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Abstract Background Burnout is prevalent among pediatric residents. Self-efficacy and resilience, as concepts of positive psychology, may be protective factors for burnout. However, no current data demonstrates the mechanism of their interaction. Objectives To investigate the pediatric residents’ status of self-efficacy, resilience, and job burnout in a university-affiliated hospital in western China. To explore relationships among them, especially the mediating effects of resilience. Methods The study was conducted with 190 pediatric residents from an A-Class women’s and children’s hospital in western China. Data included demographic characteristics, status of pediatric residents, measures of burnout (using the Physicians’ Career Burnout Questionnaire), self-efficacy (using the General Self-Efficacy Scale) and resilience (using the Connor-Davidson Resilience Scale). Multiple regression analysis and mediation analysis with bootstrapping were used to identify whether resilience mediates the relationship between self-efficacy and burnout. Results Female pediatric residents exhibited significantly lower self-efficacy (t = 2.53, p

Introduction: Dyskeratosis congenita is a rare genetic disorder characterized by abnormalities of the skin, nails, and oral mucosa. Retinal involvement in this condition is uncommon. Here, we present a case of a young male patient diagnosed with presumptive cytomegalovirus retinitis, ultimately found to be concomitant with dyskeratosis congenita. Case Presentation: A non-HIV-infected young male with recurrent infections, including aspergillus pneumonia and pneumocystis pneumonia, presented with presumptive cytomegalovirus retinitis in both eyes. Systemic manifestations included cutaneous hyperpigmentation, nail dystrophy, and oral mucosal leukoplakia. Genetic testing revealed a mutation in the DKC1 gene. The final diagnosis was dyskeratosis congenita complicated by presumptive cytomegalovirus retinitis. Conclusion: Cytomegalovirus retinitis can serve as an ocular complication of dyskeratosis congenita. When a patient presents with cytomegalovirus retinitis, a comprehensive systematic examination should be conducted as it indicates severe immunodeficiency.

Abstract Compared with the uniform linear array (ULA) under the same physical array element, the coprime array can obtain a higher degree of freedom and a larger array aperture, so it has received extensive attention from scholars in recent years. Based on the idea of interference plus noise covariance matrix (INCM) reconstruction, this study proposed a robust adaptive beamforming algorithm using the coprime array. In the virtual array generated by the coprime array, the authors prove from the perspective of virtual signals that the constructed Toeplitz matrix is equivalent to a virtual ULA with more array elements. Subsequently, a high‐resolution subspace algorithm is used to estimate the direction of arrival (DOA) of the signals, and the estimated DOA is used to reconstruct the direction vector (DV) of the coprime array. Through the eigenvalue decomposition of the reconstructed Toeplitz matrix, the corresponding relationship between the eigenvalue and the power is deduced, and the signals and noise power are estimated using the eigenvalue. Finally, combine the DV of the desired signal and the reconstructed INCM to calculate the weight vector of the proposed algorithm. The simulation results prove the superiority and effectiveness of the algorithm.

When the array structure of the sparse arrays (SA) cannot be determined, the existing beamforming algorithms designed according to specific formations such as coprime arrays (CA), nested arrays (NA), etc. will fail. To solve this problem, we propose two algorithms that are suitable for a variety of SA. In the first method, assuming that the desired signal is a non-Gaussian signal, the desired signal direction vector (DSDV) is estimated using the fourth-order cumulant, and then the interference plus noise covariance matrix (INCM) is reconstructed by integrating the area outside the desired signal. When the desired signal is a Gaussian signal, we propose the second method. The second method estimates the power and direction of arrival (DOA) of the signals by performing eigenvalue decomposition on the sampled covariance matrix (SCM) and finally calculates the weight vector. However, this method needs to estimate the DOA of the signals, so it has certain requirements for the SA structure design. The simulation results show that the proposed method has good performance and strong robustness under different SA.

In order to solve the problem of severely decreased performance under the situation of rapid moving sources and unstable array platforms, a null broadening robust adaptive beamforming algorithm based on power estimation is proposed in this paper. First of all, we estimate the interference signal power according to the characteristic subspace theory. Then, the correspondence between the signal power and steering vector (SV) is obtained based on the orthogonal property, and the interference covariance matrix (ICM) is reconstructed. Finally, with the aim of setting virtual interference sources, null broadening can be carried out. The proposed algorithm results in a deeper null, lower side lobes and higher tolerance of the desired signal steering vector mismatch under the condition of low complexity. The simulation results show that the algorithm also has stronger robustness.

As we all know, nested array can obtain a larger array aperture and more degrees of freedom using fewer sensors. In this study, we not only designed an enhanced symmetric nested array (ESNA), which achieved more consecutive lags and more unique lags compared with a generalized nested array but also developed a special cumulant matrix, in the case of a given number of sensors, which can automatically generate the largest consecutive lags of the array. First, the direction-of-arrivals (DOAs) of mixed sources are estimated using the special cumulant matrix. Then, we can estimate the range of the near-field source in the mixed source using a one-dimensional spectral search through estimated DOAs, and in the mixed sources, the near-field and far-field sources are classified by bringing in the range parameter. The largest consecutive lags and composition method of ESNA are also given, under a given number of sensors.Our algorithm has moderate computation complexity, which provides a higher resolution and improves the parameters’ estimation accuracy. Numerical simulation results demonstrate that the proposed array showed an outstanding performance under estimation accuracy and resolution ability for both DOA and range estimation compared with existing arrays of the same physical array sensors.

When there is coexistence of uncorrelated and coherent signals in sparse arrays, the conventional algorithms for direction-of-arrival (DOA) estimation using difference coarray fail. In order to solve the problems, this paper analyzes the feasibility of using spatial smoothing in sparse arrays. Firstly, we summarize the two types of sparse arrays, one consisting of identical sparse subarrays and the other consisting of several uniform linear subarrays. Then, we give the feasibility analysis and the processes of applying spatial smoothing. At last, we discuss the performance of the number of detectable coherent signals in different sparse arrays. Numerical experiments prove the conclusions proposed by the paper.

Abstract Background Meloidogyne incognita is one of the most important plant-parasitic nematodes and causes tremendous losses to the agricultural economy. Light is an important living factor for plants and pathogenic organisms, and sufficient light promotes root-knot nematode infection, but the underlying mechanism is still unclear. Results Expression level and genetic analyses revealed that the photoreceptor genes PHY, CRY, and PHOT have a negative impact on nematode infection. Interestingly, ELONGATED HYPOCOTYL5 (HY5), a downstream gene involved in the regulation of light signaling, is associated with photoreceptor-mediated negative regulation of root-knot nematode resistance. ChIP and yeast one-hybrid assays supported that HY5 participates in plant-to-root-knot nematode responses by directly binding to the SWEET negative regulatory factors involved in root-knot nematode resistance. Conclusions This study elucidates the important role of light signaling pathways in plant resistance to nematodes, providing a new perspective for RKN resistance research.

BackgroundProteus mirabilis is a Gram-negative, rod-shaped bacterium widely found in natural environments. It is known for causing a range of severe illnesses in mammals, particularly urinary tract infections (UTIs). This study evaluates the therapeutic efficacy of phage P2-71 against Proteus mirabilis in vivo and in vitro environments.MethodsThe in vitro therapeutic potential of bacteriophage P2-71 was assessed through the ability of phage to kill Proteus mirabilis by using a plate counting assay, and biofilm inhibition and biofilm lysis assays using a microtitre plate method. Additionally, an in vivo UTI model in C57BL/6Jmice was developed via urethral inoculation of the bacterium. Phage therapy was administered through urethral injection over a period of 5 days. Therapeutic outcomes were measured by analyzing bacterial load, phage titer, inflammatory markers, and histopathological changes in the urine, urogenital tissues, and spleen.ResultsIn vitro, bacteriophage P2-71 achieved significant reductions in P. mirabilis concentrations, with log reductions of 1.537 and 0.7009 CFU/mL in laboratory and urine environments, respectively (p 0.05). Concurrently, phage titers decreased over time. Importantly, phage treatment notably reduced bacterial load in the bladder, kidneys, and spleen (p

Soybean cyst nematode (Heterodera glycines, soybean cyst nematode [SCN]) disease adversely affects the yield of soybean and leads to billions of dollars in losses every year. To control the disease, it is necessary to study the resistance genes of the plant and their mechanisms. Isoflavonoids are secondary metabolites of the phenylalanine pathway, and they are synthesized in soybean. They are essential in plant response to biotic and abiotic stresses. In this study, we reported that phenylalanine ammonia-lyase (PAL) genes GmPALs involved in isoflavonoid biosynthesis, can positively regulate soybean resistance to SCN. Our previous study demonstrated that the expression of GmPAL genes in the resistant cultivar Huipizhi (HPZ) heidou are strongly induced by SCN. PAL is the rate-limiting enzyme that catalyzes the first step of phenylpropanoid metabolism, and it responds to biotic or abiotic stresses. Here, we demonstrate that the resistance of soybeans against SCN is suppressed by PAL inhibitor l-α-(aminooxy)-β-phenylpropionic acid (L-AOPP) treatment. Overexpression of eight GmPAL genes caused diapause of nematodes in transgenic roots. In a petiole-feeding bioassay, we identified that two isoflavones, daidzein and genistein, could enhance resistance against SCN and suppress nematode development. This study thus reveals GmPAL-mediated resistance against SCN, information that has good application potential. The role of isoflavones in soybean resistance provides new information for the control of SCN. [Graphic: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

In this paper, we consider the first boundary value problem for a class of steady non-Newtonian micropolar fluid equations with heat convection in the three-dimensional smooth and bounded domain $ \Omega $. By using the fixed-point theorem and introducing a family of penalized problems, under the condition that the external force term and the vortex viscosity coefficient are appropriately small, the existence and uniqueness of strong solutions of the problem are obtained.

Introduction: The nematode species Meloidogyne incognita has been responsible for significant financial losses within the agricultural sector. Nematophagous bacteria, characterised by their extensive distribution and broad spectrum of hosts, exhibit remarkable efficacy as natural antagonists against nematodes. Sneb518 (Clostridium beijerinckii) fermentation broth displayed substantial biocontrol activity against M. incognita in previous research. Optimizing fermentation conditions is a fundamental technique for dramatically enhancing end product performance. There has been no such study conducted yet on enhancing the nematicidal activities of Sneb518 (Clostridium beijerinckii) fermentation using response surface methodology (RSM).Methods: The influence of strain Sneb518 fermentation media and conditions on nematicidal activity was examined using the three-factor technique and a Plackett-Burman design, and the interaction between various fermentation factors was examined using a Box-Behnken design. The present study employed response surface methodology (RSM) to examine and enhance the nematicidal activity of Sneb518 culture filtrates by identifying and optimising the influential components.Results: Glucose, peanut cake flour, and potassium chloride as carbon, nitrogen, and inorganic salts displayed considerably increased nematicidal potential in the present study. Furthermore, the corrected mortality of J2 ranged from 52.24% to 91.15% when utilizing the Box-Behnken design. These findings clearly support the application of RSM for medium optimization. Moreover, the outcomes of the validation experiment corresponded to the model predictions.Discussion: This research has enhanced the biocontrol ability of C. beijerinckii to control M. incognita and this research has led to the advancement of new biocontrol agents.

IntroductionRoot-knot nematode disease is one of the world's most serious vegetable crop diseases. In recent years, Trichoderma spp. has been widely used in root-knot nematode disease control as a biological control agent.MethodsVirulent and attenuated strains of Trichoderma citrinoviride mediated resistance and biological control mechanism in tomato were determined.ResultsPreliminary experiments found differences in nematicidal virulence among Trichoderma citrinoviride. The 24-hour corrected mortality rate of the virulent strainT1910 was as high as 92.37%, with an LC50 of 0.5585 against the second juveniles (J2s) of Meloidogyne incognita. And the attenuated strain TC9 was 23.01%, the LC50 was 2.0615, so the virulent strain T1910 had a more substantial effect on the J2s than the attenuated strain. We found that the strong virulent strain T1910 have a good control effect on M. incognita by the pot experiment of tomato than that of the attenuated virulent strain TC9,especially the J2 and J4 numbers were inhibited inside the root knots of tomato. Theinhibition rates of virulent strains reached 85.22% and 76.91%, followed by attenuatedstrain TC9, which were 63.16% and 59.17%, respectively. To reveal the differences intomato defense pathways induced by different virulent strains, qRT-PCR was further usedto detect changes in the expression of inducement-related genes. The results showed thatthe TC9 was significantly upregulated at 5dpi, LOX1, PR1, and PDF1.2. The PR5 gene ofthe virulent strain T1910 was highly upregulated, and the JA pathway was activated laterbut weaker than the attenuated strain. The results of this study revealed that thebiocontrol mechanism of T. citrinoviride as poison killing through the virulent strain T1910 and induced resistance to M. incognita through attenuated strain, although virulence degradation also has an induced resistance effect. Moreover, the attenuated strain TC9 stimulated tomato immune response earlier than the virulent strain by nematode-associated molecular pattern-triggered (NAMP).DiscussionTherefore, the research elucidated the mechanism of multiple control of Trichoderma spp. against M. incognita.

The root-knot nematode Meloidogyne incognita is a pathogenic pest that causes severe economic loss to agricultural production by forming a parasitic relationship with its hosts. During the development of M. incognita in the host plant roots, giant cells are formed as a nutrient sink. However, the roles of sugar transporters during the giant cells gain sugar from the plant cells are needed to improve. Meanwhile, the eventual function of sugars will eventually be exported transporters (SWEETs) in nematode-plant interactions remains unclear. In this study, the expression patterns of Arabidopsis thaliana SWEETs were examined by inoculation with M. incognita at 3 days post inoculation (dpi) (penetration stage) and 18 dpi (developing stage). We found that few AtSWEETs responded sensitively to M. incognita inoculation, with the highest induction of AtSWEET1 (AT1G21460), a glucose transporter gene. Histological analyses indicated that the β-glucuronidase (GUS) and green fluorescent protein (GFP) signals were observed specifically in the galls of AtSWEET1-GUS and AtSWEET1-GFP transgenic plant roots, suggesting that AtSWEET1 was induced specifically in the galls. Genetic studies have shown that parasitism of M. incognita was significantly affected in atsweet1 compared to wild-type and complementation plants. In addition, parasitism of M. incognita was significantly affected in atsweet10 but not in atsweet13 and atsweet14, expression of which was induced by inoculation with M. incognita. Taken together, these data prove that SWEETs play important roles in plant and nematode interactions.

We studied the bioactive compound of the fungus Simplicillium chinense strain Snef5, isolated from its culture filtrate. Following purification by chromatography, the structure of the secondary metabolite, identified as 2,6-pyridinedicarboxylic acid, was determined by spectroscopic methods (IR, 1H, and 13C NMR) and scanning electron microscopy (SEM). The metabolite exhibited antimicrobial activity against M. incognita with an LD50 of 0.229 mg/ml. The light microscope was used to observe the surface and internal cellular micro-structure of the nematodes. The results of the microscopy indicated that the anatomy of the J2 of M. incognita was disrupted following exposure to 2,6-pyridinedicarboxylic acid. This is the first report on the activity of 2,6-pyridinedicarboxylic acid of S. chinense metabolites on the root knot nematode. It showed a high level of nematicidal activity. Our data on the inhibitory effects of 2,6-pyridinedicarboxylic acid suggest that secondary metabolites from Snef5 have potential use as novel biological control agents.

Abstract Background Root-knot nematode is one of the most significant diseases of vegetable crops in the world. Biological control with microbial antagonists has been emerged as a promising and eco-friendly treatment to control pathogens. The aim of this study was to screen and identify novel biocontrol agents against root-knot nematode, Meloidogyne incognita. Results A total of 890 fungal isolates were obtained from rhizosphere soil of different crops and screened by nematicidal activity assays. Snef1910 strain showed high virulence against second stage juveniles (J2s) of M. incognita and identified as Trichoderma citrinoviride by morphology analysis and biomolecular assay. Furthermore, T. citrinoviride Snef1910 significantly inhibited egg hatching with the hatching inhibition percentages of 90.27, 77.50, and 67.06% at 48, 72, and 96 h after the treatment, respectively. The results of pot experiment showed that the metabolites of T. citrinoviride Snef1910 significantly decreased the number of root galls, J2s, and nematode egg masses and J2s population density in soil and significantly promoted the growth of tomato plants. In the field experiment, the biocontrol application showed that the control efficacy of T. citrinoviride Snef1910 against root-knot nematode was more than 50%. Meanwhile, T. citrinoviride Snef1910 increased the tomato plant biomass. Conclusions T. citrinoviride strain Snef1910 could be used as a potential biological control agent against root-knot nematode, M. incognita.

Abstract Root-knot nematode (Meloidogyne incognita) is chief plant parasitic nematode of various crops globally. Meanwhile, the negative side effects on human health and environmental concerns associated with haphazard uses of chemical nematicides. Hence, the search for a safe and effective approach is more relevant. The present study was aimed to evaluate the nematicidal potential of Snef1216 (Penicillium chrysogenum) against M. incognita at different concentrations (5%, 10%, 25%, 50%, 75% and 100%) and with the nutritious medium. The egg hatching inhibition and mortality of second stage juveniles of M. incognita were assessed after 6, 12, 24, 48 and 72 h exposure. Results revealed that egg hatching inhibition and percent mortality of M. incognita increased with increasing concentration and exposure time. The highest mortality of juveniles was recorded at 100% conc. i.e., 24.20%, 36%, 66%, 78% and 97.8% at 6, 12, 24, 48 and 72 h, respectively. The highest ovicidal activity was recorded at 100% concentration with 5.20% of eggs hatching. The outcome suggested that Snef1216 (P. chrysogenum) resulted in the lowest LC50 value was recorded as 3718.496 at 6 h exposure period followed by 10479.87, 11186.682, 14838.58 and 24001.430 at 72, 12, 48 and 24 h respectively via ovicidal assay. Whereas, in the larvicidal assay, the lowest LC50 value demonstrated at 72 h being 17.628% exposure period followed by 28.345, 50.490, 215.710 and 482.595% at 48, 24, 12 and 6 h respectively. It is concluded that Snef1216 has potential being used as a biocontrol agent against M. incognita and can serve as a source of a novel nematicidal agent of fungal origin.

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.

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.

ABSTRACT: Soybean cyst nematode (SCN, Heterodera glycines) is a chief plant–parasitic nematode of soybean. Application of synthetic chemical nematicides poses negative side effects to human health and the environment. Therefore, the search for a safe and effective approach is more relevant. This study evaluated the effects of Genistein and Daidzein on the physiological index of soybean cyst nematodes, individual morphology, reversal frequency, respiration, and body fluid leaking of second–stage juveniles (J2s) of soybean cyst nematode. The results showed that body length of J2s decreased, while stylet and tail transparent area elongated. Additionally, after the treatment, the body became hollow and shrunken, the J2s stiffened, whereas the reversal frequency decreased dramatically after 24 h of treatment. Moreover, the body fluid leakage was intensified and respiration was inhibited. Oxygen consumption decreased by 86.7 % and 70.1 %, while, in contrast, electrical conductivity increased by 40.1 % and 36 % at 100 μg mL−1 of Genistein and Daidzein, respectively, after 48 h of exposure. The smaller number of J2s in soybean roots, the slower development rate, and the abnormal sexual differentiation were found in greenhouse assay. Thus, Genistein and Daidzein, especially Genistein, have strong effects on the physiological index of soybean cyst nematodes. Moreover, the effects were time and dosage–dependent.

The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, poses a serious threat to soybean production worldwide. Biological control agents have become eco-friendly candidates to control pathogens. Our previous study indicated that the biocontrol agent, Sinorhizobium fredii strain Sneb183, may induce soybean resistance to SCN. To study the mechanisms underlying induced disease resistance in the plant by Sneb183, an iTRAQ (isobaric tag for relative and absolute quantitation)-based proteomics approach was used to identify proteomic changes in SCN-infected soybean roots derived from seeds coated with the Sneb183 fermentation broth or water. Among a total of 456 identified differentially expressed proteins, 212 and 244 proteins were upregulated and downregulated, respectively, in Sneb183 treated samples in comparison to control samples. Some identified differentially expressed proteins are likely to be involved in the biosynthesis of phenylpropanoid, flavone, flavanol, and isoflavonoid and have a role in disease resistance and adaptation to environmental stresses. We used quantitative real-time PCR (qRT-PCR) to analyze key genes, including GmPAL (phenylalanine ammonia-lyase), GmCHR (chalcone reductase), GmCHS (chalcone synthase), and GmIFS (isoflavone synthase), that are involved in isoflavonoid biosynthesis in Sneb183-treated and control samples. The results showed that these targeted genes have higher expression levels in Sneb183-treated than in control samples. High performance liquid chromatography (HPLC) analysis further showed that the contents of daidzein in Sneb183-treated samples were 7.24 times higher than those in control samples. These results suggested that the Sinorhizobium fredii strain Sneb183 may have a role in inducing isoflavonoid biosynthesis, thereby resulting in enhanced resistance to SCN infection in soybean.

Antioxidants are the radical scavengers that inhibit peroxidation and other free-radical processes, which in return safeguard different organisms from various diseases attributed to radical reactions. Synthetic antioxidants inhibit free radicals, but they also have harmful side effects. However, mycochemicals of natural fungal origin are safe and best substitutes for harmful synthetic chemical antioxidants. The prime objectives of the study include appropriate qualitative and quantitative mycochemical screening, antioxidant potential, and chemical composition of Snef1216 (Penicillium chrysogenum). The study has used aluminium chloride colourimetric method, Folin–Ciocalteu reagent assay, and DPPH (1,1-diphenyl-1-picrylhydrazyl) for analysis of total flavonoid content and phenol content and antioxidant activity, respectively. However, the presence of biologically active compounds was screened through gas chromatography-mass spectrometry (GC-MS). Quantitative analysis demonstrated the existence of flavonoids, glycosides, flavones, saponins, phenols, and catecholic tannins excluding alkaloids, terpenoids, steroids, and gallic tannins. The outcomes exposed total flavonoid content and phenolic content in P. chrysogenum were 85.31 ± 1.23 mg·QE/g and 135.77 ± 1.14 mg·GAE/g, respectively. Snef1216 (P. chrysogenum) displayed the highest free-radical scavenging activity with 63.86% inhibition of DPPH. The analysis confirms that Snef1216 (P. chrysogenum) is an alternative source of natural antioxidants. The obtained data have provided the foundation for its use in agricultural, environmental, and pharmaceutical industries.

Abstract Background Soybean cyst nematode (SCN) is the most devastating pathogen of soybean. Our previous study showed that the plant growth-promoting rhizobacterium Bacillus simplex strain Sneb545 promotes soybean resistance to SCN. Here, we conducted a combined metabolomic and transcriptomic analysis to gain information regarding the biological mechanism of defence enhancement against SCN in Sneb545-treated soybean. To this end, we compared the transcriptome and metabolome of Sneb545-treated and non-treated soybeans under SCN infection. Results Transcriptomic analysis showed that 6792 gene transcripts were common in Sneb545-treated and non-treated soybeans. However, Sneb545-treated soybeans showed a higher concentration of various nematicidal metabolites, including 4-vinylphenol, methionine, piperine, and palmitic acid, than non-treated soybeans under SCN infection. Conclusions Overall, our results validated and expanded the existing models regarding the co-regulation of gene expression and metabolites in plants, indicating the advantage of integrated system-oriented analysis.

Soybean cyst nematode (SCN, Heterodera glycines) is an obligate sedentary biotroph that poses major threats to soybean production globally. Recently, multiple miRNAome studies revealed that miRNAs participate in complicated soybean-SCN interactions by regulating their target genes. However, the functional roles of miRNA and target genes regulatory network are still poorly understood. In present study, we firstly investigated the expression patterns of miR159 and targeted GmMYB33 genes. The results showed miR159-3p downregulation during SCN infection; conversely, GmMYB33 genes upregulated. Furthermore, miR159 overexpressing and silencing soybean hairy roots exhibited strong resistance and susceptibility to H. glycines, respectively. In particular, miR159-GAMYB genes are reported to be involve in GA signaling and metabolism. Therefore, we then investigated the effects of GA application on the expression of miR159-GAMYB module and the development of H. glycines. We found that GA directly controls the miR159-GAMYB module, and exogenous GA application enhanced endogenous biologically active GA1 and GA3, the abundance of miR159, lowered the expression of GmMYB33 genes and delayed the development of H. glycines. Moreover, SCN infection also results in endogenous GA content decreased in soybean roots. In summary, the soybean miR159-GmMYB33 module was directly involved in the GA-modulated soybean resistance to H. glycines.

Background: The yield of soybean is limited by the soybean cyst nematode (SCN, Heterodera glycines). Soybean transformation plays a key role in gene function research but the stable genetic transformation of soybean usually takes half a year. Methods: Here, we constructed a vector, pNI-GmUbi, in an Agrobacterium rhizogenes-mediated soybean hypocotyl transformation to induce fluorescent hairy roots (FHRs). Results: We describe the operation of FHR-SCN, a fast, efficient and visual operation pathosystem to study the gene functions in the soybean-SCN interaction. With this method, FHRs were detected after 25 days in 4 cultivars (Williams 82, Zhonghuang 13, Huipizhiheidou and Peking) and at least 66.67% of the composite plants could be used to inoculate SCNs. The demographics of the SCN could be started 12 days post-SCN inoculation. Further, GmHS1pro-1 was overexpressed in the FHRs and GmHS1pro-1 provided an additional resistance in Williams 82. In addition, we found that jasmonic acid and JA-Ile increased in the transgenic soybean, implying that the resistance was mainly caused by affecting the content of JA and JA-Ile. Conclusions: In this study, we established a pathosystem, FHR-SCN, to verify the functional genes in soybeans and the SCN interaction. We also verified that GmHS1pro-1 provides additional resistance in both FHRs and transgenic soybeans, and the resistance may be caused by an increase in JA and JA-Ile contents.

Soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is responsible for causing a major soybean disease globally. The fungal strain Penicillium janthinellum Snef1650 was evaluated against H. glycines. However, the effective determinants of the P. janthinellum strain are unknown. By performing pot experiments, a functioning compound was isolated from P. janthinellum Snef1650 through organic solvent extraction, semi-preparative HPLC, Sephadex LH-20 column chromatography, and silica gel column chromatography, and the isolated compound was identified to be scopoletin through 1H NMR, 13C NMR, and HPLC–MS. The pot experiments indicated that the treatment of soybean seeds with scopoletin drastically reduced the SCN population. The field experiments performed in 2017 and 2018 revealed that scopoletin decreased over 43.7% juveniles in the roots and over 61.55% cysts in the soil. Scopoletin treatment also promoted soybean growth and improved its yield, with an increase in plot yield by >5.33%. Scopoletin obtained from P. janthinellum Snef1650 could be used as an anti-H. glycines biocontrol agent.

The northern root-knot nematode (Meloidogyne hapla) is a critical pathogen with a wide host range. Quantitative real-time polymerase chain reaction (qRT-PCR) has been used to elucidate gene expression and function of M. hapla. Suitable reference genes are required to ensure accurate results of qRT-PCR for normalising gene expression. Eleven candidate reference genes of M. hapla were selected to evaluate gene expression stability under different conditions. The stability of candidate reference genes was ranked using RefFinder analysis, and the optimal number of reference genes was recommended with geNorm. Notably, the most stable reference genes were SDHA, Mdh, and RpS6 for all samples; SDHA and RpS6 were particularly stable during development stage treatments, whereas Mdh and RpS6 were appropriate for temperature and inorganic compound treatments. In contrast, the least stable reference genes were Actin1 during development stages and all other treatments, GAPDH for temperature treatments, and α-Tub for inorganic compound treatments. One target gene, Mh-Hsp90, was used to verify the selection of reference genes, results showed Mdh and RpS6 could be used as suitable reference genes for M. hapla, and Mdh plus RpS6 were better. Our finding contributes to further work on gene transcription analysis in M. hapla.

In plant immune responses, reactive oxygen species (ROS) act as signaling molecules that activate defense pathways against pathogens, especially following resistance (R) gene-mediated pathogen recognition. Glutathione (GSH), an antioxidant and redox regulator, participates in the removal of hydrogen peroxide (H2O2). However, the mechanism of GSH-mediated H2O2 generation in soybeans (Glycine max (L.) Merr.) that are resistant to the soybean cyst nematode (SCN; Heterodera glycines Ichinohe) remains unclear. To elucidate this underlying relationship, the feeding of race 3 of H. glycines with resistant cultivars, Peking and PI88788, was compared with that on a susceptible soybean cultivar, Williams 82. After 5, 10, and 15 days of SCN infection, we quantified γ-glutamylcysteine (γ-EC) and (homo)glutathione ((h)GSH), and a gene expression analysis showed that GSH metabolism in resistant cultivars differed from that in susceptible soybean roots. ROS accumulation was examined both in resistant and susceptible roots upon SCN infection. The time of intense ROS generation was related to the differences of resistance mechanisms in Peking and PI88788. ROS accumulation that was caused by the (h)GSH depletion-arrested nematode development in susceptible Williams 82. These results suggest that (h)GSH metabolism in resistant soybeans plays a key role in the regulation of ROS-generated signals, leading to resistance against nematodes.

Root-knot nematodes (RKNs) severely affect plants growth and productivity, and several commercial biocontrol bacteria can improve plants resistance to RKNs. Pseudomonas putida Sneb821 isolate was found to induce tomatoes resistance against Meloidogyne incognita. However, the molecular functions behind induced resistance remains unclear. Long non-coding RNA (lncRNA) is considered to be a new component that regulates the molecular functions of plant immunity. We found lncRNA was involved in Sneb821-induced tomato resistance to M. incognita. Compared with tomato inoculated with M. incognita, high-throughput sequencing showed that 43 lncRNAs were upregulated, while 35 lncRNAs were downregulated in tomatoes previously inoculated with Sneb821. A regulation network of lncRNAs was constructed, and the results indicated that 12 lncRNAs were found to act as sponges of their corresponding miRNAs. By using qRT-PCR and the overexpression vector pBI121, we found the expression of lncRNA44664 correlated with miR396/GRFs (growth-regulating factors) and lncRNA48734 was correlated with miR156/SPL (squamosal promoter-binding protein-like) transcription factors. These observations provided a novel molecular model in biocontrol bacteria-induced tomato resistance to M. incognita.

Meloidogyne incognita and Meloidogyne graminicola are root-knot nematodes (RKNs) infecting rice (Oryza sativa L.) roots and severely decreasing yield, whose mechanisms of action remain unclear. We investigated RKN invasion and development in rice roots through RNA-seq transcriptome analysis. The results showed that 952 and 647 genes were differently expressed after 6 (invasion stage) and 18 (development stage) days post inoculation, respectively. Gene annotation showed that the differentially expressed genes were classified into diverse metabolic and stress response categories. Furthermore, phytohormone, transcription factor, redox signaling, and defense response pathways were enriched upon RKN infection. RNA-seq validation using qRT-PCR confirmed that CBL-interacting protein kinase (CIPK) genes (CIPK5, 8, 9, 11, 14, 23, 24, and 31) as well as brassinosteroid (BR)-related genes (OsBAK1, OsBRI1, D2, and D11) were altered by RKN infection. Analysis of the CIPK9 mutant and overexpressor indicated that the RKN populations were smaller in cipk9 and larger in CIPK9 OX, while more galls were produced in CIPK9 OX plant roots than the in wild-type roots. Significantly fewer numbers of second-stage infective juveniles (J2s) were observed in the plants expressing the BR biosynthesis gene D2 mutant and the BR receptor BRI1 activation-tagged mutant (bri1-D), and fewer galls were observed in bri1-D roots than in wild-type roots. The roots of plants expressing the regulator of ethylene signaling ERS1 (ethylene response sensor 1) mutant contained higher numbers of J2s and developed more galls compared with wild-type roots, suggesting that these signals function in RKN invasion or development. Our findings broaden our understanding of rice responses to RKN invasion and provide useful information for further research on RKN defense mechanisms.

Soybean is an important economic crop that is often adversely affected by infection in the field with the soybean cyst nematode Heterodera glycines. Biological control is an eco-friendly method used to protect the crop against disease. The bacterium Klebsiella pneumoniae has been reported to protect rice from sheath blight and seedling blight, but its role in the control of nematode is unclear. In this study, the effect of K. pneumoniae SnebYK on the control of H. glycines was assessed. Potting experiment results showed that coating soybean seeds with K. pneumoniae SnebYK not only reduced the infection rate of H. glycines but also decreased the proportion of adult female nematodes. Field experiment results showed that K. pneumoniae SnebYK reduced both the number of H. glycines in soybean roots and the number of adult females. However, K. pneumoniae SnebYK caused low juvenile mortality in an in vitro assay. To further analyze the role of K. pneumoniae SnebYK in the inhibition of H. glycines infection, split root experiments were conducted. The results indicated that K. pneumoniae SnebYK controls H. glycines via induced systemic resistance, which reduces H. glycines penetration. Klebsiella pneumoniae SnebYK treatment also significantly increased the proportion of second-stage juveniles and decreased the proportions of third- and fourth-stage juveniles in the H. glycines population. Moreover, 48 h after inoculation with H. glycines, the expression levels of PR1, PR2, PR5, and PDF1.2 were significantly higher in soybeans pretreated with K. pneumoniae SnebYK than in control soybeans. Interestingly, besides providing protection against nematodes, K. pneumoniae SnebYK fixed nitrogen, produced ammonia, solubilized phosphate, and produced siderophores, leading to well-developed root system and an increase in soybean seedling fresh weight. These results demonstrate for the first time that K. pneumoniae SnebYK not only promotes soybean growth but also inhibits the invasion and development of H. glycines by inducing systemic resistance.

The northern root-knot nematode, Meloidogyne hapla, is one of the most important nematode pathogens occurring in cold regions. It is a sedentary, biotrophic parasites of plants and overwinter in the soil or in diseased roots. This study showed that the cold tolerance for the second-stage juveniles (J2) of M. hapla was moderate with the 50% survival temperature (S50) of -2.22°C and the fatal temperature was -6°C when cooling at 0.5°C min-1. Cryoprotective dehydration significantly enhance cold tolerance of M. hapla J2 with the lowest S50 of -3.28°C after held being at -1°C for 6 h. Moreover, cold shock and cold acclimation had significant effects on the freezing survival of M. hapla J2. The lethal temperature of eggs was -18°C. Therefore, the cold tolerance of M. hapla is sufficiently favorable to withstand winters in cold temperature environments.

[This corrects the article DOI: 10.1371/journal.pone.0182654.].

Soybean cyst nematode (SCN) is the most damaging soybean pest worldwide. To improve soybean resistance to SCN, we employed a soybean seed-coating strategy through combination of three rhizobacterial strains, including Bacillus simple, B. megaterium and Sinarhizobium fredii at various ratios. We found seed coating by such rhizobacterial strains at a ratio of 3:1:1 (thereafter called SN101) produced the highest germination rate and the mortality of J2 of nematodes. Then, the role of soybean seed coating by SN101 in nematode control was evaluated under both greenhouse and two field conditions in Northeast China in 2013 and 2014. Our results showed that SN101 treatment greatly reduced SCN reproduction and significantly promoted plant growth and yield production in both greenhouse and field trials, suggesting that SN101 is a promising seed-coating agent that may be used as an alternative bio-nematicide for controlling SCN in soybean fields. Our findings also demonstrate that combination of multiple rhizobacterial strains needs to be considered in the seed coating for better management of plant nematodes.

Soybean cyst nematode (SCN) causes heavy losses to soybean yield. In order to investigate the roles of soybean miRNAs during the early stages of infection (1 and 5 dpi), 24 small RNA libraries were constructed from SCN resistant cultivar Huipizhi (HPZ) and the susceptible Williams 82 (W82) cultivar for high-throughput sequencing. By sequencing the small RNA libraries, a total of 634 known miRNAs were identified, and 252 novel miRNAs were predicted. Altogether, 14 known miRNAs belonging to 13 families, and 26 novel miRNAs were differentially expressed and may respond to SCN infection in HPZ and W82. Similar expression results were also confirmed by qRT-PCR. Further analysis of the biological processes that these potential target genes of differentially expressed miRNAs regulate found that they may be strongly related to plant−pathogen interactions. Overall, soybean miRNAs experience profound changes in early stages of SCN infection in both HPZ and W82. The findings of this study can provide insight into miRNAome changes in both HPZ and W82 at the early stages of infection, and may provide a stepping stone for future SCN management.

Although pathogens such as nematodes are known to hijack nutrients from host plants, the mechanisms whereby nematodes obtain sugars from plants remain largely unknown. To determine the effects of nematode infection on host plant sugar allocation, soluble sugar (fructose, glucose, sucrose) content was investigated using high-performance liquid chromatography with refractive index detection and was found to increase significantly in tomato (Solanum lycopersicum, Sl) leaves and roots during early infection by root-knot nematodes (RKNs). To further analyze whether sugar transporters played a role in this process, the expression levels of sucrose transporter (SUT/SUC), Sugars Will Eventually be Exported Transporter (SWEET), tonoplast monosaccharide transporter (TMT), and vacuolar glucose transporter (VGT) gene family members were examined by qRT-PCR analysis after RKN infection. The results showed that three SlSUTs, 17 SlSWEETs, three SlTMTs, and SlVGT1 were upregulated in the leaves, whereas three SlSUTs, 17 SlSWEETs, two SlTMTs, and SlVGT1 were induced in the roots. To determine the function of the sugar transporters in the RKN infection process, we examined post-infection responses in the Atsuc2 mutant and pAtSUC2-GUS lines. β-glucuronidase expression was strongly induced at the infection sites, and RKN development was significantly arrested in the Atsuc2 mutant. Taken together, our analyses provide useful information for understanding the sugar transporter responses during early infection by RKNs in tomato.

Soybean cyst nematode (SCN), Heterodera glycines, is the most devastating pathogen of soybean worldwide. MicroRNAs (miRNAs) are a class of small, non-coding RNAs that are known to play important role in plant stress response. However, there are few reports profiling the miRNA expression patterns during pathogen stress. We sequenced four small RNA libraries from two soybean cultivar (Hairbin xiaoheidou, SCN race 3 resistant, Liaodou 10, SCN race 3 susceptible) that grown under un-inoculated and SCN-inoculated soil. Small RNAs were mapped to soybean genome sequence, 364 known soybean miRNA genes were identified in total. In addition, 21 potential miRNA candidates were identified. Comparative analysis of miRNA profiling indicated 101 miRNAs belong to 40 families were SCN-responsive. We also found 20 miRNAs with different express pattern even between two cultivars of the same species. These findings suggest that miRNA paly important role in soybean response to SCN and have important implications for further identification of miRNAs under pathogen stress.