Identification and characterization of the trnS/pseudo-tRNA/nad3/rps12 gene cluster from Coix lacryma-jobi L: organization, transcription and RNA editing

Adlay, an ancient functional plant with nutritional quality, improves human health

Adlay (Coix lacryma-jobi L.), a crop closed related to maize (Zea mays L.) and sorghum (Sorghum bicolor L.), originated in tropical/subtropical regions of Asia and Africa; southwest China primary center of this plant's origin, evolution and migration. Adlay is a traditional high-value minor crop used for both medicinal and dietary purposes. Adlay has anti-tumor, anti-bacterial, anti-inflammatory, analgesic, blood sugar-lowering, and blood lipid-lowering effects. To clarify the main bioactive components and phytochemical compounds and to fully explore their utility, this review summarizes the research done on the main functional ingredients of adlay, including amino acids and proteins, oils, vitamins and minerals, polysaccharides, and polyphenols. This study also highlighted the application of genome sequencing to tailor nutrient-rich adlay cultivars and nutraceutical product development. Additionally, the acquisition of high-density genomic data combined with next-generation phenotypic analysis will undoubtedly improve our understanding of the potential genetic regulation of adlay nutraceutical traits. This review provides new insights and ideas for the research of adlay in comparison and evolutionary genomics, and a useful reference for molecular breeding and genetic improvement of this important minor crop.

Complete sequence of kenaf (Hibiscus cannabinus) mitochondrial genome and comparative analysis with the mitochondrial genomes of other plants

Plant mitochondrial (mt) genomes are species specific due to the vast of foreign DNA migration and frequent recombination of repeated sequences. Sequencing of the mt genome of kenaf (Hibiscus cannabinus) is essential for elucidating its evolutionary characteristics. In the present study, single-molecule real-time sequencing technology (SMRT) was used to sequence the complete mt genome of kenaf. Results showed that the complete kenaf mt genome was 569,915 bp long and consisted of 62 genes, including 36 protein-coding, 3 rRNA and 23 tRNA genes. Twenty-five introns were found among nine of the 36 protein-coding genes, and five introns were trans-spliced. A comparative analysis with other plant mt genomes showed that four syntenic gene clusters were conserved in all plant mtDNAs. Fifteen chloroplast-derived fragments were strongly associated with mt genes, including the intact sequences of the chloroplast genes psaA, ndhB and rps7. According to the plant mt genome evolution analysis, some ribosomal protein genes and succinate dehydrogenase genes were frequently lost during the evolution of angiosperms. Our data suggest that the kenaf mt genome retained evolutionarily conserved characteristics. Overall, the complete sequencing of the kenaf mt genome provides additional information and enhances our better understanding of mt genomic evolution across angiosperms.

Marchantia polymorpha mitochondrial orf identifies transcribed sequence in angiosperm mitochondrial genome

Heterologous hybridizations performed using nine Marchantia polymorpha mitochondrial orfs and the sdh4 gene against angiosperm mtDNA suggested that three of them and the sdh4 gene have been conserved in the mitochondrial genome of different angiosperm species. Solanum tuberosum mtDNA fragments, which hybridized to M. polymorpha orf207 and sdh4 gene, were cloned, sequenced, and their expressions evaluated by Northern and RT-PCR. Hybridizing fragments to sdh4 gene and orf207 from potato mtDNA were shown to be transcribed, but only in the case of sdh4 gene was there homology between the protein encoded by the DNA sequence from M. polymorpha and the potato mitochondrial genome. M. polymorpha orf207 showed little similarity to an open reading frame from potato mtDNA, named here orf78. The putative proteins encoded by both orf207 and orf78 were not related, indicating that these orfs do not constitute homologous sequences.