Pub Date : 2023-10-18DOI: 10.1163/15685411-bja10284
Carla L. Ritter, Antoinette P. Malan, Leon M.T. Dicks
Summary The bacterial strain SF857 was isolated from the entomopathogenic nematode, Steinernema bakwenae SF857, found in soil samples of St Lucie cherry, a species of cherry tree, from the Muriti farm, close to Kroondal (25°44′E, 59°99′S) in the northwest province of South Africa. Strain SF857 is Gram-negative, catalase and oxidase-negative, and lecithinase-positive. Strain SF857 shared the highest 16S rRNA gene sequence similarity (97.7%) with the type strain of Xenorhabdus ishibashii . However, a comparison of housekeeping gene sequences showed that strain SF857 grouped closer to X. griffiniae , X. ehlersii and X. thuongxuanensis than to X. ishibashii . Digital DNA-DNA hybridisation (dDDH) between strain SF857 and all Xenorhabdus spp. is less than the 70% species threshold, confirming that the strain belongs to a separate species. Furthermore, the biochemical characteristics of strain SF857 differ from other Xenorhabdus spp. Based on these findings, strain SF857 represents a novel species within the genus Xenorhabdus , for which the name Xenorhabdus bakwenae sp. n. (type strain SF857 T ) is proposed. Pathogenicity bioassays with last-instar Cydia pomonella showed S. bakwenae to be highly virulent, with potential use as a biocontrol agent in apple orchards.
{"title":"Xenorhabdus bakwenae sp. n., associated with the entomopathogenic nematode Steinernema bakwenae","authors":"Carla L. Ritter, Antoinette P. Malan, Leon M.T. Dicks","doi":"10.1163/15685411-bja10284","DOIUrl":"https://doi.org/10.1163/15685411-bja10284","url":null,"abstract":"Summary The bacterial strain SF857 was isolated from the entomopathogenic nematode, Steinernema bakwenae SF857, found in soil samples of St Lucie cherry, a species of cherry tree, from the Muriti farm, close to Kroondal (25°44′E, 59°99′S) in the northwest province of South Africa. Strain SF857 is Gram-negative, catalase and oxidase-negative, and lecithinase-positive. Strain SF857 shared the highest 16S rRNA gene sequence similarity (97.7%) with the type strain of Xenorhabdus ishibashii . However, a comparison of housekeeping gene sequences showed that strain SF857 grouped closer to X. griffiniae , X. ehlersii and X. thuongxuanensis than to X. ishibashii . Digital DNA-DNA hybridisation (dDDH) between strain SF857 and all Xenorhabdus spp. is less than the 70% species threshold, confirming that the strain belongs to a separate species. Furthermore, the biochemical characteristics of strain SF857 differ from other Xenorhabdus spp. Based on these findings, strain SF857 represents a novel species within the genus Xenorhabdus , for which the name Xenorhabdus bakwenae sp. n. (type strain SF857 T ) is proposed. Pathogenicity bioassays with last-instar Cydia pomonella showed S. bakwenae to be highly virulent, with potential use as a biocontrol agent in apple orchards.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":"21 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135942874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-05DOI: 10.1163/15685411-bja10282
N. Kanzaki, Yousuke Degawa
An undescribed Sachsia species (Diplogastridae) was isolated from a dung beetle, Onthophagus sp. cf. atripennis, and the species is described here as Sachsia putridicola n. sp. The new species is characterised by its cheilostom; anterior part forming a cuticular ring, posterior part in the form of a thin-walled tube; an anisotopic gymnostom, a metastegostom with dorsal small tooth and no subventral armature, and setiform male genital papillae with the arrangement . Sachsia putridicola n. sp. is typologically similar to two previously described congeners, Sachsia zurstrasseni and Sachsia postpapillata, but can be readily distinguished by its anisotopic gymnostom (vs isotopic gymnostom in the two nominal species) and the direction of the anterior three pairs of genital papillae, which are directed sublaterally in the new species (vs second or third pair directed sublaterally in S. zurstrasseni and S. postpapillata, respectively). Phylogenetically, the new species is close to Eudiplogasterium evidentum, not S. zurstrasseni. Based on the typological and phylogenetic characters, the status of S. zurstrasseni is discussed.
从一种蜣螂 Onthophagus sp.该新种的特征是：螯足；前部形成一个角质环，后部呈薄壁管状；异色的体螯，背侧有小齿而腹下无纟的元螯，以及排列成......的刚毛状雄性生殖器乳头。Sachsia putridicola n. sp.在类型学上与之前描述的两个同属种 Sachsia zurstrasseni 和 Sachsia postpapillata 相似，但很容易通过其异位体节（与这两个标称种的异位体节相比）和前三对生殖器乳头的方向进行区分，新种的生殖器乳头朝向近侧（与 S. zurstrasseni 和 S. postpapillata 分别朝向近侧的第二或第三对生殖器乳头相比）。在系统发育上，新种接近于 Eudiplogasterium evidentum，而不是 S. zurstrasseni。根据类型学和系统发育特征，讨论了 S. zurstrasseni 的地位。
{"title":"Sachsia putridicola n. sp. (Rhabditida: Diplogastridae), isolated from an Onthophagus dung beetle (Coleoptera: Scarabaeidae) from Tsukuba, Japan","authors":"N. Kanzaki, Yousuke Degawa","doi":"10.1163/15685411-bja10282","DOIUrl":"https://doi.org/10.1163/15685411-bja10282","url":null,"abstract":"An undescribed Sachsia species (Diplogastridae) was isolated from a dung beetle, Onthophagus sp. cf. atripennis, and the species is described here as Sachsia putridicola n. sp. The new species is characterised by its cheilostom; anterior part forming a cuticular ring, posterior part in the form of a thin-walled tube; an anisotopic gymnostom, a metastegostom with dorsal small tooth and no subventral armature, and setiform male genital papillae with the arrangement . Sachsia putridicola n. sp. is typologically similar to two previously described congeners, Sachsia zurstrasseni and Sachsia postpapillata, but can be readily distinguished by its anisotopic gymnostom (vs isotopic gymnostom in the two nominal species) and the direction of the anterior three pairs of genital papillae, which are directed sublaterally in the new species (vs second or third pair directed sublaterally in S. zurstrasseni and S. postpapillata, respectively). Phylogenetically, the new species is close to Eudiplogasterium evidentum, not S. zurstrasseni. Based on the typological and phylogenetic characters, the status of S. zurstrasseni is discussed.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":"14 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139323218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-05DOI: 10.1163/15685411-bja10283
B. Waweru, Njira Njira Pili, Wim M.L. Wesemael, Cecilia Wanjau, M. G. Teklu, G. Gheysen
Finger millet (Eleusine coracana) is a staple crop for subsistence farmers and is primarily cultivated in arid and semi-arid regions. Nevertheless, there are limited data available on the occurrence of plant-parasitic nematodes that specifically target finger millet, and the damage arising from such infections. In this study, we investigated the population dynamics, damage threshold and tolerance of the lesion nematode, Pratylenchus n. sp., and the root-knot nematode, Meloidogyne javanica, on finger millet ‘P-224’. We used 11 initial population densities (Pi) of second-stage juveniles (J2): 0, 0.125, 0.25, 0.5, 1, 2, 4, 8, 16, 32 and 64 J2 (g soil)−1 for M. javanica and the same densities of mixed life-stages for Pratylenchus n. sp. The logistic growth model, Seinhorst yield loss and population dynamic models were fitted to the shoot height, plant biomass and final nematode population density. Based on the population dynamics model parameters, maximum multiplication rates and maximum population densities for each nematode species were estimated. The maximum multiplication rates (a) were 32.39 and 17.46, whilst the maximum population densities (M) were 18.83 nematodes (g soil)−1 and 19.78 J2 (g soil)−1 for Pratylenchus n. sp. and M. javanica respectively. The maximum height reached (C) was negatively affected by increasing Pi for both nematode genera, while the rate of growth (B) and the time to reach was not affected based on the logistic model. A tolerance limit (T) of 1.70 nematodes (g soil)−1 and 0.65 J2 (g soil)−1; relative minimum grain yield (m) of 0.23 and 0.40 for Pratylenchus n. sp. and M. javanica was found, respectively. The results indicate that ‘P-224’ is a good host for both Pratylenchus n. sp. and M. javanica, which significantly reduce yield. These findings can be used as a base to develop effective nematode management strategies for finger millet.
黍（Eleusine coracana）是农民自给自足的主要作物，主要在干旱和半干旱地区种植。然而，关于专门针对粟的植物寄生线虫的发生以及此类感染造成的损害的数据却很有限。在这项研究中，我们调查了病害线虫 Pratylenchus n. sp.和根结线虫 Meloidogyne javanica 在 "P-224 "指天粟上的种群动态、危害阈值和耐受性。我们使用了 11 种第二阶段幼虫（J2）的初始种群密度（Pi）：我们使用了 11 个初始种群密度（Pi）：0、0.125、0.25、0.5、1、2、4、8、16、32 和 64 J2 (g soil)-1（针对 M. javanica）和相同密度的混合生活阶段（针对 Pratylenchus n. sp.）。根据种群动态模型参数，估算出了每种线虫的最大繁殖率和最大种群密度。Pratylenchus n. sp. 和 M. javanica 的最大繁殖率（a）分别为 32.39 和 17.46，最大种群密度（M）分别为 18.83 线虫（克土壤）-1 和 19.78 J2（克土壤）-1。对于这两种线虫属来说，Pi 的增加会对达到的最大高度（C）产生负面影响，而根据 logistic 模型，生长速度（B）和达到最大高度的时间则不受影响。对 Pratylenchus n. sp.和 M. javanica 的耐受极限（T）分别为 1.70 线虫（克土壤）-1 和 0.65 J2（克土壤）-1；相对最低谷物产量（m）分别为 0.23 和 0.40。结果表明，'P-224'是 Pratylenchus n. sp.这些发现可作为制定有效的粟线虫管理策略的基础。
{"title":"Population dynamics and damage threshold of Pratylenchus n. sp. and Meloidogyne javanica on finger millet","authors":"B. Waweru, Njira Njira Pili, Wim M.L. Wesemael, Cecilia Wanjau, M. G. Teklu, G. Gheysen","doi":"10.1163/15685411-bja10283","DOIUrl":"https://doi.org/10.1163/15685411-bja10283","url":null,"abstract":"Finger millet (Eleusine coracana) is a staple crop for subsistence farmers and is primarily cultivated in arid and semi-arid regions. Nevertheless, there are limited data available on the occurrence of plant-parasitic nematodes that specifically target finger millet, and the damage arising from such infections. In this study, we investigated the population dynamics, damage threshold and tolerance of the lesion nematode, Pratylenchus n. sp., and the root-knot nematode, Meloidogyne javanica, on finger millet ‘P-224’. We used 11 initial population densities (Pi) of second-stage juveniles (J2): 0, 0.125, 0.25, 0.5, 1, 2, 4, 8, 16, 32 and 64 J2 (g soil)−1 for M. javanica and the same densities of mixed life-stages for Pratylenchus n. sp. The logistic growth model, Seinhorst yield loss and population dynamic models were fitted to the shoot height, plant biomass and final nematode population density. Based on the population dynamics model parameters, maximum multiplication rates and maximum population densities for each nematode species were estimated. The maximum multiplication rates (a) were 32.39 and 17.46, whilst the maximum population densities (M) were 18.83 nematodes (g soil)−1 and 19.78 J2 (g soil)−1 for Pratylenchus n. sp. and M. javanica respectively. The maximum height reached (C) was negatively affected by increasing Pi for both nematode genera, while the rate of growth (B) and the time to reach was not affected based on the logistic model. A tolerance limit (T) of 1.70 nematodes (g soil)−1 and 0.65 J2 (g soil)−1; relative minimum grain yield (m) of 0.23 and 0.40 for Pratylenchus n. sp. and M. javanica was found, respectively. The results indicate that ‘P-224’ is a good host for both Pratylenchus n. sp. and M. javanica, which significantly reduce yield. These findings can be used as a base to develop effective nematode management strategies for finger millet.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":"22 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139323009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-29DOI: 10.1163/15685411-bja10281
Mankanwal Goraya, Guiping Yan, Addison Plaisance, Zafar A. Handoo
Summary Plant-parasitic nematodes limit potato production by feeding on roots, reducing tuber yield and quality, and resulting in poor growth. Dagger nematodes ( Xiphinema spp.) can pose a significant threat to crop production even in low numbers. Dagger nematodes have been reported in North Dakota, USA, potato fields. In this study, a dagger nematode species was identified and its reproduction potential in 21 potato cultivars was evaluated. The dagger nematode was identified as X. americanum via morphometric measurements and DNA sequence analysis. At the molecular level, D2-D3 of 28S ribosomal RNA (rRNA) and internal transcribed spacer (ITS)-regions of rDNA were targeted. Sequencing data of D2-D3 (749 bp) showed 98.18% similarity with three isolates of X. americanum . ITS sequence (860 bp) analysis showed 97.68% similarity with an isolate of X. americanum but lower similarity with other species of Xiphinema . The phylogenetic analysis of ITS region further confirmed the species of dagger nematode as X. americanum . Using naturally infested soil, two glasshouse experiments were conducted to assess the reproduction rate of X. americanum on 21 potato cultivars belonging to four distinct market potato classes (yellow, red, white and russet). The reproduction rates were found to vary among the potato classes and cultivars. Numerically, X. americanum population density was higher in ‘Soraya’, whereas ‘Ranger Russet’, ‘Manistee’, ‘Kennebec’, ‘Russet Norkotah 278’, ‘Modoc’, ‘Pomerelle Russet’ and ‘Dakota Rose’ reduced nematode reproduction in both trials. This is the first study demonstrating the reproduction of X. americanum in potato cultivars and could be helpful to manage dagger nematodes.
{"title":"Identification and reproduction of dagger nematode, Xiphinema americanum, in potato","authors":"Mankanwal Goraya, Guiping Yan, Addison Plaisance, Zafar A. Handoo","doi":"10.1163/15685411-bja10281","DOIUrl":"https://doi.org/10.1163/15685411-bja10281","url":null,"abstract":"Summary Plant-parasitic nematodes limit potato production by feeding on roots, reducing tuber yield and quality, and resulting in poor growth. Dagger nematodes ( Xiphinema spp.) can pose a significant threat to crop production even in low numbers. Dagger nematodes have been reported in North Dakota, USA, potato fields. In this study, a dagger nematode species was identified and its reproduction potential in 21 potato cultivars was evaluated. The dagger nematode was identified as X. americanum via morphometric measurements and DNA sequence analysis. At the molecular level, D2-D3 of 28S ribosomal RNA (rRNA) and internal transcribed spacer (ITS)-regions of rDNA were targeted. Sequencing data of D2-D3 (749 bp) showed 98.18% similarity with three isolates of X. americanum . ITS sequence (860 bp) analysis showed 97.68% similarity with an isolate of X. americanum but lower similarity with other species of Xiphinema . The phylogenetic analysis of ITS region further confirmed the species of dagger nematode as X. americanum . Using naturally infested soil, two glasshouse experiments were conducted to assess the reproduction rate of X. americanum on 21 potato cultivars belonging to four distinct market potato classes (yellow, red, white and russet). The reproduction rates were found to vary among the potato classes and cultivars. Numerically, X. americanum population density was higher in ‘Soraya’, whereas ‘Ranger Russet’, ‘Manistee’, ‘Kennebec’, ‘Russet Norkotah 278’, ‘Modoc’, ‘Pomerelle Russet’ and ‘Dakota Rose’ reduced nematode reproduction in both trials. This is the first study demonstrating the reproduction of X. americanum in potato cultivars and could be helpful to manage dagger nematodes.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135247451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-28DOI: 10.1163/15685411-bja10279
Julia K. Zograf, Kseniya V. Efimova, Yulia A. Trebukhova, Olga N. Pavlyuk
Summary The family Oncholaimidae comprises ca 350 species of widespread nematodes. They are common in the seas and oceans and are also found in freshwater lakes and rivers. Here we provide the first description of Metoncholaimus species from the South China Sea. Metoncholaimus placatus sp. n. is characterised by the spicules 2.2-2.8 anal body diam. long, gubernaculum small, nearly parallel to the spicules, S-curved. Supplementary organ is composed of transversely elongated prominence with two sensillar structures (receptors). A pictorial key to the species level of Metoncholaimus species is provided. In this study, the D2-D3 domain of the LSU rDNA and the nearly full-length SSU rDNA were selected as targets for species identification. Phylogenetic relationships within the family Oncholaimidae remained unresolved despite of the various sequences analysed in different loci.
{"title":"Revision of the genus Metoncholaimus (Nematoda: Enoplida) with description of new species from the South China Sea","authors":"Julia K. Zograf, Kseniya V. Efimova, Yulia A. Trebukhova, Olga N. Pavlyuk","doi":"10.1163/15685411-bja10279","DOIUrl":"https://doi.org/10.1163/15685411-bja10279","url":null,"abstract":"Summary The family Oncholaimidae comprises ca 350 species of widespread nematodes. They are common in the seas and oceans and are also found in freshwater lakes and rivers. Here we provide the first description of Metoncholaimus species from the South China Sea. Metoncholaimus placatus sp. n. is characterised by the spicules 2.2-2.8 anal body diam. long, gubernaculum small, nearly parallel to the spicules, S-curved. Supplementary organ is composed of transversely elongated prominence with two sensillar structures (receptors). A pictorial key to the species level of Metoncholaimus species is provided. In this study, the D2-D3 domain of the LSU rDNA and the nearly full-length SSU rDNA were selected as targets for species identification. Phylogenetic relationships within the family Oncholaimidae remained unresolved despite of the various sequences analysed in different loci.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135425538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-31DOI: 10.1163/15685411-bja10280
Qing Yu, J. Gu, W. Ye
Deladenus taedae n. sp. was isolated from loblolly pine wood (Pinus taeda) intercepted in Ningbo, P.R. China, in imports from the USA. This new species is morphologically described and illustrated and characterised molecularly. Both mycetophagous and infective forms were recovered and described. The new species, D. taedae n. sp., resembles some other species of Deladenus in which the excretory pore is situated anterior to the hemizonid. The new species is characterised by the lateral fields with six lines, pointed tail ending and small spermatheca in mycetophagous females and short stylet in infective females. In mycetophagous females, the excretory pore is 74-98 μm from the anterior end and 37-54 μm anterior to the hemizonid. The partial rDNA 18S, complete internal transcribed spacer, 5.8S and partial 28S D2/D3 genes were amplified and sequenced. Phylogenetic analyses of the genes distinguished this new species from all other sequenced Deladenus species.
从宁波从美国进口火炬松(Pinus taeda)中分离得到一株火炬松Deladenus taedae n. sp。对这一新物种进行了形态学描述、图解和分子表征。食用菌和感染菌均有发现和描述。这个新种，D. taedae n. sp.，类似于一些其他种类的Deladenus，排泄孔位于半裂口的前部。新种的特点是:食菌雌虫的侧场有6条线，尾尖，精囊小，感染雌虫的花柱短。在食菌雌虫中，排泄孔位于前端74 ~ 98 μm和半裂体前端37 ~ 54 μm。扩增部分rDNA 18S、完整内转录间隔段、5.8S和部分28S D2/D3基因并测序。基因的系统发育分析将该新种与所有其他测序的Deladenus物种区分开来。
{"title":"Deladenus taedae n. sp. (Nematoda: Neotylenchidae) in Loblolly pine (Pinus taeda) woods from USA intercepted in Ningbo, P.R. China","authors":"Qing Yu, J. Gu, W. Ye","doi":"10.1163/15685411-bja10280","DOIUrl":"https://doi.org/10.1163/15685411-bja10280","url":null,"abstract":"\u0000Deladenus taedae n. sp. was isolated from loblolly pine wood (Pinus taeda) intercepted in Ningbo, P.R. China, in imports from the USA. This new species is morphologically described and illustrated and characterised molecularly. Both mycetophagous and infective forms were recovered and described. The new species, D. taedae n. sp., resembles some other species of Deladenus in which the excretory pore is situated anterior to the hemizonid. The new species is characterised by the lateral fields with six lines, pointed tail ending and small spermatheca in mycetophagous females and short stylet in infective females. In mycetophagous females, the excretory pore is 74-98 μm from the anterior end and 37-54 μm anterior to the hemizonid. The partial rDNA 18S, complete internal transcribed spacer, 5.8S and partial 28S D2/D3 genes were amplified and sequenced. Phylogenetic analyses of the genes distinguished this new species from all other sequenced Deladenus species.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44134694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-30DOI: 10.1163/15685411-bja10277
A. Čerevková, Michaela Jakubcsiková, L. Demková, M. Renčo
Soil nematode communities are one of the most used bioindicators for assessing soil health and soil conditions. However, they are dependent on the presence of plants, some of which, known as ‘invasive’, affect local biodiversity when established. This study aimed to compare the communities of soil nematodes in riverbanks non-invaded and invaded by Fallopia japonica at three sites characterised by different environmental conditions. Our findings indicated that the ecosystem had a larger impact on the nematode communities than did the environmental variability at the study sites. Soil properties, such as pH, moisture content and organic-carbon content, differed significantly amongst the sites, but the nematode communities remained similar. Organic-carbon content was lower, and soil pH was higher, in the ecosystem with invasive F. japonica. Total nematode abundance, the abundances of fungivores, herbivores, omnivores and predators, and the maturity indices were significantly lower with invasive F. japonica. Fungivorous nematodes are essential for breaking down organic matter and releasing nutrients. Herbivorous nematodes respond to changes in the vegetation, and omnivorous and predatory nematodes contribute to the overall biodiversity and ecological balance in the soil ecosystem, so their lower abundance suggests a disturbance in the soil food web. The lower maturity indices suggested a disturbance or degradation of the soil ecosystem, which could have secondary negative effects on plant growth, nutrient availability and ecosystem resilience. These findings indicate that invasion both decreased the abundance of important soil organisms and disrupted the cycling of nutrients, potentially leading to long-term negative consequences for the invaded ecosystems. Understanding and managing the effects of invasive plants such as F. japonica are crucial for preserving soil health and promoting sustainable ecosystem functioning.
{"title":"Soil nematode communities in riverbanks non-invaded and invaded by Fallopia japonica across diverse environmental conditions","authors":"A. Čerevková, Michaela Jakubcsiková, L. Demková, M. Renčo","doi":"10.1163/15685411-bja10277","DOIUrl":"https://doi.org/10.1163/15685411-bja10277","url":null,"abstract":"\u0000Soil nematode communities are one of the most used bioindicators for assessing soil health and soil conditions. However, they are dependent on the presence of plants, some of which, known as ‘invasive’, affect local biodiversity when established. This study aimed to compare the communities of soil nematodes in riverbanks non-invaded and invaded by Fallopia japonica at three sites characterised by different environmental conditions. Our findings indicated that the ecosystem had a larger impact on the nematode communities than did the environmental variability at the study sites. Soil properties, such as pH, moisture content and organic-carbon content, differed significantly amongst the sites, but the nematode communities remained similar. Organic-carbon content was lower, and soil pH was higher, in the ecosystem with invasive F. japonica. Total nematode abundance, the abundances of fungivores, herbivores, omnivores and predators, and the maturity indices were significantly lower with invasive F. japonica. Fungivorous nematodes are essential for breaking down organic matter and releasing nutrients. Herbivorous nematodes respond to changes in the vegetation, and omnivorous and predatory nematodes contribute to the overall biodiversity and ecological balance in the soil ecosystem, so their lower abundance suggests a disturbance in the soil food web. The lower maturity indices suggested a disturbance or degradation of the soil ecosystem, which could have secondary negative effects on plant growth, nutrient availability and ecosystem resilience. These findings indicate that invasion both decreased the abundance of important soil organisms and disrupted the cycling of nutrients, potentially leading to long-term negative consequences for the invaded ecosystems. Understanding and managing the effects of invasive plants such as F. japonica are crucial for preserving soil health and promoting sustainable ecosystem functioning.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41810496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-25DOI: 10.1163/15685411-bja10275
V. V. Yushin, M. Claeys, W. Bert
This paper presents the first comprehensive detailed transmission electron microscope observations of sperm development and structure of a plectid nematode. Sperm development of Anaplectus granulosus resembles that of nematodes of the order Rhabditida, known as the rhabditid pattern of spermatogenesis. It includes formation of complexes of fibrous bodies (FB) with membranous organelles (MO), which appear in spermatocytes; the complexes dissociate in the spermatids. The mature spermatozoa are bipolar cells subdivided into a pseudopod and a main cell body containing a nucleus with nine singlet centrioles, peripheral mitochondria and MOs. However, the development and structure of sperm in A. granulosus deviates remarkably from the common rhabditid pattern by an unusual early transformation of FBs into large amorphous masses in the spermatids; the subsequent formation of a concentric structure of immature spermatozoa with a predominant amorphous mass around the central nucleus and thin peripheral cytoplasm with organelles (MOs and mitochondria); and by the transformation of MO in mature spermatozoa into simple cisterns. Thus, the pattern of spermatogenesis of A. granulosus supports the close relations of Plectida and Rhabditida, but specific peculiarities of the sperm development delineate Plectida from Rhabditida and other orders.
{"title":"New pattern of nematode spermatogenesis revealed by ultrastructural observation of Anaplectus granulosus (Plectidae, Plectida)","authors":"V. V. Yushin, M. Claeys, W. Bert","doi":"10.1163/15685411-bja10275","DOIUrl":"https://doi.org/10.1163/15685411-bja10275","url":null,"abstract":"\u0000This paper presents the first comprehensive detailed transmission electron microscope observations of sperm development and structure of a plectid nematode. Sperm development of Anaplectus granulosus resembles that of nematodes of the order Rhabditida, known as the rhabditid pattern of spermatogenesis. It includes formation of complexes of fibrous bodies (FB) with membranous organelles (MO), which appear in spermatocytes; the complexes dissociate in the spermatids. The mature spermatozoa are bipolar cells subdivided into a pseudopod and a main cell body containing a nucleus with nine singlet centrioles, peripheral mitochondria and MOs. However, the development and structure of sperm in A. granulosus deviates remarkably from the common rhabditid pattern by an unusual early transformation of FBs into large amorphous masses in the spermatids; the subsequent formation of a concentric structure of immature spermatozoa with a predominant amorphous mass around the central nucleus and thin peripheral cytoplasm with organelles (MOs and mitochondria); and by the transformation of MO in mature spermatozoa into simple cisterns. Thus, the pattern of spermatogenesis of A. granulosus supports the close relations of Plectida and Rhabditida, but specific peculiarities of the sperm development delineate Plectida from Rhabditida and other orders.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43158670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-25DOI: 10.1163/15685411-bja10276
Kazuki Tadamura, Dai Mori, A. Torada, T. Yoshiga
{"title":"Ecto- and endo-parasitism of Ditylenchus destructor on garlic roots","authors":"Kazuki Tadamura, Dai Mori, A. Torada, T. Yoshiga","doi":"10.1163/15685411-bja10276","DOIUrl":"https://doi.org/10.1163/15685411-bja10276","url":null,"abstract":"","PeriodicalId":18928,"journal":{"name":"Nematology","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48469839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-21DOI: 10.1163/15685411-bja10274
Fang Yang, Jialian Xie, Mei Zhang, Hanlin Wu, Yun-liang Peng, H. Ji
Aphelenchoides besseyi is among the most devastating plant-parasitic nematodes and causes severe loss, mainly on japonica rice in China. Recently the nematode has been found to be present in the seeds of indica rice and the hybrid rice cultivars also show symptoms of the nematode damage. To understand the variations in different rice cultivars against A. besseyi, the dynamics of nematode population, the incidence of symptoms and the effects on plant yield were investigated in field experiments during 2017-2018 by inoculation of mixed stages of A. besseyi onto the seeds and seedlings of different types of rice cultivars. The results showed few nematodes could be recovered from the plants at the seedling and the end of tillering stages in all the cultivars. After flowering, the number of nematodes per panicle increased and the highest number was found in ‘Zheyou 18’ in 2017 (1050.2) and 2018 (732.1). The average incidence of the inoculated plants showing white-tip symptoms ranged from 0.5 to 10.3% and from 0.0 to 75.7% at the tillering stage in 2017 and 2018, respectively. The incidences of white-tip symptoms in the indica cultivars, including ‘9311’, ‘Minghui 63’ and ‘Nei 5 you 39’, were significantly lower than in ‘Xingxiang’, a japonica cultivar and ‘Zheyou 18’, a hybrid rice cultivar, both at the flowering stage in 2017 and at the end of the tillering stage in 2018. A strong interaction of the treatments and cultivars on the 1000-grain weight and panicle length was evident.
{"title":"Dynamics of Aphelenchoides besseyi in different rice cultivars","authors":"Fang Yang, Jialian Xie, Mei Zhang, Hanlin Wu, Yun-liang Peng, H. Ji","doi":"10.1163/15685411-bja10274","DOIUrl":"https://doi.org/10.1163/15685411-bja10274","url":null,"abstract":"\u0000Aphelenchoides besseyi is among the most devastating plant-parasitic nematodes and causes severe loss, mainly on japonica rice in China. Recently the nematode has been found to be present in the seeds of indica rice and the hybrid rice cultivars also show symptoms of the nematode damage. To understand the variations in different rice cultivars against A. besseyi, the dynamics of nematode population, the incidence of symptoms and the effects on plant yield were investigated in field experiments during 2017-2018 by inoculation of mixed stages of A. besseyi onto the seeds and seedlings of different types of rice cultivars. The results showed few nematodes could be recovered from the plants at the seedling and the end of tillering stages in all the cultivars. After flowering, the number of nematodes per panicle increased and the highest number was found in ‘Zheyou 18’ in 2017 (1050.2) and 2018 (732.1). The average incidence of the inoculated plants showing white-tip symptoms ranged from 0.5 to 10.3% and from 0.0 to 75.7% at the tillering stage in 2017 and 2018, respectively. The incidences of white-tip symptoms in the indica cultivars, including ‘9311’, ‘Minghui 63’ and ‘Nei 5 you 39’, were significantly lower than in ‘Xingxiang’, a japonica cultivar and ‘Zheyou 18’, a hybrid rice cultivar, both at the flowering stage in 2017 and at the end of the tillering stage in 2018. A strong interaction of the treatments and cultivars on the 1000-grain weight and panicle length was evident.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64643753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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