Pub Date : 2023-11-14DOI: 10.1163/15685411-bja10297
Itani P. Guga, Willem P. Steyn, M. Marais, A. Swart, C. Girgan, A. Mbatyoti, F. N. Mudau, Dirk De Waele, M. Daneel
Bush tea (Athrixia phylicoides) is an aromatic, perennial, leafy shrub that is endemic to the northeastern mountain ranges of South Africa and has a high potential for commercialisation as an alternative to caffeine-containing tea. During the summer and winter of 2018-2019, a survey was carried out at nine localities in the northeastern regions of South Africa to study the diversity of nematodes associated with bush tea and, in terms of frequency of occurrence and abundance, identify the dominant plant-parasitic nematodes. Twenty-one plant-parasitic nematode species belonging to 14 genera were identified in 90 rhizosphere soil and root samples. Meloidogyne and Helicotylenchus were the dominant plant-parasitic nematode genera. Meloidogyne javanica and Scutellonema brachyurus were found at all localities, followed by M. enterolobii, Pratylenchus brachyurus, Rotylenchulus parvus, H. martini and S. truncatum (found at 7-8 localities). Other species identified included Criconema corbetii, C. sphaerocephalus, C. xenoplax, Criconemoides ihlathum, C. parvus, Discocriconemella glabrannulata, H. dihystera, H. erythrinae, H. paraplatyurus, Hemicycliophora typica, M. hapla, M. incognita, Rotylenchulus unisexus and R. clavicaudatus. Individuals of Crossonema, Paratylenchus, Ogma, the Xiphinema americanum-group and X. americanum sensu lato could not be identified to species level due to the low number of specimens present in the samples. Comparison of the two methods used to identify the Meloidogyne populations to species level shows that morphological identification (particularly perineal pattern morphology) provided a more complete picture of the Meloidogyne species present in the samples compared with the molecular SCAR-PCR technique. High levels of Cu, K and pH were associated with the highest relative population densities (RPD% = average population density of a nematode genus/total nematode population density × 100) of Meloidogyne, whilst high levels of Al and soil resistivity were associated with the lowest RPD% of Meloidogyne. By contrast, high levels of K and pH were associated with the lowest RPD% of Helicotylenchus, whilst high levels of Al and soil resistivity were associated with the highest RPD% of Helicotylenchus.
{"title":"Plant-parasitic nematodes associated with bush tea (Athrixia phylicoides) in South Africa and their relationship with physico-chemical soil properties","authors":"Itani P. Guga, Willem P. Steyn, M. Marais, A. Swart, C. Girgan, A. Mbatyoti, F. N. Mudau, Dirk De Waele, M. Daneel","doi":"10.1163/15685411-bja10297","DOIUrl":"https://doi.org/10.1163/15685411-bja10297","url":null,"abstract":"Bush tea (Athrixia phylicoides) is an aromatic, perennial, leafy shrub that is endemic to the northeastern mountain ranges of South Africa and has a high potential for commercialisation as an alternative to caffeine-containing tea. During the summer and winter of 2018-2019, a survey was carried out at nine localities in the northeastern regions of South Africa to study the diversity of nematodes associated with bush tea and, in terms of frequency of occurrence and abundance, identify the dominant plant-parasitic nematodes. Twenty-one plant-parasitic nematode species belonging to 14 genera were identified in 90 rhizosphere soil and root samples. Meloidogyne and Helicotylenchus were the dominant plant-parasitic nematode genera. Meloidogyne javanica and Scutellonema brachyurus were found at all localities, followed by M. enterolobii, Pratylenchus brachyurus, Rotylenchulus parvus, H. martini and S. truncatum (found at 7-8 localities). Other species identified included Criconema corbetii, C. sphaerocephalus, C. xenoplax, Criconemoides ihlathum, C. parvus, Discocriconemella glabrannulata, H. dihystera, H. erythrinae, H. paraplatyurus, Hemicycliophora typica, M. hapla, M. incognita, Rotylenchulus unisexus and R. clavicaudatus. Individuals of Crossonema, Paratylenchus, Ogma, the Xiphinema americanum-group and X. americanum sensu lato could not be identified to species level due to the low number of specimens present in the samples. Comparison of the two methods used to identify the Meloidogyne populations to species level shows that morphological identification (particularly perineal pattern morphology) provided a more complete picture of the Meloidogyne species present in the samples compared with the molecular SCAR-PCR technique. High levels of Cu, K and pH were associated with the highest relative population densities (RPD% = average population density of a nematode genus/total nematode population density × 100) of Meloidogyne, whilst high levels of Al and soil resistivity were associated with the lowest RPD% of Meloidogyne. By contrast, high levels of K and pH were associated with the lowest RPD% of Helicotylenchus, whilst high levels of Al and soil resistivity were associated with the highest RPD% of Helicotylenchus.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":null,"pages":null},"PeriodicalIF":1.2,"publicationDate":"2023-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139277855","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 : 2023-11-08DOI: 10.1163/15685411-bja10296
Mihail R. Kantor, Sergei A. Subbotin, Bill Im, Zafar A. Handoo
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.
{"title":"Morphological and molecular characterisation of Longidorus patuxentensis n. sp. (Nematoda: Longidoridae) from Maryland and California, USA","authors":"Mihail R. Kantor, Sergei A. Subbotin, Bill Im, Zafar A. Handoo","doi":"10.1163/15685411-bja10296","DOIUrl":"https://doi.org/10.1163/15685411-bja10296","url":null,"abstract":"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.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135391843","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}
Summary Accurate measurements of soil nematode communities are important for an in-depth understanding of the ecological functions of soil nematodes. High throughput sequencing (HTS) has been reported extensively, but the concordance between HTS and morphological identification results is still lacking. To compare two methods, we selected bare patches (BP), short-term recovery patches (SP), middle-term recovery patches (MP) and long-term recovery patches (LP) of different restoration succession stages in three sample sites to survey the nematode characteristics. In addition to nematode community structure and community ecological function, common nematode genera in BP, SP, MP and LP were compared by two methods: HTS and morphological identification. The results show that the number of species identified in the morphological analysis was lower than using HTS. The soil nematode diversity in different recovery patches was LP > MP > SP > BP. The indices of Shannon-Wiener, Pielou, Simpson and species number of different recovery patches based on HTS reflected the biodiversity of nematode communities, which was consistent with the results of morphological identification. Of the common nematode genera, Coslenchus , Aphelenchus and Leptonchus showed a significant correlation by the two methods. Although both methods have limitations, the HTS provides a more effective means of observing soil nematode biodiversity levels for rapid insight across recovery patches in degraded alpine meadows of the Yellow River source region in our results.
{"title":"Variability in soil nematode communities across recovery patches in degraded Alpine meadows of the Yellow River source region","authors":"Guorong Chen, Jing Hu, Chengyi Li, Yandi She, Yong Wu, Xilai Li","doi":"10.1163/15685411-bja10293","DOIUrl":"https://doi.org/10.1163/15685411-bja10293","url":null,"abstract":"Summary Accurate measurements of soil nematode communities are important for an in-depth understanding of the ecological functions of soil nematodes. High throughput sequencing (HTS) has been reported extensively, but the concordance between HTS and morphological identification results is still lacking. To compare two methods, we selected bare patches (BP), short-term recovery patches (SP), middle-term recovery patches (MP) and long-term recovery patches (LP) of different restoration succession stages in three sample sites to survey the nematode characteristics. In addition to nematode community structure and community ecological function, common nematode genera in BP, SP, MP and LP were compared by two methods: HTS and morphological identification. The results show that the number of species identified in the morphological analysis was lower than using HTS. The soil nematode diversity in different recovery patches was LP > MP > SP > BP. The indices of Shannon-Wiener, Pielou, Simpson and species number of different recovery patches based on HTS reflected the biodiversity of nematode communities, which was consistent with the results of morphological identification. Of the common nematode genera, Coslenchus , Aphelenchus and Leptonchus showed a significant correlation by the two methods. Although both methods have limitations, the HTS provides a more effective means of observing soil nematode biodiversity levels for rapid insight across recovery patches in degraded alpine meadows of the Yellow River source region in our results.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135680069","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 : 2023-11-06DOI: 10.1163/15685411-bja10290
Jianfeng Gu, Xinxin Ma, Yanchun Liu, Ruihang Cai
Summary Longidorus zhengi n. sp. was recovered in the rhizosphere of Quercus aliena in China. The new species is characterised by medium-length females (3.2-4.0 mm), lip region slightly offset, anteriorly flat and separated from the rest of the body by constriction, funnel-shaped amphidial pouches, a simple guiding ring located at 57.0-60.0 μ m distance from the anterior end, stylet composed of a moderately long odontostyle (108.0-139.0 μ m) and weakly developed odontophore (56.0-68.0 μ m), 61.0-74.0 μ m long pharyngeal bulb, well-developed offset cardia, and a short conical tail with widely rounded terminus. The species has four juvenile developmental stages (J1-J4) and no male was found. The matrix codes of the new species are: A45-B23-C5-D2-E1-F2-G1-H1-I1-J1-K5. The new species was molecularly characterised using ITS1 and 28S D2-D3 rRNA gene sequences. The phylogenetic analyses placed L. zhengi n. sp. with several species described from the mainland of China, which were clustered with L. litchi , L. diadecturus and L. juglans .
{"title":"Description of Longidorus zhengi n. sp. (Nematoda: Longidoridae) from the rhizosphere of Quercus aliena in China","authors":"Jianfeng Gu, Xinxin Ma, Yanchun Liu, Ruihang Cai","doi":"10.1163/15685411-bja10290","DOIUrl":"https://doi.org/10.1163/15685411-bja10290","url":null,"abstract":"Summary Longidorus zhengi n. sp. was recovered in the rhizosphere of Quercus aliena in China. The new species is characterised by medium-length females (3.2-4.0 mm), lip region slightly offset, anteriorly flat and separated from the rest of the body by constriction, funnel-shaped amphidial pouches, a simple guiding ring located at 57.0-60.0 μ m distance from the anterior end, stylet composed of a moderately long odontostyle (108.0-139.0 μ m) and weakly developed odontophore (56.0-68.0 μ m), 61.0-74.0 μ m long pharyngeal bulb, well-developed offset cardia, and a short conical tail with widely rounded terminus. The species has four juvenile developmental stages (J1-J4) and no male was found. The matrix codes of the new species are: A45-B23-C5-D2-E1-F2-G1-H1-I1-J1-K5. The new species was molecularly characterised using ITS1 and 28S D2-D3 rRNA gene sequences. The phylogenetic analyses placed L. zhengi n. sp. with several species described from the mainland of China, which were clustered with L. litchi , L. diadecturus and L. juglans .","PeriodicalId":18928,"journal":{"name":"Nematology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135680078","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 : 2023-11-06DOI: 10.1163/15685411-bja10294
Yuji Oka
Summary A bioassay was developed to characterise the effects of nematicidal compounds and tested using low concentrations (0.125 and 0.25 mg l −1 ) of three nematicides: fluensulfone, fluopyram and fluazaindolizine. Germinating lettuce seeds with ca 2-3 mm roots were planted in a 5.5-cm-diam. Petri dish on agar containing the nematicides. Second-stage juveniles (J2) of Meloidogyne javanica and M. incognita were introduced to the agar plate immediately after planting. Alternatively, lettuce seeds were planted 48 h after introducing J2 to the plate. The number of J2 attracted to a root tip and J2 mobility were recorded 19 h after inoculation or planting, and infection rate and root length were recorded 5 days after planting. The three nematicides showed different effects on J2 of the Meloidogyne species. Fluensulfone did not inhibit infection by either species if the lettuce was planted immediately after inoculation, but their infection rates, and especially those of M. incognita , were reduced when lettuce seeds were planted 2 days later. Fluopyram reduced infection with M. javanica J2 at higher rates (>83.3%) than for M. incognita J2 (<58.4%) compared to the control, even without 48 h exposure before planting. Fluazaindolizine reduced M. incognita infection at high rates (>83.3%), although the J2 were attracted to the lettuce roots. Root lengths also showed differences in infection severity. This assay distinguished the effects of the three nematicides on the two Meloidogyne species and can also serve to screen compounds that inhibit nematode infection without killing Meloidogyne J2.
开发了一种生物测定法来表征杀线虫化合物的效果，并使用低浓度(0.125和0.25 mg l - 1)的三种杀线虫剂进行了测试:氟砜、氟吡仑和氟氮唑嗪。发芽的生菜种子，根约2-3毫米，种植在5.5厘米直径的土壤中。含有杀线虫剂的琼脂培养皿。种植后立即将javanica和M. incognita二期幼体(J2)引入琼脂平板。或者，在将J2引入培养皿后48 h种植生菜种子。接种或播种后19 h记录J2在根尖上的吸附数量和J2的迁移率，播种后5 d记录侵染率和根长。3种杀线虫剂对丝虫病种J2的影响不同。接种后立即播种时，氟砜对两种病原菌的侵染率均无抑制作用，但2天后播种时，两种病原菌的侵染率均有所降低，其中以黑穗病菌的侵染率最高。与对照相比，即使在种植前未暴露48小时，氟吡喃对爪哇菊J2的感染率(83.3%)也高于对不认识菊J2的感染率(58.4%)。虽然J2被莴苣根部吸引，但氟唑嗪对隐殖僵菌的侵染率很高(83.3%)。根长也表现出感染严重程度的差异。该实验区分了三种杀线虫剂对两种旋律线虫的作用，也可以用于筛选抑制线虫感染而不杀死旋律线虫J2的化合物。
{"title":"Bioassay to characterise the effects of nematicidal compounds on Meloidogyne species","authors":"Yuji Oka","doi":"10.1163/15685411-bja10294","DOIUrl":"https://doi.org/10.1163/15685411-bja10294","url":null,"abstract":"Summary A bioassay was developed to characterise the effects of nematicidal compounds and tested using low concentrations (0.125 and 0.25 mg l −1 ) of three nematicides: fluensulfone, fluopyram and fluazaindolizine. Germinating lettuce seeds with ca 2-3 mm roots were planted in a 5.5-cm-diam. Petri dish on agar containing the nematicides. Second-stage juveniles (J2) of Meloidogyne javanica and M. incognita were introduced to the agar plate immediately after planting. Alternatively, lettuce seeds were planted 48 h after introducing J2 to the plate. The number of J2 attracted to a root tip and J2 mobility were recorded 19 h after inoculation or planting, and infection rate and root length were recorded 5 days after planting. The three nematicides showed different effects on J2 of the Meloidogyne species. Fluensulfone did not inhibit infection by either species if the lettuce was planted immediately after inoculation, but their infection rates, and especially those of M. incognita , were reduced when lettuce seeds were planted 2 days later. Fluopyram reduced infection with M. javanica J2 at higher rates (>83.3%) than for M. incognita J2 (<58.4%) compared to the control, even without 48 h exposure before planting. Fluazaindolizine reduced M. incognita infection at high rates (>83.3%), although the J2 were attracted to the lettuce roots. Root lengths also showed differences in infection severity. This assay distinguished the effects of the three nematicides on the two Meloidogyne species and can also serve to screen compounds that inhibit nematode infection without killing Meloidogyne J2.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135680482","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}
Summary Tobriloides sinensis sp. n. is described from Shanxi province, China. It is characterised by relatively long body (1620-1935 m), two subventral teeth posterior to dorsal tooth, a short pharynx (b = 4.2-5.0), cardia three times longer than wide (91-98 μ m long and 30-37 μ m wide), female reproductive system amphidelphic, the vulva situated slightly posterior to mid-body (V = 59.0-69.9), and the tail relatively short (c = 8.4-9.7 and c′ = 4.6-5.7). The phylogenetic relationships of the new species were analysed using data from the near full length small subunit (SSU) and D2-D3 segments of large subunit (LSU) of rRNA genes. The status of T. sinensis sp. n. is discussed based on both morphological and molecular characteristics.
{"title":"Description of Tobriloides sinensis sp. n. (Nematoda: Triplonchida: Tobrilidae) from Shanxi province, north China","authors":"Gurong Yang, Meina Liu, Yibing Ma, Zengqi Zhao, Jianming Wang, Yumei Xu","doi":"10.1163/15685411-bja10289","DOIUrl":"https://doi.org/10.1163/15685411-bja10289","url":null,"abstract":"Summary Tobriloides sinensis sp. n. is described from Shanxi province, China. It is characterised by relatively long body (1620-1935 m), two subventral teeth posterior to dorsal tooth, a short pharynx (b = 4.2-5.0), cardia three times longer than wide (91-98 μ m long and 30-37 μ m wide), female reproductive system amphidelphic, the vulva situated slightly posterior to mid-body (V = 59.0-69.9), and the tail relatively short (c = 8.4-9.7 and c′ = 4.6-5.7). The phylogenetic relationships of the new species were analysed using data from the near full length small subunit (SSU) and D2-D3 segments of large subunit (LSU) of rRNA genes. The status of T. sinensis sp. n. is discussed based on both morphological and molecular characteristics.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135371383","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 : 2023-10-30DOI: 10.1163/15685411-bja10292
Sergei A. Subbotin, Tatiana V. Roubtsova, Richard M. Bostock, Zahra Tanha Maafi, Vladimir N. Chizhov, Juan E. Palomares-Rius, Pablo Castillo
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.
{"title":"DNA barcoding, phylogeny and phylogeography of the cyst nematode species of the Schachtii group from the genus Heterodera (Tylenchida: Heteroderidae)","authors":"Sergei A. Subbotin, Tatiana V. Roubtsova, Richard M. Bostock, Zahra Tanha Maafi, Vladimir N. Chizhov, Juan E. Palomares-Rius, Pablo Castillo","doi":"10.1163/15685411-bja10292","DOIUrl":"https://doi.org/10.1163/15685411-bja10292","url":null,"abstract":"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.","PeriodicalId":18928,"journal":{"name":"Nematology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136105757","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 : 2023-10-30DOI: 10.1163/15685411-bja10278
Murray D. Dunn, Antoinette P. Malan
Summary Optimising the in vitro liquid mass production process for entomopathogenic nematodes (EPN) is a critical step in the development of a cost-effective EPN biopesticide product. Recording the nematode population and growth dynamics in an Erlenmeyer shake flask environment is essential to gaining a better understanding of which factors may influence the final yield. Although infective juvenile (IJ) inoculum concentration has previously been studied, no consensus yet exists as to whether it influences the final yield. This study sought to determine the impact of IJ inoculum concentration and timing on the recovery, growth and yield of the South African EPN isolate of Steinernema yirgalemense in shake flasks. The results indicated that the IJ inoculum concentration positively affects the final IJ yield of 2.88 × 15 5 IJ ml −1 . Moreover, at higher IJ inoculum concentrations, a higher number of reproductive females and males are produced, when recovery percentages were similar. The lowest IJ inoculum concentration treatment was also the only treatment to show signs of an unwanted second generation in the final yield. The IJ inoculation timing trials confirmed that once the bacterium, Xenorhabdus indica , has ended the exponential growth phase and entered the stationary phase, it is ideal to then inoculate the IJ. However, it was found that the S. yirgalemense can be inoculated into the X. indica bacteria solution after 36 h of growth, instead of after 44-48 h. These trials demonstrated the need for further optimisation to produce consistent yields of the highly pathogenic South African EPN isolate of S. yirgalemense .
优化昆虫病原线虫(EPN)体外液体批量生产工艺是开发高性价比的EPN生物农药产品的关键一步。在Erlenmeyer摇瓶环境中记录线虫种群和生长动态对于更好地了解哪些因素可能影响最终产量至关重要。虽然以前研究过感染幼鱼(IJ)的接种浓度，但它是否影响最终产量尚未达成共识。本研究旨在确定IJ接种浓度和时间对摇瓶中南非斯坦纳马yirgalemense EPN分离株的恢复、生长和产量的影响。结果表明，IJ接种量对最终IJ产量的影响为2.88 × 15 5 IJ ml−1。此外，在较高的IJ接种浓度下，在恢复百分比相似的情况下，产生的繁殖雌虫和雄虫数量较多。最低IJ接种浓度处理也是唯一在最终产量中显示不需要的第二代的处理。IJ接种时机试验证实，一旦Xenorhabdus indica细菌的指数生长期结束，进入稳常期，则是理想的接种IJ。然而，研究发现，在生长36小时后，而不是44-48小时后，金黄色葡萄球菌可以接种到印度X.细菌溶液中。这些试验表明，需要进一步优化，以产生高致病性南非金黄色葡萄球菌EPN分离物的一致产量。
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Pub Date : 2023-10-24DOI: 10.1163/15685411-bja10291
Claudia Azpilicueta, Natalia Turuelo, María Estela Kees, Andrea Rodríguez, Carolina Cantalapiedra-Navarrete, Alba N. Ruiz-Cuenca, Juan E. Palomares-Rius
{"title":"First report of the dagger nematode, Xiphinema pachtaicum (Tulaganov, 1938) Kirjanova, 1951 in Argentina","authors":"Claudia Azpilicueta, Natalia Turuelo, María Estela Kees, Andrea Rodríguez, Carolina Cantalapiedra-Navarrete, Alba N. Ruiz-Cuenca, Juan E. Palomares-Rius","doi":"10.1163/15685411-bja10291","DOIUrl":"https://doi.org/10.1163/15685411-bja10291","url":null,"abstract":"","PeriodicalId":18928,"journal":{"name":"Nematology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135322665","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 : 2023-10-23DOI: 10.1163/15685411-bja10288
Emmanuel A. Tzortzakakis
{"title":"Survival of Xiphinema index for six years in stored clay soil from a vineyard","authors":"Emmanuel A. Tzortzakakis","doi":"10.1163/15685411-bja10288","DOIUrl":"https://doi.org/10.1163/15685411-bja10288","url":null,"abstract":"","PeriodicalId":18928,"journal":{"name":"Nematology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135461120","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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