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As one of the most economically significant Oleaceae family members, Jasminum sambac is renowned for its distinct sweet, heady fragrance. Using Illumina reads, Nanopore long reads, and HiC‐sequencing, we efficiently assembled and annotated the J. sambac genome. The high‐quality genome assembly consisted of a total of 507 Mb sequence (contig N50 = 17.6 Mb) with 13 pseudomolecules. A total of 21,143 protein‐coding genes and 303 Mb repeat sequences were predicted. An ancient whole‐genome triplication event at the base of Oleaceae (~66 million years ago [Ma], Late Cretaceous) was identified and this may have contributed to the diversification of the Oleaceae ancestor and its divergence from the Lamiales. Stress‐related (e.g., WRKY) and flowering‐related (e.g., MADS‐box) genes were located in the triplicated regions, suggesting that the polyploidy event might have contributed adaptive potential. Genes related to terpenoid biosynthesis, for example, FTA and TPS, were observed to be duplicated to a great extent in the J. sambac genome, perhaps explaining the strong fragrance of the flowers. Copy number changes in distinct phylogenetic clades of the MADS‐box family were observed in J. sambac genome, for example, AGL6‐ and Mα‐ were lost and SOC‐ expanded, features that might underlie the long flowering period of J. sambac. The structural genes implicated in anthocyanin biosynthesis were depleted and this may explain the absence of vivid colours in jasmine. Collectively, assembling the J. sambac genome provides new insights into the genome evolution of the Oleaceae family and provides mechanistic insights into floral properties. [ABSTRACT FROM AUTHOR]

In order to study the effects of exogenous GA3 and IAA on tobacco growth regulation and chemical composition, the mechanism of exogenous hormones and the optimal hormone concentration were explored based on hormone and gene levels-explore. Taking the flue, cured tobacco variety NC71 as the experimental material, this paper set different concentration treatments of exogenous hormones to detect the changes of plant height, dry matter accumulation, hormone content, related gene expression and tobacco leaf quality. The results showed that exogenous GA3 could significantly increase the plant height and pitch of flue, cured tobacco, while the relative increase of exogenous IAA was less, and the dry matter quality of tobacco plants increased with the increase of GA3 concentration. Spraying different concentrations of exogenous GA3 and IAA increased the content of GA3 and IAA in shoot tip and reduced the content of ABA and the effect of 150 mg/ L was the most obvious, the exogenous GA3 of 100 mg/ L and the exogenous IAA of 10 mg/ L were the second exogenous. GA3 significantly reduced the expression of GAI1 gene in tobacco, and IAA also reduced the relative expression of GAI gene, but the effect was relatively weak. The content of total sugar, reducing sugar and potassium in tobacco leaves sprayed with exogenous hormones increased, while the contents of total nitrogen, nicotine and chlorine decreased, and potassium in the condition of 100 mg/ L exogenous GA3 combined with IAA. The ratio of chlorine to sugar and alkali was the highest, and the quality was better, so 100 mg/ L exogenous GA3 and 10 mg/ L exogenous IAA were sprayed 15 d after transplanting according to the principle of lessness. These results provided a basis for the application of exogenous growth regulators to flue, cured tobacco in the central part of Henan province tobacco area. [ABSTRACT FROM AUTHOR]

Recombinant proteins provide new means for disease treatment, while creating considerable economic benefits. Using commercial crops (mainly tobacco), cereal crops, legumes, and vegetable crops to produce recombinant proteins with medicinal value is a hot-spot for research in "molecular farming". Although many recombinant proteins have been expressed in plants, only a small number have been successfully put into use. To overcome the problems that greatly hamper the development of recombinant protein production in plants, researchers have improved expression systems to increase the yield of recombinant proteins. Starting from analyzing the problems of low yield and/or low biological activity of recombinant proteins produced by plants, the optimization strategies to solve these problems were reviewed, and future research directions for improving the yield of recombinant proteins produced by plants were proposed.

Objective: To develop a hydroponic Nicotiana cultivation system for rapid and high-yield transient expression of recombinant proteins under laboratory conditions., Methods: To establish the hydroponic cultivation system, several parameters were examined to define the optimal conditions for the expression of recombinant proteins in plants. We used the green fluorescent protein (GFP) and the geminiviral plant transient expression vector as the model protein/expression vector. We examined the impact of Nicotiana species, the density and time of Agrobacterium infiltration, and the post-infiltration growth period on the accumulation of GFP. The expression levels of GFP in Nicotiana leaves were then examined by Western blotting and ELISA., Results: Our data indicated that a hydroponic Nicotiana cultivation system with a light intensity of 9000 LX/layer, a light cycle of 16 h day/8 h night, a temperature regime of 28 degrees celsius; day/21 degrees celsius; night, and a relative humidity of 80% could support the optimal plant growth and protein expression. After agroinfiltration with pBYGFPDsRed.R/LBA4404, high levels of GFP expression were observed in both N. benthamiana and N. tobaccum (cv. Yuyan No.5) plants cultured with this hydroponic cultivation system. An optimal GFP expression was achieved in both Nicotiana species leaves 4 days after infiltration by Agrobacterium with an OD(600) of 0.8. At a given time point, the average biomass of N. tobaccum (cv. Yuyan No.5) was significantly higher than that of N. benthamiana. The leaves from 6-week-old N. benthamiana plants and 5-week-old N. tobaccum (cv. Yuyan No.5) plants could be the optimal material for agroinfiltration., Conclusion: We have established a hydroponic cultivation system that allows robust growth of N. benthamiana and N. tobaccum (cv. Yuyan No.5) plants and the optimal GFP expression in the artificial climate box.