The lemon genome and DNA methylome unveil epigenetic regulation of citric acid biosynthesis during fruit development.

Citric acid gives lemons their unique flavor, which impacts their sensory traits and market value. However, the intricate process of citric acid accumulation during lemon fruit growth remains incompletely understood. Here, we achieved a chromosomal-level genome assembly for the 'Xiangshui' lemon variety, spanning 364.85 Mb across nine chromosomes. This assembly revealed 27 945 genes and 51.37% repetitive sequences, tracing the divergence from citron 2.85 million years ago. DNA methylome analysis of lemon fruits across different developmental stages revealed significant variations in DNA methylation. We observed decreased CG and CHG methylation but increased CHH methylation. Notably, the expression of RdDM pathway-related genes increased with fruit development, suggesting a connection with elevated CHH methylation, which is potentially influenced by the canonical RdDM pathway. Furthermore, we observed that elevated CHH DNA methylation within promoters significantly influenced the expression of key genes, critically contributing to vital biological processes, such as citric acid accumulation. In particular, the pivotal gene phosphoenolpyruvate carboxykinase (ClPEPCK), which regulates the tricarboxylic acid cycle, was strikingly upregulated during fruit development, concomitant with increased CHH methylation in its promoter region. Other essential genes associated with citric acid accumulation, such as the MYB transcription factor (ClPH1/4/5) and ANTHOCYANIN 1 (ClAN1), were strongly correlated with DNA methylation levels. These results strongly indicate that DNA methylation crucially orchestrates the metabolic synthesis of citric acid. In conclusion, our study revealed dynamic changes in DNA methylation during lemon fruit development, underscoring the significant role of DNA methylation in controlling the citric acid metabolic pathway.

What Do Chinese Families With Depressed Adolescents Find Helpful in Family Therapy? A Qualitative Study.

Despite research supporting the efficacy of family therapy for adolescent depression, little research has been done to clarify the therapeutic variables that Chinese families with depressed adolescents consider helpful in family therapy. This study explored depressed Chinese adolescents' and their parents' perceptions of the factors promoting improvement in family therapy. Twelve Chinese families with one adolescent child fulfilling the criteria for major depressive disorder were recruited. A total of 134 family therapy sessions were conducted by four therapists. After therapy, semi-structured interviews about the clients' perceptions of the helpful and effective aspects of therapy were conducted. Thematic analysis was used to analyze the transcribed dialogues. Five overarching themes emerged: factors supporting therapeutic alliance formation, the therapist's systemic attitude, systemic therapy direction, effective systemic therapy techniques, and strategies for dealing with current issues. A trustworthy therapy alliance with a competent and supportive therapist helped depressed adolescents improve by facilitating the expression of their emotions; exploring family interactions, beliefs, and emotion flows related to their symptoms; promoting their self-development; and activating their resources. The families valued the respectfulness of the therapists and their collaborative and non-authoritative approach. Adolescents' academic difficulties and crises received special attention. The possible clinical implementations of our findings in the design of family therapy strategies for depressed Chinese adolescents are discussed.

The prevalence of occult HBV infection in immunized children with HBsAg-positive parents: a hospital-based analysis.

BACKGROUND AND OBJECT: The risk of occult HBV infection (OBI) in children whose mothers are HBV carriers has received more widespread attention, but there were few reports to focus on the children with HBsAg-positive parents. In this study, we aimed to investigate the prevalence of OBI in immunized children with HBsAg-positive parents. METHODS: HBV-vaccinated Chinese hospitalized children with HBsAg-positive parents were analyzed in our investigation. Eligible subjects were tested using a standard nested PCR for all HBV genes, and analyzed by direct sequencing. RESULTS: There were 327 HBsAg-negative children included in the study out of about 9800 involved HBV-vaccinated hospitalized children. The positive rate of OBI was 3.1% (10/327) in the eligible children and 14.1% (46/327) with HBV DNA detectable. No significant differences were found between one and at least two regions positive groups (p > 0.05). The proportions of HBV DNA detectable in children with HBV father-carriers and mother-carriers were similar. The risk factors for HBV DNA-positive children could be male, anti-HBs levels, and anti-HBc positive. CONCLUSION: There are 3.1% of OBIs and 14.1% of suspected OBI in vaccinated children with HBsAg-positive parents. The potential risk of suspected OBI in children with HBsAg-positive father should not be ignored. Anti-HBc positivity may be a useful seromarker for suspected OBI screening in vaccinated children. To prevent HBV breakthrough infection, accurate and convenient method is needed to detect OBI timely and exhaustively.