Genome-Wide Survey Reveals the Microsatellite Characteristics and Phylogenetic Relationships of Harpadon nehereus

Harpadon nehereus forms one of the most important commercial fisheries along the Bay of Bengal and the southeast coast of China. In this study, the genome-wide survey dataset first produced using next-generation sequencing (NGS) was used to provide general information on the genome size, heterozygosity and repeat sequence ratio of H. nehereus. About 68.74 GB of high-quality sequence data were obtained in total and the genome size was estimated to be 1315 Mb with the 17-mer frequency distribution. The sequence repeat ratio and heterozygosity were calculated to be 52.49% and 0.67%, respectively. A total of 1,027,651 microsatellite motifs were identified and dinucleotide repeat was the most dominant simple sequence repeat (SSR) motif with a frequency of 54.35%. As a by-product of whole genome sequencing, the mitochondrial genome is a powerful tool to investigate the evolutionary relationships between H. nehereus and its relatives. The maximum likelihood (ML) phylogenetic tree was constructed according to the concatenated matrix of amino acids translated from the 13 protein-coding genes (PCGs). Monophyly of two species of the genus Harpadon was revealed in the present study and they formed a monophyletic clade with Saurida with a high bootstrap value of 100%. The results would help to push back the frontiers of genomics and open the doors of molecular diversity as well as conservation genetics studies on this species.

Identification and expression analysis of E2 ubiquitin-conjugating enzymes in cucumber

Protein ubiquitination is one of the most common modifications that can degrade or modify proteins in eukaryotic cells. The E2 ubiquitin-conjugating enzymes (UBCs) are involved in multiple biological processes of eukaryotes and their response to adverse stresses. Genome-wide survey of the UBC gene family has been performed in many plant species but not in cucumber (Cucumis sativus). In this study, a total of 38 UBC family genes (designated as CsUBC1–CsUBC38) were identified in cucumber. The phylogenetic analysis of UBC proteins from cucumber, Arabidopsis and maize indicated that these proteins could be divided into 15 groups. Most of the phylogenetically related CsUBC members had similar conserved motif patterns and gene structures. The CsUBC genes were unevenly distributed on seven chromosomes, and gene duplication analysis indicated that segmental duplication has played a significant role in the expansion of the cucumber UBC gene family. Promoter analysis of these genes resulted in the identification of many hormone-, stress- and development-related cis-elements. The CsUBC genes exhibited differential expression patterns in different tissues and developmental stages of fruit ripening. In addition, a total of 14 CsUBC genes were differentially expressed upon downy mildew (DM) infection compared with the control. Our results lay the foundation for further clarification of the roles of the CsUBC genes in the future.

Genome-wide survey of the F-box/Kelch (FBK) members and molecular identification of a novel FBK gene TaAFR in wheat

F-box proteins play critical roles in plant responses to biotic/abiotic stresses. In the present study, a total of 68 wheat F-box/Kelch ( TaFBK ) gene sequences encoding for 74 proteins were obtained in a genome-wide survey against EnsemblPlants. The 74 TaFBK proteins were divided into 5 categories based on their domain structures. The FBK proteins from wheat, Arabidopsis, and three other cereal species were grouped into 7 clades, and the number of Kelch domains present was their key clustering criterion. Sixty-eight TaFBK genes were unevenly distributed on 21 chromosomes. Most of TaFBKs were predicted to localize in the nucleus and cytoplasm. In silico analysis of a digital PCR revealed that TaFBKs were expressed at multiple developmental stages and tissues, and in response to drought and/or heat stresses. The TaFBK19 gene, a homologous to the Attenuated Far-Red Response ( AFR ) genes in other plant species, and hence named TaAFR , was selected for further analysis. The gene was isolated from the wheat line TcLr15 and its expression evaluated by quantitative real-time PCR. TaAFR transcripts were primarily detected in wheat leaves, and its expression was found to be regulated by various abiotic and biotic stresses as well as plant signaling hormones. Of particular interest, TaAFR expression was differentially regulated in the compatible vs incompatible wheat leaf rust reaction. Subcellular localization studies showed that TaAFR accumulates in the nucleus and cytoplasm. Three TaAFR-interacting proteins were identified experimentally: Skp1/ASK1-like protein (Skp1), ADP-ribosylation factor 2-like isoform X1 (ARL2) and phenylalanine ammonia-lyase (PAL). Further analysis revealed that the Skp1 protein interacted specifically with the F-box domain of TaAFR, while ARL2 and PAL were recognized by the Kelch domain. The data presented herein provides a solid foundation from which the function and metabolic network of TaAFR and other wheat FBKs can be further explored.

Genome-wide Survey of the GATA Gene Family in Camptothecin-producing Plant Ophiorrhiza Pumila

Background: Ophiorrhiza pumila (Rubiaceae) is capable of producing camptothecin (CPT), one monoterpene indole alkaloid extensively employed in the treatment of multiple cancers. Transcription factors (TF) GATA are a group of transcription regulators involved in plant development and metabolism, and show the feature of binding to the GATA motif within the promoters of target genes. However, GATA TFs have not been characterized in O. pumila. Result: In this study, a total of 18 GATA genes classified into four subfamilies were identified, which randomly distributed on 11 chromosomes of O. pumila. Gene replication and homology between O. pumila and other plant species such as Arabidopsis thaliana, Oryza sativa, Glycine max, Solanum lycopersicum, and Vitis vinifera genomes were analyzed. Tissue expression pattern revealed that OpGATA7, OpGATA12 and OpGATA13 with higher transcript in leaves, which was correlated with ASA, MK, DXS, CMS, and MECS. OpGATA7, OpGATA14 and OpGATA15 showed high expression in roots as most of the CPT biosynthetic pathway genes did, suggesting that these OpGATAs may be potential candidates regulating CPT biosynthesis in O. pumila.Conclusions: Genome-wide survey of the GATA gene family from Ophiorrhiza pumila provided insights into the involvement of GATA transcription factors in CPT biosynthesis