Segregation Of Genotypes Research Articles

Genome-wide association study of pineapple breeding population

Pineapples (Ananas comosus (L.) Merr.) are one of the most important tropical fruits. Although pineapple breeding program has been conducted in Japan, sufficient genomic information has not been adopted for breeding. The objective of this study was to identify quantitative trait loci (QTL) for pineapple breeding-related traits that can be applied to different populations. Here, we performed a genome-wide association study using seven breeding populations, including 703 individuals with genome-wide 9574 SNPs. Eleven QTLs were detected for nine traits (flesh color, flesh color values (a*, b*), bolting days, days from bolting to harvest, fruit shell color, soluble solid content, acidity, ascorbic acid content, and fruit cracking). Phenotypic value of each genotype in each population was confirmed for each QTL. Six QTLs (acidity QTL ACID-1, ascorbic acid QTL AsA-1 and AsA-2, flesh color QTL FCOL-1 and FCOLb-1, and fruit-cracking QTL CRACK-1) showed significant intergenotypic variance among all populations with genotype segregation. The obtained QTLs and their genotype information will contribute to the selection of cross-breeding parents and marker-assisted selection in pineapple breeding programs.

CAVaLRi: An Algorithm for Rapid Identification of Diagnostic Germline Variation

Clinical exome and genome sequencing (ES/GS) have become indispensable diagnostic tools for rare genetic diseases (RGD). However, the interpretation of ES/GS presents a substantial operational challenge in clinical settings. Test interpretation requires the review of hundreds of genetic variants, a task that has become increasingly challenging given the rising use of ES/GS. In response, we present Clinical Assessment of Variants by Likelihood Ratios (CAVaLRi), which employ a modified likelihood ratio (LR) framework to assign diagnostic probabilities to candidate germline disease genes. CAVaLRi models aspects of the clinical variant assessment process, taking into consideration the predicted impact of the variant, the proband and parental genotypes, and the proband’s clinical characteristics. It also factors in computational phenotype noise and weighs the relative significance of genotype, phenotype, and variant segregation information. We trained and tested CAVaLRi on variant and phenotype data from an internal cohort of 655 clinical ES cases. For validation, CAVaLRi’s performance was benchmarked against four leading gene prioritization algorithms (Exomiser’s hiPHIVE and PhenIX prioritizers, LIRICAL, and XRare) using a distinct cohort of 12,832 ES cases. Our findings reveal that CAVaLRi significantly outperforms its counterparts when clinician-curated phenotype sets are used, as evidenced by its superior precision-recall curve (PR AUC: 0.701) and average diagnostic gene rank (1.59). Notably, even when substituting highly focused clinician-curated phenotype sets with large and potentially nonspecific computationally derived phenotypes, CAVaLRi retains its precision (PR AUC: 0.658; diagnostic gene average rank: 1.68) and markedly outperforms other tools. In a large, heterogeneous validation cohort, CAVaLRi stood out as the most precise prioritization algorithm (PR AUC: 0.335; average diagnostic rank: 1.91). In conclusion, CAVaLRi presents a robust solution for prioritizing diagnostic genes, surpassing current methods. It demonstrates resilience to noisy, computationally-derived phenotypes, providing a scalable strategy to help labs focus on the most diagnostically relevant variants, thus addressing the growing demand for ES/GS interpretation.

Revealing Genetic Diversity and Population Structure in Türkiye’s Wheat Germplasm Using iPBS-Retrotransposon Markers

Investigating the genetic diversity and population structure of wheat germplasm is crucial for understanding the underlying variability essential for breeding programs and germplasm preservation. This research aims to contribute novel insights with respect to the genetic makeup and relationships among these wheat genotypes, shedding light on the diversity present within the Turkish wheat germplasm. In this study, iPBS-retrotransposon markers were employed to analyze 58 wheat genotypes, encompassing 54 landraces and 4 cultivars sourced from Türkiye. These markers serve as genetic indicators that can be used to evaluate genetic variation, build genealogical trees, and comprehend evolutionary connections. The PCR products were visualized on agarose gel, and bands were scored as present/absent. The ten iPBS primers collectively yielded an average of 16.3 alleles, generating a total of 163 polymorphic bands. The number of alleles produced by individual markers ranged from 4 (iPBS-2386) to 29 (iPBS-2219). The genetic parameters were calculated using the popgen and powermarker programs. The genetic relationships and population structures were assessed using the ntsys and structure programs. Polymorphism information content (PIC) per marker varied from 0.13 (iPBS-2390) to 0.29 (iPBS-2386), with an average value of 0.22. Shannon’s information index (I) was calculated as 1.48, while the number of effective alleles (Ne) and Nei’s genetic diversity (H) were determined to be 0.26 and 0.31, respectively. Genotype numbers 3 (Triticum dicoccum) and 10 (Triticum monococcum) exhibited the maximum genetic distance of 0.1292, signifying the highest genetic disparity. Population structure analysis revealed the segregation of genotypes into three distinct subpopulations. Notably, a substantial portion of genotypes clustered within populations correlated with the wheat species. This population structure result was consistent with the categorization of genotypes based on wheat species. The comprehensive assessment revealed noteworthy insights with respect to allele distribution, polymorphism content, and population differentiation, offering valuable implications for wheat breeding strategies and germplasm conservation efforts. In addition, the iPBS markers and wheat genotypes employed in this study hold significant potential for applications in wheat breeding research and germplasm preservation.

A medium-density genotyping platform for cultivated strawberry using DArTag technology.

Genomic prediction in breeding populations containing hundreds to thousands of parents and seedlings is prohibitively expensive with current high-density genetic marker platforms designed for strawberry. We developed mid-density panels of molecular inversion probes (MIPs) to be deployed with the "DArTag" marker platform to provide a low-cost, high-throughput genotyping solution for strawberry genomic prediction. In total, 7742 target single nucleotide polymorphism (SNP) regions were used to generate MIP assays that were tested with a screening panel of 376 octoploid Fragaria accessions. We evaluated the performance of DArTag assays based on genotype segregation, amplicon coverage, and their ability to produce subgenome-specific amplicon alignments to the FaRR1 assembly and subsequent alignment-based variant calls with strong concordance to DArT's alignment-free, count-based genotype reports. We used a combination of marker performance metrics and physical distribution in the FaRR1 assembly to select 3K and 5K production panels for genotyping of large strawberry populations. We show that the 3K and 5K DArTag panels are able to target and amplify homologous alleles within subgenomic sequences with low-amplification bias between reference and alternate alleles, supporting accurate genotype calling while producing marker genotypes that can be treated as functionally diploid for quantitative genetic analysis. The 3K and 5K target SNPs show high levels of polymorphism in diverse F. × ananassa germplasm and UC Davis cultivars, with mean pairwise diversity (π) estimates of 0.40 and 0.32 and mean heterozygous genotype frequencies of 0.35 and 0.33,respectively.

Segregation of molecular markers associated with Bph3 gene in BC5F2 population derived from Ciherang rice variety as the recipient parent

Brown planthopper (BPH), an important insect pest of rice, can cause severe damage and significant yield loss. An efficient and environmentally friendly method to control this pest is by planting resistant varieties. The brown planthopper resistance gene Bph3 from Rathu Heenati variety is closely linked to the Waxy gene that regulates amylose synthesis, the primary determinant of rice eating and cooking quality. The purposes of this study were to analyze the segregation ratio of SSR markers associated with Bph3 gene and to identify individual plants carrying homozygous allele for Bph3 gene in a BC5F2 population derived from a backcross that used Ciherang as the recurrent recipient parent. Analyses using RM589, RM586, and RM588 markers linked to Bph3 gene and RM190 marker linked to the Waxy gene indicated that the ratio of genotype segregation for each marker related to Bph3 gene did not deviate from the expected ratio with the χ 2 value was 0.956, 0.587, and 1.467 for RM589, RM586, and RM588, respectively (χ2 table = 5.991, α=0,05). All individual plants had a homozygous allele from Ciherang for Waxy gene based on the RM190 marker. As many as 25 individual plants which have homozygous Bph3 allele from Rathu Heenati and homozygous Waxy allele from Ciherang can be further developed as promising BPH-resistant rice varieties with eating and cooking quality similar to Ciherang.

ВАЛИДАЦИЯ ДНК-МАРКЕРА УСТОЙЧИВОСТИ ПОДСОЛНЕЧНИКА К РАСЕ G ЗАРАЗИХИ НА МАЛЫХ ВЫБОРКАХ

The genotypic and phenotypic segregation of 57 plants of a progeny of two heterozygous F1 sunflower hybrids was analyzed (by DNA-marker) by a trait of resistance to a broomrape race G. The observed segregation by a genotype corresponded reliably to the theoretically expected ones in monohybrid crosses due to models 3:1 and 1:2:1. The segregation by a phenotype corresponded completely to the segregation by a marker of a model 3:1. A developed marker allows selecting by a trait of sunflower resistance to the broomrape race G.

Genomics reveals a genetically isolated population of the Pacific white-sided dolphin (Lagenorhynchus obliquidens) distributed in the Sea of Japan.

The processes by which animals become genetically isolated in an open environment such as the ocean have not yet been fully elucidated. Morphologically different populations of Pacific white-sided dolphin Lagenorhynchus obliquidens are observed sympatrically in the Sea of Japan. However, genetic studies that exclusively used limited mitochondrial loci or microsatellite DNA have failed to demonstrate the existence of genetically distinct populations. Here, to reveal the population structure, we analysed genome-wide population genetic data using single nucleotide polymorphisms (SNPs) gathered in 2018-2021 from all domestic captive individuals in aquaria, the majority of which originated from the wild, as well as from some stranded individuals, together covering a wide area of coastal water around Japan (n=123). Multiplexed intersimple sequence repeat genotyping-by-sequencing analysis was performed to obtain the SNP data. Principal coordinate analysis and the clustering method structure indicated that two genetically-distinct populations exist, with little interpopulation gene flow revealed. In addition, the genotypic segregation was reflected in differences in external morphotype. Furthermore, a population demographic analysis based on the whole-genome sequences of an individual from each population indicated that sea-level changes during the Last Glacial Period probably led to allopatric divergence of this species in a limited area of the Sea of Japan, with that group subsequently sharing a distribution area with the other population. These findings yield insights into the formation of genetically isolated sympatric populations in the ocean.

The mud-dwelling clam Meretrix petechialis secretes endogenously synthesized erythromycin

Although lacking an adaptive immune system and often living in habitats with dense and diverse bacterial populations, marine invertebrates thrive in the presence of potentially challenging microbial pathogens. However, the mechanisms underlying this resistance remain largely unexplored and promise to reveal novel strategies of microbial resistance. Here, we provide evidence that a mud-dwelling clam, Meretrix petechialis, synthesizes, stores, and secretes the antibiotic erythromycin. Liquid chromatography coupled with mass spectrometry, immunocytochemistry, fluorescence in situ hybridization, RNA interference, and enzyme-linked immunosorbent assay revealed that this potent macrolide antimicrobial, thought to be synthesized only by microorganisms, is produced by specific mucus-rich cells beneath the clam's mantle epithelium, which interfaces directly with the bacteria-rich environment. The antibacterial activity was confirmed by bacteriostatic assay. Genetic, ontogenetic, phylogenetic and genomic evidence, including genotypic segregation ratios in a family of full siblings, gene expression in clam larvae, phylogenetic tree, and synteny conservation in the related genome region further revealed that the genes responsible for erythromycin production are of animal origin. The detection of this antibiotic in another clam species showed that the production of this macrolide is not exclusive to M. petechialis and may be a common strategy among marine invertebrates. The finding of erythromycin production by a marine invertebrate offers a striking example of convergent evolution in secondary metabolite synthesis between the animal and bacterial domains. These findings open the possibility of engineering-animal tissues for the localized production of an antibacterial secondary metabolite.

Heterochiasmy and the establishment of gsdf as a novel sex determining gene in Atlantic halibut.

Atlantic Halibut (Hippoglossus hippoglossus) has a X/Y genetic sex determination system, but the sex determining factor is not known. We produced a high-quality genome assembly from a male and identified parts of chromosome 13 as the Y chromosome due to sequence divergence between sexes and segregation of sex genotypes in pedigrees. Linkage analysis revealed that all chromosomes exhibit heterochiasmy, i.e. male-only and female-only meiotic recombination regions (MRR/FRR). We show that FRR/MRR intervals differ in nucleotide diversity and repeat class content and that this is true also for other Pleuronectidae species. We further show that remnants of a Gypsy-like transposable element insertion on chr13 promotes early male specific expression of gonadal somatic cell derived factor (gsdf). Less than 4.5 MYA, this male-determining element evolved on an autosomal FRR segment featuring pre-existing male meiotic recombination barriers, thereby creating a Y chromosome. Our findings indicate that heterochiasmy may facilitate the evolution of genetic sex determination systems relying on linkage of sexually antagonistic loci to a sex-determining factor.

Dynamics of phytoplankton groups in three contrasting situations of the open NW Mediterranean Sea revealed by pigment, microscopy, and flow cytometry analyses

A detailed study of phytoplankton composition and dynamics was carried out during three contrasting situations (cruises F1, F2, and F3) in the northwestern (NW) Mediterranean Sea. Haptophytes, diatoms, and green algae dominated in F1, during the spring bloom, with high nutrients and high phytoplankton biomass. In F2, the post-bloom situation with a still weak stratification and lower nutrient concentrations, we found a high spatial variability. Stations were clearly dominated by either Synechococcus, haptophytes or cryptophytes; with Synechococcus reaching the highest abundance (4 × 105 cells mL−1, 60% of the integrated chlorophyll a) reported to date for the open Mediterranean Sea. Cryptophytes accumulated close to the surface in very shallow mixed layer stations. In late summer, F3 revealed a fully developed stratification with low nutrients and a marked deep chlorophyll maximum (DCM). Prochlorococcus was present only during this cruise, mainly in deep layers together with haptophytes and pelagophytes, while haptophytes and Synechococcus dominated the upper mixed layer. Flow cytometry (FCM) and pigment-based abundance estimates for Prochlorococcus, Synechococcus and cryptophytes were well correlated, as happened also between small picoeukaryotes (FCM) and green algae (pigments), and between large picoeukaryotes (FCM) and haptophytes (pigments). Dinoflagellate abundance by microscopy and by pigments did not agree well, probably due to the presence of heterotrophic forms or because they contained pigments other than peridinin, the standard dinoflagellate marker. The decrease in size of the FCM large picoeukaryotes group with depth was presumably related to the increasing contribution of pelagophytes, with smaller cells than haptophytes, the other main component of this fraction. Cell size increase of Prochlorococcus and Synechococcus with depth suggests vertical segregation of genotypes or photoadaptation. The groups' ecological preferences are presented with respect to depth and nutrient concentrations. Synechococcus and cryptophytes occupied shallow layers; diatoms, green algae and Prochlorococcus showed a tendency for deep layers and pelagophytes for even deeper layers, while haptophyte and dinoflagellate allocations were less clear. As for nutrients, the maximum relative contributions of green algae and especially diatoms occurred when dissolved inorganic phosphorus (DIP) concentrations were highest, of Prochlorococcus, dinoflagellates and pelagophytes when lowest, and of Synechococcus and cryptophytes when DIP concentrations were low but not minimal. The contribution of haptophytes did not show a relationship with DIP concentration. These results from individual groups stand as significant exceptions to the general relationship between phytoplankton cell size and nutrient availability.

Analysis of the Segregation Distortion of FcRAN1 Genotypes Based on Whole-Genome Resequencing of Fig (Ficus carica L.) Breeding Parents.

The common fig (Ficus carica L.) has a gynodioecious breeding system, and its sex phenotype is an important trait for breeding because only female plant fruits are edible. During breeding to select for female plants, we analyzed the FcRAN1 genotype, which is strongly associated with the sex phenotype. In 12 F1 populations derived from 13 cross combinations, the FcRAN1 genotype segregation ratio was 1:1, whereas the M119-226 × H238-107 hybridization resulted in an extremely male-biased segregation ratio (178:7 = male:female). This finding suggests that the segregation distortion was caused by some genetic factor(s). A whole-genome resequencing of breeding parents (paternal and maternal lines) identified 9,061 high-impact SNPs in the parents. A genome-wide linkage analysis exploring the gene(s) responsible for the distortion revealed 194 high-impact SNPs specific to Caprifig6085 (i.e., seed parent ancestor) and 215 high-impact SNPs specific to H238-107 (i.e., pollen parent) in 201 annotated genes. A comparison between the annotated genes and the genes required for normal embryo or gametophyte development and function identified several candidate genes possibly responsible for the segregation distortion. This is the first report describing segregation distortion in F. carica.

A novel genotype of Hantaan orthohantavirus harbored by Apodemus agrarius chejuensis as a potential etiologic agent of hemorrhagic fever with renal syndrome in Republic of Korea.

Orthohantaviruses, causing hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome, pose a significant public health threat worldwide. Despite the significant mortality and morbidity, effective antiviral therapeutics for orthohantavirus infections are currently unavailable. This study aimed to investigate the prevalence of HFRS-associated orthohantaviruses and identify the etiological agent of orthohantavirus outbreaks in southern Republic of Korea (ROK). We collected small mammals on Jeju Island during 2018-2020. We detected the Hantaan virus (HTNV)-specific antibodies and RNA using an indirect immunofluorescence assay test and reverse transcription-polymerase chain reaction on Apodemus agrarius chejuensis (A. chejuensis). The prevalence of anti-HTNV antibodies among rodents was 14.1%. A total of six seropositive mouse harbored HTNV RNA. The amplicon-based next-generation sequencing provided nearly full-length tripartite genomic sequences of six HTNV harbored by A. chejuensis. Phylogenetic and tanglegram analyses were conducted for inferring evolutionary relationships between orthohantaviruses with their reservoir hosts. Phylogenetic analysis showed a novel distinct HTNV genotype. The detected HTNV genomic sequences were phylogenetically related to a viral sequence derived from HFRS patient in southern ROK. Tanglegram analysis demonstrated the segregation of HTNV genotypes corresponding to Apodemus spp. divergence. Our results suggest that A. chejuensis-borne HTNV may be a potential etiological agent of HFRS in southern ROK. Ancestral HTNV may infect A. chejuensis prior to geological isolation between the Korean peninsula and Jeju Island, supporting the co-evolution of orthohantaviruses and rodents. This study arises awareness among physicians for HFRS outbreaks in southern ROK.

Human AGR2 Deficiency Causes Mucus Barrier Dysfunction and Infantile Inflammatory Bowel Disease

Background & AimsThe gastrointestinal epithelium plays a crucial role in maintaining homeostasis with the gut microbiome. Mucins are essential for intestinal barrier function and serve as a scaffold for antimicrobial factors. Mucin 2 (MUC2) is the major intestinal gel-forming mucin produced predominantly by goblet cells. Goblet cells express anterior gradient 2 (AGR2), a protein disulfide isomerase that is crucial for proper processing of gel-forming mucins. Here, we investigated 2 siblings who presented with severe infantile-onset inflammatory bowel disease.MethodsWe performed whole-genome sequencing to identify candidate variants. We quantified goblet cell numbers using H&E histology and investigated the expression of gel-forming mucins, stress markers, and goblet cell markers using immunohistochemistry. AGR2-MUC2 binding was evaluated using co-immunoprecipitation. Endoplasmic reticulum (ER) stress regulatory function of mutant AGR2 was examined by expression studies in Human Embryonic Kidney 293T (HEK293T) using tunicamycin to induce ER stress.ResultsBoth affected siblings were homozygous for a missense variant in AGR2. Patient biopsy specimens showed reduced goblet cells; depletion of MUC2, MUC5AC, and MUC6; up-regulation of AGR2; and increased ER stress. The mutant AGR2 showed reduced capacity to bind MUC2 and alleviate tunicamycin-induced ER stress.ConclusionsPhenotype–genotype segregation, functional experiments, and the striking similarity of the human phenotype to AGR2-/- mouse models suggest that the AGR2 missense variant is pathogenic. The Mendelian deficiency of AGR2, termed “Enteropathy caused by AGR2 deficiency, Goblet cell Loss, and ER Stress” (EAGLES), results in a mucus barrier defect, the inability to mitigate ER stress, and causes infantile-onset inflammatory bowel disease.

PSIII-3 Association of heat shock factor protein 1 and prolactin receptor variants with molecular breeding values in Senepol cattle

Abstract Thermal stress has been associated with lower food intake and growth rate in beef cattle. The purpose of this study was to assess the segregation of the p.Leu462* nonsense mutation in the prolactin receptor gene (PRLR) responsible for slick hair (SH) phenotype in Senepol and a T >C missense variant (V344A) located in the heat shock transcription factor protein 1 gene (HSF1). We compared the potential association of these polymorphisms with molecular breeding values (MBV) that were estimated using a panel of commercial genetic markers (Igenity, Neogen Corp). For this, 29 females and 21 males were genotyped by PCR and sequencing. Three genotypes were observed for the p.Leu462* with frequencies of 0.02 C/C, 0.16 C/- and 0.82 -/-. For V344A only two genotypes were observed with frequencies of 0.86/TT and 0.14/TC. This polymorphism was in linkage disequilibrium with a C >T synonymous variant; therefore, for the statistical analyses, the HSF1 genotypes were combined as TT/CC and TC/CT. The GLIMMIX procedure and Tukey test of SAS were used (effect of sex, HSF1 and SH genotype and interactions). MBV for production traits such as average daily gain, tenderness, yearling weight (YW), marbling, fat thickness (FT), percent choice (PC), ribeye area (RA) and carcass weight. Effect of sex (P < .05) were found for YW (males: 6.93lbs ± 0.53, female: 5.74lbs ± 0.57) and for PC (female: 16.17±0.75, male: 15.02±0.55). Differences between HSF1 genotype combinations were significant for the MBV of RA (TC/CT: 0.96in2±0.10; TT/CC: 0.781in2±0.07 and for FT (TC/CT: 0.16in±0.02; TTCC: 0.12in±0.01). The similarity in segregation of SH responsible genotypes (C/- and -/-) and HSF1 (TC/CT and TT/CC) in Senepol could indicate a potential role of HSF1 in adaptation to heat stress in cattle with an additional effect in muscling and fat deposition.

Evolutionary history and current distribution of the West Mediterranean lineage of Brucella melitensis in Italy.

Ovine and caprine brucellosis, caused by Brucella melitensis , is one of the world’s most widespread zoonoses and is a major cause of economic losses in domestic ruminant production. In Italy, the disease remains endemic in several southern provinces, despite an ongoing brucellosis eradication programme. In this study, we used whole-genome sequencing to detail the genetic diversity of circulating strains, and to examine the origins of the predominant sub-lineages of B. melitensis in Italy. We reconstructed a global phylogeny of B. melitensis , strengthened by 339 new whole-genome sequences, from Italian isolates collected from 2011 to 2018 as part of a national livestock surveillance programme. All Italian strains belonged to the West Mediterranean lineage, which further divided into two major clades that diverged roughly between the 5th and 7th centuries. We observed that Sicily serves as a brucellosis burden hotspot, giving rise to several distinct sub-lineages. More than 20 putative outbreak clusters of ovine and caprine brucellosis were identified, several of which persisted over the 8 year survey period despite an aggressive brucellosis eradication campaign. While the outbreaks in Central and Northern Italy were generally associated with introductions of single clones of B. melitensis and their subsequent dissemination within neighbouring territories, we observed weak geographical segregation of genotypes in the southern regions. Biovar determination, recommended in routine analysis of all Brucella strains by the World Organisation for Animal Health (OIE), could not discriminate among the four main global clades. This demonstrates a need for updating the guidelines used for monitoring B. melitensis transmission and spread, both at the national and international level, and to include whole-genome-based typing as the principal method for identification and tracing of brucellosis outbreaks.

Phytochemical variability of selected basil genotypes

Basil (Ocimum basilicum L.), as an aromatic and medicinal plant, exhibits numerous of genotypes that have various applications in food and pharmaceutical industries. Thus, chemical composition is an important parameter for assessing the quality of basil. Hence, twelve European basil genotypes were cultivated under the same conditions, and isolated essential oils and methanol extracts were subjected to detailed chemical analyses and testing their biological activities. According to the analysis of the volatiles, all genotypes belong to linalool chemotype, and they were clustered into two groups. Rosmarinic acid was found to be the major phenylpropanoid, following with luteoin, kaempherol, and rutin. Principal component analysis of phenolic compounds indicated segregation of genotypes in two distinct groups. Biological activities of the isolated extracts were correlated with the concentrations of the actives, and it was found that naringenin, luteolin, and kaempherol are the main carriers of antioxidant activity, while the levels of linalool correlated with tyrosinase inhibition activity. Adversely, methyl chavicol showed negative correlations with both assays. Finally, it was found that Czech genotypes (Litra and Chladek), as well as Dutch (Bush) and Italian (Fino Verde Compatto) possess significant amounts of terpenoid linalool, together with flavonoids luteolin, naringenin, and kaempherol, and therefore, have strong biological activities required for their use in food and cosmetic industries.

Detection of Neorickettsia risticii, the agent of Potomac horse fever, in horses from Rio de Janeiro, Brazil

This study aims to report the presence of Neorickettsia risticii DNA in blood samples from naturally infected horses in Rio de Janeiro, provide clinicopathological findings related to the infection, and report the phylogenetic diversity of the 16S rDNA of N. risticii in order to evaluate its heterogeneity. Real-time quantitative polymerase chain reaction (qPCR) was performed to investigate the presence of N. risticii in samples collected from horses (n = 187). Five positive samples were found in the molecular screening. Hypoalbuminemia and high levels of creatine kinase and lactate dehydrogenase were the predominant findings in the biochemical analysis. The sequences were similar to those of N. risticii. Phylogenetic analysis revealed genotype segregation based on the geographical distribution in the N. risticii sequence clade. Dendrograms constructed with five hypervariable regions revealed that V4 distinguished Neorickettsia at the species level and produced a phylogeny that best represented the phylogeny obtained with the complete 16S rDNA sequence. This is the first report of N. risticii DNA in the blood of Brazilian horses based on sequences deposited in GenBank. Further studies are necessary to clarify the epidemiological chain of this vector-borne parasite in order to determine and establish appropriate preventive measures in the equine trading market.

Morphophysiological Traits as Indicators of Genetic Diversity in Brazilian Populations of Jatropha curcas L. Grown Under Water Deficit

Jatropha curcas L. (Euphorbiaceae) is a species grown in tropicalcountries and used for biodiesel production. Morphophysiological traits were analyzed to assess the genetic diversity in nine genotypes of J. curcas under deficit water. Seeds of plants from different populations, collected in diferente brazilian regions, were grown under two water regimes (100% and 50% tank capacity). Multivariate analysis was used to characterize genetic diversity. The UPGMA dendrogram built from the genetic distance group indicated the segregation of genotypes into five groups for growth traits and six groups for physiological traits. Then, an principal components analysis was carried out, to evaluate the pattern of character variations and then segregate the characteristics that could distinguish parental genotypes for use in plant breeding. Results showed 65.50% and 56.02% for the two first principal components of growth and physiological traits, respectively. Total root area was the most determining trait for genetic dissimilarity (18.9%) and group formation, followed by plant height (17.9%) and number of leaves (17.6%). On the other hand, stomatal conductance (gs) (24.9%) and guaiacol peroxidase (GPX) (20.9%) were the most determining physiological traits. The analysis of morphophysiological traits indicated CNPAE-298 and 299 as the most distant genotypes among the plant groups. Under water-limited conditions, total root area, plant height, gs and GPX were the most efficient traits to explain genetic dissimilarity among the genotypes, and for this reason they should be referred as a priority for further studies on genotypes selection in this species.

Selección de plantas de papaya sobresalientes en ambientes comerciales con fines de mejoramiento

Por la demanda del mercado, en las regiones productoras de México la variedad dominante es la Maradol, en diferentes niveles de calidad de fruta, ya que el tipo de semilla que se utiliza varía desde las originales F1, hasta selecciones descendientes identificadas como F2 a F5. Lo anterior, conlleva a una degeneración y segregación genotípica. De esta manera es necesaria una adecuada selección de progenitores y polinización controlada para la producción de semilla, y que este adaptada a la región de interés. Por ello, el objetivo fue seleccionar plantas de papaya sobresalientes y adaptadas a la zona productora de Michoacán. Mediante exploraciones de campo en parcelas comerciales, se identificaron y caracterizaron plantas de papaya del tipo Maradol hermafroditas y con características sobresalientes. En las plantas se seleccionaron botones florales y fueron cubiertos para provocar la autopolinización. Los frutos se colectaron en etapa de madurez y se obtuvieron las semillas. Se registraron variables morfológicas de planta y frutos, sanidad y germinación. 12 huertas presentaron plantas sobresalientes. La caracterización del progreso en el desarrollo de botón floral a frutos fue variable, pues se redujo la cantidad de frutos formados con relación a los botones cubiertos inicialmente, así como también, redujo la cantidad de frutos colectados en relación con los frutos formados. En cuanto al estado fitosanitario, se registró la presencia de virus, ácaros y otros insectos en la mayoría de las huertas registradas. La germinación fue aceptable. Se concluyó que se identificaron y caracterizaron plantas de papaya seleccionadas con base a características sobresalientes y adaptadas a la zona productora de Michoacán, para posterior estudio de mejoramiento.

Quality characteristics and protein composition of durum wheat cultivars released in the last 50 years

AbstractBackground and objectivesDespite the strong influence of proteins on quality, no research has been performed to determine the association between protein composition and quality improvements of durum wheat produced in North Dakota (ND). This research objected to identify improvements of quality traits and determine its association with variations in protein composition using 32 durum genotypes released between 1956 and 2013 in ND.FindingsCertain durum quality parameters, such as kernel weight, mixing properties, and pasta‐making characteristics, improved over the last 50 years of durum breeding. Total protein content showed nonsignificant variation; however, protein composition parameters varied significantly. Specifically, SDS extractable LMW polymeric proteins and gliadins decreased while unextractable polymeric proteins increased. These changes in protein composition parameters were significantly correlated with dough and pasta cooking quality traits.ConclusionsEnhancement of protein composition is primarily responsible for the improvement of mixing quality and cooked pasta firmness seen in durum cultivars released over the last 50 years.Significance and noveltyThese findings demonstrate that genetic advancement of mixing and pasta quality traits can be attained by segregation of genotypes based on protein composition in durum wheat breeding.