Ethylene is a gaseous phytohormone that delays flowering in Chrysanthemum morifolium Ramat. To date, however, there have been no systematic studies on genes involved in the ethylene response of this species, and the mechanism underlying ethylene-delayed flowering remains unclear. Herein, we applied RNA sequencing to characterize the ethylene response by comparing the transcriptomes of chrysanthemum cultivar ‘Jinba’ with or without ethephon treatment. Six unique RNA-seq libraries were generated. The identified differentially expressed genes (DEGs) primarily involved ethylene, auxin, and abscisic acid signaling genes; circadian clock genes; genes encoding functional proteins associated with floral transition, such as homologs of AP1/FRUITFUL-like 1 (AFL1), TERMINAL FLOWER 1 (TFL1), and so on; and genes encoding transcription factors, specifically of the MYB and bHLH families. Furthermore, quantitative RT-PCR was used to verify the DEGs identified by RNA-seq. Heterologous CmAFL1 overexpression in Arabidopsis thaliana resulted in early flowering. Our findings present a landscape of transcriptomes and reveal the candidate genes involved in the ethylene-mediated regulation of flowering time in chrysanthemum, providing useful data for further studies.

Background: Cucumber (Cucumis sativus) is one of the most important vegetable crops in the world. As conventional breeding of cucumber is very challenging, genetic engineering is an alternative option to introduce important traits such as enhanced stress resistance and nutritional value. However, the efficiency of the transformation system depends on genotypes, transformation conditions, selection agents, etc. This study aims to speed up the process of Agrobacterium-mediated transformation of cucumber. ‘ Xintai mici ’, a very popular and typical north China-type cucumber variety, was transformed with Agrobacterium GV3101. The strain carried pCAMBIA2300s plasmid, a double vector with the marker gene of neomycin phosphotransferase II ( npt II). Results: The research results indicated that cefotaxime sodium was suitable for inhibiting Agrobacterium in the stage of screening and bud elongation. Timentin was best used during rooting stage. Furthermore, 25 mg/L kanamycin was used in the early stage of screening and increased to 50 mg/L for further screening. At the bud elongation and rooting stage, 75 and 100 mg/L kanamycin was used respectively to improve the screening efficiency. In order to obtain the highest regeneration frequency of resistant buds, 50, 150, and 100 μM acetosyringone were added in the pre-culture medium, infection solution, and co-culture medium respectively. To confirm the presence of the transgenes, DNA from npt II transgenic cucumber plants was analyzed by polymerase chain reaction after transplanting resistant regenerated plants. Conclusions: We finally achieved an 8.1% conversion, which was among the highest values reported until date using cucumber ‘ Xintai mici ’. Thus an effective protocol for Agrobacterium tumefaciens -mediated genetic transformation of cucumber was optimized.