Search Results (29)

To identify the key genes conferring resistance to soybean cyst nematode race 4 (SCN4, Heterodera glycines), this study utilized 280 recombinant inbred lines (RILs) derived from the resistant cultivar Huipizhiheidou (HPD) and the susceptible cultivar Jindou23 (JD23). Through phenotypic characterization and a genome-wide association study (GWAS), a genomic region (Gm18:1,223,546–1,782,241) on chromosome 18 was mapped, yielding 14 candidate genes. GmPDH1 was validated as a critical resistance gene using reverse transcription quantitative PCR (RT-qPCR) and Kompetitive Allele Specific PCR (KASP) marker M0526. RT-qPCR revealed that GmPDH1 expression in HPD roots was upregulated 9 days post-inoculation with SCN4 compared to uninoculated controls. KASP genotyping showed that marker M0526 efficiently distinguished between resistant and susceptible plants in natural populations: 71.05% of the resistant accessions exhibited resistant or moderately resistant genotypes, whereas 81.03% of the susceptible accessions showed susceptible or highly susceptible genotypes. Functional validation demonstrated that overexpression of GmPDH1 significantly enhanced SCN4 resistance in the susceptible cultivars JD23 and Jack, whereas CRISPR/Cas9-mediated knockout of GmPDH1 in HPD attenuated its resistance. This study confirmed GmPDH1 as a key gene governing SCN4 resistance and developed an efficient molecular marker, M0526, providing theoretical insights and technical tools for dissecting nematode resistance mechanisms and advancing soybean disease-resistant breeding. Full article

Plant small peptides are critical regulators of various biological processes, including development and stress responses. Polypeptides within the DUF3774 family, known as wound-induced polypeptides (WIPs), have been identified as key players in pattern-triggered immunity (PTI) and defense mechanisms in Arabidopsis. In this study, the genome-wide identification of WIP genes in Glycine max was performed, followed by gene structure correction and validation using second-generation and full-length RNA sequencing data. A total of 31 GmWIP genes were identified and validated, mapped to chromosomes Gm06, Gm12, Gm13, and Gm06_scaffold_301. Phylogenetic analysis grouped these genes into five distinct clusters, with tandem duplication emerging as the primary mechanism for their expansion in the soybean genome. qRT-PCR analysis revealed dynamic and significant changes in GmWIP expression during soybean cyst nematode (SCN) infection in a susceptible soybean cultivar. Remarkably, 90% of the GmWIP genes were downregulated at the early stage of SCN infection (1 dpi), and further corroborated by the pGmWIPs::GUS reporter system. These findings suggest that GmWIP genes may act as regulators in the defense responses of susceptible soybean cultivars, providing a foundation for future functional studies. Full article

Cyst nematodes remain a major threat to global agricultural production, causing huge losses. To understand the parasitism of the cyst nematodes Heterodera trifolii (HT) and Heterodera schachtii (HS), we constructed whole-genome assemblies using short- and long-read sequencing technologies. The nematode genomes were 379 Mb and 183 Mb in size, with the integrated gene models predicting 40,186 and 18,227 genes in HT and HS, respectively. We found more than half of the genes predicted in HT (64.7%) and HS (53.2%) were collinear to their nearest neighbor H. glycines (HG). Large-scale duplication patterns in HT and segmental duplications of more than half of the orthologous genes indicate that the genome of HT is polyploid in nature. Functional analysis of the genes indicated that 65.6% of the HG genes existed within the HT genome. Most abundant genes in HT and HS were involved in gene regulation, DNA integration, and chemotaxis. Differentially expressed genes showed upregulation of cuticle structural constituent genes during egg and female stages and cytoskeletal motor activity-related genes in juvenile stage 2 (J2). Horizontal gene transfer analyses identified four new vitamin biosynthesis genes, pdxK, pdxH, pdxS, and fabG, of bacterial origin, to be first reported in HT and HS. Mitogenomes of HT, HS, and HG showed similar structure, composition, and codon usage. However, rates of substitution of bases in the gene nad4l were significantly different between HT and HS. The described genomes, transcriptomes, and mitogenomes of plant-parasitic nematodes HT and HS are potential bio-resources used to identify several strategies of control of the nematode. Full article

The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, 1952, is one of the most destructive plant-parasitic nematodes in soybean production worldwide. The use of resistant soybean is the most effective alternative for its management. However, SCN-resistant soybean cultivars with increased yield and favorable agronomic traits remain limited in the market. Here, we developed a new SCN-resistant soybean cultivar Nongqing 28 from the cross of the female parent cultivar An 02-318 and a male parent line F2 (Hei 99-980 × America Xiaoheidou). Resistance evaluation suggested that Nongqing 28 displayed stable resistance to SCN race 3 in pot assays and the 5-year field experiments, including inhibition of SCN development and reduction in female and cyst numbers. The average yields of Nongqing 28 were 2593 kg/ha and 2660 kg/ha in the 2-year regional trails and the 1-year production trials, with a yield increase of 6.2% and 8.1% compared with the local cultivar Nengfeng 18, respectively. The average seed fat contents in Nongqing 28 reached 21.26%. Additionally, RNA-seq analysis revealed that the resistance of Nongqing 28 to SCN infection is involved in pathogen perception and defense activation, such as reactive oxygen species burst, calcium-mediated defense signaling, hormonal signaling, the MAPK signaling cascade, and phenylpropanoid biosynthesis. In summary, this study provides a detailed characterization of a novel SCN-resistant soybean cultivar with high oil and yield potential. Full article

Soybeans, one of the most valuable crops worldwide, are annually decimated by the soybean cyst nematode (SCN), Heterodera glycines, resulting in massive losses in soybean yields and economic revenue. Conventional agricultural pesticides are generally effective in the short term; however, they pose growing threats to human and environmental health; therefore, alternative SCN management strategies are urgently needed. Preliminary findings show that phenolic acids are significantly induced during SCN infection and exhibit effective nematocidal activities in vitro. However, it is unclear whether these effects occur in planta or elicit any negative effects on plant growth traits. Here, we employed a phytochemical-based seed coating application on soybean seeds using phenolic acid derivatives (4HBD; 2,3DHBA) at variable concentrations and examined SCN inhibition against two SCN types. Moreover, we also examined plant growth traits under non-infected or SCN infected conditions. Notably, 2,3DHBA significantly inhibited SCN abundance in Race 2-infected plants with increasingly higher chemical doses. Interestingly, neither compound negatively affected soybean growth traits in control or SCN-infected plants. Our findings suggest that a phytochemical-based approach could offer an effective, more environmentally friendly solution to facilitate current SCN management strategies and fast-track the development of biopesticides to sustainably manage devastating pests such as SCN. Full article

This study aimed to evaluate the suppressive potential of different soils on soybean cyst nematodes (SCN) and to estimate the suppressive mechanism. Fifteen soils (designated as soil A to O) from different agricultural fields with varying organic inputs were added with SCN-infested soil and grown with a green soybean variety. The SCN density in the soil at 6 weeks of soybean growth was markedly different depending on the soils used, indicating a different level of disease suppressiveness. No significant correlation was observed between the SCN density and any of the soil physicochemical and biological characteristics tested. Then, to estimate a suppression mechanism, F-soil that showed the lowest density of SCN was added to the SCN-infested soil with or without streptomycin to kill bacteria and grown with soybean. SCN density was not increased by the addition of streptomycin, indicating that soil bacteria may not be involved in the suppressiveness of F-soil. In total, 128 fungal strains were isolated from the rhizosphere of F-soil and inoculated in a combination or singly in the SCN-infested soil. After repeated screenings, five strains were selected since the SCN density was consistently decreased by them. Sequence analysis showed that they were closest to Clonostachys rosea, Aspergillus niger, Aspergillus fumigatus, Fusarium oxysporum, and Cylindrodendrum alicantinum. All five strains significantly reduced the mobility of second-stage juveniles (J2). Further, C. rosea a2, A. niger a8, and F. oxysporum a25 significantly decreased hatching. Overall, the present study demonstrated that soil fungi played an important role in SCN suppression in F-soil. Full article

Soybean cyst nematode (SCN, Heterodera glycines, Ichinohe) poses a significant threat to global soybean production, necessitating a comprehensive understanding of soybean plants’ response to SCN to ensure effective management practices. In this study, we conducted dual RNA-seq analysis on SCN-resistant Plant Introduction (PI) 437654, 548402, and 88788 as well as a susceptible line (Lee 74) under exposure to SCN HG type 1.2.5.7. We aimed to elucidate resistant mechanisms in soybean and identify SCN virulence genes contributing to resistance breakdown. Transcriptomic and pathway analyses identified the phenylpropanoid, MAPK signaling, plant hormone signal transduction, and secondary metabolite pathways as key players in resistance mechanisms. Notably, PI 437654 exhibited complete resistance and displayed distinctive gene expression related to cell wall strengthening, oxidative enzymes, ROS scavengers, and Ca²⁺ sensors governing salicylic acid biosynthesis. Additionally, host studies with varying immunity levels and a susceptible line shed light on SCN pathogenesis and its modulation of virulence genes to evade host immunity. These novel findings provide insights into the molecular mechanisms underlying soybean–SCN interactions and offer potential targets for nematode disease management. Full article

Bacterial endosymbionts, in genera Wolbachia and Cardinium, infect various arthropods and some nematode groups. Manipulating these microbial symbionts presents a promising biocontrol strategy for managing disease-causing parasites. However, the diversity of Wolbachia and Cardinium in nematodes remains unclear. This study employed a genome skimming strategy to uncover their occurrence in plant-parasitic nematodes, analyzing 52 populations of 12 species. A metagenome analysis revealed varying endosymbiont genome content, leading to the categorization of strong, weak, and no evidence for endosymbiont genomes. Strong evidence for Wolbachia was found in five populations, and for Cardinium in one population, suggesting a limited occurrence. Strong Wolbachia evidence was noted in Pratylenchus penetrans and Radopholus similis from North/South America and Africa. Heterodera glycines from North America showed strong Cardinium evidence. Weak genomic evidence for Wolbachia was observed in Globodera pallida, Meloidogyne incognita, Rotylenchus reniformis, Pratylechus coffeae, Pratylenchus neglectus, and Pratylenchus thornei; for Cardinium was found in G. pallida, R. reniformis and P. neglectus; 27/52 populations exhibited no endosymbiont evidence. Wolbachia and Cardinium presence varied within nematode species, suggesting non-obligate mutualism. Wolbachia and Cardinium genomes differed among nematode species, indicating potential species-specific functionality. This study advances knowledge of plant-parasitic nematode–bacteria symbiosis, providing insights for downstream eco-friendly biocontrol strategies. Full article

The soybean cyst nematode (Heterodera glycines, SCN), is the most damaging disease of soybean in North America. While management of this pest using resistant soybean is generally still effective, prolonged exposure to cultivars derived from the same source of resistance (PI 88788) has led to the emergence of virulence. Currently, the underlying mechanisms responsible for resistance breakdown remain unknown. In this study, we combined a single nematode transcriptomic profiling approach with long-read sequencing to reannotate the SCN genome. This resulted in the annotation of 1932 novel transcripts and 281 novel gene features. Using a transcript-level quantification approach, we identified eight novel effector candidates overexpressed in PI 88788 virulent nematodes in the late infection stage. Among these were the novel gene Hg-CPZ-1 and a pioneer effector transcript generated through the alternative splicing of the non-effector gene Hetgly21698. While our results demonstrate that alternative splicing in effectors does occur, we found limited evidence of direct involvement in the breakdown of resistance. However, our analysis highlighted a distinct pattern of effector upregulation in response to PI 88788 resistance indicative of a possible adaptation process by SCN to host resistance. Full article

Soybean cyst nematode Heterodera glycines (SCN) is a major threat to global soybean production. Effective management of this disease is dependent on the development of resistant cultivars. Two SCN HG Types, 7 and 1.3.4.7. were previously identified as prevalent H. glycines populations in Northeast China. In order to evaluate soybean cultivars resistant to local SCN populations, 110 domestic commercial soybeans from different regions of Northeast China were assessed in the greenhouse to determine their potential as novel sources of resistance. The results suggested that cultivars responded differently to the two HG types. Of the 110 soybean cultivars evaluated, 24 accessions were classified as resistant or moderately resistant to HG Type 7, and five cultivars were classified as resistant or moderately resistant to HG Type 1.3.4.7. Among the tested cultivars, Kangxian 12 and Qingdou 13 had resistance response to both HG types 7 and 1.3.4.7. Thus, these broad-based SCN cultivars will be the valuable materials in the SCN resistance breeding program. Full article

Mung bean residues stimulate the hatching of soybean cyst nematode (SCN). In our previous study, combined incorporation of mung bean residues and biochar into soil can be effective in suppression of the soybean cyst nematode (SCN), Heterodera glycines, in the upper layer soil. However, there are no data available as to whether such effects are transmissible, and could for example be manifest in subsoil zones where such incorporation is confined to topsoils, via water-based pathways. We evaluated the effects of leachate passage from a biochar-amended soil in an upper soil zone to a lower zone in a microcosm-based system, upon a range of physicochemical properties and density of SCN. Disturbed soil was filled in a total of 9 cylindrical cores with two layers. The upper layer (0–15 cm) was amended with biochar at rates equivalent to 0, 0.3% or 1.8%, with bulk density set at of 1.1 g cm⁻³. The lower layer (15–25 cm) without biochar amendment was compacted to 1.2 g cm⁻³. Mung beans were grown for two weeks and incorporated into the upper layer. Water was surface-applied to the cores 4, 6, and 8 weeks after mung bean incorporation. After 16 weeks, the upper and lower layer soils were separately collected and assayed. The presence of biochar in the upper layer reduced the abundance of free-living nematodes, mainly bacterivorous, but increased that of a predator genus Ecumenicus in this zone. In the lower layer of soil under a biochar-amended upper layer, available P and soluble cations were increased as were abundances of total nematodes including Ecumenicus, resulting in greater maturity index, basal and structure indices. Notably, SCN density was decreased in lower zones by more than 90% compared to zero-biochar controls. This demonstrates that the effects of biochar upon soil properties, including impacts on biota and plant pathogens, are transmissible. Full article

Soybean cyst nematode (SCN, Heterodera glycine) is a serious damaging disease in soybean worldwide, thus resulting in severe yield losses. MicroRNA408 (miR408) is an ancient and highly conserved miRNA involved in regulating plant growth, development, biotic and abiotic stress response. Here, we analyzed the evolution of miR408 in plants and verified four miR408 members in Glycine max. In the current research, highly upregulated gma-miR408 expressing was detected during nematode migration and syncytium formation response to soybean cyst nematode infection. Overexpressing and silencing miR408 vectors were transformed to soybean to confirm its potential role in plant and nematode interaction. Significant variations were observed in the MAPK signaling pathway with low OXI1, PR1, and wounding of the overexpressing lines. Overexpressing miR408 could negatively regulate soybean resistance to SCN by suppressing reactive oxygen species accumulation. Conversely, silencing miR408 positively regulates soybean resistance to SCN. Overall, gma-miR408 enhances soybean cyst nematode susceptibility by suppressing reactive oxygen species accumulation. Full article

Cyst nematodes are one of the most important pathogens worldwide. Most cyst nematode species have been reported recently in China. From 2016 to 2020, an extensive survey of cyst nematodes was conducted in the Bashang region of Hebei Province. A total of 158 soil samples were collected, and cyst-forming nematodes were isolated from five soil samples. Morphological and molecular characterization showed that four of the cyst-forming nematode populations were Heterodera glycines (SCN), named populations of ZM, KM, CB and FN, respectively. These SCN populations were collected from Zhangbei County, Kangbao County, Chabei Management Area of Zhangjiakou and Fengning Manchu Autonomous County of Chengde, respectively, where the corresponding cyst densities were 57, 41, 103 and 31 cysts/200 cc soil. Furthermore, the populations of ZM, KM and CB were identified as race 4, whereas the FN population was identified as race 3. The cyst-forming nematode population was collected from Zhangbei County of Zhangjiakou, which was confirmed to be Heterodera schachtii (SBCN), named population ZZ, and the cyst density was 94 cysts/200 cc soil. It is a new disease of Chinese cabbage caused by SBCN based on Koch’s postulates. Fourteen cultivars from five plant families were evaluated as hosts for SBCN. Chinese cabbage (cv. Linglonghuang012) and cabbage (cv. Chunwang) were suitable hosts, while celery (cv. Yuhuang), potato (cv. Helan 15) and eggplant (cv. Junlang) were nonhosts. The obtained results regarding the occurrence, distribution, races of SCN and hosts of SBCN in the Bashang region in this study provide a reference for SCN and SBCN management. Full article

Ubiquitination is a kind of post-translational modification of proteins that plays an important role in plant response to biotic and abiotic stress. The response of soybean GmPUB genes to soybean cyst nematode (SCN, Heterodera glycines) infection is largely unknown. In this study, quantitative real-time PCR (qRT-PCR) was performed to detect the relative expression of 49 GmPUB genes in susceptible cultivar William 82 and resistant cultivar Huipizhi after SCN inoculation. The results show that GmPUB genes responded to cyst nematode infection at 1 day post-inoculation (dpi), 5 dpi, 10 dpi and 15 dpi. The expression levels of GmPUB16A, GmPUB20A, GmCHIPA, GmPUB33A, GmPUB23A and GmPUB24A were dramatically changed during SCN infection. Furthermore, functional analysis of these GmPUB genes by overexpression and RNAi showed that GmPUB20A, GmPUB33A and GmPUB24A negatively regulated soybean resistance under SCN stress. The results from our present study provide insights into the complicated molecular mechanism of the interaction between soybean and SCN. Full article

Three damaging soybean diseases, Sclerotinia stem rot caused by a fungus Sclerotinia sclerotiorum (Lid.) de Bary, Phytophthora root rot caused by a fungus Phytophthora sojae, and soybean cyst nematode (Heterodera glycines Ichinohe), are destructive to soybean growth and yield and cause huge economic losses. Biocontrol is an effective way to control soybean diseases with the advantage of being environmentally friendly and sustainable. To date, few reviews have reported the control of these three soybean diseases through biocontrol measures. In this review, the biological characteristics of the three pathogens and the incidence features of the three soybean diseases were first introduced. Then, biocontrol agents containing fungi and bacteria capable of controlling the three diseases, as well as their control abilities, were emphasized, followed by their mechanisms of biocontrol action. Bacillus and Streptomyces were found to possess the ability to control all three soybean diseases under greenhouse or field conditions. Finally, suggestions about screening new biocontrol species and deeply studied biocontrol molecular mechanisms are provided for further research on the biocontrol of soybean diseases. Full article