Clover Cyst Nematode Research Articles

Screening for resistance of Brassicaceae plant resources to clover cyst nematode

Screening for resistance of Brassicaceae plant resources to clover cyst nematode

Efficacy of a Soil Disinfection Machine for Fumigants to Clover Cyst Nematode

Clover cyst nematode, Heterodera trifolii, is one of the most important plant-parasitic nematode on Kimchicabbage in highland in Korea. Recently, a demand of soil disinfection machine for fumigants is increasing. This study was conducted to assess the control effects of a newly developed prototype soil disinfection machine to the cyst nematode. Two fumigants, dimethyl disulfide (DMDS) and metam sodium (MNa), were treated using the machine in a field, which was infected with the cyst nematode. After 4 weeks, control effects of fumigants were assessed as eggs hatching rates inside of cysts extracted from the soil, and as a number of females reproduced in roots of Kimchi-cabbage. DMDS (39 l/10 a) suppressed over 99.0% of the eggs hatching rate and the number of females reproduced. On the other hand, MNa (29 l/10 a) controlled the egg hatching rates from minimum 78.3% to maximum 99.4%, and the number of females from 34.7% to 49.3%. The control effects of two fumigants to clover cyst nematode by treated depth were no significant differences statistically. These results showed that DMDS treatment using the soil disinfection machine was expected to have the control effects for the clover cyst nematode.

DNA barcoding evidence for the North American presence of alfalfa cyst nematode, Heterodera medicaginis.

Specimens of Heterodera have been collected from alfalfa fields in Kearny County, Kansas & Carbon County, Montana. DNA barcoding with the COI mitochondrial gene indicate that the species is not Heterodera glycines, soybean cyst nematode, H. schachtii, sugar beet cyst nematode, or H. trifolii, clover cyst nematode. Maximum likelihood phylogenetic trees show that the alfalfa specimens form a sister clade most closely related to H. glycines, with a 4.7% mean pairwise sequence divergence across the 862 nucleotides of the COI marker. Morphological analyses of juveniles and cysts conform to the measurements of H. medicaginis, the alfalfa cyst nematode originally described from the USSR in 1971. Initial host testing demonstrated that the nematode reproduced on alfalfa, but not on soybeans, tomato, or corn. Collectively, the evidence suggests that this finding represents the first record of H. medicaginis in North America. Definitive confirmation of this diagnosis would require COI sequence of eastern European isolates of this species.

Spatial distribution of Heterodera trifolii in Chinese cabbage fields

Abstract Although Heterodera trifolii is commonly known as the clover cyst nematode, recently the nematode has been identified as a serious menace for Chinese cabbage growers in highland areas in Korea. Soil samples were collected from two Chinese cabbage fields highly infested with H. trifolii in highland areas of Korea, Jungsun and Samcheok, in 2014 and 2015, respectively. A total of 777 (2 × 2 m sampling area) and 414 (5 × 5 m area) soil samples were collected from Jungsun and Samcheok, respectively. The total cysts, cysts with eggs, number of eggs, and empty cysts were calculated for each sample. Distribution patterns for these variables were characterized using spatial analysis by distance indices (SADIE) and variogram model analysis. The aggregation index for cysts with eggs was higher in Jungsun (89.32) than Samcheok (3.63), which indicated that the cyst population density was higher. However, the spatial association of total cysts versus cysts with eggs was higher in Samcheok. The Gaussian model showed reasonable independent range of the nematode in Jungsun and Samcheok to be approximately 53.66 m and 48.54 m, respectively. The model suggested that each nematode sample should be taken at least 50 m apart in the given areas. Inclusion of this distribution pattern may significantly minimize the number of samples in future sampling methods, which could save time and labor, and initiate management practices by elucidating spatial variability factors that influence crop yield.

고랭지 배추재배지에서 클로버씨스트선충에 대한 살선충제의 방제효과

고랭지 배추재배지에서 클로버씨스트선충에 대한 살선충제의 방제효과

Novel RNA viruses within plant parasitic cyst nematodes.

The study of invertebrate–and particularly nematode–viruses is emerging with the advancement of transcriptome sequencing. Five single-stranded RNA viruses have now been confirmed within the economically important soybean cyst nematode (SCN; Heterodera glycines). From previous research, we know these viruses to be widespread in greenhouse and field populations of SCN. Several of the SCN viruses were also confirmed within clover (H. trifolii) and beet (H. schachtii) cyst nematodes. In the presented study, we sequenced the transcriptomes of several inbred SCN populations and identified two previously undiscovered viral-like genomes. Both of these proposed viruses are negative-sense RNA viruses and have been named SCN nyami-like virus (NLV) and SCN bunya-like virus (BLV). Finally, we analyzed publicly available transcriptome data of two potato cyst nematode (PCN) species, Globodera pallida and G. rostochiensis. From these data, a third potential virus was discovered and called PCN picorna-like virus (PLV). PCN PLV is a positive-sense RNA virus, and to the best of our knowledge, is the first virus described within PCN. The presence of these novel viruses was confirmed via qRT-PCR, endpoint PCR, and Sanger sequencing with the exception of PCN PLV due to quarantine restrictions on the nematode host. While much work needs to be done to understand the biological and evolutionary significance of these viruses, they offer insight into nematode ecology and the possibility of novel nematode management strategies.

Characterisation of populations of Heterodera trifolii Goffart, 1932 (Nematoda: Heteroderidae) in Japan and their phylogenetic relationships with closely related species

The Japanese populations of the clover cyst nematode,Heterodera trifolii, were characterised morphologically, morphometrically and molecularly. The morphology and morphometrics of six Japanese populations ofH. trifoliiwere in congruence with those of previous descriptions of this species from Germany, Italy, Japan, New Zealand, Russia, The Netherlands, UK and USA. The results of the phylogenetic analyses of the D2-D3 expansion segments of 28S rRNA gene and theCOImtDNA gene sequences discriminatedH. trifoliifrom most of the other closely related species of theSchachtiigroup. The intraspecific sequence differences in theSchachtiigroup were much higher inCOIthan in D2-D3. TheH. trifoliipopulations displayed very low levels of intraspecific variations (up to 0.3%) in theCOImtDNA gene sequences. The phylogenetic relationships ofH. trifoliiwith otherHeteroderaspecies, as inferred from the analyses of the ITS rRNA gene, D2-D3 of 28S rRNA gene andCOImtDNA gene sequences, were determined.

Концептуальные основы интегрированной защиты основных сельскохозяйственных культур от цистообразующих нематод

Objective of research. To elaborate a framework for integrated protection of agricultural crops from oat, sugar beet, Golden potato, alfalfa and clover nematodes.
 Materials and methods. The effectiveness of different anti-nematode measures was studied in 1991-2016 in Vinnyza, Kiev, Sumy, Chernigov and other regions of Ukraine. As research material served samples of soil, plants; eggs, larvae, imago; beet, oat, Golden potato, alfalfa and clover cyst nematodes. Preparation of temporary and permanent slides, determination of the species composition of cyst nematodes were carried out by standard methods [3, 6].
 Results and discussion. The framework of integrated protection of agricultural crops from oat, sugar beet, Golden potato, alfalfa and clover nematodes has been elaborated. To prevent mass reproduction of cyst-forming nematodes, the saturation of crop rotations with host plants must not exceed 40% — with cereal grains; 20% — beet and oilseed Brassica (canola, radish, and mustard); 15% — potatoes; 20% — perennial legumes. Involvement of crops and green manure in the by-products cycle has a positive effect on the level of soil fertility and activation of life activity of natural antagonists of Heteroderidae

Transcription of Biotic Stress Associated Genes in White Clover (Trifolium repens L.) Differs in Response to Cyst and Root-Knot Nematode Infection.

The transcription of four members of the Kunitz proteinase inhibitor (KPI) gene family of white clover (Trifolium repens L.), designated as Tr-KPI1, Tr-KPI2, Tr-KPI4 and Tr-KPI5, was investigated at both local infection (roots) and systemic (leaf tissue) sites in white clover in response to infection with the clover root knot nematode (CRKN) Meloidogyne trifoliophila and the clover cyst nematode (CCN) Heterodera trifolii. Invasion by the CRKN resulted in a significant decrease in transcript abundance of Tr-KPI4 locally at both 4 days post-infection (dpi) and at 8 dpi, and an increase in transcription of Tr-KPI1 systemically at 8 dpi. In contrast, an increase in transcript abundance of all four Tr-KPI genes locally at 4 and 8 dpi, and an increase of Tr-KPI1, Tr-KPI2, and Tr-KPI5 at 8 dpi systemically was observed in response to infection with the CCN. Challenge of a resistant (R) genotype and a susceptible (S) genotype of white clover with the CCN revealed a significant increase in transcript abundance of all four Tr-KPI genes locally in the R genotype, while an increase in abundance of only Tr-KPI1, Tr-KPI2, and Tr-KPI5 was observed in the S genotype, and only at 4 dpi. The transcript abundance of a member of the1-AMINOCYCLOPROPANE-1-CARBOXYLATE (ACC) SYNTHASE gene family from white clover (Tr-ACS1) was significantly down-regulated locally in response to CRKN infection at 4 and 8 dpi and at 4 dpi, systemically, while abundance increased locally and systemically at 8 dpi in response to CCN challenge. Conversely, the abundance of the jasmonic acid (JA) signalling gene, CORONATINE-INSENSITIVE PROTEIN 1 from white clover (Tr-COI1) increased significantly at 8 dpi locally in response to CRKN infection, but decreased at 8 dpi in response to CCN infection. The significance of this differential regulation of transcription is discussed with respect to differences in infection strategy of the two nematode species.

Heterodera glycines

<i>Heterodera glycines</i>

Efficacy of root digestion and maceration in determining abundance of rootinhabiting nematodes

Alternatives were sought to the standard root staining and plate counting technique for determining abundance of rootinhabiting plant parasitic nematodes as it is time consuming and laborious The use of KOH cellulase pectinase EDTA sodium hypochlorite bleach root staining or tap water alone or in combination with heating or maceration in a Waring blender was investigated as tools for extracting the root knot (Meloidogyne) clover cyst (Heterodera) and lesion (Pratylenchus) nematodes from white clover (Trifolium repens) roots Abundance of nematodes extracted from and remaining in roots after maceration was determined to assess the efficacy of the various treatments The best method involved staining roots by the standard method followed by a 10 second pulse of blender maceration For seedlings extraction of M trifoliophila nematodes by the best maceration method was not significantly different to that of the standard method but macerated samples took ca 6x less time to assess than the standard method

Plant parasitic nematodes and their management in the Maritime provinces of Canada

This paper presents a review of the plant parasitic nematodes that are of concern in New Brunswick, Nova Scotia, and Prince-Edward-Island, and the approaches used to manage them. The root lesion nematode (Pratylenchus penetrans) is the only nematode species in the region that regularly reduces crop yields. The northern root-knot nematode (Meloidogyne hapla) occasionally causes damage to carrots (Daucus carota), but population levels of this nematode species usually are very low. The clover cyst nematode (Heterodera trifolii) is widespread, but has not caused any damage to crops in the region. Management procedures used to reduce the impact of plant parasitic nematodes in the Maritime provinces, e.g. crop rotations, nematicide treatments, enforcement of quarantine regulations, and tillage practices are discussed. A nematode advisory service is also considered.

Performance of nematode-resistant white clover in field trials

Breeding for improved resistance and tolerance to the clover root-knot nematode, Meloidogyne trifoliophila, and the clover cyst nematode, Heterodera trifolii , has been successful in white c lover, Trifolium repens. White clover lines developed from three independent breeding programmes were established in field trials at Lincoln, Palmerston North, Cambridge and Kerikeri. Plants were established in areas either untreated or treated with nematicide, so as to have contrasting pest loads on the plant material and evaluated for up to 4 years. Plant vigour was scored before each grazing at each site. Clover cyst nematode cysts were counted twice in Palmerston North and all nematodes were counted in stained roots on four occasions in Cambridge. Resistant lines from the clover cyst nematode programme performed better than susceptible lines and as well as most cultivars reflecting the high level of resistance developed in this glasshouse-based programme. This resistance was also reflected in the generally lower number of cysts counted under resistant lines from Palmerston North. The root-knot nematode resistant material performed better than the susceptible and as well as most cultivars. The tolerance selections, developed under field conditions, performed as well as, or better than the cultivars. The selections from the breeding programmes have exhibited strong agronomic potential across locations and years and the best material has been crossed, with progeny being assessed in current field trials. Keywords: Heterodera trifolii, Meloidogyne trifoliophila, nematode, pasture, resistance, tolerance, white clover

Densidad poblacional de Heterodera trifolii Goffart en praderas de la zona sur de Chile

Presence of Heterodera trifolii was surveyed in 18 permanent pastures at the IX and X regions of Chile to evaluate its population. The nematode cysts were extracted with a Fenwick can extraction equipment; later they were processed using a maceration technique to examine its content of eggs and juveniles. Clover cyst nematodes were recorded in all sampled sites, the average number was 47,6 cyst per 100 cc of soil, the predominant form being collapsed and broken cysts. The average number of eggs and juveniles varied between 31 and 320, with at least 50% viable propagules. The naturalized condition of this pest was confirmed considering its wide distribution in permanent pastures of both regions.

Evidence for Systemic, Cross-resistance in White Clover ( Trifolium repens ) and Annual Medic ( Medicago truncatula var truncatula ) Induced by Biological and Chemical Agents

Soil-based growth cabinet and greenhouse experiments were designed to determine whether a resistance response previously noted in Trifolium repens to the clover cyst nematode Heterodera trifolii was systemic and also effective against a pest from a different taxon. Root applications of benzo(1,2,3)thiadiazole-7-carbothioic acid-S-methyl ester (BTH) or a Pseudomonas -like bacterial strain P29 to white clover seedlings induced resistance to the blue-green aphid, Acyrthosiphon kondoi . A similar response was observed in the annual medic, Medicago truncatula var truncatula . Estimation of lignin and callose content of whole plants at the termination of the bioassay showed no differences between treated and control plants. The significance of these findings is discussed.

Grouping of populations of Heterodera trifolii by host preference and AFLP pattern

Eight populations of clover cyst nematode, Heterodera trifolii, collected from Arkansas, Kentucky, Pennsylvania, USA and from Australia, were compared for host preference and genomic differences. Reproduction of each population on curly dock (Rumex crispus L.), mixed carnation cv. Chaubaud (Dianthus caryophyllus L.) and 14 cultivars of carnation were evaluated according to the numbers of females produced in glasshouse tests. On curly dock, five populations (1 to 5) of H. trifolii consistently reproduced abundantly, while the other three populations (6 to 8) consistently produced significantly fewer females. On cv. Chaubaud, reproduction by each population varied from test to test, and no apparent population groups could be identified. However, on 14 cultivars of carnation, populations 1 to 5 and 6 to 8 could be separated into two distinct groups on six of the cultivars (Blueboy, Peach Majestic, Tasman, Pallas, IMP White Sim and Dart) on which populations 1 to 5 did not reproduce but populations 6 to 8 did. Populations 1 to 5 apparently had more affinity for curly dock than for these six carnation cultivars, which separated these five from populations 6 to 8. DNA analysis with amplified fragment length polymorphism (AFLP) consistently revealed that populations 1 to 5 were similar and populations 6 to 8 were similar. These two groups always showed distinctly different AFLP patterns when multiple selective primer pairs were used. These results indicated that populations 1 to 5 and 6 to 8 represent two putative host races in clover cyst nematode that can be separated either by host preference test or by AFLP analysis.

Chemical and biological induction of resistance to the clover cyst nematode (Heterodera trifolii) in white clover (Trifolium repens)

AbstractPossible induction of resistance to the clover cyst nematode, Heterodera trifolii, in white clover, Trifolium repens, by application of two chemical inducers and of soil-borne Pseudomonas-like spp. and Bacillus cereus was investigated. Salicylic acid and benzo(1,2,3)thiadiazole-7-carbothioic acid-S-methyl ester, applied as a root drench in growth cabinet soil bioassays, affected development of H. trifolii in cvs Haifa and Grasslands Huia. Treatments reduced fecundity of the nematodes, increasing the proportions of distorted females and of females with fewer eggs compared to water-treated controls. Application of pectinolytic fluorescent pseudomonad strains P29 and P80, and B. cereus strain B1, induced a response similar to that resulting from the chemical induction. Both live and dead cells of P29, but not cell-free culture filtrate, induced these effects on H. trifolii. A non-pectinolytic, fluorescent pseudomonad, strain P37, had no effect. From the nature of the responses, it is concluded that the effects of both the chemical and bacterial agents have similarities to resistance. From the timing of applications and known properties of both agents, these effects seem similar to induced systemic resistance.

Below‐ground herbivory promotes soil nutrient transfer and root growth in grassland

Extremely little is known about the ecosystem‐level implications of below‐ground herbivory, which often represents the dominant form of consumption of primary productivity. We provide the first empirical evidence that low levels of below‐ground herbivory may promote soil nutrient flux and root growth of both host plants and companion plants. Low levels of white clover (Trifolium repens L.) root infection by clover cyst nematodes (Heterodera trifolii Goffart) increased root growth by 141% and 219% in the host plant and the uninfected neighbouring grass (Lolium perenne L.), respectively. Root infection increased the size of the soil microbial biomass in the root zone and the transfer of 15N from the host plant to soil and the neighbouring grass. These data suggest that low amounts of below‐ground herbivory may increase the transfer of plant carbon and nitrogen below‐ground, leading to increases in root growth and soil nutrient recycling in grasslands. Presumably, such interactions will influence the competitive interactions between plant species, altering plant community structure in grasslands.

Glyphosate application and timing of tillage of red clover affects potato response to N, soil N profile, and root and soil nematodes

The effects of glyphosate application and time of tillage of red clover on soil NO3-N profiles, the response of the subsequent potato crop to varying rates of N fertilizer application, and root and soil nematodes, were evaluated. The study was conducted over three cropping seasons on a Charlottetown fine sandy loam on Prince Edward Island. Red clover was moldboard ploughed in mid-September (early fall), or moldboard or chisel ploughed in mid-October (late fall), or moldboard ploughed in the spring. Glyphosate was applied in early fall and the dead clover was moldboard or chisel ploughed in mid-October or left undisturbed until spring. A barley control, where barley was harvested and straw incorporated with a tandem disc harrow in early September, was included. Potato were planted with 6 rates of N (0 to 250 kg ha–1 in 50-kg increments) band applied at planting. The barley control treatment produced lower potato yield without fertilizer N in all 3 yr of the study compared to red clover treatments, but potato yields were similar at high rates of applied N. Potato tuber yields after spring moldboard ploughing of red clover were higher at low N rates and lower at high N rates than yields after late fall treatment in one year of the study. Concentrations of nitrate-N in the soil in mid-November were highest following the early fall moldboard ploughing and lowest in the undisturbed clover plots. Fall soil nitrate-N levels were intermediate following the glyphosate application and late fall tillages. Early spring soil nitrate-N levels in the surface 30 cm were generally highest with the spring and late fall tillage and lowest with the early fall tillage. Levels of nitrate-N in potato petioles increased with increased rates of N application and generally increased as tillage of the red clover was delayed from early fall to late fall to spring. In general, cultivation and the application of glyphosate did not affect soil and root nematode populations. In two instances, the moldboard plough tillage treatments were associated with higher levels of the clover-cyst nematode, Heterodera trifolii. One of the tillage treatments was combined with glyphosate, but this was the only case where the herbicide had an impact on nematodes. To maximize the benefits to the subsequent potato crop and to minimize leaching of nitrate, incorporation of legume residue should be delayed until the rate of mineralization and nitrification of the legume N is minimized. It is suggested that incorporation of red clover be delayed until after mid-October for clover–potato systems on PEI. Key words: Glyphosate, nematodes, nitrate leaching, petiole nitrate-N, potato, soil nitrate-N, tillage time

Effectiveness of recurrent selection of white clover (Trifolium repens) for resistance to New Zealand populations of clover cyst nematode (Heterodera trifolii)

Abstract Selections of white clover resistant or susceptible to Heterodera trifolii in earlier rounds of a recurrent selection programme were intercrossed and selected in three further rounds of selection. Resistance and susceptibility were measured by comparisons of cysts per gram of root dry weight (cpg). In the third, fourth, and fifth rounds of recurrent selection, the mean cpg of progenies from resistant parents was 23% (n = 974), 6% (n = 870) and 11% (n = 98) of that of progenies from susceptible parents. In each selection round, the resistant selections had 31, 4 and 7% of the number of cysts on susceptible selections. The percentages of immune plants (i.e. with 0 cysts) in the resistant groups were 1, 39, and 50% after the third, fourth, and fifth rounds of recurrent selection, respectively. Inoculum from 16 populations of H. trifolii from around New Zealand was added to two resistant and two susceptible white clover lines. After one generation of nematode development there were fewer cysts on the resistant lines for each population tested. Two resistant and two susceptible lines were compared in a glasshouse trial for their reaction to parasitism by H. trifolii . Infection reduced the shoot weight of all four lines but resistant lines grew better than either one or both susceptible lines at 109, 126, and 160 days after inoculation. In contrast, the uninfected lines did not differ in shoot weight over five samplings. More cysts were recovered from susceptible lines (means of 370 and 430 cysts per plant) than from resistant lines (means of 41 and 56 cysts per plant). Results indicate that development of a white clover cultivar resistant to H. trifolii is achievable and that the resistance will be effective against the nematode in most of New Zealand. The growth study indicated that advantages will be conferred in pastures where the presence of H. trifolii causes major limitations to white clover growth and persistence. Zusammenfassung- Die Wirksamkeit einer mehrfach wiederholten Selektion von Weissklee (Trifolium repens) auf Resistenz gegen das Kleezystenalchen (Heterodera trifolii)- In einem fruheren Selektionsprogramm gegen Heterodera trifolii resistente oder anfallige Weisskleeselektionen wurden gekreuzt und in weiteren Selektionsrunden selektiert. Resistenz und Anfalligkeit wurden durch Vergleich der Anzahl der Zysten je Gramm Wurzeltrockengewicht (cpg) bestimmt. In der dritten, vierten und funften Runde der Wiederholungsselektion betrugen die cpg-Werte bei Nachkommen von resistenten Eltern 23% (n = 974), 6% (n = 870) und 11% (n = 98) der Werte bei Nachkommen anfalliger Eltern. In jeder der Selektionsrunden hatten die resistenten Selektionen nur 31, 4 und 7% der Zystenzahlen an den anfalligen Selektionen. Nach der dritten, vierten bzw. funften Selektionsrunde betrugen die Anteile immuner Pflanzen (d.h. mit 0 Zysten) 1, 39 bzw. 50%. Das Inoculum von 16 Populationen aus ganz Neuseeland wurde an zwei resistente und zwei anfallige Weisskleelinien gegeben. Nach einer Generation der Nematodenentwicklung waren an den resistenten Linien bei jeder der untersuchten Populationen weniger Zysten. Die Reaktion von zwei resistenten und zwei anfalligen Linien auf einen Befall mit H. trifolii wurde in einem Gewachshausversuch gepruft. Der Befall verringerte das Sprossgewicht aller vier Linien, doch wuchsen die resistenten Linien nach 109, 126 und 160 Tagen besser als die beiden anfalligen Linien. Im Gegensatz dazu unterschieden sich die Linien bei Nichtbefall bei funf Probenahmen im Sprossgewicht nicht voneinander. An den anfalligen Pflanzen wurden mehr Zysten gefunden (im Mittel 370 und 430 je Pflanze) als an den resistenten Pflanzen (im Mittel 41 und 56 je Pflanze). Die Ergebnisse zeigen, dass die Entwicklung einer gegen H. trifolii resistenten Weisskleesorte erreichbar ist, und dass diese Resistenz gegen die Nematoden im grossten Teil Neuseelands wirksam sein wird. Die Wachstumsuntersuchungen haben gezeigt, dass die Vorteile besonders auf solchen Weideflachen deutlich werden, wo die Anwesenheit von H. trifolii erhebliche Einschrankungen des Wachstums und des Uberdauerns von Weissklee verursacht.