Pub Date : 2023-10-20DOI: 10.1163/15685411-bja10285
Hacer Acan, Ebubekir Yüksel, Nagihan Duman, Atilla Öcal, Dilek Dinçer, Refik Bozbuğa, Şenol Yildiz, Salah-Eddine Laasli, Mohammed Amer, Ramazan Canhilal, Abdelfattah Dababat, Mustafa İmren
Summary Plant-parasitic nematodes are among the most influential soil organisms worldwide and have a detrimental impact on wheat productivity; they also play a major role in maintaining soil diversity. However, limited information is available on the biodiversity of nematodes associated with wheat cropping systems in Turkey. To address this knowledge gap, 45 wheat fields in the Afyonkarahisar Province of Turkey were sampled in 2021 in order to extract and identify nematodes. A total of 14 genera and 44 species of these nematodes were identified based on their physical traits and ITS DNA sequences examination. Shannon diversity index was used to determine the prevalence and biodiversity features of these nematodes. This study represents the first comprehensive research on plant-parasitic nematodes from wheat-growing regions in the Afyonkarahisar Province. The genera Helicotylenchus , Heterodera , Merlinius , Pratylenchoides and Pratylenchus dominated with a high relative abundance percentage >60%, and were extremely common (>90% for each). The average Shannon index of nematode species in the wheat fields was 2.20, with an evenness value of 0.81, indicating moderate diversification and good nematode evenness. This study also revealed a significant correlation between nematode genus biodiversity and edaphic, climatic and geographical factors. Finally, this research demonstrated a remarkable diversity of soil nematodes associated with wheat crops and they have the potential to be useful tools for extensive soil bio-study.
{"title":"Incidence and diversity of plant-parasitic nematodes associated with wheat-cropping systems in the inner part of the Aegean Region of Turkey","authors":"Hacer Acan, Ebubekir Yüksel, Nagihan Duman, Atilla Öcal, Dilek Dinçer, Refik Bozbuğa, Şenol Yildiz, Salah-Eddine Laasli, Mohammed Amer, Ramazan Canhilal, Abdelfattah Dababat, Mustafa İmren","doi":"10.1163/15685411-bja10285","DOIUrl":"https://doi.org/10.1163/15685411-bja10285","url":null,"abstract":"Summary Plant-parasitic nematodes are among the most influential soil organisms worldwide and have a detrimental impact on wheat productivity; they also play a major role in maintaining soil diversity. However, limited information is available on the biodiversity of nematodes associated with wheat cropping systems in Turkey. To address this knowledge gap, 45 wheat fields in the Afyonkarahisar Province of Turkey were sampled in 2021 in order to extract and identify nematodes. A total of 14 genera and 44 species of these nematodes were identified based on their physical traits and ITS DNA sequences examination. Shannon diversity index was used to determine the prevalence and biodiversity features of these nematodes. This study represents the first comprehensive research on plant-parasitic nematodes from wheat-growing regions in the Afyonkarahisar Province. The genera Helicotylenchus , Heterodera , Merlinius , Pratylenchoides and Pratylenchus dominated with a high relative abundance percentage >60%, and were extremely common (>90% for each). The average Shannon index of nematode species in the wheat fields was 2.20, with an evenness value of 0.81, indicating moderate diversification and good nematode evenness. This study also revealed a significant correlation between nematode genus biodiversity and edaphic, climatic and geographical factors. Finally, this research demonstrated a remarkable diversity of soil nematodes associated with wheat crops and they have the potential to be useful tools for extensive soil bio-study.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135616691","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 : 2023-10-20DOI: 10.1163/15685411-bja10287
Chinnasamy Sellaperumal, Santosh J. Eapen, Balakumaran Manimaran, Jeyaveeran Berliner, Selvi B. Senthamizh, Borlakunta Mahendar, Kalidasu Giridhar, Vavilapalli Sivakumar
Summary Turmeric ( Curcuma longa ) is a major spice of Indian origin. Turmeric is commonly used in Ayurvedic and Siddha medicine, and also in Indian cuisine. India produces nearly 1.2 million tonnes (Mt) of turmeric annually and is one of the world’s largest producers. Turmeric production is limited by a number of biotic and abiotic factors. Among the biotic factors, plant-parasitic nematodes (PPN) are important. They include Meloidogyne spp., Pratylenchus spp., Radopholus similis and Rotylenchulus reniformis . However, the information about the distribution, density and prominence of plant-parasitic nematodes and their interrelation with soil types is very scarce. Hence, the present comprehensive nematode survey was undertaken in the major turmeric-producing states of India: Tamil Nadu, Andhra Pradesh, Telangana and Odisha. The results indicated that Meloidogyne spp., R. reniformis , Pratylenchus spp., R. similis , Hoplolaimus spp., Helicotylenchus spp. and Tylenchorhynchus spp. were associated with turmeric. The most abundant nematodes were Meloidogyne spp. (115 individuals (100 cm 3 soil) −1 ), followed by R. reniformis (68 (100 cm 3 soil) −1 ) and Pratylenchus spp. (50 (100 cm 3 soil) −1 ). The frequency of occurrence ranged from 0 to 60%, with Meloidogyne spp. (60%) and R. reniformis (51%) being the most common. Meloidogyne spp. (38%) and Pratylenchus spp. (19%) were the most prominent nematodes in plant samples. Overall, Meloidogyne spp. followed by Pratylenchus spp., R. reniformis and R. similis were the key nematodes associated with the turmeric crop in all the four states. Further, we have identified hotspot areas for the plant-parasitic nematodes, namely: Meloidogyne spp. (16), Pratylenchus spp. (16), R. reniformis (20), and R. similis (5) on the basis of the economic threshold level. The interrelationship of soil type and nematode distribution was also investigated.
姜黄(Curcuma longa)是一种主要的印度香料。姜黄通常用于阿育吠陀和悉达医学，也用于印度美食。印度每年生产近120万吨姜黄，是世界上最大的姜黄生产国之一。姜黄的生产受到许多生物和非生物因素的限制。在生物因子中，植物寄生线虫(PPN)是一个重要的因素。它们包括Meloidogyne、Pratylenchus、Radopholus similis和Rotylenchulus reniformis。然而，关于植物寄生线虫的分布、密度和显著性及其与土壤类型的相互关系的资料非常少。因此，目前的综合线虫调查是在印度主要的姜黄生产邦:泰米尔纳德邦、安得拉邦、特伦甘纳邦和奥里萨邦进行的。结果表明:姜黄与Meloidogyne、reniformis、Pratylenchus、similis、Hoplolaimus、Helicotylenchus和Tylenchorhynchus有亲缘关系。线虫数量最多的是Meloidogyne spp.(115个(100 cm 3土壤)−1)，其次是R. reniformis(68个(100 cm 3土壤)−1)和Pratylenchus spp.(50个(100 cm 3土壤)−1)。发生频率在0 ~ 60%之间，以Meloidogyne spp.(60%)和r.r eniformis(51%)最为常见。在植物样本中最显著的线虫是Meloidogyne spp(38%)和Pratylenchus spp(19%)。总体而言，4个州与姜黄作物相关的关键线虫依次为Meloidogyne spp.、Pratylenchus spp.、reniformis r.s和similis r.s。此外，我们还根据经济阈值水平确定了植物寄生线虫的热点区域，即:Meloidogyne spp.(16)、Pratylenchus spp.(16)、R. reniformis(20)和R. similis(5)。研究了土壤类型与线虫分布的相互关系。
{"title":"Plant-parasitic nematodes, a looming threat to turmeric cultivation in India: results of recent surveys","authors":"Chinnasamy Sellaperumal, Santosh J. Eapen, Balakumaran Manimaran, Jeyaveeran Berliner, Selvi B. Senthamizh, Borlakunta Mahendar, Kalidasu Giridhar, Vavilapalli Sivakumar","doi":"10.1163/15685411-bja10287","DOIUrl":"https://doi.org/10.1163/15685411-bja10287","url":null,"abstract":"Summary Turmeric ( Curcuma longa ) is a major spice of Indian origin. Turmeric is commonly used in Ayurvedic and Siddha medicine, and also in Indian cuisine. India produces nearly 1.2 million tonnes (Mt) of turmeric annually and is one of the world’s largest producers. Turmeric production is limited by a number of biotic and abiotic factors. Among the biotic factors, plant-parasitic nematodes (PPN) are important. They include Meloidogyne spp., Pratylenchus spp., Radopholus similis and Rotylenchulus reniformis . However, the information about the distribution, density and prominence of plant-parasitic nematodes and their interrelation with soil types is very scarce. Hence, the present comprehensive nematode survey was undertaken in the major turmeric-producing states of India: Tamil Nadu, Andhra Pradesh, Telangana and Odisha. The results indicated that Meloidogyne spp., R. reniformis , Pratylenchus spp., R. similis , Hoplolaimus spp., Helicotylenchus spp. and Tylenchorhynchus spp. were associated with turmeric. The most abundant nematodes were Meloidogyne spp. (115 individuals (100 cm 3 soil) −1 ), followed by R. reniformis (68 (100 cm 3 soil) −1 ) and Pratylenchus spp. (50 (100 cm 3 soil) −1 ). The frequency of occurrence ranged from 0 to 60%, with Meloidogyne spp. (60%) and R. reniformis (51%) being the most common. Meloidogyne spp. (38%) and Pratylenchus spp. (19%) were the most prominent nematodes in plant samples. Overall, Meloidogyne spp. followed by Pratylenchus spp., R. reniformis and R. similis were the key nematodes associated with the turmeric crop in all the four states. Further, we have identified hotspot areas for the plant-parasitic nematodes, namely: Meloidogyne spp. (16), Pratylenchus spp. (16), R. reniformis (20), and R. similis (5) on the basis of the economic threshold level. The interrelationship of soil type and nematode distribution was also investigated.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135616702","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 : 2023-10-20DOI: 10.1163/15685411-bja10286
Katsumi Togashi, Hayami Kasuga, Satomi Kasuga, Koji Matsunaga, Shota Jikumaru
Summary The pine wood nematode, Bursaphelenchus xylophilus (Steiner et Buhrer), is the causative agent of pine wilt disease. It is native to North America and has been devastating pine forests in East Asia and West Europe since its introduction. The pathogenic nematode is transmitted by cerambycid beetle adults of Monochamus alternatus Hope in East Asia and M. galloprovincialis (Olivier) in West Europe. Bursaphelenchus mucronatus Mamiya et Enda is widely distributed in Eurasia and has no or little pathogenicity to pine species. If hybrids between the two species are backcrossed with B. xylophilus nematodes repeatedly, a small proportion of B. mucronatus genes will be infused into B. xylophilus genome (introgression) and may lead to adaptation to locally harsh environments. Inoculation tests in this study revealed that two of eight hybrid-derived populations from crossing B. xylophilus and B. mucronatus caused pine seedling mortalities of 36-70%. The pathogenic hybrid-derived populations carried nuclear ribosomal DNA (rDNA) of two species and B. xylophilus extra-nuclear genes, whereas non-pathogenic populations carried B. mucronatus rDNA and extranuclear genes of B. xylophilus or B. mucronatus . Thus, it is inferred that a gene or genes associated with pathogenicity are present in the nuclear genome of B. xylophilus . A laboratory experiment revealed that the pathogenic hybrid-derived population had as great an ability to board M. alternatus adults as the parental-lineage B. xylophilus isolate. Thus, the introgressive hybridisation is considered to occur in pine forests if two species cohabit in host trees.
松材线虫(Bursaphelenchus xylophilus, Steiner et Buhrer)是松材枯萎病的病原。它原产于北美，自引进以来一直破坏东亚和西欧的松林。致病性线虫是由东亚的交替单chamus alternatus Hope的陶粒甲虫成虫和西欧的加洛省单跖虫(Olivier)传播的。巨松病菌(Bursaphelenchus mucronatus Mamiya et Enda)广泛分布于欧亚大陆，对松树没有或只有很小的致病性。如果两种杂交种与嗜木线虫反复回交，一小部分嗜木线虫基因会被注入到嗜木线虫基因组中(渗入)，并可能导致其适应当地恶劣的环境。本研究的接种试验结果表明，在8个由木嗜木霉与巨巨木霉杂交而成的群体中，有2个群体的幼苗死亡率为36 ~ 70%。致病性杂交种群体携带两种病原菌的核糖体DNA (rDNA)和木褐螺旋藻的核外基因，而非致病性杂交种群体携带木褐螺旋藻或木褐螺旋藻的rDNA和核外基因。因此，我们推断，与致病性相关的一个或多个基因存在于嗜木杆菌的核基因组中。室内实验结果表明，该致病杂交种种群与亲本系嗜木耳白僵菌分离株具有同样强的寄主能力。因此，如果两个物种在寄主树上同居，则可以认为在松林中发生了渐渗杂交。
{"title":"Pathogenicity and boarding ability of hybrid-derived populations between Bursaphelenchus xylophilus and B. mucronatus (Nematoda: Aphelenchoididae)","authors":"Katsumi Togashi, Hayami Kasuga, Satomi Kasuga, Koji Matsunaga, Shota Jikumaru","doi":"10.1163/15685411-bja10286","DOIUrl":"https://doi.org/10.1163/15685411-bja10286","url":null,"abstract":"Summary The pine wood nematode, Bursaphelenchus xylophilus (Steiner et Buhrer), is the causative agent of pine wilt disease. It is native to North America and has been devastating pine forests in East Asia and West Europe since its introduction. The pathogenic nematode is transmitted by cerambycid beetle adults of Monochamus alternatus Hope in East Asia and M. galloprovincialis (Olivier) in West Europe. Bursaphelenchus mucronatus Mamiya et Enda is widely distributed in Eurasia and has no or little pathogenicity to pine species. If hybrids between the two species are backcrossed with B. xylophilus nematodes repeatedly, a small proportion of B. mucronatus genes will be infused into B. xylophilus genome (introgression) and may lead to adaptation to locally harsh environments. Inoculation tests in this study revealed that two of eight hybrid-derived populations from crossing B. xylophilus and B. mucronatus caused pine seedling mortalities of 36-70%. The pathogenic hybrid-derived populations carried nuclear ribosomal DNA (rDNA) of two species and B. xylophilus extra-nuclear genes, whereas non-pathogenic populations carried B. mucronatus rDNA and extranuclear genes of B. xylophilus or B. mucronatus . Thus, it is inferred that a gene or genes associated with pathogenicity are present in the nuclear genome of B. xylophilus . A laboratory experiment revealed that the pathogenic hybrid-derived population had as great an ability to board M. alternatus adults as the parental-lineage B. xylophilus isolate. Thus, the introgressive hybridisation is considered to occur in pine forests if two species cohabit in host trees.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135616692","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 : 2023-10-18DOI: 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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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":null,"pages":null},"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}
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