Heritable differences in abundance of bacterial rhizosphere taxa are correlated with fungal necrotrophic pathogen resistance.

Host-microbe interactions are increasingly recognized as important drivers of organismal health, growth, longevity and community-scale ecological processes. However, less is known about how genetic variation affects hosts' associated microbiomes and downstream phenotypes. We demonstrate that sunflower (Helianthus annuus) harbours substantial, heritable variation in microbial communities under field conditions. We show that microbial communities co-vary with heritable variation in resistance to root infection caused by the necrotrophic pathogen Sclerotinia sclerotiorum and that plants grown in autoclaved soil showed almost complete elimination of pathogen resistance. Association mapping suggests at least 59 genetic locations with effects on both microbial relative abundance and Sclerotinia resistance. Although the genetic architecture appears quantitative, we have elucidated previously unexplained genetic variation for resistance to this pathogen. We identify new targets for plant breeding and demonstrate the potential for heritable microbial associations to play important roles in defence in natural and human-altered environments.

Trends in hospitalization of patients undergoing endovascular treatment of thoracoabdominal aortic aneurysms based on cerebrospinal fluid drainage strategy.

OBJECTIVE: The aim of this study was to identify trends in hospital length of stay (HLOS) and intensive care unit length of stay (ICULOS), and the relationship with cerebrospinal fluid drainage (CSFD) protocols in patients undergoing fenestrated-branched endovascular aortic repair (FB-EVAR) of thoracoabdominal aortic aneurysms (TAAAs). METHODS: A retrospective review of patients who underwent elective FB-EVAR for extent I to IV TAAAs between 2008 and 2023 at a single aortic center of excellence was conducted. Patient demographics, cardiovascular comorbidities, surgical risk, technical details, CSFD strategy (prophylactic or therapeutic), procedural success, and perioperative outcomes were collected. Patients were divided into two groups based on CSFD protocol. Group 1 included patients treated before 2020 when prophylactic CSFD was performed widely, and Group 2 consisted of patients treated since 2020 with therapeutic CSFD. Primary end points were HLOS, ICULOS, major adverse events, and perioperative mortality. RESULTS: FB-EVAR was performed in 702 patients; 412 underwent elective TAAA repair and were included in the analysis. Mean age was 73 ± 8 years and 68% were male. Patient-specific manufactured devices were used in 252 patients (61%), physician-modified endografts in 110 (27%), and 50 patients (12%) were treated with off-the-shelf devices. Demographics, aneurysm extent, major adverse events (including spinal cord ischemia [SCI]), and mortality were similar in both groups. A significant reduction in mean HLOS between the groups (9 ± 9 vs 6 ± 5 days; P = .02) coincided with decreased use of prophylactic CSFD (70% vs 1.2%; P < .001), with similar rates of SCI (7.6% vs 4.9%; P = .627) and ICULOS (3 ± 3 vs 2.5 ± 3; P = .19). Patients in the therapeutic drainage cohort (group 2) had a higher incidence of congestive heart failure (24% vs 11%; P = .003), hypercholesterolemia (91% vs 80%; P = .015), chronic obstructive pulmonary disease (55% vs 37%; P = .004), and peripheral artery disease (39% vs 19%; P < .001) compared with group 1, suggesting treatment of a more complex patient cohort. On adjusted multivariable analysis accounting for American Society of Anesthesiologists score, comorbidities, and device type, the difference in HLOS remained statistically significant (P = .01). CONCLUSIONS: HLOS decreased over time in patients undergoing FB-EVAR for TAAA after transition from a prophylactic to a therapeutic CSFD protocol. This transition was the only modifiable, independent risk factor for a shorter HLOS, without an increase in SCI, albeit with similar ICULOS.

Implications and late outcomes of type II endoleaks after endovascular aneurysm repair.

OBJECTIVE: Type II endoleaks (T2ELs) are the most common cause of reintervention after endovascular aneurysm repair (EVAR). Although most resolve spontaneously, the long-term implications of T2ELs remain elusive. We aim to evaluate the impact of persistent and late T2ELs on clinical outcomes after EVAR. METHODS: This was a single-institution retrospective review of patients who underwent EVAR for degenerative infrarenal abdominal aortic aneurysm between January 2010 and June 2022 with no type I (T1EL) or III (T3EL) endoleak seen at EVAR completion. Patients were categorized based on T2EL status. Group 1 included patients with never detected or transient T2ELs (detected at EVAR completion but not after). Group 2 encompassed persistent T2ELs (seen at EVAR completion and again during follow-up) and late T2ELs (detected for the first time at any point during follow-up). Time-to-event analysis was conducted using a time-dependent approach to T2EL status. Primary outcomes included freedom from sac enlargement (SE), aneurysm-related reinterventions, and overall survival. RESULTS: A total of 803 patients met inclusion criteria. Group 1 included 418 patients (52%), of which 85% had no T2ELs and 15% had transient T2ELs. Group 2 had 385 patients; 23% had persistent T2ELs, and 77% developed a new T2EL. Patients in group 1 had a higher prevalence of smoking (88% vs 83%; P < .001), chronic obstructive pulmonary disease (33% vs 25%; P = .008), chronic kidney disease (13% vs 8%; P = .021), and a higher mean Society for Vascular Surgery score (7 vs 6 points; P = .049). No differences were found in aneurysm diameter or morphology. Mean follow-up was 5 years for the entire cohort. In Group 2, 58 patients (15%) underwent T2EL treatment, most commonly transarterial embolization. At 10 years after EVAR, Group 2 was associated with lower freedom from SE (P < .001) and abdominal aortic aneurysm-related reinterventions (P < .001) and comparable overall survival (P = .42). More T1ELs were detected during follow-up in Group 2 (6 [1%] vs 20 [5%]; P = .004), with 15 (75%) of these detected at a median of 3 years after the T2EL. No difference between groups was observed in explant (0.7% vs 2.1%; P = .130) or aneurysm rupture (0.5% vs 1.3%; P = .269) rates. CONCLUSIONS: One-half of patients treated with infrarenal EVAR developed persistent/late T2ELs, which are associated with a higher risk of SE and reinterventions. No difference in overall survival or aneurysm rupture risk was seen at 10 years, based on T2EL status or T2EL intervention. A conservative approach to T2ELs may be appropriate for most patients with absent T1ELs or T3ELs.

Assessing the Acidic and Alkaline Recalcitrance of Covalently Modified Surface Amines on Ordered Mesoporous Carbon.

Ordered mesoporous carbon (OMC) scaffolds were covalently modified with primary amine groups by means of oxidation-coupling, yielding C-O-C bonds, or organometallic activation-coupling, yielding C-C bonds. The aminated OMCs were stressed by immersion in either 1 M hydrochloric acid or 1 M sodium hydroxide solutions at room temperature for 6 h and characterized by nitrogen sorption, electron microscopy, low-angle X-ray diffraction, thermogravimetric analysis, and the 4-nitrobenzaldehyde assay. Results demonstrate that aminated surfaces of OMC by butyllithium grafting are stable toward both 1 M HCl and 1 M NaOH, whereas the oxidation-aminated OMC surfaces can withstand 1 M NaOH only. This study illustrates the importance of chemical testing to supplant chemical intuition when tailoring carbon surfaces for applications where strong acids or bases are employed. This is especially emphasized for carbonaceous materials because of the surface heterogeneity among different carbon allotropes.

Gene expression and alternative splicing contribute to adaptive divergence of ecotypes.

Regulation of gene expression is a critical link between genotype and phenotype explaining substantial heritable variation within species. However, we are only beginning to understand the ways that specific gene regulatory mechanisms contribute to adaptive divergence of populations. In plants, the post-transcriptional regulatory mechanism of alternative splicing (AS) plays an important role in both development and abiotic stress response, making it a compelling potential target of natural selection. AS allows organisms to generate multiple different transcripts/proteins from a single gene and thus may provide a source of evolutionary novelty. Here, we examine whether variation in alternative splicing and gene expression levels might contribute to adaptation and incipient speciation of dune-adapted prairie sunflowers in Great Sand Dunes National Park, Colorado, USA. We conducted a common garden experiment to assess transcriptomic variation among ecotypes and analyzed differential expression, differential splicing, and gene coexpression. We show that individual genes are strongly differentiated for both transcript level and alternative isoform proportions, even when grown in a common environment, and that gene coexpression networks are disrupted between ecotypes. Furthermore, we examined how genome-wide patterns of sequence divergence correspond to divergence in transcript levels and isoform proportions and find evidence for both cis and trans-regulation. Together, our results emphasize that alternative splicing has been an underappreciated mechanism providing source material for natural selection at short evolutionary time scales.

Long-term Mortality and Reintervention After Repair of Ruptured Abdominal Aortic Aneurysms Using VQI-matched Medicare Claims.

OBJECTIVE: The objective of this study was to compare endovascular aortic aneurysm repair (EVAR) versus open aortic repair (OAR) on mortality and reintervention after ruptured infrarenal abdominal aortic aneurysm (rAAA) repair in the Vascular Quality Initiative (VQI). BACKGROUND: The optimal treatment modality for rAAA remains debated, with little data on long-term comparisons. METHODS: VQI rAAA repairs (2004-2018) were matched with Medicare claims (VQI-VISION). Primary outcomes were in-hospital and long-term mortality. Secondary outcome was reintervention. Inverse probability weighting was used to adjust for treatment selection, and Cox Proportional Hazards models and negative binomial regressions were used for analysis. Landmark analysis was performed among patients surviving hospital discharge. RESULTS: Among 1885 VQI/Medicare rAAA patients, 790 underwent OAR, and 1095 underwent EVAR. Median age was 76 years; 73% were male. Inverse probability weighting produced comparable groups. In-hospital mortality was lower after EVAR versus OAR (21% vs 37%, odds ratio: 0.52, 95% CI, 0.4-0.7). One-year mortality rates were lower for EVAR versus OAR [hazard ratio (HR) 0.74, 95% CI, 0.6-0.9], but not statistically different after 1 year (HR: 0.95, 95% CI, 0.8-1.2). This implies additional benefits to EVAR in the short term. Reintervention rates were higher after EVAR than OAR at 2 and 5 years (rate ratio: 1.79 95% CI, 1.2-2.7 and rate ratio:2.03 95% CI, 1.4-3.0), but not within the first year. Reintervention was associated with higher mortality risk for both OAR (HR: 1.66 95% CI, 1.1-2.5) and EVAR (HR: 2.14 95% CI, 1.6-2.9). Long-term mortality was similar between repair types (HR: 0.99, 95% CI, 0.8-1.2). CONCLUSIONS: Within VQI/Medicare patients undergoing rAAA repair, the perioperative mortality rate favors EVAR but equalizes after 1 year. Reinterventions were more common after EVAR and were associated with higher mortality regardless of treatment.

Multicenter Study to Evaluate Endovascular Repair of Extent I-III Thoracoabdominal Aneurysms Without Prophylactic Cerebrospinal Fluid Drainage.

OBJECTIVE: To assess outcomes of fenestrated-branched endovascular aortic repair (FB-EVAR) of Extent I-III thoracoabdominal aortic aneurysms (TAAAs) without prophylactic cerebrospinal fluid drainage (CSFD). BACKGROUND: Prophylactic CSFD has been routinely used during endovascular TAAA repair, but concerns about major drain-related complications have led to revising this paradigm. METHODS: We reviewed a multicenter cohort of 541 patients treated for Extent I-III TAAAs by FB-EVAR without prophylactic CSFD. Spinal cord injury (SCI) was graded as ambulatory (paraparesis) or nonambulatory (paraplegia). Endpoints were any SCI, permanent paraplegia, response to rescue treatment, major drain-related complications, mortality, and patient survival. RESULTS: There were 22 Extent I, 240 Extent II and 279 Extent III TAAAs. Thirty-day mortality was 3%. SCI occurred in 45 patients (8%), paraparesis occurring in 23 (4%) and paraplegia in 22 patients (4%). SCI was more common in patients with Extent I-II compared with Extent III TAAAs (12% vs. 5%, P =0.01). Rescue treatment included permissive hypertension in all patients, with CSFD in 22 (4%). Symptom improvement was noted in 73%. Twelve patients (2%) had permanent paraplegia. Two patients (0.4%) had major drain-related complications. Independent predictors for SCI by multivariate logistic regression were sustained perioperative hypotension [odds ratio (OR): 4.4, 95% confidence interval (95% CI): 1.7-11.1], patent collateral network (OR: 0.3, 95% CI: 0.1-0.6), and total length of aortic coverage (OR: 1.05, 95% CI: 1.01-1.10). Patient survival at 3 years was 72%±3%. CONCLUSION: FB-EVAR of Extent I-III TAAAs without CSFD has low mortality and low rates of permanent paraplegia (2%). SCI occurred in 8% of patients, and rescue treatment improved symptoms in 73% of them.

Incidence and risk factors for interval aortic events during staged fenestrated-branched endovascular aortic repair.

OBJECTIVE: Staged endovascular repair of complex aortic aneurysms with first-stage thoracic endovascular aortic repair may decrease the risk of spinal cord ischemia (SCI) associated with fenestrated-branched endovascular aortic repair (FB-EVAR) of thoracoabdominal aortic aneurysms or optimize the proximal landing zone in the cases requiring total aortic arch repair. However, a limitation of multistaged procedures is the risk of interval aortic events (IAEs) including mortality from a ruptured aneurysm. We aim to identify the incidence of and risk factors associated with IAEs during staged FB-EVAR. METHODS: This was a single-center, retrospective review of patients who underwent planned staged FB-EVAR from 2013 to 2021. Clinical and procedural details were reviewed. End points were the incidence of and risk factors associated with IAEs (defined as rupture, symptoms, and unexplained death) and outcomes in patients with or without IAEs. RESULTS: Of 591 planned FB-EVAR patients, 142 underwent first-stage repairs. Twenty-two did not have a planned second stage because of frailty, preference, severe comorbidities, or complications after the first stage and were excluded. The remaining 120 patients (mean age: 73 ± 6 years, 51% female) were planned for second-stage completion FB-EVAR and comprised our cohort. The incidence of IAEs was 13% (16 of 120). This included confirmed rupture in 6 patients, possible rupture in 4, symptomatic presentation in 4, and early unexplained interval death with possible rupture in 2. The median time to IAEs was 17 days (range: 2-101 days), and the median time to uncomplicated completion repairs was 82 days (interquartile range: 30-147 days). Age, sex, and comorbidities were similar between the groups. There were no differences in familial aortic disease, genetically triggered aneurysms, aneurysm extent, or presence of chronic dissection. Patients with IAEs had significantly larger aneurysm diameters than those without IAEs (76.6 vs 66.5 mm, P ≤ .001). This difference persisted with indexing for body surface area (aortic size index: 3.9 vs 3.5 cm/m2, P = .04) and height (aortic height index: 4.5 vs 3.9 cm/m, P ≤ .001). IAE mortality was 69% (11 of 16) compared with no perioperative deaths for those with uncomplicated completion repairs. CONCLUSIONS: The incidence of IAEs was 13% in patients planned for staged FB-EVAR. This represented a notable morbidity, including rupture, which must be balanced with SCI and landing zone optimization when planning repair. Larger aneurysms, especially when adjusted for body surface area, are associated with IAEs. Minimizing time between stages vs single-stage repairs for larger (>7 cm) complex aortic aneurysms in patients with reasonable SCI risk should be considered when planning repair.

Mid-Term Outcomes of "Complete Aortic Repair": Surgical or Endovascular Total Arch Replacement With Thoracoabdominal Fenestrated-Branched Endovascular Aortic Repair.

OBJECTIVE: To describe a single-center experience of "complete aortic repair" consisting of surgical or endovascular total arch replacement/repair (TAR) followed by thoracoabdominal fenestrated-branched endovascular aortic repair (FB-EVAR). METHODS: We reviewed 480 consecutive patients who underwent FB-EVAR with physician-modified endografts (PMEGs) or manufactured stent-grafts between 2013 and 2022. From those, we selected only patients treated with open or endovascular arch repair and distal FB-EVAR for aneurysms involving the ascending, arch and thoracoabdominal aortic segments (zones 0-9). Manufactured devices were used under an investigational device exemption protocol. Endpoints included early/in-hospital mortality, mid-term survival, freedom from secondary intervention, and target artery instability. RESULTS: There were 22 patients, 14 men and 8 women with a median age of 72±7 years. Thirteen postdissection and 9 degenerative aortic aneurysms were repaired with a mean maximum diameter of 67±11 mm. Time from index aortic procedure to aneurysm exclusion was 169 and 270 days in those undergoing 2- and 3-stage repair strategies, respectively. The ascending aorta and aortic arch were treated with 19 surgical and 3 endovascular TAR procedures. Three (16%) surgical arch procedures were performed elsewhere, and perioperative details were unavailable. Mean bypass, cross-clamp, and circulatory arrest times were 295±57, 216±63, and 46±11 minutes, respectively. There were 4 major adverse events (MAEs) in 2 patients: both required postoperative hemodialysis, 1 had postbypass cardiogenic shock necessitating extracorporeal membrane oxygenation, and the other required evacuation of an acute-on-chronic subdural hematoma. Thoracoabdominal aortic aneurysm repair was performed with 17 manufactured endografts and 5 PMEGs. There was no early mortality. Six (27%) patients experienced MAEs. There were 4 (18%) cases of spinal cord injury with 3 (75%) experiencing complete symptom resolution before discharge. Mean follow-up was 30±17 months in which there were 5 patient deaths-0 aortic related. Eight patients required ≥1 secondary intervention, and 6 target arteries demonstrated instability (3 IC, 1 IIIC endoleaks; 2 TA stenoses). Kaplan-Meier 3-year estimates of patient survival, freedom from secondary intervention, and target artery instability were 78±8%, 56±11%, and 68±11%, respectively. CONCLUSION: Complete aortic repair with staged surgical or endovascular TAR and distal FB-EVAR is safe and effective with satisfactory morbidity, mid-term survival, and target artery outcomes. CLINICAL IMPACT: The presented study demonstrates that repair of the entirety of the aorta - via total endovascular or hybrid means- is safe and effective with low rates of spinal cord ischemia. Cardiovascular specialists within comprehensive aortic teams at should feel confident that staged repair of the most complex degenerative and post-dissection thoracoabdominal aortic aneurysms can be safely performed in their patients with complication profile similar to that of less extensive repairs. Meticulous and intentional case planning is imperative for immediate and long-term success.

The sunflower genome provides insights into oil metabolism, flowering and Asterid evolution.

The domesticated sunflower, Helianthus annuus L., is a global oil crop that has promise for climate change adaptation, because it can maintain stable yields across a wide variety of environmental conditions, including drought. Even greater resilience is achievable through the mining of resistance alleles from compatible wild sunflower relatives, including numerous extremophile species. Here we report a high-quality reference for the sunflower genome (3.6 gigabases), together with extensive transcriptomic data from vegetative and floral organs. The genome mostly consists of highly similar, related sequences and required single-molecule real-time sequencing technologies for successful assembly. Genome analyses enabled the reconstruction of the evolutionary history of the Asterids, further establishing the existence of a whole-genome triplication at the base of the Asterids II clade and a sunflower-specific whole-genome duplication around 29 million years ago. An integrative approach combining quantitative genetics, expression and diversity data permitted development of comprehensive gene networks for two major breeding traits, flowering time and oil metabolism, and revealed new candidate genes in these networks. We found that the genomic architecture of flowering time has been shaped by the most recent whole-genome duplication, which suggests that ancient paralogues can remain in the same regulatory networks for dozens of millions of years. This genome represents a cornerstone for future research programs aiming to exploit genetic diversity to improve biotic and abiotic stress resistance and oil production, while also considering agricultural constraints and human nutritional needs.

Estimating phylogenies from genomes: A beginners review of commonly used genomic data in vertebrate phylogenomics.

Despite the increasing feasibility of sequencing whole genomes from diverse taxa, a persistent problem in phylogenomics is the selection of appropriate genetic markers or loci for a given taxonomic group or research question. In this review, we aim to streamline the decision-making process when selecting specific markers to use in phylogenomic studies by introducing commonly used types of genomic markers, their evolutionary characteristics, and their associated uses in phylogenomics. Specifically, we review the utilities of ultraconserved elements (including flanking regions), anchored hybrid enrichment loci, conserved nonexonic elements, untranslated regions, introns, exons, mitochondrial DNA, single nucleotide polymorphisms, and anonymous regions (nonspecific regions that are evenly or randomly distributed across the genome). These various genomic elements and regions differ in their substitution rates, likelihood of neutrality or of being strongly linked to loci under selection, and mode of inheritance, each of which are important considerations in phylogenomic reconstruction. These features may give each type of marker important advantages and disadvantages depending on the biological question, number of taxa sampled, evolutionary timescale, cost effectiveness, and analytical methods used. We provide a concise outline as a resource to efficiently consider key aspects of each type of genetic marker. There are many factors to consider when designing phylogenomic studies, and this review may serve as a primer when weighing options between multiple potential phylogenomic markers.

Midterm Clinical Outcomes of Retrograde Open Mesenteric Stenting for Mesenteric Ischemia.

BACKGROUND: Retrograde open mesenteric stenting (ROMS) has become a mainstay in treatment of mesenteric ischemia; however, follow-up in contemporary studies is limited. METHODS: A single-center retrospective review of patients undergoing ROMS from 2007 to 2020 was conducted. Demographics, presentation, and procedural details were reviewed. End points were morbidity and mortality, technical success, primary patency, reinterventions, and freedom from clinical recurrence. RESULTS: ROMS was performed in 34 patients, 19 female (56%). Mean age was 71 ± 10 years. Eighteen patients (53%) presented with acute mesenteric ischemia (AMI), 11 (32%) with acute-on-chronic, and 5 (15%) with chronic mesenteric ischemia. Etiology was chronic atherosclerosis with/without in-situ thrombosis in 28 patients (82%), superior mesenteric artery dissection in 3, and 1 each with embolic, vasculitic, and nonocclusive ischemia. Four patients (12%) had prior mesenteric procedures (3 Celiac/1 superior mesenteric artery stent) and 1 had unsuccessful transbrachial stenting attempt. Technical success, defined as successful stenting through a retrograde approach was attained in 31 patients (91%), with the 3 remaining patients treated with transbrachial stenting in 2 and iliomesenteric bypass in 1. Covered stents were used in 21 patients (64%) with or without stent extension with bare-metal stents. Eight patients (23%) required thromboembolectomy and 9 (26%) underwent patch angioplasty. Thirty-day mortality rate was 35%, all in patients with AMI (10) or acute-on-chronic (2). Eighteen patients (53%) underwent bowel resection, all presenting acutely. Early reinterventions within the first 30 days were required in 5 patients (15%), including 2 redo ROMS with thrombectomy and endarterectomy, 2 percutaneous stent extensions, and 1 aortic septum fenestration with coiling of a jejunal branch pseudoaneurysm. With a median follow-up of 3.7 (interquartile range: 0.8-5.0) years, in patients surviving discharge, 5 required reintervention yielding freedom from reintervention rates of 87% at 1 year and 71% at 3 years. All postdischarge reinterventions were endovascular with no conversion to bypass. The overall 1-year and 3-year primary patency rates were 70% and 61% (primary-assisted patency at 1 and 3 years was 87% and secondary patency at 1 and 3 years was 97%). The freedom from symptom recurrence was 95% at 1 and 3 years. CONCLUSIONS: ROMS carries high rates of technical success in patients with mesenteric ischemia, despite a high chronic atherosclerotic burden. Although mid-term patency rates are acceptable, AMI is still associated with high early morbidity and mortality, with high rates of associated bowel resection. ROMS is a valuable tool in the armamentarium of vascular surgeons.

Rhodium-Catalyzed Asymmetric Arylation-Induced Glycolate Aldol Additions of Silyl Glyoxylates.

(Diene)Rh(I) complexes catalyze the stereoselective three-component coupling of silyl glyoxylates, arylboronic acids, and aldehydes to give glycolate aldol products. The participation of Rh-alkoxides in the requisite Brook rearrangement was established through two component Rh-catalyzed couplings of silyl glyoxylates with ArB(OH)2 to give silyl-protected mandelate derivatives. The intermediacy of a chiral Rh-enolate was inferred through enantioselective protonation using a chiral Rh-catalyst. Diastereoselective three-component couplings with aldehydes as terminating electrophiles to give racemic products were best achieved with a bulky aryl ester on the silyl glyoxylate reagent. Optimal enantioselective couplings were carried out with the tert-butyl ester variant using an anisole-derived enantiopure tricyclo[3.2.2.02,4 ]nonadiene ligand.

Adaptation to distinct habitats is maintained by contrasting selection at different life stages in sunflower ecotypes.

Conspecific populations living in adjacent but contrasting microenvironments represent excellent systems for studying natural selection. These systems are valuable because gene flow is expected to force genetic homogeneity except at loci experiencing divergent selection. A history of reciprocal transplant and common garden studies in such systems, and a growing number of genomic studies, have contributed to understanding how selection operates in natural populations. While selection can vary across different fitness components and life stages, few studies have investigated how this ultimately affects allele frequencies and the maintenance of divergence between populations. Here, we study two sunflower ecotypes in distinct, adjacent habitats by combining demographic models with genome-wide sequence data to estimate fitness and allele frequency change at multiple life stages. This framework allows us to estimate that only local ecotypes are likely to experience positive population growth (λ > 1) and that the maintenance of divergent adaptation appears to be mediated via habitat- and life stage-specific selection. We identify genetic variation, significantly driven by loci in chromosomal inversions, associated with different life history strategies in neighbouring ecotypes that optimize different fitness components and may contribute to the maintenance of distinct ecotypes.

Aneurysms of the superior mesenteric artery and its branches.

OBJECTIVE: Aneurysms of the superior mesenteric artery (SMA) and its branches are rare and account for only 6% to 15% of all visceral artery aneurysms. In the present report, we have described our 30-year experience with the management of aneurysms of the SMA and its branches at a high-volume referral center. METHODS: A retrospective review of all patients with a diagnosis of an aneurysm of the SMA or one of its branches from 1988 to 2018 was performed. Pseudoaneurysms and mycotic aneurysms were excluded. The clinical presentation, etiology, aneurysm shape and size, treatment modalities, and outcomes were analyzed. The growth rate of the aneurysms was estimated using linear regression. RESULTS: A total of 131 patients with 144 aneurysms were reviewed. The patients were primarily men (64%), with a median age of 60 years. Of the 144 aneurysms, 57 were fusiform, 30 were saccular, and 57 were dissection-associated aneurysms. Of the 131 patients, 41 had had an isolated SMA branch aneurysm. Degenerative aneurysms were the most common etiology (66%). A total of 35 patients (27%) were symptomatic at presentation. Of the 144 aneurysms, 111 had multiple computed tomography angiograms available, with a median follow-up of 43.6 months (interquartile range, 10.6-87.2 months). Only 18 aneurysms (16%) had had an estimated growth rate of ≥1.0 mm/y. The initial aneurysm size was significantly associated with the growth rate for the fusiform aneurysms (odds ratio [OR], 1.13; 95% confidence interval [CI], 1.0-1.3]; P = .02) but not for the saccular (OR, 0.91; 95% CI, 0.76-1.1; P = 1.1) or dissection-associated (OR, 1.2; 95% CI, 0.91-1.5; P = .20) aneurysms. Acute abdominal pain (OR, 5.9; 95% CI, 1.6-22; P = .01) and chronic abdominal pain (OR, 3.7; 95% CI, 1.1-13; P = .04) were associated with aneurysm growth. Only two patients had a ruptured aneurysm, both of whom presented with rupture with no prior imaging studies. These two patients had a diagnosis of fibromuscular dysplasia and systemic lupus erythematosus, respectively. Of the 131 patients, 46 (34%) had undergone operative repair, including 36 open revascularizations and 8 endovascular procedures. The average aneurysm size for these 46 patients was 24.0 ± 8.6 mm. One patient died perioperatively, and nine patients experienced perioperative complications (25%). Of the 144 aneurysms, 91 were <20 mm, with an average size of 13.4 ± 3.1 mm. These 91 aneurysms had been followed up for a median of 120.8 months (interquartile range, 30.5-232.2 months), with no ruptures within this cohort during the follow-up period. CONCLUSIONS: The present study represents one of the largest series on aneurysms of the SMA and its branches. Our results showed that aneurysms of the SMA are relatively stable. Patients with symptomatic and fusiform aneurysms had a greater risk of growth. Aneurysms <20 mm with a degenerative etiology can be safely monitored without treatment.

Imprinting of canine IGF2 and H19.

Genomic imprinting occurs in therian mammals and is a phenomenon whereby the two alleles of a gene are differentially expressed, based on the sex of the parent from whom the alleles were inherited. The allelic differences in expression are the consequence of different epigenetic modifications that are established in the sperm or oocyte during gametogenesis and transmitted at fertilization to offspring. A small minority of genes is regulated in this way but they have important biological functions, and aberrant regulation of imprinted genes contributes to disease aetiology in humans and other animals. The factors driving the evolution of imprinted genes are also of considerable interest, as these genes appear to forego the benefits of diploidy. To broaden the phylogenetic analysis of genomic imprinting, we began a study of imprinted genes in the domestic dog, Canis familiaris. In this report, we show that canine IGF2 and H19 are imprinted, with parent-of origin-dependent monoallelic expression patterns in neonatal umbilical cord. We identify a putative imprint control region associated with the genes, and provide evidence for differential methylation of this region in a somatic tissue (umbilical cord) and for its hypermethylation in the male germline. Canis familiaris is fast becoming a highly informative system for elucidating disease processes and evolution, and the study of imprinted genes in this species may help in understanding how these genes contribute to the generation of morphological and behavioral diversity.

Rapid evolutionary changes in gene expression in response to climate fluctuations.

There is now abundant evidence of rapid evolution in natural populations, but the genetic mechanisms of these changes remain unclear. One possible route to rapid evolution is through changes in the expression of genes that influence traits under selection. We examined contemporary evolutionary gene expression changes in plant populations responding to environmental fluctuations. We compared genome-wide gene expression, using RNA-seq, in two populations of Brassica rapa collected over four time points between 1997 and 2014, during which precipitation in southern California fluctuated dramatically and phenotypic and genotypic changes occurred. By combining transcriptome profiling with the resurrection approach, we directly examined evolutionary changes in gene expression over time. For both populations, we found a substantial number of differentially expressed genes between generations, indicating rapid evolution in the expression of many genes. Using existing gene annotations, we found that many changes occurred in genes involved in regulating stress responses and flowering time. These appeared related to the fluctuations in precipitation and were potentially adaptive. However, the evolutionary changes in gene expression differed across generations within and between populations, indicating largely independent evolutionary trajectories across populations and over time. Our study provides strong evidence for rapid evolution in gene expression, and indicates that changes in gene expression can be one mechanism of rapid evolutionary responses to selection episodes. This study also illustrates that combining resurrection studies with transcriptomics is a powerful approach for investigating evolutionary changes at the gene regulatory level, and will provide new insights into the genetic basis of contemporary evolution.

Breeding for sustainable oilseed crop yield and quality in a changing climate.

As the effects of climate change continue to alter crop-growing conditions year-to-year on both prime and marginal agricultural landscapes, we must consider the effects not only on yield but also on quality. This is particularly true for oilseed crops. In this review, we explore the importance of oilseeds in general and the specific uses of major oilseed crops including soybean, sunflower, canola, peanut, and cottonseed. We review the physiology of seed oil production, from the perspective of the plant's adaptation to environmental changes. Of particular importance is the role of temperature and water availability on oil synthesis. We then discuss how this influences genetic variation, phenotype variability due to environment, and the interaction of genetics and environment to affect composition and yield of vegetable oils. The ability to predict these effects using genomics and bioinformatics is an important new frontier for breeders to maximize stability of a desired fatty acid composition for their crop over increasingly extreme agricultural environments.

Genetic loci underlying quantitative resistance to necrotrophic pathogens Sclerotinia and Diaporthe (Phomopsis), and correlated resistance to both pathogens.

KEY MESSAGE: We provide results rooted in quantitative genetics, which combined with knowledge of candidate gene function, helps us to better understand the resistance to two major necrotrophic pathogens of sunflower. Necrotrophic pathogens can avoid or even benefit from plant defenses used against biotrophic pathogens, and thus represent a distinct challenge to plant populations in natural and agricultural systems. Sclerotinia and Phomopsis/Diaporthe are detrimental pathogens for many dicotyledonous plants, including many economically important plants. With no well-established methods to prevent infection in susceptible plants, host-plant resistance is currently the most effective strategy. Despite knowledge of a moderate, positive correlation in resistance to the two diseases in sunflower, detailed analysis of the genetics, in the same populations, has not been conducted. We present results of genome-wide analysis of resistance to both pathogens in a diversity panel of 218 domesticated sunflower genotypes of worldwide origin. We identified 14 Sclerotinia head rot and 7 Phomopsis stem canker unique QTLs, plus 1 co-located QTL for both traits, and observed extensive patterns of linkage disequilibrium between sites for both traits. Most QTLs contained one credible candidate gene, and gene families were common for the two disease resistance traits. These results suggest there has been strong, simultaneous selection for resistance to these two diseases and that a generalized mechanism for defense against these necrotrophic pathogens exists.

Genetics of alternative splicing evolution during sunflower domestication.

Alternative splicing enables organisms to produce the diversity of proteins necessary for multicellular life by using relatively few protein-coding genes. Although differences in splicing have been identified among divergent taxa, the shorter-term evolution of splicing is understudied. The origins of novel splice forms, and the contributions of alternative splicing to major evolutionary transitions, are largely unknown. This study used transcriptomes of wild and domesticated sunflowers to examine splice differentiation and regulation during domestication. We identified substantial splicing divergence between wild and domesticated sunflowers, mainly in the form of intron retention. Transcripts with divergent splicing were enriched for seed-development functions, suggesting that artificial selection impacted splicing patterns. Mapping of quantitative trait loci (QTLs) associated with 144 differential splicing cases revealed primarily trans-acting variation affecting splicing patterns. A large proportion of identified QTLs contain known spliceosome proteins and are associated with splicing variation in multiple genes. Examining a broader set of wild and domesticated sunflower genotypes revealed that most differential splicing patterns in domesticated sunflowers likely arose from standing variation in wild Helianthus annuus and gained frequency during the domestication process. However, several domesticate-associated splicing patterns appear to be introgressed from other Helianthus species. These results suggest that sunflower domestication involved selection on pleiotropic regulatory alleles. More generally, our findings indicate that substantial differences in isoform abundances arose rapidly during a recent evolutionary transition and appear to contribute to adaptation and population divergence.