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Aphelenchoides besseyi is the causal agent of soybean green stem and foliar retention syndrome known as “Soja Louca II.” This nematode has recently been reported parasitizing cotton in Brazil. In Costa Rica, it causes the symptoms known as “amachamiento” and false angular spots in common bean (Phaseolus vulgaris). Due to the great importance of beans to Brazilian agriculture, the objective of this research was to study the pathogenicity of A. besseyi in common bean under greenhouse conditions, including its endoparasitic relationships by staining root and shoot system tissues with fuchsin acid. In addition, A. besseyi was collected and quantified from shoot systems 30 days after inoculation by washing the tissue in water and blender centrifugal flotation. We observed the symptoms of amachamiento, leaf and vein deformation in the expanded trifoliate leaves, and also leaves with necrotic, brown to reddish and angular lesions, characteristics from false angular spot, and deformed stems characterized by enlargement of nodes, retortions, and necrotic lesions. High numbers of nematodes were found inside common bean plants. This is the first report of the pathogenicity and symptoms caused by A. besseyi in common bean in Brazil. These findings are important for development of management strategies to avoid losses on bean cropped in infested areas.

Summary Aphelenchoides pseudogoodeyi has recently been reported in association with seeds of forage grasses and rice in Brazil and senescent strawberry plants, in the United States. This nematode is likely a mycophagous species; however, so far, its pathogenicity potential to plants is unclear. This study aimed to verify the pathogenicity of A. pseudogoodeyi to two species of ornamental plants. The experiments were conducted by inoculating A. pseudogoodeyi onto Bird’s-Nest Fern (Asplenium nidus) and Oriental Lily (Lilium speciosum) leaves, using two inoculation methods (with and without injury). After 40 days of inoculation (DAI) in Bird’s-Nest Fern and 5, 10, 20 and 40 DAI in Oriental Lily, the pathogenicity and the host efficiency were evaluated by symptoms observation and by severity, final nematode population and reproductive factor (RF), respectively. Additionally, a histopathological study was performed by inoculating A. pseudogoodeyi onto Bird’s-Nest Fern for observing anatomical alterations. A. pseudogoodeyi was able to cause local necrotic lesions on both Bird’s-Nest Fern and Oriental Lily leaves. However, the presence of injury was essential to enable A. pseudogoodeyi to penetrate and cause those symptoms in both plant species. Also, the total population of A. pseudogoodeyi decreased drastically over time and RF was A. pseudogoodeyi penetrated into the foliar tissue and induced a total destruction of the mesophyll and collapse of the cells, with the formation of large intercellular spaces. It is concluded that A. pseudogoodeyi is an opportunistic pathogen as injury was required to induce symptoms in Bird’s-Nest Fern and Oriental Lily.

Foliar nematodes represent a minor feeding group within the genus Aphelenchoides Fischer, 1894. The facultative plant parasitic species A. blastophthorus can cause crinkling of leaves, reduced vigor, and stunting of agricultural and ornamental plants. Here we report the first finding of A. blastophthorus in leaves, crowns, and roots of strawberry plants collected in Switzerland in 2018. Species identification was confirmed by morphological and morphometric characterization supported by molecular barcoding of 18S ribosomal RNA (18S), 28S ribosomal RNA (28S), and cytochrome c oxidase I (COI) gene fragment analyses. Phylogenetic analysis of 18S indicated that A. blastophthorus was grouped within close distance to A. fragariae, a well-known foliar nematode affecting strawberry plants. Furthermore, the newly generated molecular barcodes of the partial 28S and COI of A. blastophthorus will support species identification in the future.

To establish the amplification and detection system for the chrysanthemum foliar nematode (CFN), Aphelenchoides ritzemabosi, the loop-mediated isothermal amplification (LAMP), which includes two external primers (F3/B3), two inner primers (FIP/BIP) and one loop primer (LF), was designed based on the CFN 18S ribosomal RNA gene. The DNA samples were amplified by LAMP primers using isothermal amplification (65 °C). The amplified products were detected by electrophoresis and visual inspection of fluorescent dyes. Detection of CFN in a sample was confirmed when the electrophoresis results show a DNA ladder or the mixtures in the tubes showed green fluorescence. The results showed that the LAMP method could not only detect and identify a single female, male, juvenile and egg of CFN but also directly detect CFN in mixed nematode species samples and plant tissue samples. The sensitivity of the LAMP assay was 100-fold dilution of single nematode DNA.

Beech leaf disease (BLD) was first reported in 2012 in Lake County, Ohio on American beech trees (Fagus grandifolia Ehrh.). Since then, it spread across the Northeastern United States and has been reported from Ohio, Pennsylvania, New York, New Jersey, Connecticut, Rhode Island, Maine, West Virginia, and Ontario, Canada (Carta et al. 2020; Mara and LaMondia 2020, Reid et al. 2020). The symptoms of BLD are characterized by dark interveinal banding of leaves appearing soon after spring flush that become chlorotic and necrotic through autumn, resulting in canopy thinning in advanced stages, followed in some young trees by death. Litylenchus crenatae mccannii has similar morphological characteristics with Litylenchus crenatae (Kanzaki et al. 2019) reported on Fagus crenata from Japan. However that beech species has not shown BLD symptoms or yielded any L. crenatae mccannii in North America. There are several morphological differences between the two. The North American subspecies have shorter post-uterine sac, narrower body width in mature females, shorter tail in immature females, longer tail in mature females, and longer stylet in males when compared to the Japanese subspecies (Carta et al. 2020). BLD symptoms were found on American beech trees in Prince William Forest Park, Prince William County, Virginia in June, 2021. The affected leaves contained females, males, and juveniles with morphometrics consistent with L. crenatae mccannii (Carta et al. 2020). The crude genomic DNA from a live single Litylenchus was prepared with freeze-thaw lysis (Carta and Li, 2019). The ITS PCR were performed by using the procedures and primer set, ITS-CL-F2 and 28S-CL-R described in the previous study (Carta and Li, 2020). The visualization, the cleanup and the direct DNA sequencing of the PCR products were performed by using the procedures described in the previous studies (Carta and Li, 2018 and 2019). Sequences were submitted to GenBank as accessions MZ611855 and MZ611856. This represents the first report of BLD in Virginia. It is also approximately 300 miles south of the 2020 detection of BLD from New Cumberland, WV, and represents the southernmost detection of the disease and nematode in North America. The author(s) declare no conflict of interest. References Carta, L.K., Li, S. 2018. Improved 18S small subunit rDNA primers for problematic nematode amplification. Journal of Nematology. 50, 533-542. Carta, L.K., Li, S. 2019. PCR amplification of a long rDNA segment with one primer pair in agriculturally important nematodes. Journal of Nematology. 51, e2019-26. Carta, L.K., Li, S. 2020. Improvement of long segment ribosomal PCR amplification for the molecular taxonomic identification of Litylenchus crenatae mccannii in beech trees with beech leaf disease. Journal of Nematology. 52, e2020-016. Kanzaki, N., Ichihara, Y., Aikawa, T., Ekino, T., Masuya, H. 2019. Litylenchus crenatae n. sp. (Tylenchomorpha: Anguinidae), a leaf gall nematode parasitising Fagus crenata Blume Nematology 21 (1), 5-22. http://www.brill.com/nematology doi: 10.1163/15685411-00003190 Marra, R.E., LaMondia, J. 2020. First report of beech leaf disease, caused by the foliar nematode, Litylenchus crenatae mccannii, on American beech (Fagus grandifolia) in Connecticut. Plant Disease (early view). https://doi.org/10.1094/PDIS-02-20-0442-PDN Reed, S. E., Greifenhagen, S., Yu, Q., Hoke A., Burke D. J., Carta L. K., Handoo Z.A., Kantor, M.R., Koch, J. 2020. Foliar nematode, Litylenchus crenatae ssp. mccannii, population dynamics in leaves and buds of beech leaf disease-affected trees in Canada and the US. Forest Pathology 50 (3), e12599.

Nematodes are Earth’s most numerous multicellular animals and include species that feed on bacteria, fungi, plants, insects, and animals. Foliar nematodes are mostly pathogens of ornamental crops in greenhouses, nurseries, forest trees, and field crops. Nematode identification has traditionally relied on morphological and anatomical characters using light microscopy and, in some cases, scanning electron microscopy (SEM). This review focuses on morphometrical and brief molecular details and key characteristics of some of the most widely distributed and economically important foliar nematodes that can aid in their identification. Aphelenchoides genus includes some of the most widely distributed nematodes that can cause crop damages and losses to agricultural, horticultural, and forestry crops. Morphological details of the most common species of Aphelenchoides (A. besseyi, A. bicaudatus, A. fragariae, A. ritzemabosi) are given with brief molecular details, including distribution, identification, conclusion, and future directions, as well as an updated list of the nominal species with its synonyms. Litylenchus is a relatively new genus described in 2011 and includes two species and one subspecies. Species included in the Litylenchus are important emerging foliar pathogens parasitizing trees and bushes, especially beech trees in the United States of America. Brief morphological details of all Litylenchus species are provided.

There are nematodes of several genera that feed on plant stems and foliage, including Aphelenchoides, Bursaphelenchus, Anguina, Ditylenchus and Litylenchus. Herein, we apply the common name “foliar nematode” specifically to plant-feeding nematodes in the genus Aphelechoides, specifically Aphelenchoides besseyi, Aphelenchoides fragariae, and Aphelenchoides ritzemabosi. While most members of Aphelenchoides are fungivorous (feed on fungi), these three species have populations that are facultative plant-parasites that can feed on live plant tissue. Ten other species of Aphelenchoides also are recognized as facultative plant-parasites, but these are not as commonly encountered or as economically significant as the aforementioned species. Unlike most plant-parasitic nematodes, foliar nematodes can infest the aerial portions of plants rather than dwelling strictly in soil and plant roots. Damage from their feeding can reduce yield in food crops and ruin the appearance of ornamentals.https://edis.ifas.ufl.edu/in1279

Summary Aphelenchoides fragariae (Ritzema Bos, 1890) Christie, 1932 was isolated from leaves of silver birch (Betula pendula Roth) seedlings proving that the source of infection was anemones plants. This is the first report to our best knowledge showing that the source of nematode infection of a woody plant could be a perennial plant. A. fragariae was identified by morphometric and molecular analyses. Morphological diagnosis based on the bending shape of the tail of males and pronounced apex and rostrum proved to be the most accurate reliable characteristic. On the opposite, the high variability of the mucron shape in female tails made the identification by microscopic analyses difficult. Identification of the species was confirmed by analysis of 28S rDNA sequences. The morphometric data of adults extracted from silver birch was compared with that of nematodes isolated from Anemone hupehensis (Lemoine) Lemoine. Males body length varied highly in samples collected from both host plant species.

In 2013 and 2014, the effects of different products and plant extracts in the control of Aphelenchoides ritzemabosi (Schwartz, 1911) Steiner and Buhrer, 1932 on Anemone hupehensis plants variety Prinz Heinrich were estimated. Experiments were carried out under containerized cultivation. Evaluation of the effectiveness of nematicides was conducted using two common methods based on the number of nematodes per leaf and the percentage of damaged leaves. In both experiments oxamyl and abamectin, with aqueous extract of Allium sativum, were the most effective (efficacy about 40%). The aqueous bulb extracts of A. sativum, solution of extracts of Quillaja saponaria and solution of spirotetramat in combination with aqueous extract of A. sativum were ineffective. In both experimental years, the significant correlation between the number of nematodes in leaves and the sampling date was recorded. Based on Spearman rank correlation test and regression, it was shown that counting of nematodes in leaves is still the most reliable method for diagnosis of the damage caused by foliar nematodes.

The objective of this research was to determine the capability of Aphelenchoides besseyi of being seed-transmitted in common bean. During 2007 and 2008, seeds were collected from nematode-infested common bean plants (cv. Cabécar) previously showing characteristic symptoms, in commercial plantations of the Brunca region of Costa Rica (southeastern area of the country). Between September 2008 and September 2009 the seeds were sowed in plastic pots in a greenhouse located in Veracruz, Pérez Zeledón, Costa Rica. Once seeds germinated, plants were observed weekly to determine the appearance of “amachamiento” symptoms and detect the cases of disease transmission by seed. To support the previous work, seeds from “amachamiento” diseased plants (cv. Cabécar) were collected in commercial common bean plantations in five localities of the Brunca region of Costa Rica in 2014. The seeds were carried to Estación Experimental Agrícola Fabio Baudrit Moreno of Universidad de Costa Rica located in Alajuela, where they were examined in a laboratory to determine the presence of A. besseyi specimens. Contrary to indicated for A. besseyi in rice and pastures, crops in which this pathogen is seed-transmitted, in common bean it was not possible find specimens of this nematode nor diseased plants from seeds of infested plants. The results obtained indicate that, under these experimental conditions, seeds are not an effective way for the transmission and dissemination of the “amachamiento” disease in common bean. El objetivo del presente trabajo fue determinar la capacidad de Aphelenchoides besseyi de ser transmitido por medio de la semilla en frijol. Durante el 2007 y 2008 se recolectaron semillas de plantas de frijol (cv. Cabécar) con síntomas característicos de amachamiento, en plantaciones comerciales de la región Brunca de Costa Rica (sureste del país). Entre setiembre del 2008 y setiembre del 2009, las semillas se sembraron en potes plásticos dentro de una casa de mallas en Veracruz de Pérez Zeledón, Costa Rica. Una vez emergidas, las plantas fueron observadas semanalmente para determinar la aparición de síntomas de amachamiento y detectar los casos de transmisión del nematodo en la semilla. Como respaldo a lo anterior, durante el 2014 se recolectaron semillas de plantas de frijol (cv. Cabécar) con síntomas de amachamiento, en plantaciones comerciales de cinco localidades de la región Brunca de Costa Rica. Las semillas se examinaron en un laboratorio de la Estación Experimental Agrícola Fabio Baudrit Moreno de la Universidad de Costa Rica en Alajuela, para determinar la presencia de especímenes de A. besseyi. En contraste con lo indicado para A. besseyi en arroz y pasturas, donde este patógeno se transmite por semilla, en frijol no fue posible rescatar individuos de este nematodo ni encontrar plantas enfermas a partir de semillas provenientes de plantas infestadas. Los resultados obtenidos indican que, bajo estas condiciones experimentales, la semilla de frijol no fue una vía efectiva para la transmisión y diseminación del amachamiento.

The foliar nematode (Aphelenchoides fragariae) is a quarantined pest that infects a broad range of herbaceous and woody plants. Previous work has demonstrated its remarkable ability to survive rapid and extreme desiccation, although the specific molecular mechanisms underlying its anhydrobiotic response have not been characterized. The authors used RNA sequencing and de novo transcriptome assembly to compare patterns of gene expression between hydrated and 24-hr desiccated nematodes. In total, 2,083 and 953 genes were significantly up- and downregulated, respectively, in desiccated nematodes. Of the 100 annotated genes with the largest positive fold-changes, more than one third encoded putative detoxification-related proteins. Genes encoding enzymes of Phase I and Phase II detoxification systems were among the most strongly upregulated in the transcriptome, including 35 cytochrome p450s, 23 short chain dehydrogenase/reductases, 5 glutathione-S-transferases, and 22 UDP-glucuronosyltransferases. Genes encoding heat shock proteins, unfolded protein response enzymes, and intrinsically disordered proteins were also upregulated. Anhydrobiosis in A. fragariae appears to involve both strategies to minimize protein misfolding and aggregation, and wholesale induction of the cellular detoxification machinery. These processes may be controlled in part through the activity of forkhead transcription factors similar to Caenorhabditis elegans' daf-16, a number of which were differentially expressed under desiccation. The foliar nematode (Aphelenchoides fragariae) is a quarantined pest that infects a broad range of herbaceous and woody plants. Previous work has demonstrated its remarkable ability to survive rapid and extreme desiccation, although the specific molecular mechanisms underlying its anhydrobiotic response have not been characterized. The authors used RNA sequencing and de novo transcriptome assembly to compare patterns of gene expression between hydrated and 24-hr desiccated nematodes. In total, 2,083 and 953 genes were significantly up- and downregulated, respectively, in desiccated nematodes. Of the 100 annotated genes with the largest positive fold-changes, more than one third encoded putative detoxification-related proteins. Genes encoding enzymes of Phase I and Phase II detoxification systems were among the most strongly upregulated in the transcriptome, including 35 cytochrome p450s, 23 short chain dehydrogenase/reductases, 5 glutathione-S-transferases, and 22 UDP-glucuronosyltransferases. Genes encoding heat shock proteins, unfolded protein response enzymes, and intrinsically disordered proteins were also upregulated. Anhydrobiosis in A. fragariae appears to involve both strategies to minimize protein misfolding and aggregation, and wholesale induction of the cellular detoxification machinery. These processes may be controlled in part through the activity of forkhead transcription factors similar to Caenorhabditis elegans’ daf-16, a number of which were differentially expressed under desiccation.

A foliar nematode, Litylenchus crenatae ssp. mccannii, is associated with beech leaf disease (BLD) symptoms. Information about the types of tissues parasitized and how nematode populations fluctuate in these tissues over time is needed to improve surveys as well as understand the nematodes role in BLD. During this study, the nematode was detected throughout the known range of BLD by researchers at both Canadian and US institutions using a modified pan method to extract nematodes. Monthly collections of symptomatic and asymptomatic leaves during the growing season (May–October), and leaves and buds between growing seasons (November– March), revealed that nematodes were present in all tissue types. Progressively larger numbers of nematodes were detected in symptomatic leaves from Ohio and Ontario, with the greatest detections at the end of the growing season. Smaller numbers of nematodes were detected in asymptomatic leaves from BLD-infected trees, typically at the end of the growing season. The nematode was detected overwintering in buds and detached leaves. The discovery of small numbers of nematodes in detached leaves at one location before BLD was detected indicates that nematodes may have been present before disease symptoms were expressed. Other nematodes, Plectus and Aphelenchoides spp., were infrequently detected in small numbers. Our findings support the involvement of the nematode in BLD and indicate that symptoms develop only when certain requirements, such as infection of buds, are met. We also found that the nematode can be reliably detected in buds and leaves using the modified pan extraction method.

Symptoms of beech leaf disease (BLD), first reported in Ohio in 2012, include interveinal greening, thickening and often chlorosis in leaves, canopy thinning and mortality. Nematodes from diseased leaves of American beech (Fagus grandifolia) sent by the Ohio Department of Agriculture to the USDA, Beltsville, MD in autumn 2017 were identified as the first recorded North American population of Litylenchus crenatae (Nematology, 21, 2019, 5), originally described from Japan. This and other populations from Ohio, Pennsylvania and the neighbouring province of Ontario, Canada showed some differences in morphometric averages among females compared to the Japanese population. Ribosomal DNA marker sequences were nearly identical to the population from Japan. A sequence for the COI marker was also generated, although it was not available from the Japanese population. The nematode was not encountered in Fagus crenata (its host in Japan) living among nematode-infested Fagus grandifolia in the Holden Arboretum, nor has L. crenatae been reported in American beech in Japan. The morphological and host range differences in North American populations are nomenclaturally distinguished as L. crenatae mccannii ssp. n. from the population in Japan. Low-temperature scanning electron microscopy (LT-SEM) demonstrated five lip annules and a highly flexible cuticle. Females, juveniles and eggs were imaged within buds with a Hirox Digital microscope and an LT-SEM. Nematodes swarmed to the tips of freshly cut beech buds, but explants could not be maintained. Inoculation of fresh nematodes from infested leaves or buds to buds or leaves of F. grandifolia seedlings resulted in BLD leaf symptoms. Injuring dormant buds prior to nematode application, in fall or spring, promoted the most reliable symptom expression. The biogeography and physiology of anguinid nematode leaf galling, and potential co-factors and transmission are discussed.

Plant parasitic nematodes are recognized as one of the most important limiting factor in crop production worldwide and Mexico is not an exception. Economic losses caused by nematodes are influenced by growing system type (multicropping, monocropping, crop rotation in open-field and greenhouse conditions, among others), species involved and their population densities. In Mexico, damages and losses are caused mainly by lesion nematodes (Pratylenchus spp. and Radopholus similis), the stem and bulb nematode (Ditylenchus dipsaci), root knot nematodes (Meloidogyne spp.), false root knot nematode (Nacobbus aberrans), cyst nematodes (Globodera spp. and Punctodera chalcoensis), the citrus nematode (Tylenchulus semipenetrans), virus transmitting nematodes (Xiphinema spp.), foliar nematode species (Aphelenchoides spp.) and red ring nematode (Bursaphelenchus cocophilus). Some of these nematodes have been observed in commercial plantations, crop fields and greenhouses where mono-cropping is more common and crop rotation is not practiced.

The most important plant parasitic nematodes associated with crop production in the states of Texas and Oklahoma are the root-knot nematodes. Meloidogyne incognita limits cotton production. M. arenaria, M. haplanaria, M. javanica (Texas) and M. hapla (Oklahoma) limit peanut production. M. hapla is the most common root-knot nematode affecting potato, though other species including M. chitwoodi have been found on this crop. M. partityla has been found on pecans, M. graminis on grass species, and M. marylandi on turf. Other nematode species that can be highly damaging include the citrus nematode (Tylenchulus semipenetrans) on citrus in the Lower Rio Grande Valley, the reniform nematode (Rotylenchus reniformis) on cotton, soybean cyst nematode (Heterodera glycines) on soybean, sting nematode (Belonolaimus longicaudatus) on several crops, stem and bulb nematode (Ditylenchus dipsaci) primarily on alfalfa in Oklahoma, and the foliar nematode (Aphlenchoides besseyi) on rice and ornamentals.

The rice white tip nematode (RWTN), Aphelenchoides besseyi and the chrysanthemum foliar nematode (CFN), Aphelenchoides ritzemabosi are migratory plant parasitic nematodes that infect the aboveground parts of plants. In this research, Arabidopsis thaliana was infected by RWTN and CFN under indoor aseptic cultivation, and the nematodes caused recognizable symptoms in the leaves. Furthermore, RWTN and CFN completed their life cycles and proliferated. Therefore, A. thaliana was identified as a new host of RWTN and CFN. The optimum inoculum concentration for RWTN and CFN was 100 nematodes/plantlet, and the optimum inoculum times were 21 and 24 days, respectively. For different RWTN populations, the pathogenicity and reproduction rates were different in the A. thaliana Col-0 ecotype and were positively correlated. The optimum A. thaliana ecotypes were Col-0 and WS, which were the most susceptible to RWTN and CFN, respectively. Additionally, RWTN was ectoparasitic and CFN was ecto- and endoparasitic in A. thaliana. The RWTN and CFN migrated from inoculated leaves to the entire plantlet, and the number of nematodes in different parts of A. thaliana was not correlated with distance from the inoculum point. This is a detailed study of the behavior and infection process of foliar nematodes on A. thaliana.

Dendrobium orchid, Dendrobium nobile, is one of the most widespread ornamentals. Besides durability and high keeping quality, its fragrant, waxy and variable coloured flowers are having a high market demand. Dendrobium orchid was found to be one of the favourable hosts for foliar nematode, Aphelenchoides besseyi. The cross inoculation study confirmed the association of Foliar nematode, A. besseyi in Dendrobium. The nematode was found to remain active on plants round the year under polyhouse condition with high temperature and relative humidity affecting the quantity and quality of flower appreciably.

The draft genome of “ Rathayibacter tanaceti ” VKM Ac-2596 is 3.17 Mb in size with an average G+C content of 70.7% and comprises at least two nonidentical copies of ribosomal small subunit (SSU-rRNA) genes. The semiconductor sequencing platform Ion Torrent was used.

The chrysanthemum foliar nematode (CFN), Aphelenchoides ritzemabosi, is a plant parasitic nematode that attacks many plants. In this study, a transcriptomes of mixed-stage population of CFN was sequenced on the Illumina HiSeq 2000 platform. 68.10 million Illumina high quality paired end reads were obtained which generated 26,817 transcripts with a mean length of 1,032 bp and an N50 of 1,672 bp, of which 16,467 transcripts were annotated against six databases. In total, 20,311 coding region sequences (CDS), 495 simple sequence repeats (SSRs) and 8,353 single-nucleotide polymorphisms (SNPs) were predicted, respectively. The CFN with the most shared sequences was B. xylophilus with 16,846 (62.82%) common transcripts and 10,543 (39.31%) CFN transcripts matched sequences of all of four plant parasitic nematodes compared. A total of 111 CFN transcripts were predicted as homologues of 7 types of carbohydrate-active enzymes (CAZymes) with plant/fungal cell wall-degrading activities, fewer transcripts were predicted as homologues of plant cell wall-degrading enzymes than fungal cell wall-degrading enzymes. The phylogenetic analysis of GH5, GH16, GH43 and GH45 proteins between CFN and other organisms showed CFN and other nematodes have a closer phylogenetic relationship. In the CFN transcriptome, sixteen types of genes orthologues with seven classes of protein families involved in the RNAi pathway in C. elegans were predicted. This research provides comprehensive gene expression information at the transcriptional level, which will facilitate the elucidation of the molecular mechanisms of CFN and the distribution of gene functions at the macro level, potentially revealing improved methods for controlling CFN.

We identified and characterized a β-1,4-endoglucanase, Afr-ENG-1, in the foliar nematode Aphelenchoides fragariae that is differentially expressed when the nematode feeds on fungi or plants. When individuals from hosta plants were transferred to a fungus culture, expression of the enzyme decreased 1,812-fold after five generations on the fungus diet. Afr-eng-1 was readily detected in the genome of 75% of nematodes from the plant population but only in 38% of the diet-changed population. The gene cannot be detected in nematodes maintained on fungus for over 100 generations. Diet was also associated with changes in nematode body size and in the severity of symptoms caused on hosta leaves. Plant-diet nematodes caused larger lesions and were longer and thinner than fungus-diet nematodes. Nematodes moved from a plant diet to a fungus diet for five generations had the same body size as the nematodes that had fed on the fungus for 100 generations. Full-length sequences of Afr-eng-1 were obtained and found to encode a glycosyl hydrolase family 5 protein. This is the first β-1,4-endoglucanase and plant-parasitism-related gene described in the genus Aphelenchoides.

Leaf blight symptoms and abnormal defoliation were found on Stachys riederi var. japonica, a medicinal plant, grown at Hongcheon, Gangwon province, Korea in 2007. A foliar nematode, Aphelenchoides fragariae was isolated from infected leaf tissues. The symptoms observed on host plant were leaf blotching, discoloration and browning of tissues, tan-colored interveinal necrotic lesions and large dead patches of necrotic tissues. This is the first report of A. fragariae occurring on S. riederi var. japonica.