AlliumDB: a central portal for comparative and functional genomics in Allium.

The genus Allium belongs to the botanical family Amaryllidaceae and includes economically important crops such as onion, garlic, bunching onion, and leek, used as vegetables, spices, and traditional medicines. The large sizes of Allium genomes hamper the genetic dissection of agronomically important traits and molecular breeding. With the growing accumulation of genomic, resequencing, transcriptome, and phenotypic data, the demand for an integrative Allium database is increasing. Here we present a user-friendly database, AlliumDB (https://allium.qau.edu.cn), as a functional genomics hub integrating public and in-house data. The database contains all currently available nuclear and organelle genomes for Allium species, with genes comprehensively annotated based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, orthology, gene families, protein families (Pfam), and non-coding RNA families (Rfam). Transcriptome and variation profiles are integrated into dynamic visualization tools. We took phenotypic photographs and generated trait records for hundreds of Allium germplasms collected worldwide, which are included in the database. We incorporated JBrowse for the visualization of gene structures, RNA sequencing data, and variation data. Analysis tools such as the basic local alignment search tool (BLAST), sequence fetch, enrichment, and motif analyses are available to explore potential gene functions. This database incorporates comprehensive Allium genotypic and phenotypic datasets. As the community assembles new genomes and generates resequencing data for Allium germplasms, the database will be improved and continuously updated with these multi-omics data and comparative genomic studies. We expect the AlliumDB database to become a key resource for the study of Allium crops.

One-dimensional transition metal dihalide nanowires as robust bipolar magnetic semiconductors.

One-dimensional (1D) materials with robust ferromagnetic ground states are difficult to achieve but provide a significant platform for potential spintronic device applications in future. Herein, a new family of 1D transition metal dihalide (TMCl2; where TM = Cu, Co, Cr) nanowires are proposed by using first-principles calculations. Their dynamic stability is ensured by Born-Oppenheimer molecular dynamics simulations. The electronic structures demonstrate that both CoCl2 and CuCl2 nanowires are promising bipolar magnetic semiconductors (BMSs) and can be converted into 1D half-metal materials by a small amount of carrier doping. The CrCl2 nanowire is an antiferromagnetic semiconductor (AFS). The formation of a BMS is attributed to the superexchange coupling between the Co/Cu atoms through the 3p orbitals in the Cl atoms. By using Monte Carlo simulations, we found that the CoCl2 nanowire has a Curie point of 6 K, while the CuCl2 nanowire has a corresponding Curie point of 14 K. Our results allow us to put forward a strategy to realize 1D BMSs and to design low-dimensional AF spintronic devices.