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This systematic review examined the role of social environment in pre-death grief experiences of dementia caregivers. Ninety-three Chinese and English articles were included from a comprehensive search of empirical studies using nine databases. Six social environment domains were generated: the person with dementia, dyadic relationship, family members and the wider community, health and social care services, place of care, and social-cultural contexts. A complex interplay between caregivers and their social environments that aggravate and attenuate pre-death grief experiences is evident. Research has focused mainly on the effects of people with dementia and dyadic relationships and has paid modest attention to the effects of family, relatives, and health and social care services. Caregivers' experiences with their friends, fellow caregivers, the wider community, and social-cultural norms are influential but understudied. Future research could adopt a systems thinking approach with sociological perspectives to generate a comprehensive and nuanced understanding of pre-death grief experiences.
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In a widowed family, the surviving parent and children face the loss together. However, most previous research in bereavement has focused on individual experiences. Although the family perspective has been introduced into the field, neither theories nor empirical research has explored mutual interaction. Dyadic coping reflects the family perspective and has been proven to be an influential factor in couples facing life adversities. Nevertheless, it has not been explored in the context of bereavement-specific stressors, including loss- and restoration-related stressors, nor in the parent-child relationship. This research is the first exploration of parent-child dyadic coping in widowed families in the bereavement context and aims to form a comprehensive conceptualization of parent-child dyadic coping following bereavement. Qualitative semistructured interviews were conducted with 20 parents and children from widowed families in mainland China (11 surviving children and nine widowed parents, representing 19 families). Constructivist grounded theory was used to guide the analysis. The main themes identified were dyadic coping-related cognitions, loss-oriented dyadic coping, restoration-oriented dyadic coping, and contextual factors. Three foci (thou, we, and I) were identified for both loss- and restoration-oriented dyadic coping. A conceptualization model of bereavement dyadic coping within widowed families was developed. This study extends the single I-coping perspective in bereavement coping to a we-coping perspective, provides an interactional- and operational-level knowledge on dual-process coping, acknowledges the bilateral interaction in parent-child relationships, and offers implications for bereavement support practice for widowed families. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
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Aflicción , Viudez , Femenino , Humanos , Estudios Retrospectivos , Padres/psicología , Adaptación Psicológica , Relaciones Padres-HijoRESUMEN
OBJECTIVES: Caregiving for family members at their end of life is stressful. Caregivers' strain, burden, or stress has been measured in various geographical and sociodemographic contexts. The concept of stress, burden, and strain are sometimes used interchangeably. By analysing the factor structure of the Chinese version of the Modified Caregiver Strain Index (C-M-CSI), this study aimed to examine the caregiving strain concept and its demographic correlates. METHODS: A sample of 453 family caregivers of patients with a terminal illness in Hong Kong was employed. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were performed. In addition, generalized linear models (GLM) were used to examine the demographic correlates. RESULTS: The EFA yielded a 3-factor model termed "Perception of Caregiving," "Empathetic Strain," and "Adjustment Demand." This 3-factor model explained 50% of the variance and showed good internal consistency. The CFA confirmed the 3-factor construct with satisfactory internal reliability (χ2 [61, N = 226] = 108.86, p < 0.001, CFI = 0.96, TLI = 0.95, SRMR = 0.04, and RMSEA = 0.06). Inspired by this factor structure and concepts of stress and strain from engineering discipline, a new model of caregiver strain is proposed. Additionally, family caregivers of non-cancer patients, who were not living with the patient, or younger were associated negatively with different dimensions of caregiver strain. SIGNIFICANCE OF RESULTS: The results gave insights into the advancement of the conceptualization of caregiver strain, its multidimensional nature, and process of change, which inform directions for future research and practices.
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Grief-related beliefs play an important role in bereavement adjustment. This study aimed to investigate the patterns and correlates of grief-related beliefs among recently bereaved adults (n = 311). Latent class analysis results suggested three meaningful grief belief classes could be identified: the High grief belief class (24.1%), Predominantly counterfactual thoughts class (42.4%), and Low belief class (33.4%). Members in the High grief belief class reported the highest levels of grief symptoms, depression and PTSD symptoms, loneliness, and functional impairment. Compared with the Low belief class, unmarried people, people in poor health, individuals who lost parents, partners, or children, and those who experienced violent or unexpected death were more likely to belong to the High grief belief class. Findings of this study support the importance of examining grief-related cognitions in research and clinical practice, especially counterfactual thoughts about the death, which may need to be specifically screened and targeted in treatment.
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Aflicción , Trastornos por Estrés Postraumático , Niño , Adulto , Humanos , Análisis de Clases Latentes , Trastornos por Estrés Postraumático/diagnóstico , Pesar , PadresRESUMEN
The meaning of patient deaths is key to understanding professional bereavement. To validate its construct, we applied partial least square structural equation modeling (PLS-SEM) to online survey data from 563 Chinese physicians and nurses. Both the personal meaning and professional meaning contribute significantly while not interchangeably to the meaning of patient deaths. In addition to the loss of an acquaintance, the loss of a valuable life, and the loss of a professional goal, patient deaths can also mean trauma, bad luck, identity crisis, a warning, a learning opportunity, and a time to empathize with others' sufferings.
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Aflicción , Cuidadores , Humanos , Pesar , Encuestas y CuestionariosRESUMEN
Bereavement during the COVID-19 pandemic may have some unique characteristics that become potential risk factors (e.g., absence of grief rituals, no opportunity to say goodbye to the deceased and loneliness caused by social distancing) for acute grief. Avoidance processes could be significant mediators in the context of the pandemic. The current study aimed to investigate whether and how these COVID-19-related risk factors were related to acute grief severity. Bereaved adults (n = 319) who lost significant others during the COVID-19 pandemic completed a self-report questionnaire package measuring COVID-19-related factors, grief severity and depressive and anxious avoidance. Regression analyses suggested that among the three potential risk factors (loneliness, grief rituals and opportunity to say goodbye), loneliness was significantly associated with acute grief after controlling for basic demographic and loss-related information. Structural equation models suggested that depressive avoidance and anxious avoidance partially mediated the associations of loneliness with acute grief severity. The findings indicate that dealing with loss during the COVID-19 pandemic warrants further exploration concerning how potential environmental risk factors may impede adaptation to loss. Depressive and anxious avoidance processes may play important roles in grief interventions for isolated and lonely bereaved people.
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Aflicción , COVID-19 , Adulto , Humanos , Pandemias , Pesar , Factores de RiesgoRESUMEN
BACKGROUND: Patients with terminal illnesses have different symptoms. The goal of palliative care is to alleviate the suffering induced by these symptoms. Available research on symptoms has focused on their prevalence or identification of clusters. Little is known about the central symptoms contributing to the maintenance of the whole system of symptoms or the mechanism of influence between symptoms, particularly between physical and psychosocial symptoms. AIM: The study used network analysis to explore symptom clusters among patients with terminal illnesses and identify the central symptoms, the bridge symptoms, and pathways between physical and psychosocial symptoms. DESIGN AND SETTING/PARTICIPANTS: This is a retrospective cohort study using baseline symptom assessment of 677 adults with terminal illnesses receiving care from the Integrated Community End-of-Life Care Support Teams. RESULTS: Three symptom clusters were identified: physical, psychological, and practical clusters. "Weakness or lack of energy" was identified as the crucial symptom affecting the changes of other symptoms, followed by depression and anxiety. Three connections between the psychological and physical symptoms were identified: anxiety-pain, depression-constipation, and perceived family anxiety-poor appetite pathways. Pathways of practical concern-peace and practical concern-depression were indicated between practical and psychological symptoms. CONCLUSIONS: This study is the first of its kind to investigate the connections and mechanism of influence between symptoms among patients with terminal illnesses. It offers clear pathways for intervention with the most influential symptoms of weakness, anxiety, and depression.
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Ansiedad , Depresión , Fatiga , Cuidado Terminal , Enfermo Terminal , Adulto , Humanos , Ansiedad/diagnóstico , Ansiedad/terapia , Cuidados Paliativos , Calidad de Vida , Estudios Retrospectivos , Síndrome , Enfermo Terminal/psicología , Depresión/diagnóstico , Depresión/terapia , Fatiga/diagnóstico , Fatiga/terapiaRESUMEN
The outbreak of the COVID-19 pandemic brought new challenges to mourning and growth of bereaved. The purpose is to explore the relationship between the prolonged grief (PG) symptoms and the post-traumatic growth (PTG) of recently bereaved people during the COVID-19 period, and the mediating role of meaning making. 305 participants were recruited to complete the Posttraumatic Growth Inventory, Inventory of Complicated Grief, and Integration of Stressful Life Experiences Scale. Hierarchical multiple regression analyses and Medcurve in SPSS were adapted to test the hypotheses. The results revealed that there was a curvilinear relationship between PG and PTG and meaning making had a completely mediating effect on this relationship. Different intervention goals - whether alleviating distress or cultivating growth - should be set up according to the level of grief for recently bereaved individuals during COVID-19. More attention should be paid to the role of meaning making in the future clinical practice.
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Hong Kong experienced the SARS pandemic in 2003. Seventeen years later, the Covid-19 pandemic now challenges Hong Kong and the world. This study aims to unveil the impact of the pandemic on health social workers. One hundred and sixty-six health care social workers in Hong Kong were recruited to join a cross-sectional online survey from November 2020 to March 2021. This paper includes the analysis of the demographic information, fear of contamination, resilience, perceived social support and physical health only. Irrespective of the demographic background, the level of fear of contamination, resilience, perceived social support and physical health were similar. The mean scores of the two dimensions of fear of contamination (Harm avoidance: m = 7.49, s.d. = 3.25; Disgust avoidance: m = 7.75, s.d. = 2.90) were higher than those of general public and clinical samples with Obsessive-Compulsive Disorder. No moderation effects were found in resilience and perceived social support in the relationship of fear of contamination and physical health. Instead, direct effects were shown.The impact of the pandemic on health social workers was universal. Psychoeducational programs to alleviate the fear of contamination and organizational-level interventions to improve workplace social support are highly needed.
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COVID-19 , Pandemias , COVID-19/epidemiología , Estudios Transversales , Miedo , Hong Kong , Humanos , Apoyo Social , Trabajadores SocialesRESUMEN
COVID-19 has caused nearly 4.3 million deaths all around the world. People who have experienced loss during this special period may find it difficult to adapt to life after loss, and may even suffer from prolonged grief disorder or other mental health problems. However, there is a huge gap of grief research in China, with almost no comprehensive grief intervention training system or very few professional grief consultants. Considering the large number of bereaved individuals who are suffering from grief and other mental health problems, it is significant to develop a suitable and effective intervention protocol immediately. This article illustrates a study protocol initiated by a Chinese university to investigate the mental health of bereaved individuals during the COVID-19 pandemic and train grief counselors to provide grief counseling to the bereaved, as well as to evaluate the effectiveness of the grief counseling. The method is as follows: (1) 300 psychological counselors will be recruited to attend the grief counseling training. Assessments will be conducted at three time points: baseline (T0), after the basic training (T1), and after the advanced training (T2); (2) 500 bereaved Chinese will be recruit to join the online survey and will be assessed at two time points with a six-month interval; and (3) a two-armed (grief counseling versus wait-list controls) RCT (random control trials) will be conducted with 160 bereaved individuals. Assessments will be conducted at three time points: before randomization (baseline, T0), at the post-counseling (T1), and three months after the post-counseling (T2). Primary outcomes will be assessed by the Prolonged Grief Questionnaire (PG-13), the 20-item PTSD Checklist for DSM-5 (PCL-5), the Depression Anxiety and Stress Scale (DASS-21), and the Posttraumatic Growth Inventory (PTGI). This research will help develop grief research and grief counseling in China, as well as provide professional mental health services for individuals who may suffer from grief-related disorders in the future.
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Aflicción , COVID-19 , China , Consejo , Pesar , Humanos , Estudios Longitudinales , Pandemias , Ensayos Clínicos Controlados Aleatorios como Asunto , SARS-CoV-2RESUMEN
BACKGROUND: Delivery of community-based end-of-life care for patients and family members has been recognized as an important public health care approach. Despite differences in different healthcare settings and the significance of a person-centered approach, little research has investigated facilitators of community-based end-of-life care from the perspective of service recipients. In particular, there has been limited exploration of strategies to ensure positive outcomes at an operational level. AIM: To explore factors facilitating positive end-of-life care provision in community-based settings and how these are achieved in practice, from the perspectives of patients and family caregivers. DESIGN: A qualitative cross-sectional descriptive study was undertaken through semi-structured interviews with patients and family caregivers subjected to thematic analysis. SETTING/PARTICIPANTS: Ten patients and 16 family caregivers were recruited from an end-of-life community care program provided by four non-governmental organizations in Hong Kong. RESULTS: Seven core themes were identified: positive emotions about the relationship, positive appraisals of the relationship, care through inquiring about recipients' circumstances, instrumentality of care (i.e. information, coaching on care, practical help, psychological support, multiple activities), comprehensiveness of care (i.e. diversity, post-death care, family-level wellbeing), structure of care (i.e. timely follow-up, well-developed system), and qualities of workers. CONCLUSIONS: Improvement in service quality might be achieved through alternating the perceptions or emotional reactions of care recipients toward care providers and increased use of sensitive inquiry. Comprehensive care and positive outcomes might be facilitated by addressing the dualities of care by providing diverse choices in pre-death and post-death care.
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Cuidadores , Cuidado Terminal , Estudios Transversales , Familia , Hong Kong , Humanos , Investigación CualitativaRESUMEN
The death of a family member affects not only individual family members but also their relationships and interactions. Grief has been studied mostly as an intrapersonal experience. Adopting the family perspective, this systematic scoping review focused on parent-child relationships in widowed families so as to identify what is already known on this topic and the research gaps for future study. The review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. Four databases (Web of Science, Psycinfo, PubMed, and CINAHL Plus) were searched. Search terms were combinations of two concepts: (1) loss of a parent (20 terms) and (2) parent-child (eight terms). 5,419 studies were identified during the search, of which 36 studies were included in the review following two rounds of screening. Four research themes emerged, and the aggregated findings were identified: (a) The surviving parent and children are likely to become closer following the loss of a parent, while other relevant factors need to be taken into account; (b) Better parent-child relationships play a protective role in children's adjustment to loss; (c) The surviving parent and children's adjustment to loss are interdependent; (d) Through parenting, communication style, coping strategy, and other attributes, the surviving parent can influence their children's adjustment. Gender and age differences were identified in parent-child relationships. The findings further justify the importance of a family perspective when conducting research and practice on bereavement. Several research gaps were identified. Existing studies paid insufficient attention to children's agency and bidirectional relationships, and the interaction process and its role underlying parent-child bidirectional causality. A conceptual framework of parent-child relationships in widowed families is proposed based on these findings.
La muerte de un miembro de la familia afecta no solo a los miembros individuales de la familia, sino también sus relaciones e interacciones. El duelo se ha estudiado habitualmente como experiencia intrapersonal. Adoptando la perspectiva familiar, esta revisión sistemática exploratoria se centró en las relaciones entre progenitor e hijos en familias donde había fallecido uno de los progenitores con el objetivo de identificar lo que ya se sabe sobre este tema y las deficiencias en las investigaciones para futuros estudios. La revisión sigue las pautas de la extensión para revisiones sistemáticas exploratorias de los Ítems de Referencia para Publicar Revisiones Sistemáticas Exploratorias y Metaanálisis (PRISMA-ScR). Se realizaron búsquedas en cuatro bases de datos (Web of Science, Psycinfo, PubMed y CINAHL Plus). Los términos buscados fueron combinaciones de dos conceptos: (1) pérdida de un progenitor (20 términos) y (2) progenitor-hijo (ocho términos). Se identificaron 5419 estudios durante la búsqueda, de los cuales 36 se incluyeron en la revisión después de dos rondas de selección. Surgieron cuatro temas de investigación y se indicaron los resultados colectivos: a. El progenitor superviviente y los hijos tienden a desarrollar un vínculo más estrecho después de la muerte del otro progenitor, si bien es necesario tener en cuenta otros factores relevantes; b. Una mejor relación entre progenitores e hijos desempeña un papel protector en la adaptación de los hijos a la pérdida; c. La adaptación a la pérdida del progenitor superviviente y de los hijos es independiente; d. Mediante la crianza, el estilo de comunicación, la estrategia de afrontamiento y otros atributos, el progenitor superviviente puede influir en la adaptación de sus hijos. Se identificaron las diferencias de género y de edad en las relaciones entre progenitores e hijos. Los resultados justifican además la importancia de una perspectiva familiar a la hora de llevar a cabo investigaciones y prácticas sobre la pérdida de un ser querido. Se detectaron varias deficiencias en las investigaciones. Los estudios existentes prestaron poca atención a la voluntad de los hijos y a las relaciones bidireccionales, así como al proceso de interacción y su papel detrás de la causalidad bidireccional entre progenitores e hijos. Sobre la base de estos resultados, se propone un marco conceptual de relaciones entre padres e hijos en familias donde falleció uno de los progenitores.
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Aflicción , Viudez , Femenino , Humanos , Relaciones Padres-Hijo , Responsabilidad Parental , PadresRESUMEN
In contrast to typical radially symmetrical flowers, zygomorphic flowers, such as those produced by pea (Pisum sativum L.), have bilateral symmetry, manifesting dorsoventral (DV) and organ internal (IN) asymmetry. However, the molecular mechanism controlling IN asymmetry remains largely unclear. Here, we used a comparative mapping approach to clone SYMMETRIC PETALS 1 (SYP1), which encodes a key regulator of floral organ internal asymmetry. Phylogenetic analysis showed that SYP1 is an ortholog of Arabidopsis thaliana LIGHT-DEPENDENT SHORT HYPOCOTYL 3 (LSH3), an ALOG (Arabidopsis LSH1 and Oryza G1) family transcription factor. Genetic analysis and physical interaction assays showed that COCHLEATA (COCH, Arabidopsis BLADE-ON-PETIOLE ortholog), a known regulator of compound leaf and nodule identity in pea, is involved in organ internal asymmetry and interacts with SYP1. COCH and SYP1 had similar expression patterns and COCH and SYP1 target to the nucleus. Furthermore, our results suggested that COCH represses the 26S proteasome-mediated degradation of SYP1 and regulates its abundance. Our study suggested that the COCH-SYP1 module plays a pivotal role in floral organ internal asymmetry development in legumes.
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Flores/genética , Morfogénesis/genética , Pisum sativum/genética , Proteínas de Plantas/genética , Dominios y Motivos de Interacción de Proteínas , Carácter Cuantitativo Heredable , Secuencia de Aminoácidos , Clonación Molecular , Genes de Plantas , Estudios de Asociación Genética , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismoRESUMEN
BACKGROUND: The interaction among plants and their pollinators has been a major factor which enriched floral traits known as pollination syndromes and promoted the diversification of flowering plants. One of the bee-pollination syndromes in Faboideae with keel blossoms is the formation of a landing platform by wing and keel petals. However, the molecular mechanisms of elaborating a keel blossom remain unclear. RESULTS: By performing large scale mutagenesis, we isolated and characterized a mutant in Vigna radiata, love on wings (low), which shows developmental defects in petal asymmetry and vasculature, leading to a failure in landing platform formation. We cloned the locus through map-based cloning together with RNA-sequencing (RNA-seq) analysis. We found that LOW encoded a nucleus-localized Dof-like protein and was expressed in the flower provascular and vascular tissues. A single copy of LOW was detected in legumes, in contrast with other taxa where there seems to be at least 2 copies. Thirty one Dof proteins have been identified from the V. radiata's genome, which can be further divided into four Major Cluster of Orthologous Groups (MCOGs). We also showed that ectopic expression of LOW in Arabidopsis driven by its native promoter caused changes in petal vasculature pattern. CONCLUSIONS: To summarize, our study isolated a legume Dof-like factor LOW from V. radiata, which affects vasculature development in this species and this change can, in turn, impact petal development and overall morphology of keel blossom.
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Flores/fisiología , Proteínas de Plantas/fisiología , Vigna/fisiología , Arabidopsis/genética , Fabaceae/genética , Flores/anatomía & histología , Genes de Plantas , Mutagénesis , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente , Polinización , Factores de Transcripción/genética , Factores de Transcripción/fisiología , Vigna/anatomía & histología , Vigna/genéticaRESUMEN
Many studies suggest that there are distinct regulatory processes controlling compound leaf development in different clades of legumes. Loss of function of the LEAFY (LFY) orthologs results in a reduction of leaf complexity to different degrees in inverted repeat-lacking clade (IRLC) and non-IRLC species. To further understand the role of LFY orthologs and the molecular mechanism in compound leaf development in non-IRLC plants, we studied leaf development in unifoliate leaf (un) mutant, a classical mutant of mungbean (Vigna radiata L.), which showed a complete conversion of compound leaves into simple leaves. Our analysis revealed that UN encoded the mungbean LFY ortholog (VrLFY) and played a significant role in leaf development. In situ RNA hybridization results showed that STM-like KNOXI genes were expressed in compound leaf primordia in mungbean. Furthermore, increased leaflet number in heptafoliate leaflets1 (hel1) mutants was demonstrated to depend on the function of VrLFY and KNOXI genes in mungbean. Our results suggested that HEL1 is a key factor coordinating distinct processes in the control of compound leaf development in mungbean and its related non-IRLC legumes.
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MAIN CONCLUSION: The results provide a significant verification of functional redundancy and diversity of CUC/NAM genes in legumes. The CUP-SHAPED COTYLEDON/NO APICAL MERISTEM (CUC/NAM) orthologs play key roles for plant organ boundary formation and organ development. Here, we performed a forward screen of the gamma irradiation mutagenesis population in mungbean and characterised a mutant, reduced rachis and fused leaflets (rrf1), which gave rise to the formation of compound leaves with reduced rachis and fused leaflets. Map-based cloning revealed that RRF1 encoded a CUC/NAM protein in mungbean. Phylogenetic analysis indicated that legume CUC1/CUC2 genes were classified as belonging to two subclades, and there are different copies of CUC1/CUC2 genes in legumes. Transcriptomic analysis showed that expression levels of a set of developmental regulators, including class I KNOTTED-LIKE HOMEOBOXI (KNOXI) gene and LATERAL ORGAN BOUNDARIES DOMAIN (LBD) gene, were altered in rrf1 mutants compared to the wild-type plants. Furthermore, rrf1 genetically interacted with heptafoliate leaflets1 (hel1), a mutant displaying a seven-leaflet compound leaf, to regulate leaf development in mungbean. Our results suggest functional redundancy and diversity of two subclades of CUC1/CUC2 genes in legumes, following the duplication of an ancestral gene.
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Genes de Plantas/fisiología , Hojas de la Planta/crecimiento & desarrollo , Proteínas de Plantas/fisiología , Vigna/crecimiento & desarrollo , Clonación Molecular , Perfilación de la Expresión Génica , Regulación del Desarrollo de la Expresión Génica/genética , Regulación de la Expresión Génica de las Plantas/genética , Genes de Plantas/genética , Filogenia , Hojas de la Planta/genética , Proteínas de Plantas/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Vigna/genéticaRESUMEN
An orchid flower exhibits a zygomorphic corolla with a well-differentiated labellum. In Cymbidium sinense, many varieties with peloric or pseudopeloric flowers have been bred during centuries of domestication. However, little is known about the molecular basis controlling orchid floral zygomorphy and the origin of these varieties. Here, we studied the floral morphogenesis of C. sinense and transcriptome-wide enriched differentially expressed genes among different varieties. The floral zygomorphy of C. sinense is established in the early developmental process. Out of 27 MIKCC-MADS factors, we found two homeotic MADS genes whose expression was down-regulated in peloric varieties but up-regulated in pseudopeloric varieties. CsAP3-2 expressed in the inner floral organs co-operates with a labellum-specific factor CsAGL6-2, asymmetrically promoting the differentiation of inner tepals. Interestingly, we detected exon deletions on CsAP3-2 in peloric varieties, indicating that loss of B-function results in the origin of peloria. Additional petaloid structures developed when we ectopically expressed these genes in Arabidopsis, suggesting their roles in floral morphogenesis. These findings indicate that the interplay among MADS factors would be crucial for orchid floral zygomorphy, and mutations in these factors may have maintained during artificial selection.
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Orchidaceae/genética , Proteínas de Plantas/metabolismo , Transcriptoma/genética , Regulación de la Expresión Génica de las Plantas/genética , Regulación de la Expresión Génica de las Plantas/fisiología , Filogenia , Fitomejoramiento , Proteínas de Plantas/genéticaRESUMEN
Pea (Pisum sativum L.) is a model plant that has been used in classical genetics and organ development studies. However, its large and complex genome has hindered research investigations in pea. Here, we generated transcriptomes from different tissues or organs of three pea accessions using next-generation sequencing to assess single nucleotide polymorphisms (SNPs), and further investigated petal differentially expressed genes to elucidate the mechanisms regulating floral zygomorphy. Eighteen samples were sequenced, which yielded a total of 617 million clean reads, and de novo assembly resulted in 87,137 unigenes. A total of 9044 high-quality SNPs were obtained among the three accessions, and a consensus map was constructed. We further discovered several dorsoventral asymmetrically expressed genes that were confirmed by qRT-PCR among different petals, including previously reported three CYC-like proliferating cell factor (TCP) genes. One MADS-box gene was highly expressed in dorsal petals, and several MYB factors were predominantly expressed among dorsal, lateral, and/or ventral petals, together with a ventrally expressed TCP gene. In sum, our comprehensive database complements the existing resources for comparative genetic mapping and facilitates future investigations in legume zygomorphic flower development.
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Flores/genética , Pisum sativum/genética , Polimorfismo de Nucleótido Simple , Flores/crecimiento & desarrollo , Regulación del Desarrollo de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Genoma de Planta , Pisum sativum/crecimiento & desarrollo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , TranscriptomaRESUMEN
The diverse pigmentation patterns of flower corollas probably result from pollinator-mediated selection. Previous studies demonstrated that R2R3-MYB factors may have been recruited in the regulation of corolla pigmentation. However, how R2R3-MYBs became so diverse in their regulation of different pigmentation patterns remains unclear. Here, we studied a Lamiales species, Torenia fournieri, which has elaborate zygomorphic flowers with dorsal-ventral asymmetries in corolla pigmentation. We found recent gene duplication events in CYCLOIDEA-like (CYC-like) and RADIALIS-like (RAD-like) genes, and functionally analyzed three dorsal-specific expression factors: TfCYC1, TfCYC2, and TfRAD1. We found that the CYC-RAD module coordinates petal shape and corolla pigmentation, as ectopic expression of TfCYC2 or TfRAD1 disrupted the asymmetric corolla pigmentation pattern and produced strongly dorsalized flowers. Dorsal petal identity was lost when TfCYC2 was down-regulated or when TfRAD1 was knocked out. In T. fournieri, the diversified CYC and RAD genes have evolved regulatory loops, and TfCYC2 binds directly to the regulatory regions of an R2R3-MYB factor gene, TfMYB1, which might lead to its asymmetric expression and ultimately establish the asymmetric pigmentation pattern. These findings support the existence of a regulatory module that integrates dorsal-ventral patterning and asymmetric corolla pigmentation in T. fournieri.