Light-driven biodegradation of chloramphenicol by photosensitized Shewanella oneidensis MR-1.

Efficient and sustainable degradation of chloramphenicol has piqued the interest of the scientific community. This study constructed a photosensitized biohybrid system using Shewanella oneidensis MR-1 and cadmium sulfide (CdS). This system could efficiently degrade chloramphenicol with robust stability. Inhibitor experiments and transcriptome analysis revealed that reduced nicotinamide adenine dinucleotide dehydrogenase, iron-sulfur cluster, menaquinone, cytochrome b561, cytochrome c, cytochrome P450, and formate dehydrogenase/hydrogenase are involved in direct electron transfer from S. oneidensis MR-1 to photogenerated holes of CdS. The S. oneidensis MR-1/CdS biohybrid alleviated chloramphenicol-induced physiological impairments, which can be attributed to the decreased levels of extracellular polymeric substances, malondialdehyde, and extracellular membrane permeability and the increased levels of superoxide dismutase and catalase activities. The GCN5-related N-acetyltransferase, alkene reductase, and carboxymuconolactone decarboxylase promoted the inactivation and further degradation of chloramphenicol. In summary, this study demonstrated the potential applications of the S. oneidensis MR-1/CdS biohybrid in the remediation of chloramphenicol contamination.

Transcriptome-wide association analyses reveal the impact of regulatory variants on rice panicle architecture and causal gene regulatory networks.

Panicle architecture is a key determinant of rice grain yield and is mainly determined at the 1-2 mm young panicle stage. Here, we investigated the transcriptome of the 1-2 mm young panicles from 275 rice varieties and identified thousands of genes whose expression levels were associated with panicle traits. Multimodel association studies suggested that many small-effect genetic loci determine spikelet per panicle (SPP) by regulating the expression of genes associated with panicle traits. We found that alleles at cis-expression quantitative trait loci of SPP-associated genes underwent positive selection, with a strong preference for alleles increasing SPP. We further developed a method that integrates the associations of cis- and trans-expression components of genes with traits to identify causal genes at even small-effect loci and construct regulatory networks. We identified 36 putative causal genes of SPP, including SDT (MIR156j) and OsMADS17, and inferred that OsMADS17 regulates SDT expression, which was experimentally validated. Our study reveals the impact of regulatory variants on rice panicle architecture and provides new insights into the gene regulatory networks of panicle traits.