Segregation Analysis of SSR, SNP, and AFLP Markers in F2 Population of Solanum lycopersicum × S. arcanum (Analisis Segregasi Marka SSR, SNP, dan AFLP pada Populasi F2 Persilangan Solanum lycopersicum × S. arcanum)

Distorted marker segregation is a common phenomenon in interspecific cross of various crops. Previous mapping study of earlyblight fungus (Alternaria solani) resistance loci showed 52% marker distortion in the genetic linkage map of 176 F2 progeniesderived from Solanum lycopersicum cv. Solentos × S. arcanum LA2157. The objectives of this study were to analyze in detail themarker segregation in the map and to determine the cause of segregation distortion by calculating the allele and genotypefrequencies of each marker. Out of 371 mapped markers, 192 markers deviated from the expected Mendelian ratio of 1 : 2 : 1.Distorted markers occurred in all chromosomes, ranging from 1% to 92%. Surplus of S. arcanum homozygotes contributed mostto the skewness (40%), followed by heterozygotes (18%), and S. lycopersicum homozygotes (5%). The allele frequencies of 152markers deviated from the expected allele homogeneity frequency, indicating that their segregation might be affected bygamethophytic selection. Sixty-one markers deviated from the expected F2 genotype frequency distribution, indicating that theirsegregation might be influenced by zygotic selection. Thirty-seven of the distorted markers showed deviation from expectedfrequencies of allele homogeneity and F2 genotype frequency distribution. Distorted markers can be retained in linkage analysissince chromosomal regions containing distorted markers showed linkage with early blight fungus resistance loci. Furtheridentification of the mechanism contributing segregation distortion requires detailed and extensive mapping studies

Variation In Aggressiveness And Aflp Among Alternaria Solani Isolates From Indonesia

Alternaria solani is a necrotroph fungus that causes three-phased diseases in tomato. Management of the pathogen by using resistant cultivars requires knowledge on the aggressiveness and genetic diversity of the fungus. The aims of this study were to isolate A. solani from major tomato and potato producing areas in Indonesia and to study their aggressiveness and genetic variability. Twenty two A. solani isolates were recovered from early blighted tomato and potato in Central and West Java. A. alternata was also isolated from tomato leaves in West Java and North Sumatra, indicating that early blight in Indonesia may be caused by more than one Alternaria species. Resistance tests of four tomato genotypes to selected A. solani isolates revealed that local isolates were more aggressive in inciting early blight and stem lesion than an imported isolate from USA. This implies that introduced breeding materials must be tested to local isolates to obtain effective resistance genes. Cluster analysis based on amplified fragment length polymorphism (AFLP) obtained from EcoRI+AG and MseI+C primer amplification separated 28 local and Taiwan isolates from the US isolate, which was coincided with aggressiveness separation between the local isolates and the US isolate. Three clusters of AFLP genotypes which did not associate with geographic origin were observed among tropical isolates. The low genetic diversity among the Indonesian isolates suggests clonal population structure with wide distribution. Successful local tomato breeding requires the availability of local A. solani collection with well-characterized aggressiveness level and molecular diversity to obtain effective resistance genes

Longitudinal Changes in Circulating Ketone Body Levels in Patients With Acute Heart Failure:A Post Hoc Analysis of the EMPA-Response-AHF Trial

Background: Ketone bodies are endogenous fuels produced by the liver under conditions of metabolic or neurohormonal stress. Circulating ketone bodies are increased in patients with chronic heart failure (HF), yet little is known about the effect of acute HF on ketosis. We tested the hypothesis that ketogenesis is increased in patients with acute decompensated HF. Methods and results: This was a post hoc analysis of 79 patients with acute HF included in the EMPA-RESPONSE-AHF trial, which compared sodium-dependent glucose-cotransporter protein 2 inhibitor treatment with empagliflozin for 30 days with placebo in patients with acute HF [NCT03200860]. Plasma concentrations of ketone bodies acetone, β-hydroxybutyrate, and acetoacetate were measured at baseline and 5 different timepoints. Changes in ketone bodies over time were monitored using repeated measures analysis of variance. In the total cohort, median total ketone body concentration was 251 µmol/L (interquartile range, 178–377 µmol/L) at baseline, which gradually decreased to 202 µmol/L (interquartile range, 156–240 µmol/L) at day 30 (P = .041). Acetone decreased from 60 µmol/L (interquartile range, 34–94 µmol/L) at baseline to 30 µmol/L (interquartile range, 21–42 µmol/L) ( P < .001), whereas β-hydroxybutyrate and acetoacetate remained stable over time. Higher acetone concentrations were correlated with higher N-terminal pro brain natriuretic peptide levels (r = 0.234; P = .039). Circulating ketone bodies did not differ between patients treated with empagliflozin or placebo throughout the study period. A higher acetone concentration at baseline was univariately associated with a greater risk of the composite end point, including in-hospital worsening HF, HF rehospitalizations, and all-cause mortality after 30 days. However, after adjustment for age and sex, acetone did not remain an independent predictor for the combined end point. Conclusions: Circulating ketone body concentrations, and acetone in particular, were significantly higher during an episode of acute decompensated HF compared with after stabilization. Treatment with empagliflozin did not affect ketone body concentrations in patients with acute HF

QTL identification for early blight resistance (Alternaria solani) in a Solanum lycopersicum x S. arcanum cross.

Alternaria solani (Ellis and Martin) Sorauer, the causal agent of early blight (EB) disease, infects aerial parts of tomato at both seedling and adult plant stages. Resistant cultivars would facilitate a sustainable EB management. EB resistance is a quantitatively expressed character, a fact that has hampered effective breeding. In order to identify and estimate the effect of genes conditioning resistance to EB, a quantitative trait loci (QTL) mapping study was performed in F2 and F3 populations derived from the cross between the susceptible Solanum lycopersicum (syn. Lycopersicon esculentum) cv. `Solentos¿ and the resistant Solanum arcanum (syn. Lycopersicon peruvianum) LA2157 and genotyped with AFLP, microsatellite and SNP markers. Two evaluation criteria of resistance were used: measurements of EB lesion growth on the F2 plants in glasshouse tests and visual ratings of EB severity on foliage of the F3 lines in a field test. A total of six QTL regions were mapped on chromosomes 1, 2, 5¿7, and 9 with LOD scores ranging from 3.4 to 17.5. Three EB QTL also confer resistance to stem lesions in the field, which has not been reported before. All QTL displayed significant additive gene action; in some cases a dominance effect was found. Additive × additive epistatic interactions were detected between one pair of QTL. For two QTL, the susceptible parent contributed resistance alleles to both EB and stem lesion resistance. Three of the QTL showed an effect in all tests despite methodological and environmental differences

Genetic dissection of photoperiod response based on GWAS of pre-anthesis phase duration in spring barley

Heading time is a complex trait, and natural variation in photoperiod responses is a major factor controlling time to heading, adaptation and grain yield. In barley, previous heading time studies have been mainly conducted under field conditions to measure total days to heading. We followed a novel approach and studied the natural variation of time to heading in a world-wide spring barley collection (218 accessions), comprising of 95 photoperiod-sensitive (Ppd-H1) and 123 accessions with reduced photoperiod sensitivity (ppd-H1) to long-day (LD) through dissecting pre-anthesis development into four major stages and sub-phases. The study was conducted under greenhouse (GH) conditions (LD; 16/8 h; ∼20/∼16°C day/night). Genotyping was performed using a genome-wide high density 9K single nucleotide polymorphisms (SNPs) chip which assayed 7842 SNPs. We used the barley physical map to identify candidate genes underlying genome-wide association scans (GWAS). GWAS for pre-anthesis stages/sub-phases in each photoperiod group provided great power for partitioning genetic effects on floral initiation and heading time. In addition to major genes known to regulate heading time under field conditions, several novel QTL with medium to high effects, including new QTL having major effects on developmental stages/sub-phases were found to be associated in this study. For example, highly associated SNPs tagged the physical regions around HvCO1 (barley CONSTANS1) and BFL (BARLEY FLORICAULA/LEAFY) genes. Based upon our GWAS analysis, we propose a new genetic network model for each photoperiod group, which includes several newly identified genes, such as several HvCO-like genes, belonging to different heading time pathways in barley

An assessment of the durability and susceptibility of scab resistance in apple cultivars

Durable resistance to scab (Venturia inaequalis) of newly introduced cultivars is needed to achieve a considerable reduction of pesticide use. However, the assessment in the field on the level and durability of scab resistance is time and space consuming. A proper and fast indoor test should be a convenient tool to discard cultivars with a limited level of resistance at an early stage. As a result, field tests can include only the better cultivars. This approach has been tried out by comparing field data with data from a glasshouse test, comprising twelve new and seven well-known susceptible and resistant (with and without Vf) cultivars which have been tested with six isolates of scab from different origins, virulence and aggressiveness, including race 6 and 7. Young trees on M.9 rootstock were infected and after a 17 day period at high humidity, sporulation and chlorosis have been observed. If the set of isolates is broad and well-chosen it seems possible to assess susceptibility and possibly also durability. To optimize the choice of isolates, it is desirable to know the pedigree of the cultivars that are tested. In addition, this procedure allows the use of highly virulent and aggressive races, that should be avoided in field tests for the risk of spreadin

Dmrt1 polymorphism covaries with sex-determination patterns in Rana temporaria.

Patterns of sex-chromosome differentiation and gonadal development have been shown to vary among populations of Rana temporaria along a latitudinal transect in Sweden. Frogs from the northern-boreal population of Ammarnäs displayed well-differentiated X and Y haplotypes, early gonadal differentiation, and a perfect match between phenotypic and genotypic sex. In contrast, no differentiated Y haplotypes could be detected in the southern population of Tvedöra, where juveniles furthermore showed delayed gonadal differentiation. Here, we show that Dmrt1, a gene that plays a key role in sex determination and sexual development across all metazoans, displays significant sex differentiation in Tvedöra, with a Y-specific haplotype distinct from Ammarnäs. The differential segment is not only much shorter in Tvedöra than in Ammarnäs, it is also less differentiated and associates with both delayed gonadal differentiation and imperfect match between phenotypic and genotypic sex. Whereas Tvedöra juveniles with a local Y haplotype tend to ultimately develop as males, those without it may nevertheless become functional XX males, but with strongly female-biased progeny. Our findings suggest that the variance in patterns of sex determination documented in common frogs might result from a genetic polymorphism within a small genomic region that contains Dmrt1. They also substantiate the view that recurrent convergences of sex determination toward a limited set of chromosome pairs may result from the co-option of small genomic regions that harbor key genes from the sex-determination pathway