Polymorphisms at amino acid positions 85 and 86 in succinate dehydrogenase subunit C of Colletotrichum siamense: Implications for fitness and intrinsic sensitivity to SDHI fungicides.

Among succinate dehydrogenase inhibiter (SDHI) fungicides, penthiopyrad and benzovindiflupyr particularly inhibit Colletotrichum. Studying SDH amino acid polymorphism in Colletotrichum, along with its fungicide binding sites, is key to understanding their mechanisms of action. This study explores the SDH amino acid polymorphisms in Colletotrichum siamense strains from rubber trees in China and their interaction with SDHI fungicides, specifically penthiopyrad and benzovindiflupyr. Sequencing revealed most polymorphisms were in the SDHC subunit, particularly at positions 85 and 86, which are key to penthiopyrad resistance. Among 33 isolates, 33.3 % exhibited a substitution at position 85, and 9 % at position 86. A strain with W85L and T86N substitutions in SDHC showed reduced SDH activity, ATP content, mycelial growth, and virulence, and decreased sensitivity to penthiopyrad but not benzovindiflupyr. Molecular docking with Alphafold2 modeling suggested distinct binding modes of the two fungicides to C. siamense SDH. These findings underscore the importance of SDHC polymorphisms in C. siamense's fitness and sensitivity to SDHIs, enhancing our understanding of pathogen-SDHI interactions and aiding the development of novel SDHI fungicides.

Perceived stress and psychological disorders in healthcare professionals: a multiple chain mediating model of effort-reward imbalance and resilience.

Background: Healthcare professionals have shown more psychological disorders such as anxiety and depression due to the nature of work, which can cause job burnout, decrease the quality of medical services, and even endanger medical safety. The aim of the study is to explore the serial multiple mediating role of effort- reward imbalance and resilience between perceived stress and psychological disorders among healthcare professionals. Methods: A cross-sectional study was conducted in China from February to April 2023. A total of 2098 healthcare professionals at a tertiary general hospital was investigated by the following self-reported questionnaires: Hospital Anxiety and Depression Scale (HADS), Perceived Stress Scale (PSS), The Effort-Reward Imbalance (ERI), Healthcare professionals Resilience Scale (MSRS). Results: Anxiety and depression are interrelated (r = 0.362, p < 0.01), and they were positively related to perceived stress (r = 0.640/0.607, p < 0.01) and ERI (r = 0.422/0.383, p < 0.01), and negatively related to resilience (r = -0.343/-0.320, p < 0.01). After controlling demographic factors, the variance in anxiety and depression was explained by perceived stress was 37.7 and 35.0%. Bootstrap analyses examining the pathway of perceived stress-ERI-resilience-anxiety revealed significant direct effects [B = 0.560, 95%CI (0.528, 0.591)], as well as indirect effects mediated independently by ERI [B = 0.045, 95%CI (0.029, 0.060)], resilience [B = 0.031, 95%CI (0.017, 0.047)], or a combination of both [B = 0.004, 95%CI (0.002, 0.007)]. Similarly, in the path of perceived stress-ERI-resilience-anxiety-depression, significant direct effects were found [B = -0.310, 95%CI(0.265, 0.351)], along with indirect effects mediated individually by ERI [B = 0.033, 95%CI(0.013, 0.052)], resilience [B = 0.014, 95%CI (0.001, 0.028)], and anxiety [B = 0.218, 95%CI (0.190, 0.246)], or by both or three together (B = 0.032). Conclusion: This study proved the hypothesis that ERI and resilience played a mediating role in perceived stress and psychological disorders, revealed the potential mechanism of anxiety in stress and depression, and proposed a solution for perceived stress to psychological distress, which can provide a basis for the intervention of healthcare professionals in the face of mental health crisis.