A 12.4-day periodicity in a close binary system after a supernova.

Neutron stars and stellar-mass black holes are the remnants of massive star explosions1. Most massive stars reside in close binary systems2, and the interplay between the companion star and the newly formed compact object has been theoretically explored3, but signatures for binarity or evidence for the formation of a compact object during a supernova explosion are still lacking. Here we report a stripped-envelope supernova, SN 2022jli, which shows 12.4-day periodic undulations during the declining light curve. Narrow Hα emission is detected in late-time spectra with concordant periodic velocity shifts, probably arising from hydrogen gas stripped from a companion and accreted onto the compact remnant. A new Fermi-LAT γ-ray source is temporally and positionally consistent with SN 2022jli. The observed properties of SN 2022jli, including periodic undulations in the optical light curve, coherent Hα emission shifting and evidence for association with a γ-ray source, point to the explosion of a massive star in a binary system leaving behind a bound compact remnant. Mass accretion from the companion star onto the compact object powers the light curve of the supernova and generates the γ-ray emission.

Wheat fungal endophyte communities are inseparable from the host and influence plant development.

Plants harbor complex and highly diverse fungal endophyte communities (FECs), making it difficult to evaluate the functional role of individual taxa, subsets of the community, or the FEC as a whole. To reduce the complexity of this system, we aimed to produce fungi-null wheat (Triticum aestivum) plants. To this end, we treated seeds with heat and fungicides and generated plants from rescued embryos and callus tissue. A culture-based approach and reverse transcription PCR analysis were negative, indicating that all treatments produced plants apparently free of fungi. However, the analysis of DNA using digital droplet PCR and next-generation sequencing revealed that tissues from all treatments retained low levels but diversity-rich FECs. While the FECs varied in composition across treatments and tissues, they all included core taxa of the mycobiome. The reduced fungal biomass, along with the changes in FEC composition, negatively affected plant development, supporting a FEC contribution to proper plant development and fitness. Our discovery that a large part of the FEC cannot be separated from plants and can be transmitted through seeds and tissue culture calls for reevaluation of particular microbiome paradigms, such as core taxa concepts, transmission modes, and functional species.IMPORTANCEThe native microbiome in a given plant must be considered when evaluating the effect of a single taxon or synthetic community. The pre-existing microbiome can interact with artificially added microbial cargo, which affects the final outcome. Such issues can be at least partially solved by the use of endophyte-free plants, which provide a clean background that should be useful in determining the effect of a single taxon, taxa combinations, or the entire microbiome on plant performance. Previous reports regarded plants as endophyte-free or axenic by the lack of fungal growth on culture media or the generation of plants from tissue cultures. We showed here that while fungi could not be isolated from fungicide-treated or tissue culture-regenerated plants, nevertheless, all plants contained rich fungal endophyte communities; namely, it was impossible to create fungi-free wheat plants. Our results call for rethinking fundamental microbiome-related concepts, such as core taxa, transmission mode, and functional species.

Serum Magnesium Is Associated with Long-Term Survival of Non-ST-Elevation Myocardial Infarction Patients.

BACKGROUND: Low serum magnesium (sMg) is associated with cardiovascular risk factors and atherosclerotic disease. OBJECTIVE: To evaluate the association between sMg levels on admission and clinical outcomes in hospitalized non-ST-elevation myocardial infarction (NSTEMI) patients. METHODS: A retrospective analysis of all patients admitted to a single tertiary center with a primary diagnosis of NSTEMI. Patients with advanced chronic kidney disease were excluded. Clinical data were collected and compared between lower sMg quartile patients (Q1; sMg < 1.9 mg/dL) and all other patients (Q2-Q4; sMg ≥ 1.9 mg/dL). RESULTS: The study cohort included 4552 patients (70% male, median age 69 [IQR 59-79]) who were followed for a median of 4.4 (IQR 2.4-6.6) years. The median sMg level in the low sMg group was 1.7 (1.6-1.8) and 2.0 (2.0-2.2) mg/dL in the normal/high sMg group. The low sMg group was older (mean of 72 vs. 67 years), less likely to be male (64% vs. 72%), and had higher rates of comorbidities, including diabetes, hypertension, and atrial fibrillation (59% vs. 29%, 92% vs. 85%, and 6% vs. 5%; p < 0.05 for all). Kaplan-Meier survival analysis demonstrated significantly higher cumulative death probability at 4 years in the low sMg group (34% vs. 22%; p log rank <0.001). In a multivariable analysis model adjusted for sex, significant comorbidities, coronary interventions during the hospitalization, and renal function, the low sMg group exhibited an independent 24% increased risk of death during follow up (95% CI 1.11-1.39; p < 0.001). CONCLUSIONS: Low sMg is independently associated with higher risk of long-term mortality among patients recovering from an NSTEMI event.

Genome-wide association mapping of rust resistance in Aegilops longissima.

The rust diseases, including leaf rust caused by Puccinia triticina (Pt), stem rust caused by P. graminis f. sp. tritici (Pgt), and stripe rust caused by P. striiformis f. sp. tritici (Pst), are major limiting factors in wheat production worldwide. Identification of novel sources of rust resistance genes is key to developing cultivars resistant to rapidly evolving pathogen populations. Aegilops longissima is a diploid wild grass native to the Levant and closely related to the modern bread wheat D subgenome. To explore resistance genes in the species, we evaluated a large panel of Ae. longissima for resistance to several races of Pt, Pgt, and Pst, and conducted a genome-wide association study (GWAS) to map rust resistance loci in the species. A panel of 404 Ae. longissima accessions, mostly collected from Israel, were screened for seedling-stage resistance to four races of Pt, four races of Pgt, and three races of Pst. Out of the 404 accessions screened, two were found that were resistant to all 11 races of the three rust pathogens screened. The percentage of all accessions screened that were resistant to a given rust pathogen race ranged from 18.5% to 99.7%. Genotyping-by-sequencing (GBS) was performed on 381 accessions of the Ae. longissima panel, wherein 125,343 single nucleotide polymorphisms (SNPs) were obtained after alignment to the Ae. longissima reference genome assembly and quality control filtering. Genetic diversity analysis revealed the presence of two distinct subpopulations, which followed a geographic pattern of a northern and a southern subpopulation. Association mapping was performed in the genotyped portion of the collection (n = 381) and in each subpopulation (n = 204 and 174) independently via a single-locus mixed-linear model, and two multi-locus models, FarmCPU, and BLINK. A large number (195) of markers were significantly associated with resistance to at least one of 10 rust pathogen races evaluated, nine of which are key candidate markers for further investigation due to their detection via multiple models and/or their association with resistance to more than one pathogen race. The novel resistance loci identified will provide additional diversity available for use in wheat breeding.

Serine peptidases and increased amounts of soluble proteins contribute to heat priming of the plant pathogenic fungus Botrytis cinerea.

Botrytis cinerea causes gray mold disease in leading crop plants. The disease develops only at cool temperatures, but the fungus remains viable in warm climates and can survive periods of extreme heat. We discovered a strong heat priming effect in which the exposure of B. cinerea to moderately high temperatures greatly improves its ability to cope with subsequent, potentially lethal temperature conditions. We showed that priming promotes protein solubility during heat stress and discovered a group of priming-induced serine-type peptidases. Several lines of evidence, including transcriptomics, proteomics, pharmacology, and mutagenesis data, link these peptidases to the B. cinerea priming response, highlighting their important roles in regulating priming-mediated heat adaptation. By imposing a series of sub-lethal temperature pulses that subverted the priming effect, we managed to eliminate the fungus and prevent disease development, demonstrating the potential for developing temperature-based plant protection methods by targeting the fungal heat priming response. IMPORTANCE Priming is a general and important stress adaptation mechanism. Our work highlights the importance of priming in fungal heat adaptation, reveals novel regulators and aspects of heat adaptation mechanisms, and demonstrates the potential of affecting microorganisms, including pathogens through manipulations of the heat adaptation response.

Distinct Features Based on Partitioning of the Endophytic Fungi of Cereals and Other Grasses.

Endophytic fungi form a significant part of the plant mycobiome. Defining core members is crucial to understanding the assembly mechanism of fungal endophytic communities (FECs) and identifying functionally important community members. We conducted a meta-analysis of FECs in stems of wheat and five wild cereal species and generated a landscape of the fungal endophytic assemblages in this group of plants. The analysis revealed that several Ascomycota members and basidiomycetous yeasts formed an important compartment of the FECs in these plants. We observed a weak spatial autocorrelation at the regional scale and high intrahost variations in the FECs, suggesting a space-related heterogeneity. Accordingly, we propose that the heterogeneity among subcommunities should be a criterion to define the core endophytic members. Analysis of the subcommunities and meta-communities showed that the core and noncore members had distinct roles in various assembly processes, such as stochasticity, universal dynamics, and network characteristics, within each host. The distinct features identified between the community partitions of endophytes aid in understanding the principles that govern the assembly and function of natural communities. These findings can assist in designing synthetic microbiomes. IMPORTANCE This study proposes a novel method for diagnosing core microbiotas based on prevalence of community members in a meta-community, which could be determined and supported statistically. Using this approach, the study found stratification in community assembly processes within fungal endophyte communities (FECs) in the stems of wheat and cereal-related wild species. The core and noncore partitions of the FECs exhibited certain degrees of determinism from different aspects. Further analysis revealed abundant and consistent interactions between rare taxa, which might contribute to the determinism process in noncore partitions. Despite minor differences in FEC compositions, wheat FECs showed distinct patterns in community assembly processes compared to wild species, suggesting the effects of domestication on FECs. Overall, our study provided a new approach for identifying core microbiota and provides insights into the community assembly processes within FECs in wheat and related wild species.

The wheat stem rust resistance gene Sr43 encodes an unusual protein kinase.

To safeguard bread wheat against pests and diseases, breeders have introduced over 200 resistance genes into its genome, thus nearly doubling the number of designated resistance genes in the wheat gene pool1. Isolating these genes facilitates their fast-tracking in breeding programs and incorporation into polygene stacks for more durable resistance. We cloned the stem rust resistance gene Sr43, which was crossed into bread wheat from the wild grass Thinopyrum elongatum2,3. Sr43 encodes an active protein kinase fused to two domains of unknown function. The gene, which is unique to the Triticeae, appears to have arisen through a gene fusion event 6.7 to 11.6 million years ago. Transgenic expression of Sr43 in wheat conferred high levels of resistance to a wide range of isolates of the pathogen causing stem rust, highlighting the potential value of Sr43 in resistance breeding and engineering.

Treatment of late paravalvular regurgitation after transcatheter aortic valve implantation: prognostic implications.

AIMS: Paravalvular regurgitation (PVR) after transcatheter aortic valve implantation (TAVI) is associated with increased morbidity and mortality. The effect of transcatheter interventions to treat PVR after the index TAVI was investigated. METHODS AND RESULTS: A registry of consecutive patients who underwent transcatheter intervention for ≥ moderate PVR after the index TAVI at 22 centers. The principal outcomes were residual aortic regurgitation (AR) and mortality at 1 year after PVR treatment. A total of 201 patients were identified: 87 (43%) underwent redo-TAVI, 79 (39%) plug closure, and 35 (18%) balloon valvuloplasty. Median TAVI-to-re-intervention time was 207 (35; 765) days. The failed valve was self-expanding in 129 (63.9%) patients. The most frequent devices utilized were a Sapien 3 valve for redo-TAVI (55, 64%), an AVP II as plug (33, 42%), and a True balloon for valvuloplasty (20, 56%). At 30 days, AR ≥ moderate persisted in 33 (17.4%) patients: 8 (9.9%) after redo-TAVI, 18 (25.9%) after plug, and 7 (21.9%) after valvuloplasty (P = 0.036). Overall mortality was 10 (5.0%) at 30 days and 29 (14.4%) at 1 year: 0, 8 (10.1%), and 2 (5.7%) at 30 days (P = 0.010) and 11 (12.6%), 14 (17.7%), and 4 (11.4%) at 1 year (P = 0.418), after redo-TAVI, plug, and valvuloplasty, respectively. Regardless of treatment strategy, patients in whom AR was reduced to ≤ mild had lower mortality at 1 year compared with those with AR persisting ≥ moderate [11 (8.0%) vs. 6 (21.4%); P = 0.007]. CONCLUSION: This study describes the efficacy of transcatheter treatments for PVR after TAVI. Patients in whom PVR was successfully reduced had better prognosis. The selection of patients and the optimal PVR treatment modality require further investigation.

General versus Regional Anesthesia and Neonatal Data: A Propensity-Score-Matched Study.

OBJECTIVE: This study aimed to evaluate whether there is a difference in neonatal outcomes with general anesthesia (GA) versus regional anesthesia (RA) when induction of anesthesia to delivery time (IADT) is prolonged (≥10 minutes). STUDY DESIGN: This is a retrospective case-control study that included cases from July 2014 until August 2020. We reviewed all singleton pregnancies delivered between 24 and 42 weeks of gestation with IADT ≥ 10 minutes. Urgent deliveries, those who received RA for labor pain management or started cesarean delivery under RA and converted to GA, as well as cases with fetal anomalies, were excluded. The propensity score (PS) matching method was performed using age, ethnicity/race, body mass index, gestational age at delivery, preexisting maternal comorbidities, and pregnancy complications. Analyses were performed with SAS software version 9.4. RESULTS: During the study period, we identified 258 cases meeting inclusion criteria. After the PS matching was applied, the study sample was reduced to 60 cases in each group. The median IADT and uterine incision to delivery time were similar between groups (41.5 [30.5, 52] vs. 46 minutes [38, 53.5], p = 0.2 and 1.5 [1, 3] vs. 2 minutes [1, 3], respectively). There was no significant difference between groups with respect to arterial or venous cord pH (7.24 [7.21, 7.26] vs. 7.23 [7.2, 7.27], p = 0.7 and 7.29 [7.26, 7.33] vs. 7.3 [7.26, 7.33], p = 0.4, respectively). Nor were there any associations between maternal characteristics and Apgar's score at 5 minutes, except for Apgar's score at 1 minute (p < 0.001). No significant difference was identified in the rate of admission to the neonatal intensive care unit (NICU; 11 [52.4%] vs. 10 [47.6%], p = 0.8) or NICU length of stay between GA and RA (4 [3, 14] vs. 4.5 [3, 11], p = 0.9). CONCLUSION: Our data indicate that even with prolonged IADT, favorable neonatal outcomes are seen with both GA and RA, in contrast with previous studies performed decades ago. KEY POINTS: · Improving cesarean delivery safety, including the safety of anesthesia, is of paramount importance.. · Reappraisal of historical outcomes is warranted as advances in the medical field unfold.. · Favorable neonatal outcomes are seen with both general and regional anesthesia..

Killing softly: a roadmap of Botrytis cinerea pathogenicity.

Botrytis cinerea, a widespread plant pathogen with a necrotrophic lifestyle, causes gray mold disease in many crops. Massive secretion of enzymes and toxins was long considered to be the main driver of infection, but recent studies have uncovered a rich toolbox for B. cinerea pathogenicity. The emerging picture is of a multilayered infection process governed by the exchange of factors that collectively contribute to disease development. No plant shows complete resistance against B. cinerea, but pattern-triggered plant immune responses have the potential to significantly reduce disease progression, opening new possibilities for producing B. cinerea-tolerant plants. We examine current B. cinerea infection models, highlight knowledge gaps, and suggest directions for future studies.

Botrytis cinerea Transcription Factor BcXyr1 Regulates (Hemi-)Cellulase Production and Fungal Virulence.

Botrytis cinerea is an agriculturally notorious plant-pathogenic fungus with a broad host range. During plant colonization, B. cinerea secretes a wide range of plant-cell-wall-degrading enzymes (PCWDEs) that help in macerating the plant tissue, but their role in pathogenicity has been unclear. Here, we report on the identification of a transcription factor, BcXyr1, that regulates the production of (hemi-)cellulases and is necessary for fungal virulence. Deletion of the bcxyr1 gene led to impaired spore germination and reduced fungal virulence and reactive oxygen species (ROS) production in planta. Secreted proteins collected from the bcxyr1 deletion strain displayed a weaker cell-death-inducing effect than the wild-type secretome when infiltrated to Nicotiana benthamiana leaves. Transcriptome sequencing (RNA-seq) analysis revealed 41 genes with reduced expression in the Δbcxyr1 mutant compared with those in the wild-type strain, of which half encode secreted proteins that are particularly enriched in carbohydrate-active enzyme (CAZyme)-encoding genes. Among them, we identified a novel putative expansin-like protein that was necessary for fungal virulence, supporting the involvement of BcXyr1 in the regulation of extracellular virulence factors. IMPORTANCE PCWDEs are considered important components of the virulence arsenal of necrotrophic plant pathogens. However, despite intensive research, the role of PCWDEs in the pathogenicity of necrotrophic phytopathogenic fungi remains ambiguous. Here, we demonstrate that the transcription factor BcXyr1 regulates the expression of a specific set of secreted PCWDE-encoding genes and that it is essential for fungal virulence. Furthermore, we identified a BcXyr1-regulated expansin-like gene that is required for fungal virulence. Our findings provide strong evidence for the importance of PCWDEs in the pathogenicity of B. cinerea and highlight specific PCWDEs that might be more important than others.

Early Invasive Strategy and Outcome of Non-ST-Segment Elevation Myocardial Infarction Patients With Chronic Kidney Disease.

BACKGROUND: Current guidelines suggest that an early invasive strategy should be considered for the treatment of non-ST-segment elevation myocardial infarction (NSTEMI). Although chronic kidney disease (CKD) is common among NSTEMI patients, these patients are under-represented in clinical trials, and data regarding their management are limited. OBJECTIVES: The authors sought to evaluate the association between early invasive strategy and long-term survival among patients with NSTEMI and CKD. METHODS: This was a retrospective analysis of 7,107 consecutive NSTEMI patients between 2008 and 2021. Patients were dichotomized into early (≤24 hours) and delayed invasive groups and stratified by kidney function. Inverse probability treatment weighting was used to adjust for differences in baseline characteristics. The primary outcome was all-cause mortality. RESULTS: The final study population comprised 3,529 invasively treated patients with a median age of 66 years (IQR: 58-74 years), 1,837 (52%) of whom were treated early. There were 483 (14%) patients with at least moderate CKD (estimated glomerular filtration rate [eGFR] <45 mL/min/1.73 m2). During a median follow-up of 4 years (IQR: 2-6 years), 527 (15%) patients died. After inverse probability treatment weighting, an early invasive strategy was associated with a significant 30% lower mortality compared with a delayed strategy (HR: 0.7; 95% CI: 0.56-0.85). The association between early invasive strategy and mortality was modified by eGFR (Pinteraction < 0.001) and declined with lower renal function, with no difference in mortality among patients with eGFR <45 mL/min/1.73 m2 (HR: 0.89; 95% CI: 0.64-1.24). CONCLUSIONS: Among NSTEMI patients, the association of early invasive strategy with long-term survival is modified by CKD and was not observed in patients with eGFR <45 mL/min/1.73 m2.

Management and outcome of patients with non-ST elevation myocardial infarction and intercurrent non-coronary precipitating events.

AIMS: To evaluate the effect of an intercurrent non-coronary illness on the management and outcome of patients with non-ST-segment elevation myocardial infarction (NSTEMI). METHODS AND RESULTS: Consecutive hospitalized patients with a primary diagnosis of NSTEMI between August 2008 and December 2019 at Sheba Medical Center. All patients' records were reviewed for the presence of a non-coronary precipitating event (NCPE): a major intercurrent acute non-coronary illness or condition, either cardiac or non-cardiac. The primary outcome was all-cause mortality. Cox regression with interaction analysis was applied. Final study population comprised 6491 patients, of whom 2621 (40%) had NCPEs. Patients with NCPEs were older (77 vs. 69 years) and more likely to have comorbidities. The most prevalent event was infection (35%, n = 922). During a median follow-up of 30 months, 2529 patients died. Patients with NCPEs were 43% more likely to die during follow-up in a multivariable model (95% CI: 1.31-1.55). Invasive strategy was associated with a 55% lower mortality among patients without NCPE and only 44% among patients with NCPE (P for interaction < 0.001). Dual antiplatelet therapy (DAPT) was associated with a 20% lower mortality in patients without NCEP and a non-significant mortality difference among patients with NCPE (P for interaction = 0.014). Sub-analysis by the specific NCPE showed the highest mortality risk among patients with infectious precipitant. The lower mortality associated with invasive strategy was not observed in this subgroup. CONCLUSION: Among NSTEMI patients, the presence of an NCPE is associated with poor survival and modifies the effect of management strategies.

Pathogenic strategies and immune mechanisms to necrotrophs: Differences and similarities to biotrophs and hemibiotrophs.

Pathogenesis in plant diseases is complex comprising diverse pathogen virulence and plant immune mechanisms. These pathogens cause damaging plant diseases by deploying specialized and generic virulence strategies that are countered by intricate resistance mechanisms. The significant challenges that necrotrophs pose to crop production are predicted to increase with climate change. Immunity to biotrophs and hemibiotrophs is dominated by intracellular receptors that recognize specific effectors and activate resistance. These mechanisms play only minor roles in resistance to necrotrophs. Pathogen- or host-derived conserved pattern molecules trigger immune responses that broadly contribute to plant immunity. However, certain pathogen or host-derived immune elicitors are enriched by the virulence activities of necrotrophs. Different plant hormones modulate systemic resistance and cell death that have differential impacts on resistance to pathogens of different lifestyles. Knowledge of mechanisms that contribute to resistance to necrotrophs has expanded. Besides toxins and cell wall degrading enzymes that dominate the pathogenesis of necrotrophs, other effectors with subtle contributions are being identified.

Invasive Management in Older Adults (≥80 Years) With Non-ST Elevation Myocardial Infarction.

OBJECTIVE: To evaluate the association of invasive management (coronary angiogram) with all-cause mortality among older adult (≥80 years of age) patients presenting with non-ST elevation myocardial infarction (NSTEMI) by frailty status. PATIENTS AND METHODS: This study used a retrospective cohort of consecutive older adult patients who were hospitalized with NSTEMI as their primary clinical diagnosis between August 1, 2008, and December 31, 2019. Cox regression models were applied with stratification by frailty status (low, medium, and high). Extensive sensitivity analyses were conducted including propensity score matching and inverse probability treatment weighting models. RESULTS: The study population included 2317 patients with median age of 86 years (IQR, 83-90 years) of whom 1243 (53.6%) were men. Patients who were managed invasively (n=581 [25%]) were less likely to be frail (7% vs 44%, P<.001). During the follow-up (median, 19 months, IQR, 4-41 months), 1599 (69%) patients died. In a multivariable Cox model, invasive approach was associated with adjusted hazard ratio (HR) of 0.61 (95% CI, 0.53 to 0.71) for the risk of death. The benefit of invasive approach was consistent among low, medium, and high frailty subgroups with adjusted HRs of 0.74 (95% CI, 0.58 to 0.93), 0.65 (95% CI, 0.50 to 0.85), and 0.52 (95% CI, 0.34 to 0.78), respectively (P for interaction = 0.48). Results were consistent with propensity score matching and inverse probability treatment weighting analyses (HR, 0.6; 95% CI, 0.50 to 0.71 and HR, 0.67; 95% CI, 0.55 to 0.82, respectively). Sensitivity analysis addressing potential immortal time bias and residual confounding yielded similar results. CONCLUSION: Invasive approach is associated with improved survival among older adults with NSTEMI irrespective of frailty status.

Jasmonic acid pathway is required in the resistance induced by Acremonium sclerotigenum in tomato against Pseudomonas syringae.

The use of fungal endophytes is considered as a new tool to confer resistance in plants against stresses. However, the mechanisms involved in colonization as well as in the induction of resistance by the endophytes are usually unclear. In this work, we tested whether a fungal endophyte isolated from an ancestor of wheat could induce resistance in plants of a different class from the ones that were isolated from the beginning. Seeds of Solanum lycopersicum were inoculated with Acremonium sclerotigenum and after four weeks, seedlings were inoculated with the bacterium Pseudomonas syringae pv tomato. Plants inoculated with endophytes showed significantly lower symptoms of infection as well as lower levels of colony forming units compared with control plants. Moreover, the presence of the endophytes induced an enhancement of Jasmonic acid (JA) upon inoculation with P. syringae compared with endophyte free plants. To ascertain the implication of JA in the resistance induced by A. sclerotigenum, two mutants defective in JA were tested. Results showed that the endophyte is not able to induce resistance in the mutant spr2, which is truncated in the first step of JA biosynthesis. On the contrary, acx1 mutant plants, which are unable to synthesize JA from OPC8, show a phenotype similar to wild type plants. Moreover, experiments with GFP-tagged endophytes showed no differences in the colonization in both mutants. In conclusion, the jasmonic acid pathway is required for the resistance mediated by the endophyte A. sclerotigenum in tomato against the biotrophic bacterium P. syringae but is not necessary for the colonization.

Aegilops sharonensis genome-assisted identification of stem rust resistance gene Sr62.

The wild relatives and progenitors of wheat have been widely used as sources of disease resistance (R) genes. Molecular identification and characterization of these R genes facilitates their manipulation and tracking in breeding programmes. Here, we develop a reference-quality genome assembly of the wild diploid wheat relative Aegilops sharonensis and use positional mapping, mutagenesis, RNA-Seq and transgenesis to identify the stem rust resistance gene Sr62, which has also been transferred to common wheat. This gene encodes a tandem kinase, homologues of which exist across multiple taxa in the plant kingdom. Stable Sr62 transgenic wheat lines show high levels of resistance against diverse isolates of the stem rust pathogen, highlighting the utility of Sr62 for deployment as part of a polygenic stack to maximize the durability of stem rust resistance.

Botrytis cinerea BcSSP2 protein is a late infection phase, cytotoxic effector.

Botrytis cinerea is a broad-host-range necrotrophic phytopathogen responsible for serious diseases in leading crops. To facilitate infection, B. cinerea secretes a large number of effectors that induce plant cell death. In screening secretome data of B. cinerea during infection stage, we identified a phytotoxic protein (BcSSP2) that can also induce immune resistance in plants. BcSSP2 is a small, cysteine-rich protein without any known domains. Transient expression of BcSSP2 in leaves caused chlorosis that intensifies with time and eventually leads to death. Point mutations in eight of 10 cysteine residues abolished phytotoxicity, but residual toxic activity remained after heating treatment, suggesting contribution of unknown epitopes to protein phytotoxicity. The expression of bcssp2 was low during the first 36 h after inoculation and increased sharply upon transition to late infection stage. Deletion of bcssp2 did not cause statistically significant changes in lesions size on bean and tobacco leaves. Further analyses indicated that the phytotoxicity of BcSSP2 is negatively regulated by the receptor-like kinases BAK1 and SOBIR1. Collectively, our findings show that BcSSP2 is an effector protein that toxifies the host cells, but is also recognized by the plant immune system.

Genome sequences of three Aegilops species of the section Sitopsis reveal phylogenetic relationships and provide resources for wheat improvement.

Aegilops is a close relative of wheat (Triticum spp.), and Aegilops species in the section Sitopsis represent a rich reservoir of genetic diversity for the improvement of wheat. To understand their diversity and advance their utilization, we produced whole-genome assemblies of Aegilops longissima and Aegilops speltoides. Whole-genome comparative analysis, along with the recently sequenced Aegilops sharonensis genome, showed that the Ae. longissima and Ae. sharonensis genomes are highly similar and are most closely related to the wheat D subgenome. By contrast, the Ae. speltoides genome is more closely related to the B subgenome. Haplotype block analysis supported the idea that Ae. speltoides genome is closest to the wheat B subgenome, and highlighted variable and similar genomic regions between the three Aegilops species and wheat. Genome-wide analysis of nucleotide-binding leucine-rich repeat (NLR) genes revealed species-specific and lineage-specific NLR genes and variants, demonstrating the potential of Aegilops genomes for wheat improvement.