Association Between Insomnia and Cognitive Frailty Among Older Patients With Chronic Heart Failure: Multiple Mediating Effects of Depressive Symptoms and Social Support.

BACKGROUND: Older patients with chronic heart failure (CHF) are prone to insomnia. Studies have shown that insomnia affects the onset of cognitive frailty and is also strongly associated with depressive symptoms and social support. However, information on how these factors interact to influence cognitive frailty remains underexplored. OBJECTIVE: Our aim in this study was to explore the multiple mediating roles of depressive symptoms and social support in the relationship between insomnia and cognitive frailty. METHODS: We recruited 300 hospitalized older patients with CHF to participate in this study. The participants completed the Athens Insomnia Scale, Geriatric Depression Scale, Montreal Cognitive Assessment, FRAIL Scale, and Social Support Rating Scale. The mediation hypothesis was tested using a multiple mediation model and bootstrapping method. RESULTS: In this study, 44% of the patients experienced insomnia, and 51.3% were in a state of cognitive frailty. Our main findings suggest that insomnia has an indirect effect on cognitive frailty through 2 pathways: the multiple mediating effects of depressive symptoms and social support, and a single mediating effect of depressive symptoms. The direct effect of insomnia on cognitive frailty is also significant. CONCLUSIONS: Older patients with CHF who experience insomnia tend to have more severe depressive symptoms, cognitive frailty, and poor social support. Thus, interventions to recognize insomnia early, improve depressive symptoms, and provide social support may reduce cognitive frailty in older patients with CHF. Longitudinal studies are necessary to further refine our findings and address the limitations of the current study.

Screening candidate genes for fruit size based on QTL-seq in Chinese jujube.

Introduction: Fruit size is an important economic trait affecting jujube fruit quality, which has always been the focus of marker-assisted breeding of jujube traits. However, despite a large number of studies have been carried out, the mechanism and key genes regulating jujube fruit size are mostly unknown. Methods: In this study, we used a new analysis method Quantitative Trait Loci sequencing (QTL-seq) (bulked segregant analysis) to screen the parents 'Yuhong' and 'Jiaocheng 5' with significant phenotypic differences and mixed offspring group with extreme traits of large fruit and small fruit, respectively, and, then, DNA mixed pool sequencing was carried out to further shortening the QTL candidate interval for fruit size trait and excavated candidate genes for controlling fruit size. Results: The candidate intervals related to jujube fruit size were mainly located on chromosomes 1, 5, and 10, and the frequency of chromosome 1 was the highest. Based on the QTL-seq results, the annotation results of ANNOVAR were extracted from 424 SNPs (single-nucleotide polymorphisms) and 164 InDels (insertion-deletion), from which 40 candidate genes were selected, and 37 annotated candidate genes were found in the jujube genome. Four genes (LOC107428904, LOC107415626, LOC125420708, and LOC107418290) that are associated with fruit size growth and development were identified by functional annotation of the genes in NCBI (National Center for Biotechnology Information). The genes can provide a basis for further exploration and identification on genes regulating jujube fruit size. Discussion: In summary, the data obtained in this study revealed that QTL intervals and candidate genes for fruit size at the genomic level provide valuable resources for future functional studies and jujube breeding.

Network Analysis on Family Resilience, Fear of Progression, and Quality of Life in Chinese Patients with Pulmonary Hypertension.

BACKGROUND: The long-term quality of life of Chinese patients with pulmonary hypertension has been seriously compromised. Interventions to enhance patient quality of life of are urgently required. OBJECTIVE: To investigate the relationship between quality of life and its influencing factors in patients through network analysis. METHOD: 247 patients with pulmonary hypertension in 3 hospitals in Jinan, Shandong Province, self-reported their immediate family resilience, fear of progression, and quality of life via questionnaires. A mixed graphical model was constructed to investigate the relationship among multidimensional structures of variables. RESULTS: A total of 247 patients (173 female and 74 male) were included (age 18-34, n=115; age 35-49, n=99; age 50-64, n=23; age > 65 years, n=10). "Family communication and problem solving" was at the center of the network, with serving as a bridge node. Within communities, the strongest edge was "Family communication and problem solving-maintaining a positive outlook." Across communities, the strongest edge between family resilience and quality of life was "Family communication and problem solving-environmental domain quality of life," and the strongest edge across the fear of progression and quality of life was "physiological health fear-psychological domain quality of life." CONCLUSIONS: Family resilience and fear of progression may affect the quality of life in patients with pulmonary hypertension. Developing a program with "family communication and problem solving" as a primary target may reduce patient fear of progression, enhance family resilience, and improve patient quality of life.

ZjWRKY23 and ZjWRKY40 Promote Fruit Size Enlargement by Targeting and Downregulating Cytokinin Oxidase/Dehydrogenase 5 Expression in Chinese Jujube.

Fruit size is crucial for fruit trees, as it contributes to both quality and yield. However, the underlying mechanism of fruit size regulation remains largely unknown. Taking advantage of using a fruit double-sized bud mutant of Chinese jujube, "Jinkuiwang" and its wild type, "Jinsixiaozao", we carried out a comprehensive study on the mechanism of fruit size development in jujube. Using weighted gene coexpression network analyses, a number of candidate regulators for fruit size including those involved in hormonal signaling pathways, transcription factors, and heat shock proteins were identified. A hub gene named cytokinin oxidase/dehydrogenase 5 (ZjCKX5), responsible for cytokinin degradation, was found to play a negative role in regulating fruit size development, and overexpressing ZjCKX5 in tomato and Arabidopsis resulted in much smaller fruits and dwarf plants. Furthermore, another two hub genes, ZjWRKY23 and ZjWRKY40 transcription factors, were found to participate in fruit size regulation by targeting and downregulating the ZjCKX5 expression. Overexpressing ZjWRKY23 or ZjWRKY40 in tomato led to much larger fruits and promoted plant architecture. Based on these results, a molecular framework for jujube fruit size regulation, namely, ZjWRKY-ZjCKX5 module, was proposed. This study provides a new insight into the molecular networks underlying fruit size regulation.

Anatomical observation and transcriptome analysis of branch-twisted mutations in Chinese jujube.

BACKGROUND: Plant organs grow in a certain direction and organ twisted growth, a rare and distinctive trait, is associated with internal structure changes and special genes. The twisted branch mutant of Chinese jujube jujube, an important fruit tree native to China and introduced to nearly 50 countries, provides new typical materials for exploration of plant twisted growth. RESULTS: In this study, the cytological characteristics and related genes of twisted branches in Chinese jujube were revealed by microscopy observation and transcriptome analysis. The unique coexistence of primary and secondary structures appeared in the twisted parts of branches, and special structures such as collateral bundle, cortical bundles, and internal phloem were formed. Ninety differentially expressed genes of 'Dongzao' and its twisted mutant were observed, in which ZjTBL43, ZjFLA11, ZjFLA12 and ZjIQD1 were selected as candidate genes. ZjTBL43 was homologous to AtTBL43 in Arabidopsis, which was involved in the synthesis and deposition of cellular secondary wall cellulose. The attbl43 mutant showed significant inflorescence stem bending growth. The transgenic lines of attbl43 with overexpression of ZjTBL43 were phenotypically normal.The branch twisted growth may be caused by mutations in ZjTBL43 in Chinese jujube. AtIQD10, AtFLA11 and AtFLA12 were homologous to ZjIQD1, ZjFLA11 and ZjFLA12, respectively. However, the phenotype of their function defect mutants was normal. CONCLUSION: In summary, these findings will provide new insights into the plant organ twisted growth and a reference for investigation of controlling mechanisms of plant growth direction.

Relationship between quality of life, fear of disease progression, and coping styles in patients with pulmonary hypertension: A network analysis.

A poor quality of life (QoL) in patients with pulmonary hypertension (PH) is often associated with emotional disturbances and the ability to cope. Little is known, however, about the intrinsic links among the QoL, fear of disease progression (FoP), and coping styles in patients with PH. The purpose of this study was to elucidate the relationships among QoL, FoP, and coping styles in patients with PH. We conducted a cross-sectional survey of 247 patients from a tertiary hospital in Jinan, China and analyzed the relationships using network analysis. Participants completed the World Health Organization's Quality of Life Questionnaire, Fear of Disease Progression Questionnaire and Simple Coping Style Questionnaire during the survey period. The total QoL, positive coping, and negative coping scores were 46.55 ± 10.46, 31.75 ± 6.85, and 18.75 ± 4.66, respectively. The QoL psychological domain had the strongest centrality, deserving more attention than other domains. The coping styles were bridge nodes that connected the whole network, where negative coping and social family FoP, and positive coping and both social and psychological QoL had the strongest positive correlations. There were no significant sex-based or age-based differences in the networks. To improve QoL and psychological well-being in people with PH, healthcare professionals must focus on issues beyond the patient's physical health. Specifically, they should focus on positive coping styles, while developing interventions to promote positive coping and reduce negative coping styles.

The mediating effects of social support and depressive symptoms on activities of daily living and social frailty in older patients with chronic heart failure.

OBJECTIVES: To investigate the level of social frailty (SF) in older patients with chronic heart failure (CHF) and examine the mediating role of social support and depressive symptoms between activities of daily living and SF. METHODS: Using a convenience sampling method, 205 older patients with CHF were recruited from China between November 2021 and May 2022. Activities of daily living, social support, depressive symptoms, and SF were assessed using a self-administered questionnaire. Data were analyzed using structural equation modeling. RESULTS: The final model obtained a good fit. Activities of daily living in older patients with CHF were directly related to SF. The multiple mediation analysis revealed that the relationship between activities of daily living and SF was mediated by social support (effect: -0.010, 95% CI [-0.021, -0.003]) and depressive symptoms (effect: -0.011, 95% CI [-0.019, -0.005) separately, and serially (effect: -0.007, 95% CI [-0.012, -0.003). CONCLUSIONS: Social support and depressive symptoms are multiple mediating variables in the relationship between activities of daily living and SF. Activities of daily living can improve patients' SF through social support and depressive symptoms.

Heterogeneous trajectories of kinesiophobia and their effects on rehabilitation outcomes after total knee arthroplasty: a prospective cohort study.

BACKGROUND: Kinesiophobia is one of the most common and aversive psychological phenomena among patients after total knee arthroplasty (TKA). This study aimed to identify trajectories of kinesiophobia, examine factors distinguishing these trajectories, and clarify the association between trajectories of kinesiophobia and rehabilitation outcomes. METHODS: In this prospective cohort study, the patients who underwent TKA were recruited between December 2021 and April 2022 from three orthopedic wards of a tertiary hospital in China. Kinesiophobia was measured using the Tampa Scale for Kinesiophobia at baseline (T0), and then at 1 month (T1) and 3 months (T2) after TKA to perform latent class growth analysis. Meanwhile, rehabilitation outcomes were assessed at 3 months after TKA, using the Kessler Psychological Distress Scale, the Hospital for Special Surgery-Knee Scale, Barthel Index, and the Impact on Participation and Autonomy questionnaire. RESULTS: The four kinesiophobia trajectories identified were as follows: low stable group (n = 120), rapid recovering group (n = 31), slow recovering group (n = 48), and stable moderate group (n = 58). Body mass index, employment status, heart disease, and pain degree significantly predicted trajectory groups (all p < 0.05). Analysis of variance revealed significant differences between the four kinesiophobia trajectories concerning all rehabilitation outcomes, except for the activities of daily living. CONCLUSION: Distinct kinesiophobia trajectories were identified, and nurses should assess the kinesiophobia of patients after TKA in the early phase. Patients in the slow recovering group are worthy of a specific focus because of their poor recovery after undergoing TKA. As important sources of psychosocial care, nurses need to customize psychological interventions for patients after TKA depending on each kinesiophobia trajectory.

Construction and Validation of Machine Learning Algorithms to Predict Chronic Post-Surgical Pain Among Patients Undergoing Total Knee Arthroplasty.

BACKGROUND: Chronic post-surgical pain (CPSP) is a common but undertreated condition with a high prevalence among patients undergoing total knee arthroplasty (TKA). An effective model for CPSP prediction has not been established yet. AIMS: To construct and validate machine learning models for the early prediction of CPSP among patients undergoing TKA. DESIGN: A prospective cohort study. PARTICIPANTS/SUBJECTS: A total of 320 patients in the modeling group and 150 patients in the validation group were recruited from two independent hospitals between December 2021 and July 2022. They were followed up for 6 months to determine the outcomes of CPSP through telephone interviews. METHODS: Four machine learning algorithms were developed through 10-fold cross-validation for five times. In the validation group, the discrimination and calibration of the machine learning algorithms were compared by the logistic regression model. The importance of the variables in the best model identified was ranked. RESULTS: The incidence of CPSP in the modeling group was 25.3%, and that in the validation group was 27.6%. Compared with other models, the random forest model achieved the best performance with the highest C-statistic of 0.897 and the lowest Brier score of 0.119 in the validation group. The top three important factors for predicting CPSP were knee joint function, fear of movement, and pain at rest in the baseline. CONCLUSIONS: The random forest model demonstrated good discrimination and calibration capacity for identifying patients undergoing TKA at high risk for CPSP. Clinical nurses would screen out high-risk patients for CPSP by using the risk factors identified in the random forest model, and efficiently distribute preventive strategy.

A novel nomogram for predicting risk of malnutrition in patients with heart failure.

Background and aims: This study aimed to explore the risk factors of malnutrition in patients with heart failure and construct a novel nomogram model. Methods and results: A cross-sectional study based on the STROBE checklist. Patients with heart failure from July 2020 to August 2021 were included. Patients were divided into a malnutrition group and a normal nutrition group based on the Society's recommended AND-ASPEN standard. Logistic regression was used to analyze the independent risk factors for malnutrition. A new prediction model of nomogram was constructed based on the risk factors, and its fit and prediction performance were evaluated. Of 433 patients, 66 (15.2%) had malnutrition and 367 (84.8%) had normal nutrition, Logistic regression analyses showed that the risk factors for malnutrition were total protein, hemoglobin, triglyceride, and glucose levels. The regression model based on the above four variables showed an area under the curve of 0.858. The novel nomogram model had a sensitivity of 78.5% and a specificity of 77.3%. After 2000 bootstrap resampling iterations, AUC was 0.852. Conclusions: The novel nomogram model can predict the odds of malnutrition in patients with heart failure at the early stage of admission, and can provide a reference for nursing staff to optimize nutritional care for inpatient with heart failure and to develop a discharge nutritional care plan.

Prevalence of cognitive frailty among older adults in China: a systematic review and meta-analysis.

OBJECTIVE: This study aimed to investigate the prevalence of cognitive frailty among older adults in China. DESIGN: Systematic review and meta-analysis. METHODS: We searched the Cochrane Library, PubMed, Web of Science, Embase, China National Knowledge Infrastructure(CNKI), Wanfang, Chinese Biomedical Literature and Weipu (VIP) databases to collect information on the epidemiology of cognitive frailty among older adults in China. The study period was from the establishment of the database to March 2022. Two researchers independently screened the literature, extracted the data and assessed the risk of bias in the included studies. All statistical analyses were performed using Stata V.15.0. RESULTS: We screened 522 records, of which 28 met the inclusion criteria. The results of the meta-analysis showed that the prevalence of cognitive frailty among older adults in China was 15%(95%CI (0.13%,0.17%)). The prevalence of cognitive frailty was higher in hospitals and nursing homes than in communities. Moreover, the prevalence of cognitive frailty was higher in women than in men. Furthermore, the prevalence rates of cognitive frailty in North China Hospital, older adults aged≥80 years, and illiterate individuals were 25%, 29%, and 55%, respectively. CONCLUSIONS: In conclusion, in China, the prevalence of cognitive frailty is higher among older adults, is higher in women than in men, is higher in hospitals and nursing homes than in communities, and is higher in North China than other regions. Moreover, the higher the educational level, the lower the prevalence of cognitive frailty. Multimodal interventions for cognitive frailty, including increased exercise, nutritional support, increased socialisation opportunities and multifactorial strategies, may be effective in preventing cognitive frailty. These findings have important implications for adjusting healthcare and social care systems. PROSPERO REGISTRATION NUMBER: CRD42023390486.

Genome-wide screening of the RNase T2 gene family and functional analyses in jujube (Ziziphus jujuba Mill.).

BACKGROUND: Ribonuclease (RNase T2) plays crucial roles in plant evolution and breeding. However, there have been few studies on the RNase T2 gene family in Ziziphus jujuba Mill., one of important dried fruit tree species. Recently, the released sequences of the reference genome of jujube provide a good chance to perform genome-wide identification and characterization of ZjRNase gene family in the jujube. RESULTS: In this study, we identified four members of RNase T2 in jujube distributed on three chromosomes and unassembled chromosomes. They all contained two conserved sites (CASI and CASII). Analysis of the phylogenetic relationships revealed that the RNase T2 genes in jujube could be divided into two groups: ZjRNase1 and ZjRNase2 belonged to class I, while ZjRNase3 and ZjRNase4 belonged to class II. Only ZjRNase1 and ZjRNase2 expression were shown by the jujube fruit transcriptome analysis. So ZjRNase1 and ZjRNase2 were selected functional verification by overexpression transformation of Arabidopsis. The overexpression of these two genes led to an approximately 50% reduction in seed number, which deserve further attention. Moreover, the leaves of the ZjRNase1 overexpression transgenic lines were curled and twisted. Overexpression of ZjRNase2 resulted in shortened and crisp siliques and the production of trichomes, and no seeds were produced. CONCLUSION: In summary, these findings will provide new insights into the molecular mechanisms of low number of hybrid seeds in jujube and a reference for the future molecular breeding of jujube.

The association between team resilience and team performance in nurses during COVID-19 pandemic: a network analysis.

BACKGROUND: Compared to other healthcare workers, nurses are more vulnerable to the potentially devastating effects of pandemic-related stressors. Studies have not yet investigated the deeper characteristics of the relationship between team resilience and team performance among nurses during the COVID-19 pandemic. This study aimed to elucidate the characteristics of team resilience and performance networks among nurses during the pandemic. METHODS: A cross-sectional study involving 118 nursing teams comprising 1627 practice nurses from four tertiary-A and secondary-A hospitals in Shandong Province, China, was conducted. Analyzing and Developing Adaptability and Performance in Teams to Enhance Resilience Scale and the Team Effectiveness Scale were used to measure team resilience and performance, respectively. The estimation of the network model and calculation of related metrics, network stability and accuracy, and network comparison tests were performed using R 4.0.2. RESULTS: Node monitoring had the highest centralities in the team resilience and performance network model, followed by node anticipation, cooperation satisfaction, and cooperation with other departments. Moreover, node cooperation satisfaction and learning had the highest levels of bridge centrality in the entire network. CONCLUSION: Monitoring, anticipation, cooperation satisfaction, cooperation with other departments, and learning constituted core variables maintaining the team resilience-performance network structure of nurses during the pandemic. Clinical interventions targeting core variables may be effective in maintaining or promoting both team resilience and performance in this population.

Construction of a highly saturated genetic map and identification of quantitative trait loci for leaf traits in jujube.

Chinese jujube (Ziziphus jujuba Mill.), a member of the genus Ziziphus, which comes under the family Rhamnaceae, is the most important species in terms of its economic, ecological, and social benefits. To dissect the loci associated with important phenotypical traits and analyze their genetic and genomic information in jujube, a whole-genome resequencing (WGR) based highly saturated genetic map was constructed using an F1 hybrid population of 140 progeny individuals derived from the cross of 'JMS2' × 'Jiaocheng 5'. The average sequencing depth of the parents was 14.09× and that of the progeny was 2.62×, and the average comparison efficiency between the sample and the reference genome was 97.09%. Three sets of genetic maps were constructed for a female parent, a male parent, and integrated. A total of 8,684 markers, including 8,158 SNP and 526 InDel markers, were evenly distributed across all 12 linkage groups (LGs) in the integrated map, spanning 1,713.22 cM with an average marker interval of 0.2 cM. In terms of marker number and density, this is the most saturated genetic map of jujube to date, nearly doubling that of the best ones previously reported. Based on this genetic map and phenotype data from 2019 to 2021, 31 leaf trait QTLs were identified in the linkage groups (LG1, 15; LG3, 1; LG5, 8; LG7, 4; LG8, 1, and LG11, 2), including 17 major QTLs. There were 4, 8, 14, and 5 QTLs that contributed to leaf length, leaf width, leaf shape index, and leaf area, respectively. Six QTLs clusters were detected on LG1 (8.05 cM-9.52 cM; 13.12 cM-13.99 cM; 123.84 cM-126.09 cM), LG5 (50.58 cM-50.86 cM; 80.10 cM-81.76 cM) and LG11 (35.98 cM-48.62 cM). Eight candidate genes were identified within the QTLs cluster regions. Annotation information showed that 4 genes (LOC107418196, LOC107418241, LOC107417968, and LOC112492570) in these QTLs are related to cell division and cell wall integrity. This research will provide a valuable tool for further QTL analysis, candidate gene identification, map-based gene cloning, comparative mapping, and marker-assisted selection (MAS) in jujube.

Prevalence and impact of malnutrition on readmission among hospitalized patients with heart failure in China.

AIMS: Malnutrition is common in patients with heart failure (HF) and is associated with poorer quality of life and increased mortality; however, an effective screening tool for malnutrition and its impact on the readmission of patients with HF is uncertain. Our objectives were to study (i) the nutritional status of Chinese hospitalized patients with HF and its impact on readmission and (ii) the validity of seven malnutrition screening tools. METHODS AND RESULTS: In this study, univariate and multivariate analyses of Cox proportional hazards regression were used to determine important predictors of readmission. The endpoint was readmission due to HF or non-HF. A total of 402 patients were included (66.4% male, median age 62 years [range: 20-92 years], median NT-proBNP 5,229 ng/L). During a median follow-up of 159 days, 150 patients (37%) were readmitted to the hospital. After adjusting for confounders, only malnutrition assessed using the Controlling Nutritional Status (CONUT) nutrition score was independently associated with readmission (P = 0.0293). A base model for predicting readmission with a C-statistic of 0.680 and subsequent addition of various nutritional screening tools improved its performance over the base model. Patients with malnutrition had a twofold increased risk of readmission. CONCLUSIONS: We found that the prevalence of malnutrition among hospitalized patients with HF in China is very high and that malnutrition significantly increases the risk of readmission in these patients. CONUT is a validated screening tool for malnutrition and may provide valuable prognostic information.

ZjSEP3 modulates flowering time by regulating the LHY promoter.

BACKGROUND: SEPALLATA3 (SEP3), which is conserved across various plant species, plays essential and various roles in flower and fruit development. However, the regulatory network of the role of SEP3 in flowering time at the molecular level remained unclear. RESULTS: Here, we investigated that SEP3 in Ziziphus jujuba Mill. (ZjSEP3) was expressed in four floral organs and exhibited strong transcriptional activation activity. ZjSEP3 transgenic Arabidopsis showed an early-flowering phenotype and altered the expression of some genes related to flowering. Among them, the expression of LATE ELONGATED HYPOCOTYL (AtLHY), the key gene of circadian rhythms, was significantly suppressed. Yeast one-hybrid (Y1H) and electrophoretic mobility shift assays (EMSAs) further verified that ZjSEP3 inhibited the transcription of AtLHY by binding to the CArG-boxes in its promoter. Moreover, ZjSEP3 also could bind to the ZjLHY promoter and the conserved binding regions of ZjSEP3 were found in the LHY promoter of various plant species. The ectopic regulatory pathway of ZjSEP3-AtLHY was further supported by the ability of 35S::AtLHY to rescue the early-flowering phenotype in ZjSEP3 transgenic plants. In ZjSEP3 transgenic plants, total chlorophyll content and the expression of genes involved in chlorophyll synthesis increased during vegetative stages, which should contribute to its early flowering and relate to the regulatory of AtLHY. CONCLUSION: Overall, ZjSEP3-AtLHY pathway represents a novel regulatory mechanism that is involved in the regulation of flowering time.

The historical and current research progress on jujube-a superfruit for the future.

Jujube (Ziziphus jujuba Mill.), or Chinese date, is the most important species of Rhamnaceae, a large cosmopolitan family, and is one of the oldest cultivated fruit trees in the world. It originates from the middle and lower reaches of the Yellow River, the 'mother river' of the Chinese people. It is distributed in at least 48 countries on all continents except Antarctica and is becoming increasingly important, especially in arid and semiarid marginal lands. Based on a systematic analysis of the unique characteristics of jujube, we suggest that it deserves to be recognized as a superfruit. We summarized historical research achievements from the past 3000 years and reviewed recent research advances since 1949 in seven fields, including genome sequencing and application, germplasm resources and systematic taxonomy, breeding and genetics, cultivation theory and techniques, pest control, postharvest physiology and techniques, and nutrition and processing. Based on the challenges facing the jujube industry, we discuss eight research aspects to be focused on in the future.

Genome-wide identification, characterization of the MADS-box gene family in Chinese jujube and their involvement in flower development.

MADS-box genes encode transcription factors that are involved in plant development control (particularly in floral organogenesis) and signal transduction pathways, though a comprehensive analysis of MADS-box family proteins in Chinese jujube (Ziziphus jujuba Mill.) is still missing. Here, we report a genome-wide analysis of the MADS-box gene family in Chinese jujube. Based on phylogenetic analyses, 52 jujube MADS-box genes were classified into 25 MIKCC-type, 3 MIKC*-type, 16 Mα, 5 Mß and 3 Mγ genes. 37 genes were randomly distributed across all 12 putative chromosomes. We found that the type II genes are more complex than the type I genes and that tandem duplications have occurred in three groups of MADS-box genes. Meanwhile, some gene pairs in the same clade displayed similar or distinct expression profiles, suggesting possible functional redundancy or divergence. MIKCC-type genes exhibited typical temporal and spatial expression patterns in the four whorls of floral tissues. The expressions of B, C/D and E-type genes were significantly suppressed in phyllody as compared to flower, providing valuable evidence for their involvement in flower development. This study is the first comprehensive analysis of the MADS-box family in jujube, and provides valuable information for elucidating molecular regulation mechanism of jujube flower development.

The complex jujube genome provides insights into fruit tree biology.

The jujube (Ziziphus jujuba Mill.), a member of family Rhamnaceae, is a major dry fruit and a traditional herbal medicine for more than one billion people. Here we present a high-quality sequence for the complex jujube genome, the first genome sequence of Rhamnaceae, using an integrated strategy. The final assembly spans 437.65 Mb (98.6% of the estimated) with 321.45 Mb anchored to the 12 pseudo-chromosomes and contains 32,808 genes. The jujube genome has undergone frequent inter-chromosome fusions and segmental duplications, but no recent whole-genome duplication. Further analyses of the jujube-specific genes and transcriptome data from 15 tissues reveal the molecular mechanisms underlying some specific properties of the jujube. Its high vitamin C content can be attributed to a unique high level expression of genes involved in both biosynthesis and regeneration. Our study provides insights into jujube-specific biology and valuable genomic resources for the improvement of Rhamnaceae plants and other fruit trees.

Rapid SNP discovery and a RAD-based high-density linkage map in jujube (Ziziphus Mill.).

BACKGROUND: Ziziphus Mill. (jujube), the most valued genus of Rhamnaceae, comprises of a number of economically and ecologically important species such as Z. jujuba Mill., Z. acidojujuba Cheng et Liu and Z. mauritiana Lam. Single nucleotide polymorphism (SNP) markers and a high-density genetic map are of great benefit to the improvement of the crop, mapping quantitative trait loci (QTL) and analyzing genome structure. However, such a high-density map is still absent in the genus Ziziphus and even the family Rhamnaceae. The recently developed restriction-site associated DNA (RAD) marker has been proven to be most powerful in genetic map construction. The objective of this study was to construct a high-density linkage map using the RAD tags generated by next generation sequencing. RESULTS: An interspecific F1 population and their parents (Z. jujuba Mill. 'JMS2' × Z. acidojujuba Cheng et Liu 'Xing 16') were genotyped using a mapping-by-sequencing approach, to generate RAD-based SNP markers. A total of 42,784 putative high quality SNPs were identified between the parents and 2,872 high-quality RAD markers were grouped in genetic maps. Of the 2,872 RAD markers, 1,307 were linked to the female genetic map, 1,336 to the male map, and 2,748 to the integrated map spanning 913.87 centi-morgans (cM) with an average marker interval of 0.34 cM. The integrated map contained 12 linkage groups (LGs), consistent with the haploid chromosome number of the two parents. CONCLUSION: We first generated a high-density genetic linkage map with 2,748 RAD markers for jujube and a large number of SNPs were also developed. It provides a useful tool for both marker-assisted breeding and a variety of genome investigations in jujube, such as sequence assembly, gene localization, QTL detection and genome structure comparison.