Transcriptomic Analysis of Verbena bonariensis Leaves Under Low-Temperature Stress.

Verbena bonariensis is a valuable plant for both ornament and flower border. As a major constraint, low temperature affects the growing development and survival of V. bonariensis. However, there are few systematic studies in terms of molecular mechanism on the tolerance of low temperature in V. bonariensis. In this study, Illumina sequencing technology was applied to analyze the cold resistance mechanism of plants. Six cDNA libraries were obtained from two samples of two groups, the cold-treated group and the control group. A total of 271,920 unigenes were produced from 406,641 assembled transcripts. Among these, 19,003 differentially expressed genes (DEGs) (corrected p-value <0.01, |log2(fold change) | >3) were obtained, including 9852 upregulated and 9151 downregulated genes. The antioxidant enzyme system, photosynthesis, plant hormone signal transduction, fatty acid metabolism, starch and sucrose metabolism pathway, and transcription factors were analyzed. Based on these results, series of candidate genes related to cold stress were screened out and discussed. The physiological indexes related to response mechanism of low temperature were tested. Eleven upregulated DEGs were validated by Quantitative Real-time PCR. In this study, we provided the transcriptome sequence resource of V. bonariensis and used these data to realize its molecular mechanism under cold stress. The results contributed to valuable clues for genetic studies and helped to screen candidate genes for cold-resistance breeding.

Whole-Transcriptome Sequence Analysis of Verbena bonariensis in Response to Drought Stress.

Drought is an important abiotic factor that threatens the growth and development of plants. Verbena bonariensis is a widely used landscape plant with a very high ornamental value. We found that Verbena has drought tolerance in production practice, so in order to delve into its mechanism of drought resistance and screen out its drought-resistance genes, we used the RNA-Seq platform to perform a de novo transcriptome assembly to analyze Verbena transcription response to drought stress. By high-throughput sequencing with Illumina Hiseq Xten, a total of 44.59 Gb clean data was obtained from T01 (control group) and T02 (drought experiment group). After assembly, 111,313 unigenes were obtained, and 53,757 of them were annotated by compared databases. In this study, 4829 differentially expressed genes were obtained, of which 4165 were annotated. We performed GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analyses, and explored a lot of differently expressed genes related to plant energy production, hormone synthesis, cell signal transduction, and metabolism to understand the stress response of Verbena in drought stress. In addition, we also found that a series of TFs related to drought-resistance of Verbena and provide excellent genetic resources for improving the drought tolerance of crops.

[Verbena canadensis Britt mutants with altered development of flowers and inflorescences generated by chemical mutagenesis].

Rose vervain is a little-known ornamental annual plant. The adaptive properties (drought and cold resistance) and long period of flowering make this species promising for growing in flower gardens and containers. Chemical mutagenesis widely used for various plant species was applied to induce character variation in Rose vervain. The properties of development of flowers and inflorescences in lines descending from the M3--M5 mutants generated by the seed exposure to chemical mutagens diethyl sulfate and nitrosomethylurea were considered.