Genome-wide expression analysis of vegetative organs during developmental and herbicide-induced whole plant senescence in Arabidopsis thaliana.

BACKGROUND: Whole plant senescence represents the final stage in the life cycle of annual plants, characterized by the decomposition of aging organs and transfer of nutrients to seeds, thereby ensuring the survival of next generation. However, the transcriptomic profile of vegetative organs during this death process remains to be fully elucidated, especially regarding the distinctions between natural programmed death and artificial sudden death induced by herbicide. RESULTS: Differential genes expression analysis using RNA-seq in leaves and roots of Arabidopsis thaliana revealed that natural senescence commenced in leaves at 45-52 days after planting, followed by roots initiated at 52-60 days. Additionally, both organs exhibited similarities with artificially induced senescence by glyphosate. Transcription factors Rap2.6L and WKRY75 appeared to serve as central mediators of regulatory changes during natural senescence, as indicated by co-expression networks. Furthermore, the upregulation of RRTF1, exclusively observed during natural death, suggested its role as a regulator of jasmonic acid and reactive oxygen species (ROS) responses, potentially triggering nitrogen recycling in leaves, such as the glutamate dehydrogenase (GDH) shunt. Root senescence was characterized by the activation of AMT2;1 and GLN1;3, facilitating ammonium availability for root-to-shoot translocation, likely under the regulation of PDF2.1. CONCLUSIONS: Our study offers valuable insights into the transcriptomic interplay between phytohormones and ROS during whole plant senescence. We observed distinct regulatory networks governing nitrogen utilization in leaf and root senescence processes. Furthermore, the efficient allocation of energy from vegetative organs to seeds emerges as a critical determinant of population sustainability of annual Arabidopsis.

The Biochemical and Pathological Correlates of Successful Semen Cryopreservation From Patients With Testicular Cancer: A Single Tertiary Center Experience.

OBJECTIVE: To determine the predictors for success with regard to semen cryopreservation and good semen quality of patients with testicular cancer. MATERIALS AND METHODS: A total of 50 men (aged 16-36 years) with testicular cancer, referred for semen cryopreservation prior to gonadotoxic treatment, were included. Age, alpha fetal protein (α-FP), beta human chorionic gonadotropin, lactate dehydrogenase, clinical staging, tumor volume, and pathological reports were evaluated as correlates of successful semen cryopreservation and good semen quality. RESULTS: The overall success rate was 52%. α-FP (4113.1 ng/mL vs 81.2 ng/mL) and tumor volume (77.7 mL vs 25.5 mL) were significantly higher in the failure group as compared to the success group. The seminoma to nonseminomatous germ cell tumor ratio was lower in the failure group as compared to the success group (9/17 vs 3/21). There was nearly a significant difference (P = .066). The optimal cutoff value for α-FP > 1000 ng/mL showed the highest Youden index (0.689) and resulted in a sensitivity of 0.625 and specificity of 1.0 for predicting poor outcome. In terms of multivariate analysis, the α-FP (P = .013), tumor volume (P = .047), and α-FP > 1000 ng/mL (P = .010) were significantly associated with poor semen quality and failure to preserve semen. Sperm quality was found to be higher in the seminoma versus the nonseminomatous germ cell tumor patients in: sperm concentration (21.5 million/mL vs 11.8 million/mL, P < .027). Furthermore, tumor volume is correlated to α-FP (P = .018) and is weakly correlated to lactate dehydrogenase (P = .067) CONCLUSION: Elevated α-FP and tumor volume are independently poor factors for semen quality and semen cryopreservation. In clinical use, α-FP is a noninvasive tool to predict the success of semen cryopreservation and patients with α-FP > 1000 ng/mL should be informed of the higher risk of poor semen quality and semen cryopreservation concerns.