CmDOF18 positively regulates salinity tolerance in Chrysanthemum morifolium by activating the oxidoreductase system.

BACKGROUND: Chrysanthemum, one of the four major cut flowers all over the world, is very sensitive to salinity during cultivation. DNA binding with one finger (DOF) transcription factors play important roles in biological processes in plants. The response mechanism of CmDOF18 from chrysanthemum to salt stress remains unclear. RESULTS: In this study, CmDOF18 was cloned from Chrysanthemum morifolium, and its expression was induced by salinity stress. The gene encodes a 291-amino acid protein with a typical DOF domain. CmDOF18 was localized to the nucleus in onion epidermal cells and showed transcriptional activation in yeast. CmDOF18 transgenic plants were generated to identify the role of this gene in resistance to salinity treatment. Chrysanthemum plants overexpressing CmDOF18 were more resistant to salinity stress than wild-type plants. Under salinity stress, the malondialdehyde content and leaf electrolyte conductivity in CmDOF18-overexpressing transgenic plants were lower than those in wild-type plants, while the proline content, chlorophyll content, superoxide dismutase activity and peroxidase activity were higher than those in wild-type plants. The opposite findings were observed in gene-silenced plants compared with wild-type plants. The gene expression levels of oxidoreductase increased in CmDOF18-overexpressing transgenic plants but decreased in CmDOF18-SRDX gene-silenced transgenic plants. CONCLUSION: In summary, we analyzed the function of CmDOF18 from chrysanthemum, which may regulate salinity stress in plants, possibly due to its role in the regulation of oxidoreductase.

The complete chloroplast genome of Dianella ensifolia (Asphodelaceae).

Dianella ensifolia (L.) Redouté 1802 is a plant known for its significant medicinal values. In this study, we presented its chloroplast genome. The length of the chloroplast genome was found to be 156,571 bp, with a GC content of 37.86%. It consisted of a large single-copy (LSC) of 85,318 bp and a small single-copy (SSC) of 18,307 bp, a pair of inverted repeats (IRs) of 26,473 bp each that separated the LSC and SSC regions. The chloroplast genome of D. ensifolia consisted of 114 unique genes, including 80 protein-coding genes, four rRNA genes, and 30 tRNA genes. Through phylogenetic analysis, we identified a close relationship between D. ensifolia and D. nigra. This newly sequenced chloroplast genome not only enhances our understanding of the genome of Dianella, but also provides valuable insights for the evolutionary study of the family Asphodelaceae.

Transcriptomic Analysis of Green Leaf Plants and White-Green Leaf Mutants in Haworthia cooperi var. pilifera.

Haworthia cooperi var. pilifera is a succulent plant with ornamental value. The white-green leaf mutant (wl) showed a significant difference in leaf color from the wild-type plant (WT). In this study, we integrated the transcriptomes of wl and WT plants to screen differentially expressed genes related to leaf color variation. The results of transcriptome analysis showed that 84,163 unigenes were obtained after de novo assembly and the NR database annotated the largest number of unigenes, which accounted for 57.13%, followed by NT (43.02%), GO (39.84%), Swiss-Prot (39.25%), KEGG (36.06%), and COG (24.88%). Our finding showed that 2586 genes were differentially expressed in the two samples, including 1996 down-regulated genes and 590 up-regulated genes. GO analysis predicted that these differentially expressed genes (DEGs) participate in 12 cellular components, 20 biological processes, and 13 molecular function terms and KEGG analysis showed that metabolic pathways, plant-pathogen interaction, glycerophospholipid metabolism, endocytosis, plant hormone signal transduction, and ether lipid metabolism were enriched among all identified pathways. Through functional enrichment analysis of DEGs, we found that they were involved in chloroplast division and the biosynthesis of plant pigments, including chlorophyll, carotenoids, anthocyanin, and transcription factor families, which might be related to the formation mechanism of leaf color. Taken together, these results present insights into the difference in gene expression characteristics in leaves between WT and wl mutants and provide a new insight for breeding colorful leaf phenotypes in succulent plants.

The complete chloroplast genome and phylogenetic analysis of Acalypha hispida Burm. f. (Euphorbiaceae), an ornamental and medicinal plant.

Acalypha hispida Burm. f. (1768) is an evergreen shrub native to New Guinea and the Bismarck Archipelago. Currently, it is widely cultivated as an ornamental and medicinal plant in tropical and subtropical areas worldwide. This study characterized the complete chloroplast genome of A. hispida, which is 172,122 bp in length and consists of large single-copy (LSC) and small single-copy (SSC) regions of 97,025 bp and 19,787 bp, respectively, that are separated by a pair of 27,655 bp inverted repeat (IR) regions. The overall GC content of the genome is 34.22%. The genome contains 131 genes, including 86 protein-coding, 37 tRNA, and eight rRNA genes. Phylogenetic analysis indicates that A. hispida is closely related to Ricinus communis and Cleidiocarpon cavaleriei in the Euphorbiaceae family. The complete chloroplast genome of A. hispida provides genomic resources and potential markers suitable for future species identification and speciation studies of the genus Acalypheae and will also provide important information on the phylogenetic relationships of the Euphorbiaceae family.