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.

A hybrid approach for patent ductus arteriosus closure using the Amplatzer Duct Occluder.

OBJECTIVE: We performed closure of the patent ductus arteriosus (PDA) using a hybrid approach with an Amplatzer Duct Occluder. METHODS: Six patients (two males and four females) underwent PDA closure at a mean age of 7.8 months (range 2-24 months) and a mean weight of 6.6 kg (range 4.5-13 kg). The main pulmonary artery (MPA) was exposed via a minimally invasive left parasternal second intercostal space incision. Under transesophageal echocardiography guidance, the PDA occluder was implanted via direct puncture of the MPA. RESULTS: The procedure was successful in all patients with no residual shunt. There were no hospital deaths, and the postoperative course was uneventful. All patients were discharged on the 3rd to 4th day. There was no residual shunt in any patient on midterm follow-up. CONCLUSIONS: The novel hybrid approach is a safe, minimal invasive procedure. Further experience and longer follow-up of these patients is necessary to conclude whether this technique is applicable to all the patients with a PDA.