Salivary Protein Cyclin-Dependent Kinase-like from Grain Aphid Sitobion avenae Suppresses Wheat Defense Response and Enhances Aphid Adaptation.

Aphids are insect pests that suck phloem sap and introduce salivary proteins into plant tissues through saliva secretion. The effector of salivary proteins plays a key role in the modulation of host plant defense responses and enhancing aphid host adaptation. Based on previous transcriptome sequencing results, a candidate effector cyclin-dependent kinase-like (CDK) was identified from the grain aphid Sitobion avenae. In this study, the function of SaCDK in wheat defense response and the adaptation of S. avenae was investigated. Our results showed that the transient overexpression of SaCDK in tobacco Nicotiana benthamiana suppressed cell death triggered by mouse pro-apoptotic protein-BAX or Phytophthora infestans PAMP-INF1. SaCDK, delivered into wheat cells through a Pseudomonas fluorescens-mediated bacterial type III secretion system, suppressed callose deposition in wheat seedlings, and the overexpression of SaCDK in wheat significantly decreased the expression levels of salicylic acid and jasmonic acid signaling pathway-related genes phenylalanine ammonia lyase (PAL), pathogenesis-related 1 protein (PR1), lipoxygenase (LOX) and Ω-3 fatty acid desaturase (FAD). In addition, aphid bioassay results showed that the survival and fecundity of S. avenae were significantly increased while feeding on the wheat plants carrying SaCDK. Taken together, our findings demonstrate that the salivary protein SaCDK is involved in inhibiting host defense response and improving its host adaptation, which lays the foundation to uncover the mechanism of the interaction of cereal aphids and host plants.

Transposition, duplication, and divergence of the telomerase RNA underlies the evolution of Mimulus telomeres.

Telomeres are nucleoprotein complexes with a crucial role of protecting chromosome ends. It consists of simple repeat sequences and dedicated telomere-binding proteins. Because of its vital functions, components of the telomere, for example its sequence, should be under strong evolutionary constraint. But across all plants, telomere sequences display a range of variation and the evolutionary mechanism driving this diversification is largely unknown. Here, we discovered in Monkeyflower (Mimulus) the telomere sequence is even variable between species. We investigated the basis of Mimulus telomere sequence evolution by studying the long noncoding telomerase RNA (TR), which is a core component of the telomere maintenance complex and determines the telomere sequence. We conducted total RNA-based de novo transcriptomics from 16 Mimulus species and analyzed reference genomes from 6 species, and discovered Mimulus species have evolved at least three different telomere sequences: (AAACCCT)n, (AAACCCG)n, and (AAACCG)n. Unexpectedly, we discovered several species with TR duplications and the paralogs had functional consequences that could influence telomere evolution. For instance, M. lewisii had two sequence-divergent TR paralogs and synthesized a telomere with sequence heterogeneity, consisting of AAACCG and AAACCCG repeats. Evolutionary analysis of the M. lewisii TR paralogs indicated it had arisen from a transposition-mediate duplication process. Further analysis of the TR from multiple Mimulus species showed the gene had frequently transposed and inserted into new chromosomal positions during Mimulus evolution. From our results, we propose the TR transposition, duplication, and divergence model to explain the evolutionary sequence turnovers in Mimulus and potentially all plant telomeres.

Association between implanted cardioverter-defibrillators and mortality for patients with left ventricular ejection fraction between 30% and 35.

BACKGROUND: Consensus guidelines support the use of implanted cardioverter-defibrillators (ICD) for primary prevention of sudden cardiac death in patients with either non-ischaemic or ischaemic cardiomyopathy with left ventricular ejection fraction (LVEF) ≤35%. However, evidence from trials for efficacy specifically for patients with LVEF near 35% is weak. Past trials are underpowered for this population and future trials are unlikely to be performed. METHODS: Patients with lowest LVEF between 30% and 35% without an ICD prior to the lowest-LVEF echo (defined as 'time zero') were identified by querying echocardiography data from 28 November 2001 to 9 July 2020 at the Massachusetts General Hospital linked to ICD treatment status. To assess the association between ICD and mortality, propensity score matching followed by Cox proportional hazards models considering treatment status as a time-dependent covariate was used. A secondary analysis was performed for LVEF 36%-40%. RESULTS: Initially, 526 440 echocardiograms representing 266 601 unique patients were identified. After inclusion and exclusion criteria were applied, 6109 patients remained for the analytical cohort. In bivariate unadjusted comparisons, patients who received ICDs were substantially more often male (79.8% vs 65.4%, p<0.0001), more often white (87.5% vs 83.7%, p<0.046) and more often had a history of ventricular tachycardia (74.5% vs 19.1%, p<0.0001) and myocardial infarction (56.1% vs 38.2%, p<0.0001). In the propensity matched sample, after accounting for time-dependence, there was no association between ICD and mortality (HR 0.93, 95% CI 0.75 to 1.15, p=0.482). CONCLUSIONS: ICD therapy was not associated with reduced mortality near the conventional LVEF threshold of 35%. Although this treatment design cannot definitively demonstrate lack of efficacy, our results are concordant with available prior trial data. A definitive, well-powered trial is needed to answer the important clinical question of primary prevention ICD efficacy between LVEF 30% and 35%.

SmCSP4 from aphid saliva stimulates salicylic acid-mediated defence responses in wheat by interacting with transcription factor TaWKRY76.

Aphid salivary proteins are critical in modulating plant defence responses. Grain aphid Sitobion miscanthi is an important wheat pest worldwide. However, the molecular basis for the regulation of the plant resistance to cereal aphids remains largely unknown. Here, we show that SmCSP4, a chemosensory protein from S. miscanthi saliva, is secreted into wheat plants during aphid feeding. Delivery of SmCSP4 into wheat leaves activates salicylic acid (SA)-mediated plant defence responses and subsequently reduces aphid performance by deterring aphid feeding behaviour. In contrast, silencing SmCSP4 gene via nanocarrier-mediated RNAi significantly decreases the ability of aphids to activate SA defence pathway. Protein-protein interaction assays showed that SmCSP4 directly interacts with wheat transcriptional factor TaWRKY76 in plant nucleus. Furthermore, TaWRKY76 directly binds to the promoter of SA degradation gene Downy Mildew Resistant 6 (DMR6) and regulates its gene expression as transcriptional activator. SmCSP4 secreted by aphids reduces the transcriptional activation activity of TaWRKY76 on DMR6 gene expression, which is proposed to result in increases of SA accumulation and enhanced plant immunity. This study demonstrated that SmCSP4 acts as salivary elicitor that is involved in activating SA signalling defence pathway of wheat by interacting with TaWRKY76, which provide novel insights into aphid-cereal crops interactions and the molecular mechanism on induced plant immunity.

Two salivary proteins Sm10 and SmC002 from grain aphid Sitobion miscanthi modulate wheat defense and enhance aphid performance.

The grain aphid Sitobion miscanthi is a serious pest of wheat that causes severe economic damage by sucking phloem sap and transmitting plant viruses. Here, two putative salivary effector homologs from S. miscanthi (Sm10 and SmC002) were selected based on sequence similarity to other characterized aphid candidate effectors. These effectors were then delivered into wheat cells separately via the type III secretion system of Pseudomonas fluorescens to elucidate their functions in the regulation of plant defenses and host fitness. The results showed that the delivery of either Sm10 or SmC002 into wheat plants significantly suppressed callose deposition and affected the transcript levels of callose synthase genes. The expression levels of salicylic acid (SA)-associated defense genes were upregulated significantly in wheat leaves carrying either Sm10 or SmC002. Moreover, LC-MS/MS analysis revealed that wheat SA levels significantly increased after the delivery of the two effectors. The results of aphid bioassays conducted on the wheat plants carrying Sm10 or SmC002 showed significant increases in the survival and fecundity of S. miscanthi. This study demonstrated that the Sm10 and SmC002 salivary effectors of S. miscanthi enhanced host plant susceptibility and benefited S. miscanthi performance by regulating wheat defense signaling pathways.

Developmental, Reproduction, and Feeding Preferences of the Sitobion avenae Mediated by Soil Silicon Application.

Silicon occupies an important position in the nutrient requirements of wheat. It has been reported that silicon enhances plant resistance to phytophagous insects. However, only limited research has been carried out on the effects of silicon application to wheat and Sitobion avenae populations. In this study, three silicon fertilizer concentrations were treated for potted wheat seedlings, including 0 g/L, 1 g/L, and 2 g/L of water-soluble silicon fertilizer solution. The effect of silicon application on the developmental period, longevity, reproduction, wing pattern differentiation, and other vital life table parameters of the S. avenae were determined. The cage method and the Petri dish isolated leaf method were used to determine the effect of silicon application on the feeding preference of the winged and wingless aphid. The results showed silicon application had no significant effect on the aphid instar of 1-4; although, 2 g/L silicon fertilizer prolonged the nymph stage and 1 and 2 g/L of silicon application all shortened the adult stage and reduced the longevity and fertility of the aphid. Two instances of silicon application reduced the net reproductive rate (R0), intrinsic rate of increase (rm), and finite rate of increase (λ) of the aphid. A 2 g/L silicon application prolonged the population doubling time (td), significantly reduced the mean generation time (T), and increased the proportion of winged aphids. The results also demonstrated that the selection ratio of winged aphids in wheat leaves treated with 1 g/L and 2 g/L silicon was reduced by 8.61% and 17.88%, respectively. The number of aphids on leaves treated with 2 g/L silicon was significantly reduced at 48 and 72 h of aphids released, and the application of silicon to wheat was detrimental to the feeding preference of S. avenae. Therefore, the application of silicon at 2 g/L to wheat has an inhibitory effect on the life parameters and feeding preference of S. avenae.

Population Growth of Fall Armyworm, Spodoptera frugiperda Fed on Cereal and Pulse Host Plants Cultivated in Yunnan Province, China.

The fall armyworm, Spodoptera frugiperda is a major agricultural pest in China, and has migrated from its continuous breeding area to other parts of China. In our study, the biological behaviors of S. frugiperda fed on maize, wheat, barley, faba beans, and soya beans were evaluated in a growth chamber. Results indicated that maize-fed S. frugiperda larvae performed well, as evidenced by shorter larva-adult periods, adult pre-oviposition period (APOP), total pre-oviposition period (TPOP), and generation time (T), and a higher survival rate, intrinsic (r) and finite (λ) rate of increase, and net reproductive rate (Ro), However, S. frugiperda larvae performed weakly when fed barley and faba bean plants, as indicated by lower survival rates, r, and λ, and longer pre-adult period, TPOP, and T. A heavier pupal weight of both sexes was recorded on faba beans (0.202 g) and a lighter weight on barley (0.169 g). Fecundity was higher when fed faba beans and maize, and lower when fed wheat and barley. Thus, maize was the most optimal and barley was the least optimal host plant, followed by faba beans, for S. frugiperda larvae growth and development. This study enhances our knowledge of S. frugiperda in these host plants and can help in the design of management approaches.

Backbone and side chain chemical shift assignment of diisopropyl fluorophosphatase (DFPase) from Loligo vulgaris, an organophosphorus-degrading enzyme.

NMR chemical shift assignments are reported for backbone (15N, 1H) and partial side chain (13Cα and ß, side chain 1H) atoms of diisopropyl fluorophosphatase (DFPase), a calcium-dependent phosphotriesterase capable of hydrolyzing phosphorus - fluorine bonds in a variety of toxic organophosphorus compounds. Analysis of residues lining the active site of DFPase highlight a number of residues whose chemical shifts can be used as a diagnostic of binding and detection of organophosphorus compounds.

Room-temperature structural studies of SARS-CoV-2 protein NendoU with an X-ray free-electron laser.

NendoU from SARS-CoV-2 is responsible for the virus's ability to evade the innate immune system by cleaving the polyuridine leader sequence of antisense viral RNA. Here we report the room-temperature structure of NendoU, solved by serial femtosecond crystallography at an X-ray free-electron laser to 2.6 Å resolution. The room-temperature structure provides insight into the flexibility, dynamics, and other intrinsic properties of NendoU, with indications that the enzyme functions as an allosteric switch. Functional studies examining cleavage specificity in solution and in crystals support the uridine-purine cleavage preference, and we demonstrate that enzyme activity is fully maintained in crystal form. Optimizing the purification of NendoU and identifying suitable crystallization conditions set the benchmark for future time-resolved serial femtosecond crystallography studies. This could advance the design of antivirals with higher efficacy in treating coronaviral infections, since drugs that block allosteric conformational changes are less prone to drug resistance.

Functional analysis of odorant-binding proteins for the parasitic host location to implicate convergent evolution between the grain aphid and its parasitoid Aphidius gifuensis.

(E)-ß-farnesene (EBF) is a typical and ecologically important infochemical in tri-trophic level interactions among plant-aphid-natural enemies. However, the molecular mechanisms by which parasitoids recognize and utilize EBF are unclear. In this study, we functionally characterized 8 AgifOBPs in Aphidifus gifuensis, one dominant endo-parasitoid of wheat aphid as well as peach aphid in China. Among which, AgifOBP6 was the only OBP upregulated by various doses of EBF, and it showed a strong binding affinity to EBF in vitro. The lack of homology between AgifOBP6 and EBF-binding proteins from aphids or from other aphid natural enemies supported that this was a convergent evolution among insects from different orders driven by EBF. Molecular docking of AgifOBP6 with EBF revealed key interacting residues and hydrophobic forces as the main forces. AgifOBP6 is widely expressed among various antennal sensilla. Furthermore, two bioassays indicated that trace EBF may promote the biological control efficiency of A. gifuensis, especially on winged aphids. In summary, this study reveals an OBP (AgifOBP6) that may play a leading role in aphid alarm pheromone detection by parasitoids and offers a new perspective on aphid biological control by using EBF. These results will improve our understanding of tri-trophic level interactions among plant-aphid-natural enemies.

Fatigue in NTSB investigations 2013-2019: evidence of accidents and injuries.

This study updates the prevalence of operator fatigue as a causative factor in accidents investigated by the National Transportation Safety Board (NTSB) and the associated injury severity in fatigue-related accidents. In total, 394 investigations were analyzed and 12% of them identified fatigue. The prevalence of fatigue varied among the transportation modes, ranging from 28% of aviation to 7% of marine. Most fatigue-related accidents (48%) occurred during late night or morning. Compared to non-fatigued operators, fatigued operators were more involved in severe or fatal injuries (odds ratio [OR] 2.30; 95% confidence interval [CI] [1.66, 2.95]) and injuries to non-operators (OR 3.32; 95% CI [2.70, 3.95]). Obstructive sleep apnea (OSA) was identified as a probable cause, contributing cause or finding in 15% of fatigue-related accidents, and in 85.7% of these accidents the operator met OSA screening criteria. Thus, opportunities remain for preventing fatigue-related accidents, including through more systematic operator screening for OSA.

Proteomic and Transcriptomic Analysis for Identification of Endosymbiotic Bacteria Associated with BYDV Transmission Efficiency by Sitobion miscanthi.

Sitobion miscanthi, an important viral vector of barley yellow dwarf virus (BYDV), is also symbiotically associated with endosymbionts, but little is known about the interactions between endosymbionts, aphid and BYDV. Therefore, two aphids' geographic populations, differing in their BYDV transmission efficiency, after characterizing their endosymbionts, were treated with antibiotics to investigate how changes in the composition of their endosymbiont population affected BYDV transmission efficiency. After antibiotic treatment, Rickettsia was eliminated from two geographic populations. BYDV transmission efficiency by STY geographic population dropped significantly, by -44.2% with ampicillin and -25.01% with rifampicin, but HDZ geographic population decreased by only 14.19% with ampicillin and 23.88% with rifampicin. Transcriptomic analysis showed that the number of DEGs related to the immune system, carbohydrate metabolism and lipid metabolism did increase in the STY rifampicin treatment, while replication and repair, glycan biosynthesis and metabolism increased in the STY ampicillin treatment. Proteomic analysis showed that the abundance of symbionin symL, nascent polypeptide-associated complex subunit alpha and proteasome differed significantly between the two geographic populations. We found that the endosymbionts can mediate vector viral transmission. They should therefore be included in investigations into aphid-virus interactions and plant disease epidemiology. Our findings should also help with the development of strategies to prevent virus transmission.

Biogenesis of telomerase RNA from a protein-coding mRNA precursor.

Telomerase is a eukaryotic ribonucleoprotein (RNP) enzyme that adds DNA repeats onto chromosome ends to maintain genomic stability and confer cellular immortality in cancer and stem cells. The telomerase RNA (TER) component is essential for telomerase catalytic activity and provides the template for telomeric DNA synthesis. The biogenesis of TERs is extremely divergent across eukaryotic kingdoms, employing distinct types of transcription machinery and processing pathways. In ciliates and plants, TERs are transcribed by RNA polymerase III (Pol III), while animal and ascomycete fungal TERs are transcribed by RNA Pol II and share biogenesis pathways with small nucleolar RNA (snoRNA) and small nuclear RNA (snRNA), respectively. Here, we report an unprecedented messenger RNA (mRNA)-derived biogenesis pathway for the 1,291 nucleotide TER from the basidiomycete fungus Ustilago maydis. The U. maydis TER (UmTER) contains a 5'-monophosphate, distinct from the 5' 2,2,7-trimethylguanosine (TMG) cap common to animal and ascomycete fungal TERs. The mature UmTER is processed from the 3'-untranslated region (3'-UTR) of a larger RNA precursor that possesses characteristics of mRNA including a 5' 7-methyl-guanosine (m7G) cap, alternative splicing of introns, and a poly(A) tail. Moreover, this mRNA transcript encodes a protein called Early meiotic induction protein 1 (Emi1) that is conserved across dikaryotic fungi. A recombinant UmTER precursor expressed from an mRNA promoter is processed correctly to yield mature UmTER, confirming an mRNA-processing pathway for producing TER. Our findings expand the plethora of TER biogenesis mechanisms and demonstrate a pathway for producing a functional long noncoding RNA from a protein-coding mRNA precursor.

The salivary effector protein Sg2204 in the greenbug Schizaphis graminum suppresses wheat defence and is essential for enabling aphid feeding on host plants.

Aphids secrete diverse repertoires of salivary effectors into host plant cells to promote infestation by modulating plant defence. The greenbug Schizaphis graminum is an important cereal aphid worldwide. However, the secreted effectors of S. graminum are still uncharacterized. Here, 76 salivary proteins were identified from the watery saliva of S. graminum using transcriptome and proteome analyses. Among them, a putative salivary effector Sg2204 was significantly up-regulated during aphid feeding stages, and transient overexpression of Sg2204 in Nicotiana benthamiana inhibited cell death induced by BAX or INF1. Delivering Sg2204 into wheat via the type III secretion system of Pseudomonas fluorescens EtAnH suppressed pattern-triggered immunity (PTI)-associated callose deposition. The transcript levels of jasmonic acid (JA)- and salicylic acid (SA)-associated defence genes of wheat were significantly down-regulated, and the contents of both JA and SA were also significantly decreased after delivery of Sg2204 into wheat leaves. Additionally, feeding on wheat expressing Sg2204 significantly increased the weight and fecundity of S. graminum and promoted aphid phloem feeding. Sg2204 was efficiently silenced via spray-based application of the nanocarrier-mediated transdermal dsRNA delivery system. Moreover, Sg2204-silenced aphids induced a stronger wheat defence response and resulted in negative impacts on aphid feeding behaviour, survival and fecundity. Silencing of Sg2204 homologues from four aphid species using nanocarrier-delivered dsRNA also significantly reduced aphid performance on host plants. Thus, our study characterized the salivary effector Sg2204 of S. graminum involved in promoting host susceptibility by suppressing wheat defence, which can also be regarded as a promising RNAi target for aphid control.

Salivary Effector Sm9723 of Grain Aphid Sitobion miscanthi Suppresses Plant Defense and Is Essential for Aphid Survival on Wheat.

Aphid salivary effectors play important roles in modulating plant defense responses. The grain aphid Sitobion miscanthi is one of the most economically important cereal aphids worldwide. However, little information is available on the identification and functional analysis of salivary effectors of S. miscanthi. In this study, a candidate salivary effector Sm9723 was identified, which was specifically expressed in aphid salivary glands and highly induced during the aphid feeding phase. Transient overexpression of Sm9723 in Nicotiana benthamiana suppressed BAX and INF1-induced cell death. Further, Sm9723 overexpression inhibited N. benthamiana defense responses by reducing pattern-triggered immunity associated callose deposition and expression levels of jasmonic and salicylic acid-associated defense genes. In addition, the salivary effector Sm9723 of S. miscanthi was effectively silenced through nanocarrier-mediated dsRNA delivery system. After silencing Sm9723, fecundity and survival of S. miscanthi decreased significantly, and the aphid feeding behavior was also negatively affected. These results suggest salivary effector Sm9723 is involved in suppressing plant immunity and is essential in enabling aphid virulence, which could be applied as potential target gene for RNAi-mediated pest control of S. miscanthi.

Plant telomere biology: The green solution to the end-replication problem.

Telomere maintenance is a fundamental cellular process conserved across all eukaryotic lineages. Although plants and animals diverged over 1.5 billion years ago, lessons learned from plants continue to push the boundaries of science, revealing detailed molecular mechanisms in telomere biology with broad implications for human health, aging biology, and stress responses. Recent studies of plant telomeres have unveiled unexpected divergence in telomere sequence and architecture, and the proteins that engage telomeric DNA and telomerase. The discovery of telomerase RNA components in the plant kingdom and some algae groups revealed new insight into the divergent evolution and the universal core of telomerase across major eukaryotic kingdoms. In addition, resources cataloging the abundant natural variation in Arabidopsis thaliana, maize (Zea mays), and other plants are providing unparalleled opportunities to understand the genetic networks that govern telomere length polymorphism and, as a result, are uncovering unanticipated crosstalk between telomeres, environmental factors, organismal fitness, and plant physiology. Here we recap current advances in plant telomere biology and put this field in perspective relative to telomere and telomerase research in other eukaryotic lineages.

Spatial Expression Analysis of Odorant Binding Proteins in Both Sexes of the Aphid Parasitoid Aphidius gifuensis and Their Ligand Binding Properties.

In China, Aphidius gifuensis is one of the most common endoparasitoids of the green peach aphid Myzus persicae and grain aphid Sitobion miscanthi in the field. Insect odorant-binding proteins (OBPs) play vital roles in odor perception during feeding, host searching, mating and oviposition. In addition, some OBPs are involved in other physiological processes such as gustation and reproduction. In the present study, a comparative antennal transcriptomic analysis was applied between male and female A. gifuensis. The spatial expression patterns among antennae, heads, thoraxes, abdomens and legs of OBPs in both sexes were further profiled. Fifteen AgifOBPs were predicted, and 14 of them were identified by gene cloning, including 12 classic OBPs and 2 min-C OBPs. As expected, all OBPs were mainly expressed at high levels in antennae, heads or legs which are sensory organs and tissues. Finally, ligand binding properties of 2 OBPs (AgifOBP7 and AgifOBP9) were further evaluated. Female leg specifically expressed AgifOBP9 displays a broad and high binding property to aphid alarm pheromones, plant green volatiles and aphid sex pheromones (Ki < 10 µΜ). However, female leg specifically expressed AgifOBP7 displays poor affinity for all tested ligands except CAU-II-11 ((E)-3,7-dimethylocta-2,6-dien-1-yl-2-hydroxy-3-methoxybenzoate), a reported (E)-ß-farnesene (EBF) analog with an exceptionally high binding affinity (Ki = 1.07 ± 0.08 µΜ). In summary, we reported the spatial expression pattern of the OBP repertoire in A. gifuensis, and further studied the binding properties of OBP7 and OBP9, which are mainly expressed in female legs, laying the foundation for the dissection of the contribution of OBPs to chemosensation in A. gifuensis.

Biochemical and Morphological Mechanisms Underlying the Performance and Preference of Fall Armyworm (Spodoptera frugiperda) on Wheat and Faba Bean Plants.

Spodoptera frugiperda (J. E. Smith), which attacked China in 2019, remains a significant threat to wheat production. Wheat-faba bean intercropping systems prevent damage caused by wheat aphids; however, the potential role in S. frugiperda control remains unclear. Here, the adaptability and preferences of S. frugiperda to wheat and its common intercropped plant, faba bean, were evaluated to implement an eco-friendly approach for S. frugiperda management. Their adaptability showed that both hosts could support S. frugiperda to complete their life cycle; however, the larvae performed worse on faba bean compared with on wheat. The biochemical analysis revealed that faba bean plants had lower contents of soluble sugars and total proteins but higher levels of phenolics and tannins than in wheat leaves. The gravid S. frugiperda preferred (during the preference assays) to oviposit on wheat rather than on faba bean plants in cage tests. The wheat odor was preferred over the faba bean odor in the Y-tube olfactometer bioassays. The morphological scanning electron microscopy (SEM) showed increased trichome density on wheat leaves. Therefore, the faba bean plants displayed antibiosis on larvae and were repellent to female moths, thus, suggesting that faba bean plants could serve as a push crop to be intercropped with wheat for S. frugiperda control for wheat fields.

Screening and Evaluation for Antixenosis Resistance in Wheat Accessions and Varieties to Grain Aphid, Sitobion miscanthi (Takahashi) (Hemiptera: Aphididae).

The grain aphid, Sitobion miscanthi causes serious damage by removing nutritional content from wheat plants and transmitting viral diseases. The use of resistant wheat cultivars is an effective method of aphid management. To identify S. miscanthi resistant cultivars, preliminary antixenosis resistance screening was conducted on 112 Ethiopian and 21 Chinese wheat accessions and varieties along with bioassay to test for further antixenosis resistance, identification of aphid feeding behavior using electrical penetration graph (EPG), and imaging of leaf trichome densities using a 3D microscope. According to antixenosis resistance screening, one highly-resistant, 25 moderately-resistant, and 38 slightly-resistant wheat cultivars to S. miscanthi were identified. Aphid choice tests showed that Luxuan266, 243726, and 213312 were the least preferred after 12, 24, 48, and 72 h of S. miscanthi release. Longer duration of Np, longer time to first probe, and shorter duration of E2 waveforms were recorded in Lunxuan266, 243726, and 213312 than in Beijing 837. The trichome density on adaxial and abaxial leaf surfaces of Lunxuan266, 243726 and 213312 was significantly higher than on those of Beijing 837. We concluded that Lunxuan266, 243726, and 213312 were antixenosis resistant to S. miscanthi based on the choice test, EPG results, and leaf trichome densities.