Transcriptomic analysis reveals the molecular basis of photoperiod-regulated sex differentiation in tropical pumpkins (Cucurbita moschata Duch.)

Abstract Background Photoperiod, or the length of the day, has a significant impact on the flowering and sex differentiation of photoperiod-sensitive crops. The “miben” pumpkin (the main type of Cucurbita moschata Duch.) is well-known for its high yield and strong disease resistance. However, its cultivation has been limited due to its sensitivity to photoperiod. This sensitivity imposes challenges on its widespread cultivation and may result in suboptimal yields in regions with specific daylength conditions. As a consequence, efforts are being made to explore potential strategies or breeding techniques to enhance its adaptability to a broader range of photoperiods, thus unlocking its full cultivation potential and further promoting its valuable traits in agriculture. Results This study aimed to identify photoperiod-insensitive germplasm exhibiting no difference in sex differentiation under different day-length conditions. The investigation involved a phenotypic analysis of photoperiod-sensitive (PPS) and photoperiod-insensitive (PPIS) pumpkin materials exposed to different day lengths, including long days (LDs) and short days (SDs). The results revealed that female flower differentiation was significantly inhibited in PPS_LD, while no differences were observed in the other three groups (PPS_SD, PPIS_LD, and PPIS_SD). Transcriptome analysis was carried out for these four groups to explore the main-effect genes of sex differentiation responsive to photoperiod. The main-effect gene subclusters were identified based on the principal component and hierarchical cluster analyses. Further, functional annotations and enrichment analysis revealed significant upregulation of photoreceptors (CmCRY1, F-box/kelch-repeat protein), circadian rhythm-related genes (CmGI, CmPRR9, etc.), and CONSTANS (CO) in PPS_LD. Conversely, a significant downregulation was observed in most Nuclear Factor Y (NF-Y) transcription factors. Regarding the gibberellic acid (GA) signal transduction pathway, positive regulators of GA signaling (CmSCL3, CmSCL13, and so forth) displayed higher expression levels, while the negative regulators of GA signaling, CmGAI, exhibited lower expression levels in PPS_LD. Notably, this effect was not observed in the synthetic pathway genes. Furthermore, genes associated with ethylene synthesis and signal transduction (CmACO3, CmACO1, CmERF118, CmERF118-like1,2, CmWIN1-like, and CmRAP2-7-like) showed significant downregulation. Conclusions This study offered a crucial theoretical and genetic basis for understanding how photoperiod influences the mechanism of female flower differentiation in pumpkins

Improvement in clinical and economic outcomes with empiric antibiotic therapy covering atypical pathogens for community-acquired pneumonia patients: a multicenter cohort study

Objective: To determine the effectiveness of empiric antibiotic regimens covering atypical pathogens with respect to detailed clinical and economic outcomes in community-acquired pneumonia (CAP). Methods: A population-based, multicenter, retrospective cohort study was conducted from June 2010 to May 2011. Patients with a diagnosis of CAP were enrolled and categorized into two groups according to the initial antibiotic strategy used – covering or not covering atypical pathogens. Regression analysis was performed to assess their clinical outcomes (all-cause mortality, clinical improvement rate after 72 h of antimicrobial therapy, and clinical cure rate) and economic outcomes (length of stay, hospitalization costs, and antibiotic expenditure). Results: A total of 827 patients met the criteria for CAP; 561 (67.8%) received antibiotics with atypical pathogen coverage (APC group), while 266 (32.2%) did not (non-APC group). Regression analysis revealed that the all-cause mortality was much lower in the APC group than in the non-APC group (0.9% vs. 4.9%, respectively), with an odds ratio (OR) of 0.18 (95% confidence interval (CI) 0.06–0.49). Clinical improvement at 72 h (87.7% vs. 85.0%, p = 0.274) and the clinical cure rate (91.1% vs. 88.3%, p = 0.213) were more favorable in the APC group, but with no significant difference compared to the non-APC group. Moreover, the APC group had a shorter mean length of stay (APC 10.2 days vs. non-APC 11.6 days, p < 0.001). In addition, the mean total hospitalization costs for the APC group were markedly lower compared with the non-APC group (US$1172.7 vs. US$ 1510.7; p < 0.001). Conclusion: Antimicrobial treatment covering atypical pathogens for hospitalized CAP patients is associated with reduced mortality and economic burden