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At least 19 recordsLinked to original sources
PubMed2025

Genome-wide association study to dissect the genetic architecture of bolting-related traits in carrot (Daucus carota).

As a crucial root vegetable, the phenomenon of bolting and flowering presents a significant challenge to the commercial value of carrot. However, the genetic mechanism of carrot bolting remains to be fully elucidated. In this study, we conducted a two-year cultivation experiment with a population of 240 carrots to examine traits associated with bolting. We conducted whole-genome sequencing on these carrots and subsequently performed population structure analysis, as well as genome-wide association studies (GWAS). A total of nine single nucleotide polymorphism (SNP) loci were identified across diverse environmental conditions that exhibited significant associations with bolting speed and other traits. Furthermore, within 93 candidate genes identified, the RING-domain zinc-finger protein LOC108205243 was determined to play a significant role in the regulation of bolting traits. The SNPs and candidate genes identified in this research may serve as molecular markers for bolting traits, thereby offering essential resources for genetic engineering breeding efforts aimed at managing bolting in carrots.

Daucus carota↗
PubMed2005

Variation at two flowering time genes within and among populations of Arabidopsis thaliana: comparison with markers and traits.

Flowering Locus C (FLC) and Frigida are two interacting genes controlling flowering time variation in Arabidopsis thaliana. Variation at these genes was surveyed in 12 A. thaliana populations sampled in France. These populations were also screened for variation at molecular markers [12 microsatellites and 19 cleaved amplified polymorphic sequence (CAPS) markers] and at seven quantitative traits measured with and without vernalization. Seven populations were highly polymorphic at markers (H(S) = 0.57 at microsatellites, 0.24 at CAPS) and showed heritable variation for bolting time and some other traits. Five populations were genetically fixed or nearly fixed. Q(ST) for bolting time without vernalization was significantly higher than F(ST), suggesting local divergent selection. One of the two haplotype groups at FLC (FLC(A)) was very predominant (frequency of 99%). The first exon of Frigida showed elevated nonsynonymous variation, and nine loss-of-function mutations were found throughout the gene. The association between loss-of-function and earlier bolting was confirmed. Overall, 18 Frigida haplotypes were detected. The pattern of variation at Frigida was largely similar to that found at markers and traits, with the same populations being fixed or highly diverse. Metapopulation dynamics is thus probably the main factor shaping genetic variation in A. thaliana. However, F(ST) for functional (FRI) vs. nonfunctional (FRI(Delta)) haplotypes was significantly higher than F(ST) at markers. This suggested that loss-of-function at Frigida is under local selection for flowering time.

Arabidopsis↗
PubMed2003

The contribution of spontaneous mutation to variation in environmental response in Arabidopsis thaliana: responses to nutrients.

Although the evolutionary importance of spontaneous mutation is evident, its contribution to the evolution of ecological specificity remains unclear, because the environmental sensitivity of effects of new mutations has received little empirical attention. To address this issue, we report a greenhouse in which we grew plants from 20 mutation-accumulation (MA) lines, advanced by selfing and single-seed descent from a single common founder to generation 17, as well as plants from five lines representing the founder, in high and low nutrient conditions. We examined 11 traits throughout life history, including germination, survivorship, bolting date, flowering date, leaf number, leaf size, early and late height, mean fruit size, total seed weight, and reproductive biomass. Comparison of trait means between the two generations did not support the commonly held view that new mutations affecting fitness in these MA lines are strongly biased toward deleterious effects. We detected significant variance among MA lines for one fitness component, mean fruit size, but we did not detect a significant contribution of mutations accumulated in these MA lines to genotype by environment interaction (GEI). These results suggest that other evolutionary mechanisms play a more important role than spontaneous mutation alone in establishing the GEI found for wild collections and lab accessions of Arabidopsis thaliana in previous studies.

Arabidopsis↗
PubMed2002

Novel loci control variation in reproductive timing in Arabidopsis thaliana in natural environments.

Molecular biologists are rapidly characterizing the genetic basis of flowering in model species such as Arabidopsis thaliana. However, it is not clear how the developmental pathways identified in controlled environments contribute to variation in reproductive timing in natural ecological settings. Here we report the first study of quantitative trait loci (QTL) for date of bolting (the transition from vegetative to reproductive growth) in A. thaliana in natural seasonal field environments and compare the results with those obtained under typical growth-chamber conditions. Two QTL specific to long days in the chamber were expressed only in spring-germinating cohorts in the field, and two loci specific to short days in the chamber were expressed only in fall-germinating cohorts, suggesting differential involvement of the photoperiod pathway in different seasonal environments. However, several other photoperiod-specific QTL with large effects in controlled conditions were undetectable in natural environments, indicating that expression of allelic variation at these loci was overridden by environmental factors specific to the field. Moreover, a substantial number of QTL with major effects on bolting date in one or more field environments were undetectable under controlled environment conditions. These novel loci suggest the involvement of additional genes in the transition to flowering under ecologically relevant conditions.

Arabidopsis↗
PubMed2006

Quantitative trait loci analysis of leaf and plant longevity in Arabidopsis thaliana.

The natural variation in leaf and plant longevity in Arabidopsis thaliana was analysed in a set of 45 ecotypes and 155 recombinant inbred lines derived from a Cape Verde Islands (Cvi) x Landsberg erecta (Ler) cross. Post-bolting longevity was inversely related to time to flowering and rosette leaf number in the set of 45 ecotypes, with Cvi having the longest and Ler the shortest post-bolting longevity. The recombinant inbred line population was tested under low or high soil nutrient levels (LN or HN, respectively). Three quantitative trait loci (QTL), one in chromosome 3 and two in chromosomes 1 and 5, were associated with longevity of the 6th rosette leaf under LN and HN, respectively. Four QTL for post-bolting longevity were found in chromosomes 1, 3, 4, and 5, and two in chromosomes 1 and 5 under LN and HN, respectively. An epistatic interaction affecting post-bolting longevity under LN, but not HN, was detected. Ler and Cvi carry a mix of increasing and decreasing alleles for the QTL affecting longevity of the 6th leaf and post-bolting longevity. Longevity of the 6th rosette leaf was associated with different QTL than post-bolting longevity, and it was affected by different QTL depending on nutrient availability. By contrast, the major QTL affecting post-bolting longevity exerted significant effects irrespective of soil nutrient availability.

Arabidopsis↗
PubMed2003

Suboptimal timing of reproduction in Lobelia inflata may be a conservative bet-hedging strategy.

Age and size at reproduction are important components of fitness, and are variable both within and among angiosperm species. The fitness consequences of such life-history variation are most readily studied in organisms that reproduce only once in their lifetime. The timing of the onset of reproduction (bolting) in the monocarpic perennial, Lobelia inflata, occurs over a range of dates within a season, and may be postponed to a later year. Empirical relationships among life-history traits, derived from over 950 wild-growing and experimentally manipulated plants in the field, are used to model an optimal changing size threshold (norm of reaction) for bolting over the growing season. Comparisons are made between observed and expected norms of reaction governing bolting. An apparently suboptimal bolting schedule that precludes bolting beyond an early (conservative) date is observed, and is found to be qualitatively consistent with conservative bet hedging under unpredictable season lengths. On this basis we propose the schedule of bolting as a plausible example of a conservative bet-hedging strategy. The results underscore the critical need for long-term studies of fluctuating selection to distinguish suboptimality from bet hedging.

Adaptation, Biological↗
PubMed2003

[Mapping and analysis QTL controlling some morphological traits in Chinese cabbage (Brassica campestris L. ssp. pekinensis)].

An AFLP and RAPD genetic map with 352 markers and a RIL (recombinant inbred lines) population from the cross of two cultivated Chinese cabbage lines were employed in mapping and analysis quantitative trait loci (QTL). The number, location, variation explained and additive effect of QTL underlying nine morphological traits were determined by using composite interval mapping method. Fifty putative QTL, including five for plant growth habit, six for plant height, five for plant diameter, seven for leaf length, four for leaf width, six for leaf length/leaf width ratio, seven for petiole length, four for petiole width and six for bolting character, were mapped on 14 linkage groups. There were unequal gene effects and unequal variation explained on the expression of many morphological traits. These results are fundamentals for molecular assisted selection of morphological traits in Chinese cabbage breeding.

Brassica↗
PubMed2005

Plasticity genes and plasticity costs: a new approach using an Arabidopsis recombinant inbred population.

Earlier flowering is triggered by vernalization in some but not all Arabidopsis ecotypes, often reflecting allelic variation at the FRIGIDA (FRI) locus. Using a recombinant inbred (RI) population polymorphic at FRI, we examined fitness consequences of variation for plasticity. Flowering and fitness were scored for 68 RI genotypes following full and partial vernalization treatments. Within-environment and mixed-model anovas estimated variance components for a genotype effect and a G x E term, respectively. Selection analyses examined whether delayed bolting increases fitness; a plasticity costs analysis asked whether increased plasticity lowers fitness. We also explored whether trait QTL had environment-specific effects, colocated in the immediate vicinity of FRI, or overlapped with fitness QTL. Selection may favor fri alleles and constitutive early flowering, especially in conditions that only partially vernalize plants. Plasticity costs, detected only after partial vernalization and only marginally significant, were nonetheless consistent with FRI-FLC function. We discuss how information about QTL with environment-specific effects, fitness QTL, and knowledge about plasticity genes can improve interpretation of selection or plasticity cost analyses.

Adaptation, Physiological↗
PubMed2004

A multigroup item response theory analysis of the psychopathy checklist--revised.

Item response theory was used to investigate the functioning of the Psychopathy Checklist-Revised (PCL-R; R. D. Hare, 1991, 2003) in several offender populations. With male criminal offenders (N=3,847) as a reference group, differential item functioning analyses were performed for 3 comparison groups: female criminal offenders (N=1,219), male forensic psychiatric patients (N=1,246), and male criminal offenders scored from file reviews (N=2,626). Results are discussed in the context of the 2-factor, 4-facet model for the PCL-R (R. D. Hare, 2003; J. Parker, G. Sitarenios, & R. D. Hare, 2003). Application of a multigroup graded response model to all 4 groups suggests scalar equivalence may hold at least approximately for each population, although the PCL-R provided slightly greater information about the latent trait of psychopathy for male criminal offenders scored from the standard procedure.

Adult↗
PubMed2006

[Genetic study of a new color of the beet Beta vulgaris L].

A new genetic character of the beet Beta vulgaris L., named stem color, was described and studied genetically. This character was shown to be dominant trait and monogenically inherited. The first-year beet plants with the genotype Stc/_have red leafstalks, weakly colored central rib, and colored storage root; however, the root itself is not colored. The second-year plants have a red-colored low third of the floral shoot. The plants with the genotype stc/stc are uncolored. The Stc gene was localized to the first linkage group at a distance of 17.5 +/- 2.1 crossing over units from the gene B (Bolting), which controls the annual-perennial habit of beet.

Beta vulgaris↗
PubMed1996

Clonal analysis of the late flowering fca mutant of Arabidopsis thaliana: cell fate and cell autonomy.

Plants that are homozygous for the fca mutation bolt and flower later than wild-type (FCA) plants. The mutation has little or no effect on the fate map of the dry seed, except that the central cells give rise to further rosette leaves instead of the bolting stem, cauling leaves and inflorescence. The large and variable sectors affecting the late rosette leaves of fca plants were used to generate an abstract frequency-distance fate map of vegetative growth. The map relates the initiation of leaves in the plant apex to their final arrangements. The map was found to be a shallow dome with phyllotaxy superimposed on its surface. X-irradiation was used to provoke loss of the FCA allele from cells in heterozygous seeds. The resulting fca sectors had no effect on the plant phenotype. Even when L2 and L3 cells at the centre of the meristem could not produce the FCA gene product, bolting and flowering was unaffected. The genotypically fca mutant tissue was incorporated into phenotypically normal stems, cauline leaves and flowers. Possible reasons for the non-autonomous behaviour of the trait are discussed.

Arabidopsis↗
PubMedDate not supplied

Psychological effects upon exposure to polyhalogenated dibenzodioxins and dibenzofurans.

Thirty workers who had been exposed to combustion products for several years due to testing of flame retarding qualities of building materials and 30 controls from the same facility were investigated. Concentrations found in samples taken from different places of the facility were up to 14,660 microg/kg for polybrominated dibenzofurans and up to 67.1 microg/kg for polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs). Physical examination, routine laboratory parameters, and blood fat concentrations of PCDDs and PCDFs revealed normal findings. Neurotoxic symptoms showed a weak tendency of overrepresentation among the exposed workers. The frequency of neurobehavioural symptoms increased significantly with trait anxiety independent of exposure to combustion products.

Adult↗
PubMed2006

Leaf-specific suppression of deoxyhypusine synthase in Arabidopsis thaliana enhances growth without negative pleiotropic effects.

Deoxyhypusine synthase (DHS) mediates the first of two enzymatic reactions required for the post-translational activation of eukaryotic translation initiation factor 5A (eIF5A), which in turn is thought to facilitate translation of specific mRNAs. Analyses of GUS activity in transgenic Arabidopsis plants expressing the GUS reporter gene under regulation of the promoter for AtDHS revealed that the expression of DHS changes both spatially and temporally as development progresses. In particular, DHS is expressed not only in rosette leaves, but also in the anthers of developing flowers. To determine the role of DHS in leaves, transgenic plants in which DHS was selectively suppressed in rosettes of Arabidopsis plants were prepared. This was achieved by expressing AtDHS 3'-UTR cDNA as a transgene under regulation of the promoter for AtRbcS2, a gene encoding the small subunit of Rubisco. The dominant phenotypic traits of the DHS-suppressed plants proved to be a dramatic enhancement of both vegetative and reproductive growth. As well, the onset of leaf senescence in the DHS-suppressed plants was delayed by approximately 1 week, but there was no change in the timing of bolting. In addition, there was no evidence for the negative pleiotropic effects, including stunted reproductive growth and reduced seed yield, noted previously for transgenic plants in which DHS was constitutively suppressed. The results indicate that DHS plays a pivotal role in both growth and senescence.

3' Untranslated Regions↗
PubMed1990

Expression and performance in transgenic pigs.

Recent research clearly shows that fusion genes can be microinjected into a pronucleus of an ovum and integrate into the pig genome. Animals with such fusion genes are called 'transgenic'. The percentage of injected ova that developed into transgenic pigs varied among experiments from 0.31% to 1.73%. The percentage of transgenic pigs that expressed the fusion gene ranged from 17% to 100%. Eleven different regulatory sequences have been used for fusion genes transferred into pigs. Some of these regulatory sequences directed strong gene expression, but control over level of expression was inadequate. Other regulatory sequences directed weak expression, but imparted only brief spikes of induced expression. The predominant gene coding sequences transferred were for growth-related hormones. Elevation of growth hormone (GH) in expressing transgenic pigs enhanced plasma concentrations of insulin-like growth factor-I (IGF-I), insulin, and glucose, improved feed efficiency about 15%, and markedly reduced subcutaneous fat compared to nontransgenic siblings. Growth rate was enhanced in some transgenic GH pigs but not in others, possibly due to dietary limits. The 'over-expression' of GH was detrimental to the general health of most transgenic pigs. The most prevalent problems were lethargy, lameness, and gastric ulcers. Gilts that expressed foreign GH genes were anoestrous. Boars that expressed foreign GH genes lacked libido, but their semen was fertile when used by artificial insemination. Six different fusion genes have been transmitted from transgenic founders to progeny. Most of the transgenic pigs that produced progeny transmitted the fusion gene as an autosomal dominant trait to about half of their progeny. Regulatory sequences that will permit full control of gene expression must be developed before the full potential of gene transfer in pigs can be realized.

Animals↗
PubMed1990

Effects of gonadotropin treatment on ovarian follicle growth and granulosal cell aromatase activity in prepuberal gilts.

This experiment was conducted to compare the ability of USDA porcine FSH-B-1 (pFSH), USDA porcine LH-B-1 (pLH), and pregnant mare's serum gonadotropin (PMSG) to grow large follicles and induce granulosal cell aromatase activity in prepuberal gilts. Twenty-four gilts (164 d old) received one of four treatments by i.m. injection: 1) saline once, n = 8; 2) pFSH (8 micrograms/kg BW, nine times at 8-h intervals), n = 5; 3) pLH (2 micrograms/kg BW, nine times at 8-h intervals), n = 6; or 4) PMSG (15 IU/kg BW, once), n = 5. At slaughter, 72 h after the first injection, the ovaries to saline-treated gilts contained an average of 104 surface antral follicles 1 to 3 mm in diameter. compared to treatment with saline, pFSH increased (P less than .05) the number of follicles 46%, whereas pLH or PMSG decreased (P less than .05) the number by 70 and 84%, respectively. Compared with saline, treatment with PMSG or pLH induced growth of large follicles (7 to 9 mm) (10.8 and 4.8 follicles/gilt, respectively), increased plasma estrogen, increased granulosal cell aromatase activity, and decreased plasma FSH by 51 and 69%; treatment with pFSH had no significant effect on these traits. Results indicate that injected pFSH did not cause growth of large follicles or induce granulosal cell aromatase activity in prepuberal gilts. In contrast, LH initiated growth and increased granulosal cell aromatase activity in a small number of follicles and accelerated atresia among the remaining follicles.

Animals↗
PubMed2001

Transgenic radish (Raphanus sativus L. longipinnatus Bailey) by floral-dip method--plant development and surfactant are important in optimizing transformation efficiency.

Transgenic radish (Raphanus sativus L. longipinnatus Bailey) plants were produced from the progeny of plants which were dipped into a suspension of Agrobacterium carrying both the beta-glucuronidase (gusA) gene and a gene for resistance to the herbicide Basta (bar) between T-DNA border sequences. The importance of development of the floral-dipped plant and presence of surfactant in the inoculation medium were evaluated in terms of transgenic plant production. Plants dipped at the primary bolt stage of growth, into a suspension of Agrobacterium containing 0.05% (v/v) Silwet L-77 resulted in optimum transformation efficiency, with 1.4% from 1110 seeds. The presence of Pluronic F-68 or Tween 20 in the inoculation medium was beneficial towards transgenic plant output compared to treatments without surfactant. Putative transformed T1 plants were efficiently selected by spraying with 0.03% (v/v) Basta and all herbicide-resistant plants tested positive for GUS activity when analysed both histochemically and fluorometrically. Southern analysis revealed that both the gusA and bar genes integrated into the genome of transformed plants and segregated as dominant Mendelian traits. These results demonstrate that radish can be genetically modified for the improvement of this important vegetable crop.

Aminobutyrates↗
PubMed2002

Is multiple chemical sensitivity a clinically defined entity?

In 1996 a WHO/IPCS Workshop has suggested to use as an appropriate descriptor of MCS the broader term "Idiopathic Environmental Intolerances (IEI)", in order to incorporate "a number of disorders sharing similar symptomatologies". Research was strongly encouraged. The following points have been put forward as a precondition to define MCS as a clinical entity: (a) establishment of diagnostic criteria, (b) identification of pathogenic mechanisms, together with, (c) an explanation of relationship between exposures and symptoms. Against this background, progress made in the fields of sensory physiology and neurobehaviour research must be debated. In particular, recent results on processing of cognitive stimuli have to be considered. IEI/MCS patients exhibited differences vs. controls in their reactions to intranasal challenge, consistent with changes in cognitive processing of suprathreshold chemosensory information. Trait anxiety and focus of attention have clearly been identified as major components in eliciting neurobehavioural MCS symptoms. Hence, the question as to whether MCS should be regarded as a clinically defined entity remains controversial, but important progress can be noticed in elucidating and defining the nature of this phenomenon, by a combined effort of several disciplines (toxicology and behavioural toxicology, psychology and psychophysiology, and clinical medicine). The new situation will call for a re-evaluation of traditional positions.

Cognition↗
PubMed2006

Relevance of the deletion polymorphisms of the glutathione S-transferases GSTT1 and GSTM1 in pharmacology and toxicology.

Although cytosolic glutathione S-transferase (GST) enzymes occupy a key position in biological detoxification processes, two of the most relevant human isoenzymes, GSTT1-1 and GSTM1-1, are genetically deleted (non-functional alleles GSTT1*0 and GSTM1*0) in a high percentage of the human population, with major ethnic differences. The structures of the GSTT and GSTM gene areas explain the underlying genetic processes. GSTT1-1 is highly conserved during evolution and plays a major role in phase-II biotransformation of a number of drugs and industrial chemicals, e.g. cytostatic drugs, hydrocarbons and halogenated hydrocarbons. GSTM1-1 is particularly relevant in the deactivation of carcinogenic intermediates of polycyclic aromatic hydrocarbons. Several lines of evidence suggest that hGSTT1-1 and/or hGSTM1-1 play a role in the deactivation of reactive oxygen species that are likely to be involved in cellular processes of inflammation, ageing and degenerative diseases. There is cumulating evidence that combinations of the GSTM1*0 state with other genetic traits affecting the metabolism of carcinogens (CYP1A1, GSTP1) may predispose the aero-digestive tract and lung, especially in smokers, to a higher risk of cancer. The GSTM1*0 status appears also associated with a modest increase in the risk of bladder cancer, consistent with a GSTM1 interaction with carcinogenic tobacco smoke constituents. Both human GST deletions, although largely counterbalanced by overlapping substrate affinities within the GST superfamily, have consequences when the organism comes into contact with distinct man-made chemicals. This appears relevant in industrial toxicology and in drug metabolism.

Alleles↗