indicates that this period of time is optimum to silence this nematode gene using the RNAi method. Silencing of the Mhi-vap-1 gene interfered with the completion of the nematode life cycle and caused a reduction in nematode attraction to roots, penetration and infection of plants. A small difference in the number of females and galls formed was also observed, which caused a small decrease in the nematode reproduction factor. The use of RNAi silencing of the Meloidogyne effector gene Mhi-vap-1 showed that this gene is important for the plant-nematode interaction during the early events of infection and could be a target gene for anti-nematode strategies. [ABSTRACT FROM AUTHOR]

Density-dependent growth patterns suggested that under phytonematicides population densities of plant-parasitic nematodes could either be stimulated, neutral or inhibited, thereby resulting in 'inconsistent results' concept. The objective of this study was to determine whether post-application sampling of the citrus nematode (Tylenchulus semipenetrans Cobb) population densities under untreated control, Nemarioc-AG phytonematicide and aldicarb on rough lemon (Citrus jambhiri Lush.) seedlings could provide quantitative evidence of 'inconsistent results'. Uniform three-month old C. jambhiri seedlings in plastic pots containing 2700 ml growing mixture were each inoculated with 10000 T. semipenetrans eggs and second-stage juveniles (J2). A week after inoculation, seedlings were split into three groups of seventy each and subjected to once-off treatment of untreated control, 2 g Nemarioc-AG phytonematicide and 2 g aldicarb. Five seedlings from each group were randomly placed on greenhouse benches to serve as a sampling block, with a total of 14 blocks. The entire block was sampled on a weekly basis and assessed for final nematode population density (Pf). After the final assessment, Pf under untreated control over increasing sampling intervals exhibited positive quadratic relations, with the model explaining 90% associations, with optimum Pf of 13804 eggs and J2 at six weeks postapplication. In contrast, Pf over increasing sampling intervals under phytonematicide and aldicarb exhibited negative quadratic relations, with the model explaining 95 and 92% associations, respectively. The two had minimum Pf at 974 eggs and J2 and 2205 eggs and J2, respectively, each at approximately six weeks. In conclusion, opposite temporal cyclic nematode population growth patterns post-application of nematicidal products and untreated control provided empirically-based evidence of 'inconsistent results' in nematode management under phytonematicides. [ABSTRACT FROM AUTHOR]

Attempts are underway to cultivate Moringa oleifera Lam. in tropical areas as a developmental crop due to its nutritional, pharmacological and industrial applications. However, the success of developmental-plant-related projects depends on the degree of nematode resistance in the introduced plants to the tropical root-knot (Meloidogyne species) nematodes. The objective of this study was to determine the degree of nematode resistance in M. oleifera seedlings to M. incognita race 2 and M. javanica under greenhouse conditions. Two parallel experiments were conducted, with seedlings in each inoculated with a series of different nematode species. At 56 days after inoculation, the M. incognita race 2 and M. javanica reproductive factor (RF) values ranged from 0-0.34 and 0.01-0.42, respectively. Nematode infection did not have any effect on plant growth variables. In conclusion, M. oleifera was resistant to population densities of tropical Moloidogyne species in South Africa. [ABSTRACT FROM AUTHOR]

High infection rates of roots of wild kiwifruit (Actinidia chinensis Planch) and soil infestation by a root-knot nematode were found in Anshun, GuiZhou Province, China. Morphology, esterase phenotype and molecular analyses confirmed that this nematode was different from previously described root-knot nematodes. In this report, the species is described, illustrated and named Meloidogyne aberrans sp. nov. The new species has a unique combination of characters. A prominent posterior protuberance, round and faint perineal pattern and a medium-length stylet (13.6–15.5 μm) characterized the females. Second-stage juveniles (J2) were characterized by a smooth lip region with distinctly protruded medial lips and a depression in outline at the oral aperture, a relatively long stylet (15.9–16.8 μm), four incisures in the lateral field and a very short, even poorly defined, hyaline tail terminus (2.2–5.5 μm). More incisures (11–15) existed in the lateral field of males, and the stylet and spicules of males were 18.2–19.6 μm and 22.7–36.8 μm long respectively. Egg masses were typically produced within the roots of kiwifruit. The new species had a rare Est phenotype, S2. Phylogenetic trees inferred from SSU, LSU D2D3, ITS, and partial coxII-16S rRNA revealed that M. aberrans sp. nov. was within the Meloidogyne clade and was distinguished from all described root-knot nematodes. Moreover, from histopathological observations, M. aberrans sp. nov. induced the formation of multinucleate giant cells. [ABSTRACT FROM AUTHOR]

The increased incidence of the crown gall disease caused by Agrobacterium tumefaciens has long been associated with activities of root-knot nematodes (Meloidogyne spp.). Pot experiments on tomato were designed to assess plant vitality, nematode reproduction, and crown gall incidence in combined infection with Agrobacterium and Meloidogyne spp. on tomato roots. Results suggest that tomato plants infected with pathogenic A. tumefaciens 2 days before the nematodes show enhanced plant defense against M. ethiopica resulting in lower egg and gall counts on roots 45 and 90 days postinoculation (dpi); no significantly enhanced defense was observed when the plant was inoculated with bacteria and nematodes at the same time. Split-root experiments also showed that the observed interaction was systemic. Reverse-transcription quantitative polymerase chain reaction analysis that targeted several genes under plant hormonal control suggests that the suppression was mediated via systemic acquired resistance by the pathogenesis-related protein 1 and that M. ethiopica did not enhance the defense reaction of tomato against Agrobacterium spp. Nematodes completely inhibited tumor growth in a 45-day experiment if inoculated onto the roots before the pathogenic bacteria. We conclude that the observed antagonism in the tested pathosystem was the result of initially strong plant defense that was later suppressed by the invading pathogen and pest. [ABSTRACT FROM AUTHOR]

Aphelenchoides eldaricus n. sp. is described and illustrated from wood and bark samples of a dead Mondell pine in Kermanshah Province, western Iran. The new species has a body length of 597 (507-700) μm (females) and 662 (636-695) μm (males). The cuticle is weakly annulated with three lateral lines and the lip region is offset. The stylet is 9.6 (9-10) μm long with small basal swellings and the excretory pore is located ca one body diam. posterior to the metacorpus valve. The spicules are large with the dorsal limb 40 (38-42) μm long with a prominent rostrum and rounded apex. The female tail is conical, tapering gradually to an acute terminus with a simple ventral mucron. The male tail bears six (2 + 2 + 2) caudal papillae and a well-developed mucron. The new species belongs to the Group 2 category of Aphelenchoides species and is close to four known species, namely A. cibolensis, A. indicus, A. rutgersi and A. sacchari. Molecular analyses of the partial 18S and the D2-D3 expansion segments of the 28S rRNA gene confirmed its morphological status as a new species. [ABSTRACT FROM AUTHOR]

Soybean cyst nematode (SCN) ( Heterodera glycines Ichinohe) is a highly recalcitrant endoparasite of soybean roots, causing more yield loss than any other pest. To identify quantitative trait loci (QTL) controlling resistance to SCN (HG type 2.5.7, race 1), a genome-wide association study (GWAS) was performed. The association panel, consisting of 120 Chinese soybean cultivars, was genotyped with 7189 single nucleotide polymorphism (SNPs). A total of 6204 SNPs with minor allele frequency >0.05 were used to estimate linkage disequilibrium (LD) and population structure. The mean level of LD measured by r declined very rapidly to half its maximum value (0.51) at 220 kb. The overall population structure was approximately coincident with geographic origin. The GWAS results identified 13 SNPs in 7 different genomic regions significantly associated with SCN resistance. Of these, three SNPs were localized in previously mapped QTL intervals, including rhg1 and Rhg4. The GWAS results also detected 10 SNPs in 5 different genomic regions associated with SCN resistance. The identified loci explained an average of 95.5% of the phenotypic variance. The proportion of phenotypic variance was due to additive genetic variance of the validated SNPs. The present study identified multiple new loci and refined chromosomal regions of known loci associated with SCN resistance. The loci and trait-associated SNPs identified in this study can be used for developing soybean cultivars with durable resistance against SCN. [ABSTRACT FROM AUTHOR]

Urbanization affects ecosystem function and environmental quality through shifts in ecosystem fluxes that are brought on by features of the built environment. Green infrastructure (GI) has been suggested as a best management practice (BMP) to address urban hydrologic and ecological impacts of the built environment, but GI practice has only been studied from a limited set of climatic conditions and disciplinary approaches. Here, we evaluate GI features in a semiarid city from the perspective of soil ecology through the application of soil nematode community analysis. This study was conducted to investigate soil ecological interactions in small-scale GI as a means of assessing curb-cut rain garden basin design in a semiarid city. We looked at the choice of mulching approaches (organic vs. rock) and how this design choice affects the soil ecology of rain basins in Tucson, AZ. We sampled soils during the monsoon rain season and assessed the soil nematode community as a bioindicator of soil quality and biogeochemical processes. We found that the use of organic mulch in GI basins promotes enhanced soil organic matter contents and larger nematode populations. Nematode community indices point to enhanced food web structure in streetscape rain garden basins that are mulched with organic material. Results from this study suggest that soil management practices for GI can help promote ecological interactions and ecosystem services in urban ecosystems. [ABSTRACT FROM AUTHOR]

Root knot nematodes (RKN) cause major losses in tomato. Some strains of Streptomyces are known to prevent RKN disease in plants, but little attention has been given to their biocontrol effects in crops such as tomato. In this study, pot experiments were conducted to assess the effects of a Streptomyces agent (1:1 mixture of S. pactum and S. Rochei ) for biocontrol of RKN disease in tomato. We quantified endophytes in tomato roots, as well as microbes and nematodes in root zone soil with or without inoculation of Streptomyces . Additionally, we measured the plant biomass and physiobiochemical traits of tomato at different growth stages. The results showed that after inoculation of Streptomyces : (i) The RKN disease index of tomato plants decreased by 37%. The quantity of bacterial-feeding nematodes decreased by 14% in root zone soil, while the quantity of fungal-feeding and plant parasitic nematodes increased by 10% and 137%, respectively. (ii) The fresh weight of shoot and root increased by 14% and 35%, respectively. Meanwhile, the polyphenol oxidase activity of leaves increased by 33% at the seedling stage. (iii) The total number of culturable bacteria decreased by 49% in root knots. Regarding the total number of culturable microbes in root zone soil, bacteria and actinomycetes also decreased by 18% and 10%, respectively, whereas fungi increased by 20%. Moreover, the quantity of both plant growth-promoting bacteria and nematicidal bacteria increased, while the quantity of plant-pathogenic bacteria decreased. In conclusion, the Streptomyces agent could reduce RKN disease in tomato by activating the systemic resistance and defensive mechanism against nematode infection. This agent triggered complex interactions between plants, microbes, and nematodes in the micro-ecosystem of root zone soil, resulting in decreased RKN infection ability and/or enhanced tomato disease resistance. [ABSTRACT FROM AUTHOR]

The complex parasitic strategy of Meloidogyne incognita appears to involve simultaneous expression of its pharyngeal gland-specific effector genes in order to colonize the host plants. Research reports related to effector crosstalk in phytonematodes for successful parasitism of the host tissue is yet underexplored. In view of this, we have used in planta effector screening approach to understand the possible interaction of pioneer genes (msp-18 and msp-20, putatively involved in late and early stage of M. incognita parasitism, respectively) with other unrelated effectors such as cell-wall modifying enzymes (CWMEs) in M. incognita. Host-induced gene silencing (HIGS) strategy was used to generate the transgenic eggplants expressing msp-18 and msp-20, independently. Putative transformants were characterized via qRT-PCR and Southern hybridization assay. SiRNAs specific to msp-18 and msp-20 were also detected in the transformants via Northern hybridization assay. Transgenic expression of the RNAi constructs of msp-18 and msp-20 genes resulted in 43.64-69.68% and 41.74-67.30% reduction in M. incognita multiplication encompassing 6 and 10 events, respectively. Additionally, transcriptional oscillation of CWMEs documented in the penetrating and developing nematodes suggested the possible interaction among CWMEs and pioneer genes. The rapid assimilation of plant-derived carbon by invading nematodes was also demonstrated using 14C isotope probing approach. Our data suggests that HIGS of msp-18 and msp-20, improves nematode resistance in eggplant by affecting the steady-state transcription level of CWME genes in invading nematodes, and safeguard the plant against nematode invasion at very early stage because nematodes may become the recipient of bioactive RNA species during the process of penetration into the plant root. [ABSTRACT FROM AUTHOR]

Aphelenchoidid nematodes were collected from the sycones of Ficus subgenus Pharmacosycea from Central America. Two new species of Ficophagus were recovered, and are described herein as F. maxima sp. n. and F. yoponensis sp. n. from Ficus maxima and F. yoponensis, respectively. They are differentiated from other species of the genus by a combination of morphological characters including having C-shaped females and spiral males, EP opening close to the lips, a short to long post-uterine sac, spicule characters, three pairs of subventral caudal papillae, DNA sequence data, biogeographical range, and host wasp and Ficus species affiliation. The new species are differentiated from each other by spicule characters, length of the post-uterine sac, spermatheca shape, and female tail shape. In addition, three morphospecies were collected from sycones of Ficus glabrata, F. insipida and F. tonduzii, respectively. Their morphological descriptions are presented but these taxa are not formally named as they currently lack molecular data. [ABSTRACT FROM AUTHOR]

The Korean cyst nematode, Heterodera koreana, was recorded for the first time from Japan and characterised morphologically, morphometrically and molecularly. In total, 41 populations were detected from soil samples collected from the rhizosphere of four bamboo species in Japan: 31 populations from moso bamboo (Phyllostachys edulis), seven from madake (P. bambusoides), two from henon bamboo (P. nigra var. henonis) and one from fish pole bamboo (P. aurea). The morphology and morphometrics of the Japanese population were in agreement with those of the original description of H. koreana from South Korea and other subsequent descriptions from China and Iran, with the exception of some minor differences. The results of the phylogenetic analyses of the D2-D3 expansion segments of 28S rRNA gene and ITS rRNA gene sequences confirmed the species identification and phylogenetic relationship of H. koreana with other Heterodera species. The COI mtDNA gene sequences were obtained for the first time for H. koreana. Three COI haplotypes found in Japanese H. koreana populations showed a characteristic geographical distribution in Japan. [ABSTRACT FROM AUTHOR]

Aphelenchoidid nematodes associated with the syconia of two dominant fig species, Ficus hispida and F. racemosa, were surveyed in Banda Aceh, Indonesia. Nematodes were isolated from sycones and pollinating wasps of these two fig species from four localities in the area, and identified based on the molecular sequences of two genetic loci, D2-D3 expansion segments of large subunit ribosomal RNA (D2-D3 LSU) and mitochondrial cytochrome oxidase subunit I (mtCOI). Molecular sequences of D2-D3 LSU and mtCOI were successfully determined for 44 and 19 individual nematodes, respectively, and these sequences were separated into four clades, i.e., types A-D of D2-D3 LSU and types I-IV of mtCOI. Phylogenetic analysis of the DNA sequences deposited in the GenBank database showed that the DNA sequences corresponded to three species, namely, Martininema baculum (type B/II), Ficophagus fleckeri (types A/I, D/IV) and F. cf. centerae (type C/III). Within these species, F. fleckeri was separated into two clades as suggested in previous studies and thus it may possibly reflect the existence of two different taxa, F. fleckeri and a cryptic species. The Indonesian F. cf. centerae was monophyletic with, but clearly separated from, the Chinese population of F. centerae and thus the Indonesian population is potentially an undescribed species. Overall, the species composition of fig-associated aphelenchoidids in the Aceh region seemed intermediate between continental Chinese and Australian species. However, further material collections followed by detailed morphological analyses are necessary to characterise or describe these fig-associated aphelenchoidids in Indonesia. [ABSTRACT FROM AUTHOR]

A new cyst nematode, herein described as Globodera agulhasensis n. sp., was found parasitising Senecio burchelli in the Western Cape Province, South Africa. Second-stage juveniles are characterised by a well developed stylet of 23.5 (22.5-24.8) μm with rounded to anteriorly flattened knobs. The dorsal pharyngeal gland outlet is 4.4 (3.5-6.5) μm posterior to the stylet knobs. The tail is 56 (49-64) μm long and the length of the hyaline region is 25 (19-29) μm. The cysts are characterised by their ovate to spherical shape, short neck, the presence of subcuticular punctations over the entire body and the absence of bullae or vulval bodies. Six to 12 cuticular ridges/lines are present on the outer surface of the cyst between the anus and vulval basin. Granek's ratio is 1.7 (1.0-3.0), the vulval basin diam. 17.6 (11.7-26.1) μm and the distance between vulval basin and anus is 28.6 (19.1-47.0) μm. Males have a stylet length of 26.1 (24.4-27.7) μm and spicule length of 30.3 (27.2-33.8) μm with a rounded tip. Females have a stylet length of 22.1 (19.0-24.4) μm, a large median bulb almost filling the body diam., and a short vulval slit 4.2 (3.2-6.6) μm long. Phylogenetic relationships of G. agulhasensis n. sp. with other species of the genus, inferred from ITS-rRNA sequences by using the neighbour-joining (NJ), maximum likelihood (ML) and maximum parsimony method (MP), indicate that G. agulhasensis n. sp. is included in the clade of Globodera sp. that parasitise non-solanaceous plants, forming a monophyletic group with unidentified Globodera spp. from Portugal, G. millefolii and G. artemisiae. For diagnostic purposes, three restriction enzymes, Hpy8I, RsaI and XceI were selected as being able to discriminate between G. agulhasensis n. sp. and other Globodera spp. present in South Africa. [ABSTRACT FROM AUTHOR]

Lilium longiflorum cv. Nellie White, commonly known as Easter lily, is an important floral crop with an annual wholesale value of over $26 million in the United States. The root-lesion nematode, Pratylenchus penetrans, is a major pest of lily due to the significant root damage it causes. In this study, we investigated the cytological aspects of this plant-nematode interaction using bright-field and transmission electron microscopy. We took advantage of an in vitro culture method to multiply lilies and follow the nematode infection over time. Phenotypic reactions of roots inoculated with P. penetrans were evaluated from 0 to 60 d after nematode infection. Symptom development progressed from initial randomly distributed discrete necrotic areas to advanced necrosis along entire roots of each inoculated plant. A major feature characterizing this susceptible host response to nematode infection was the formation of necrosis, browning, and tissue death involving both root epidermis and cortical cells. Degradation of consecutive cell walls resulted in loss of cell pressure, lack of cytoplasmic integrity, followed by cell death along the intracellular path of the nematode's migration. Pratylenchus penetrans was never seen in the vascular cylinder as the layer of collapsed endodermal cells presumably blocked the progression of nematodes into this area of the roots. This study presents the first detailed cytological characterization of P. penetrans infection of Easter lily plants. [ABSTRACT FROM AUTHOR]

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Root extracts of six different plants viz., soybean, sesame, chenopod, bell-pepper, maize and marigold @10 and 20 % , with an exposure period of 24, 48 and 72 hr, were evaluated for their efficacy against egg hatching and juvenile (J2) mortality of Meloidogyne incognita, commonly known as root knot nematode. At 20 per cent concentration, no egg hatching was recorded in any of the root extract (except marigold) up to 72 hr of exposure. At 10 per cent concentration, root extracts of all the intercrops (except for bell-pepper) were effective enough to restrict the egg hatching. At both the concentrations, root extracts of all the intercrops (except soybean) caused considerable juvenile mortality (52.23-100 per cent) over control and marigold root extract was observed to be the most effective. [ABSTRACT FROM AUTHOR]