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From 2016 to 2021, nematode surveys in Florida strawberry fields revealed several species of foliar nematodes (Aphelenchoides spp.). Aphelenchoides besseyi sensu stricto was detected only in 2016 and 2017 on photosynthetic strawberry leaves/buds, but other not well characterized populations of Aphelenchoides sp. were found on declining/dessicated leaves. Morphological analyses showed that these samples of Aphelenchoides sp. consisted of A. bicaudatus, a species detected in Florida for the first time, and A. rutgersi, a species previously reported in Florida from the citrus rhizosphere. These two species differed from A. besseyi in the shape of their tail terminus: bifurcate in A. bicaudatus; mucronate with a ventral thin mucro in A. rutgersi; and stellate in A. besseyi. One population each of these species was used for morphological and molecular analyses after being reared on Monilinia fructicola. Body and tail length differences were observed among Florida A. bicaudatus and other populations from the Far East and South Africa. Phylogenetic analyses of the rRNA gene sequences showed that Florida A. bicaudatus grouped with those of species from South Korea, Taiwan, and the Netherlands and several other populations listed as Aphelenchoides sp. from Brazil, Costa Rica, and Japan, which were considered as representatives of A. bicaudatus in this study. Similarly, sequences of Florida A. rutgersi grouped with those from environmental samples in Japan and North Carolina, which were listed as Aphelenchoides sp. and were considered as representatives of A. rutgersi in this study. Photosynthetic strawberry leaf samples were free from both A. bicaudatus and A. rutgersi, indicating that these two species did not damage strawberry. They were associated with desiccated leaves and/or propagative stolons, usually infected by fungi, confirming that they are mycetophagous under field conditions in this study. Results of soybean leaf inoculation on moist filter paper containing A. bicaudatus specimens showed that this species could become phytophagous under artificial conditions. Nematodes penetrated the leaf epidermis and migrated into the mesophyll causing leaf tissue discoloration/necrosis, which remained localized within the infested area. Soybean leaf damage was almost negligible, and no nematode reproduction was observed in the inoculated soybean areas.

Draft genome sequences of 28 strains of Microbacteriaceae from plants infested by plant-parasitic nematodes were obtained using Illumina technology. The sequence data will provide useful baseline information for the development of comparative genomics and systematics of Microbacteriaceae and facilitate understanding of molecular mechanisms involved in interactions between plants and nematode-associated bacterial complexes.

Recombinase polymerase amplification (RPA) is an isothermal in vitro nucleic acid amplification technique that has been adopted for simple, robust, rapid, reliable diagnostics of nematodes. In this study, the real-time RPA assay and RPA assay combined with lateral flow dipsticks (LF-RPA) have been developed targeting the ITS rRNA gene of the British root-knot nematode, Meloidogyne artiellia. The assay provided specific and rapid detection of this root-knot nematode species from crude nematode extracts without a DNA extraction step with a sensitivity of 0.125 second-stage juvenile (J2) specimen per a reaction tube for real-time RPA during 11 min and a sensitivity of 0.5 J2 specimens per a reaction tube for LF-RPA during 25 min. The RPA assays were validated with a wide range of non-target root-knot nematodes. The LF-RPA assay has great potential for nematode diagnostics in the laboratory having minimal available equipment.

Draft genome sequences of 13 bacterial strains from the family Microbacteriaceae were generated using Illumina technology. The genome sizes varied from 3.0 to 4.8 Mb, and the DNA G+C content was 68.1 to 72.5%. The sequences obtained will contribute to the development of genome-based taxonomy and understanding of molecular interactions between bacteria and plants.

Complete and draft genome sequences of 12 Rathayibacter strains were generated using Oxford Nanopore and Illumina technologies. The genome sizes of these strains are 3.21 to 4.61 Mb, with high G+C content (67.2% to 72.7%) genomic DNA. Genomic data will provide useful baseline information for natural taxonomy and comparative genomics of members of the genus Rathayibacter.

Specimens of a tylenchid nematode were recovered in 2019 from soil samples collected from a corn field, located in Pickens County, South Carolina, USA. A moderate number of Tylenchus sp. adults (females and males) were recovered. Extracted nematodes were examined morphologically and molecularly for species identification, which indicated that the specimens of the tylenchid adults were a new species, described herein as Tylenchus zeae n. sp. Morphological examination and the morphometric details of the specimens were very close to the original descriptions of Tylenchus sherianus and T. rex. However, females of the new species can be differentiated from these species by body shape and length, shape of excretory duct, distance between anterior end and esophageal intestinal valve, and a few other characteristics given in the diagnosis. Males of the new species can be differentiated from the two closely related species by tail, spicules, and gubernaculum length. Cryo-scanning electron microscopy confirmed head bearing five or six annules; four to six cephalic sensilla represented by small pits at the rounded corners of the labial plate; a small, round oral plate; and a large, pit-like amphidial opening confined to the labial plate and extending three to four annules beyond it. Phylogenetic analysis of 18S rRNA gene sequences placed Tylenchus zeae n. sp. in a clade with Tylenchus arcuatus and several Filenchus spp., and the mitochondrial cytochrome oxidase c subunit 1 (COI) gene region separated the new species from T. arcuatus and other tylenchid species. In the 28S tree, T. zeae n. sp. showed a high level of sequence divergence and was positioned outside of the main Tylenchus-Filenchus clade.

The hop cyst nematode, Heterodera humuli, is a pest of hop with the potential to substantially limit yields worldwide. To enable molecular-based diagnostics, a real-time PCR assay for the identification of H. humuli was designed. Polymorphism in the COIII gene fragments was used to design species-specific primers and a TaqMan probe. The specificity of the primer and probe set was tested against different populations of H. humuli and non-target cyst nematodes in multiplex reactions. In multiplex real-time PCR experiments with specific and universal primer and probe sets, fluorescent signals were simultaneously monitored for COIII and D3 of 28S rRNA target genes. Assays with species-specific primers and probe were able to detect DNA extracted from 0.0016 of a H. humuli second-stage juvenile per reaction while showing no reaction with non-target species. [ABSTRACT FROM AUTHOR]

A new nematode species, Bursaphelenchus ussuriensis sp. n. is described in the bark beetle–elm tree association (Scolytus jacobsoni and Ulmus davidiana var. japonica f. suberosa) in the Asian Pacific region of Russia. The new species belongs to the Hofmanni group of Bursaphelenchus and is closest to B. ulmophilus. Its characteristics are as follows: lateral field with three incisures, body length 497–771 µm, post-uterine sac 3.6–5.4 times vulval body diam, 56 (39–66)% of vulva–anus distance, and spicule length 10.3 (9.5–12.5 µm). The new species differs from all species of the Hofmanni group in the closely situated P3 and P4 male caudal papillae and the GP5 small 'glandpapillae' pair on the butterfly-like papillae plate, in the set of P1, P2, P3, P4, GP5; vs. in all other species, the P4 papillae pair is absent in the pattern of P1, P2, P3, GP5. The phylogenetic position of B. ussuriensis sp. n. with other species of the Hofmanni group were reconstructed using the D2–D3 expansion segments of 28S and ITS rRNA gene sequence analysis. Sequences of twelve mitochondrial protein-coding genes of B. cocophilus, B. fraudulentus, B. michalskii, B. ussurensis sp. n., and B. willibaldi were obtained in this study. Phylogenetic relationships among eighteen Bursaphelenchus species based on the analysis of the mtDNA sequence dataset are provided and discussed. A modified diagnosis of the Hofmanni group is proposed. [ABSTRACT FROM AUTHOR]

Draft genome sequences of 11 bacteria belonging to the family Microbacteriaceae were obtained using Illumina technology. The genomes of these strains have sizes from 3.14 to 4.30 Mb with their genomic DNA characterized as having high G+C contents (above 65%). These genomic data will be useful for natural taxonomy and comparative genomic studies of bacterial strains of the family Microbacteriaceae.

Summary: A new species, Ditylenchoides anyae sp. n., recovered from soil in the headland areas of non-cultivated fields in Alborz Province, Iran, is described and illustrated based on its morphological, morphometric, and molecular characters. The new species was characterised by a slender body and length of 784 (663-925) μ m (females) and 667-712 μ m (males), lip region continuous, stylet length 6.4 (6.0-7.0) μ m, lateral fields with four incisures, and excretory pore situated 110 (82-137) μ m from the anterior end, median bulb of pharynx fusiform, non-muscular, and non-valvate, isthmus elongate, slender ending at a pyriform basal pharyngeal bulb not overlapping intestine, vulva with distinct and relatively large lateral flaps, a well-developed post-vulval uterine sac, 31.3 (27-35) μ m long, a female tail elongate-conoid with pointed terminus; and male with adanal bursa and spicules 21-22 μ m long. The new species was characterised using the D2-D3 expansion segments of 28S rRNA, ITS rRNA, and partial 18S rRNA gene sequences. Phylogenetic analyses of the genus Ditylenchoides are given based on the analysis of these genes. [ABSTRACT FROM AUTHOR]

Summary: A new species of the genus Sychnotylenchus Rühm, 1956, S. kulinchi sp. n., inhabiting the bark beetle galleries of Pityogenes chalcographus in Pinus koraiensis was found in the Primorsky Krai of Russia. The new species differs morphologically from the closely related species S. yasinskii and S. mayor in having a shorter body length (626-1030 vs 1250-1280 and 1935-1455 μ m, respectively) and from S. sparnugus in having a greater value of the ratio between spicule length and tail length (0.9-11 vs less than 0.7). Phylogenetic analysis of the partial 18S rRNA, D2-D3 expansion segments of the 28S rRNA, the ITS rRNA and COI gene sequences showed that the Russian S. kulinichi sp. n. population grouped with populations from Israel and an unspecified locality that were identified incorrectly as Ditylenchus forepolitor , which are considered conspecific with S. kulinichi sp. n. in this study. Phylogenetic analyses aiming to clarify the controversial taxonomic status of Neoditylenchus and Sychnotylenchus species indicated that, although the genus Sychnotylenchus was paraphyletic in some phylogenetic trees, testing of alternative topologies for the 18S rRNA, D2-D3 of 28S rRNA and ITS rRNA gene trees and datasets using the maximum likelihood method did not exclude the monophyly of this genus and did not justify the validity of the genus Neoditylenchus , which should be considered a junior synonym of Sychnotylenchus as proposed by Fortuner & Maggenti (1987). Molecular phylogeny showed close relationships of Sychnotylenchus with plant-parasitic nematodes from the genera Ficotylus , Orrina and Pterotylenchus , and also with the insect-associated genus Neomisticius. A polytomous key listing 24 morphological diagnostic characters for the identification of 33 species of Sychnotylenchus is provided, along with a table listing associated bark beetle species. [ABSTRACT FROM AUTHOR]

In 2018 to 2019, soil and root samples from some declining peach orchards were collected in Edgefield County, South Carolina, USA. Excavated roots of Guardian® peach (Prunus persica) rootstock showed strong gall symptoms. Extracted root-knot nematodes (RKN) were identified by both morphological and molecular methods as M. floridensis. This is the first detection of the peach RKN in South Carolina and the third state in the USA after Florida and California.

In August of 2021, several cysts with juveniles and eggs were discovered during a vegetation survey conducted at the Arlington National Cemetery, Virginia. Eight soil samples were collected from the rhizosphere region of the common grass (Festuca arundinacea L.) and processed at the Mycology and Nematology Genetic Diversity and Biology Laboratory (MNGDBL). Cysts were light to dark brown in color, and oval to pear-shaped without bullae in young cysts but present in older cysts and with prominent vulval cone. The juveniles had slightly concave stylet knobs projecting sometimes anteriorly, tail tapering gradually to a narrowly rounded terminus, and hyaline tail terminus conspicuous at least twice the length of stylet. The molecular analysis included the analysis of three gene sequence fragments: D2–D3 of 28S rRNA, ITS rRNA, and COI. The nematode species was identified by both morphological and molecular means as Stone's cyst nematode, Punctodera stonei. Detection of P. stonei in Virginia represents a new record of this species in the United States, and a second report after Canada in North America.

Summary: A new genus and species of anguinid nematode, Cotylenchus cleo gen. n., sp. n., was recovered from leaves of the western sword fern, Polystichum munitum , growing in rainforests in several locations of Olympic National Park, Washington State, USA. This new anguinid nematode induced distinct necrotic and chlorotic symptoms on fern leaves characterised by yellowing, light to brown areas between veins. The new species is characterised by a long and slender body, six incisures in the lateral field, robust stylet (12.0-13.5 μ m) with large and rounded knobs, pyriform to elongate and abutting basal pharyngeal bulb, and long conical tail with pointed terminus; females having posteriorly located vulva (V = 74-80%) and well-developed post-vulval uterine sac (26-59 μ m) and males having spicules 20-23 μ m long. Phylogenetic analysis of the partial 18S rRNA and the D2-D3 expansion segments of the 28S rRNA genes showed that this anguinid nematode formed a separate evolutionary lineage different from all other Anguinidae taxa. The new species was also characterised by sequencing the ITS rRNA and COI genes. [ABSTRACT FROM AUTHOR]

In April-August 2018, samples of galled roots with rhizosphere soil were collected from almond orchards in Atwater, Merced County and Bakersfield, Kern County, California. Almond trees (Prunus dulcis) grafted on ‘Hansen 536’ and ‘Brights Hybrid®5’ (peach-almond hybrid) rootstocks showed strong symptoms of growth decline. Extracted root-knot nematodes were identified by both morphological and molecular methods as M. floridensis. Meloidogyne floridensis was initially found in Florida, USA, and has not been reported from any other states and countries. This is a first report of M. floridensis in California and outside of Florida.

Summary: A new needle nematode species, Longidorus patuxentensis n. sp., was collected along the banks of the Western Branch Patuxent River from Upper Marlboro, MD, USA, and described herein. Female body length of the new species ranges from 3.8 to 5.2 mm, with a set off lip region by depression, 77-92 μ m long odontostyle, 40-53 μ m long odontophore, vulva located at 46.3-50.1% and tail conoid with bluntly rounded tip. The new species has four juvenile developmental stages and no males. It looks morphologically similar to L. breviannulatus , L. elongatus , L. martini , L. americanus , L. grandis , L. sabalanicus and L. sturhani by having a ventrally curved to spiral body, generally similar lip region and conoid tail with a rounded terminus, but differs from these species by the odontostyle, odontophore, total stylet length and a few other characters. Phylogenetic analysis of the D2-D3 expansion segments of 28S rRNA gene sequences placed L. patuxentensis n. sp. in a clade with L. litchi , L. fangi , L. jonesi , L. diadecturus and Longidorus sp. The D2-D3 sequence of L. patuxentensis n. sp. was identical to that of Longidorus sp.5 collected from Juglans sp. growing in Butte County, California, USA. The D2-D3 of 28S and ITS1 rRNA and COI gene sequences indicated that the Maryland and California populations belong to the same species, described herein as L. patuxentensis n. sp. [ABSTRACT FROM AUTHOR]

Summary: Cyst-forming nematodes of the genus Heterodera are highly derived and economically important plant parasites. The Schachtii group of this genus is one of the largest ones with a total of 18 species parasitising dicotyledons. In this study, we provided comprehensive phylogenetic analyses of several hundred COI and ITS rRNA gene sequences of selected species from the Schachtii group, including H. betae , H. cajani , H. ciceri , H. galeopsidis , H. glycines , H. medicaginis , H. mediterranea , H. schachtii , H. sonchophila and H. trifolii , using Bayesian inference, maximum likelihood, and statistical parsimony. One hundred and twenty four new COI , 57 ITS rRNA and eight hsp90 gene sequences from 81 nematode populations collected in 19 countries were obtained in this study. Our study showed that the ITS rRNA gene has limited discrimination power compared to the COI gene. However, our analysis also revealed that partial COI gene sequences were identical for H. trifolii , H. betae and H. galeopsidis. Based on the results of phylogeographical analysis and age estimation of clades with a molecular clock approach, it was hypothesised that the majority of the Schachtii group species originated and diversified in the Mediterranean Basin biodiversity hotspot during the Pleistocene and then dispersed from this region across the world. The Sino-Japanese Floristic Region is likely one of the centres of diversification for the soybean cyst nematode, which showed distinct population structure. The possible role of hybridisation and polyploidisation in the evolution of species of the Schachtii group is discussed. [ABSTRACT FROM AUTHOR]