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Background: Major depressive disorder (MDD) is one of the most common mental disorders in adolescence carrying a serious risk of adverse development later in life. Extant treatments are limited in effectiveness and have high drop-out and relapse rates. A body of literature has been published on the association between distressing/ traumatic experiences and development and maintenance of MDD, but the effectiveness of a trauma-focused treatment approach for MDD has hardly been studied. This study aims to determine the effectiveness of eye movement desensitization and reprocessing (EMDR) therapy as stand-alone intervention in adolescents diagnosed with MDD. Methods: This study will be a randomized controlled trial with two conditions: (1) EMDR treatment (6 sessions) and (2) waiting list condition (WL: 6 weeks, followed by EMDR treatment). First, participants receive a baseline measure after which they will be randomized. Participants will be assessed post-intervention after which the WL participants will also receive six EMDR sessions. Follow-up assessments will be conducted at 3 and 6 months follow-up. Study population: In total, 64 adolescents (aged 12–18) diagnosed with a major depressive disorder (DSM-5) and identified memories of at least one distressing or traumatic event related to the depressive symptomatology will be included. Main study parameters/endpoints: Primary outcome variables will be the percentage of patients meeting criteria for MDD classification, and level of depressive symptoms. Secondary outcome measures include symptoms of PTSD, anxiety, and general social-emotional problems. At baseline, family functioning and having experienced emotional abuse or neglect will be assessed to explore whether these factors predict post-treatment outcome. Discussion: With the present study, we aim to investigate whether EMDR as a trauma-focussed brief intervention may be effective for adolescents with a primary diagnosis of MDD. EMDR has been proven an effective treatment for traumatic memories in other disorders. It is hypothesized that traumatic memories play a role in the onset and maintenance of depressive disorders. Particularly in adolescence, early treatment of these traumatic memories is warranted to prevent a more chronic or recurrent course of the disorder. Trial registration: International Clinical Trial Registry Platform (ICTRP): NL9008 (30–10-2020). [ABSTRACT FROM AUTHOR]

An inventory of genetic differences in flowering time in Arabidopsisis presented and discussed. Many genes influence the transition to flowering in a quantitative way. Two groups of mutants and natural variants can be distinguished: those that are responsive to environmental factors and those that are less responsive or unresponsive. it is possible that all late/early-flowering mutants isolated to date carry a mutation with an effect, either promotive or repressive, on a floral repressor. The interaction between light perception and flowering has been studied by analysis of phytochrome -- and cryptochrome deficient mutants, which showed that phyA and probably also cryptochrome have a promotive role in flowering, whereas phyB and other stable phytochromes have an inhibitory role. A circadian rhythm is important in establishing daylength sensitivity, as was shown by the phenotype of the elf3 mutants. [ABSTRACT FROM AUTHOR]

A dwarf mutant of Arabidopsis thaliana (L.) Heynh. was found to be less sensitive to applied gibberellins than the wild type, and this character was controlled by one partially-dominant gene (denoted Gai) located on chromosome 1. This mutant resembled gibberellin-deficient mutants since not only stem growth, but also apical dominance and seed germination were reduced. However, in contrast to the latter mutants, gibberellin does not reverse these effects in the Gai mutant. The insensitivity of the mutant could be quantified in much more detail in the recombinant of this mutation with the GA deficient mutant. ga-1/ga-1. Endogenous gibberellins of the Gai mutant did not differ from the wild type either in quantity or composition. The data suggest that the gene controls a step involved in gibberellin action. [ABSTRACT FROM AUTHOR]

Abscisic acid (ABA) insensitive mutants of Arabidopsis thaliana (L.) Heynh. were isolated by selecting plants which grew well on medium containing 10μM ABA. From the progeny of approximately 3500 mutagen-treated seeds, five mutants of at least three different loci were isolated. Three mutants were characterized, moreover, by a reduced seed dormancy and by symptoms of withering, indicating disturbed water relations and, therefore, resembled phenotypically the ABA-deficient mutants we described earlier in this species. Two mutants showed in addition only a reduction of seed dormancy. Compared to wild type, all mutants showed similar or increased levels of endogenous ABA in developing seeds and fruits (siliquae). The role of the different genes involved in relation to the mechanism of ABA action. [ABSTRACT FROM AUTHOR]

Presents a systematic and quantitative comparison of double mutants of representative alleles at ten of the late-flowering mutant loci of Arabidopsis. Materials and methods used; Examples of clear epistatic relationships among flowering-time genes in Arabidopsis; Results and discussion.

The use of genetics in plant biology aims at the physiological and molecular genetical characterization of the phenotypic variation for the trait under study. Efficient mutant and gene isolation procedures have been developed for a number of plant models such as Arabidopsis thaliana. For this, the map position of the genes and insertion mutagenesis are used. The latter also allows the characterization of genes that are not easily recognized in mutant approaches, by using enhancer or gene-trapping procedures and reverse genetics. In addition to mutants, natural variation present among wild and cultivated varieties of a species provides an important source of genetic variation. The use of molecular markers, advanced mapping populations and specific cytogenetic stocks in case of polyploids, enables a detailed characterization of such natural variation even when it is of a quantitative and polygenic nature. Examples of the various genetic approaches are given. [ABSTRACT FROM AUTHOR]

Naturally occurring genetic variation for contents of cationic minerals in seeds of Arabidopsis thaliana was studied by screening a series of accessions (ecotypes) for Ca, Fe, K, Mg, Mn, Na, Zn, and for total contents of P. Variation was observed for all minerals and correlations between contents of various minerals were present, most noticeably between Ca and Mg, P and Mg, and P and Mn. The genetic basis of this variation was further studied by QTL analysis, using the Landsberg erecta (L er) × Cape Verde Islands (Cvi) recombinant inbred population. For all minerals, except Na, one or more QTL were detected, explaining up to 78% of the variation. The map positions of several QTL were confirmed by analysis of near isogenic lines, carrying small Cvi introgressions in L er background. Interesting co-locations of QTL suggest pleiotropic effects, due to physiological coupling of the accumulation of certain minerals or to linkage of different genes. By comparing the map positions of QTL with the positions of genes expected to play a role in cation translocation, several candidate genes are suggested. [ABSTRACT FROM AUTHOR]

Phytate (myo-inositol-1,2,3,4,5,6-hexakisphosphate, InsP6) is the most abundant P-containing compound in plants, and an important anti-nutritional factor, due to its ability to complex essential micro-nutrients, e.g. iron and zinc. Analysis of natural variation for InsP6 and Pi accumulation in seeds and leaves for a large number of accessions of Arabidopsis thaliana, using a novel method for InsP6 detection, revealed a wide range of variation in InsP6 and Pi levels, varying from 7.0 mg to 23.1 mg of InsP6 per gram of seed. Quantitative trait locus (QTL) analysis of InsP6 and Pi levels in seeds and leaves, using an existing recombinant inbred line population, was performed in order to identify a gene(s) that is (are) involved in the regulation of InsP6 accumulation. Five genomic regions affecting the quantity of the InsP6 and Pi in seeds and leaves were identified. One of them, located on top of chromosome 3, affects all four traits. This QTL appears as the major locus responsible for the observed variation in InsP6 and Pi contents in the Ler/Cvi RIL population; the Ler allele decreases the content of both InsP6 and Pi in seeds and in leaves. The InsP6/Pi locus was further fine-mapped to a 99-kb region, containing 13 open reading frames. The maternal inheritance of the QTL and the positive correlation between InsP6 and total Pi levels both in seeds and in leaves indicate that the difference in InsP6 level between Ler and Cvi is likely to be caused by a difference in transport rather than by an alteration in the biosynthesis. Therefore, we consider the vacuolar membrane ATPase subunit G, located in the region of interest, as the most likely candidate gene for InsP6/Pi. [ABSTRACT FROM AUTHOR]

The tomato (Solanum lycopersicum L.) slender mutant procera (pro) was analysed for its relationship with gibberellin (GA) by combining it with GA deficiency due to the gib-1 mutation. The sensitivity to GA biosynthesis inhibitors and the GA content were measured in the pro gib-1 double mutant. In the gib-1 mutant background, the pro mutation strongly reduced the GA requirement for seed germination and stem growth and almost fully restored the morphological leaf defects of the gib-1 mutant. An end-of-day far-red light treatment, when applied to the various genotypes, indicated that GAs are required for a response to this treatment, but that it act independently of the Pro gene product. [ABSTRACT FROM AUTHOR]

Photomorphogenesis of tomato (Lycopersicon esculentum Mill.) is being studied with the aid of mutants which are modified either in their photoreceptor composition or in their signal transduction chain(s). Phytochrome chromophore mutants, presumably deficient in all phytochromes, and mutants specifically deficient in phytochrome A (phyA) or B1(phyB1) have been used to study the roles played by phytochromes in photomorphogenesis. In addition, other mutants, including transgenic lines overproducing phyA, exhibit exaggerated photomorphogenesis. Studies using these mutants are reviewed, with emphasis being placed on anthocyanin biosynthesis and plastid development as model systems for the dissection of the complex interactions between photoreceptors and to elucidate the nature of photoreceptor transduction chains. Recently, new mutants have been isolated by screening in a phyA,phyB1-deficient background. The novel phenotypes selected are candidates for mutants in additional photoreceptors or their transduction chains. [ABSTRACT FROM AUTHOR]

Siliqua development was studied in the wild type line Landsberg erecta and the GA‐sensitive mutant ga‐1 of Arabidopsis thaliana (L.) Heynh. Reciprocal crosses between wild type and ga‐l mutant, and self pollinations of either parent have shown that siliqua growth is determined by endogenous GAs originating from maternal tissues and embryo. The ga‐1 mutant either self pollinated or cross‐pollinated with wild type pollen showed reduced siliqua growth, which to a large extent could be overcome by exogenously applied GAs. The siliquae of the ga‐1 mutant possessed very reduced ent‐kaurene synthesizing capacity and no detectable endogenous GA‐activity indicating an early block in the GA‐biosynthetic pathway. Seed weight is not affected by GA‐deficiency during development. [ABSTRACT FROM AUTHOR]