Borneol is one of the most important pharmacodynamic components in Artemisia argyi, which has antibacterial, anti-inflammatory, analgesic and other pharmacological activities. The synthesis and metabolism of borneol are affected by many kinds of enzymes, and borneol dehydrogenase is one of the key enzymes that can oxidize borneol to camphor. In this study, the contents of borneol and camphor in 35 germplasm resources of A. argyi leaves were determined by Gas chromatograph-mass spectrometer (GC-MS), based on the full-length transcriptome results of A. argyi and homology comparison analysis, the first borneol dehydrogenase encoding gene AArBDH1 was cloned in A. argyi, the gene structure and the physical and chemical properties of the encoded protein were analyzed, the function of the encoded protein was identified. The results showed that the contents of borneol and camphor were quite various in different varieties, in some germplasm, the content of camphor was even higher than borneol, indicating that a large amount of borneol was oxidized to camphor, which seriously reduced the content of borneol in A. argyi leaves. The AArBDH1 contained 2 exons and 1 intron, and the length of its open reading frame was 870 bp, which encoded 289 amino acids. AArBDH1 gene expression levels were measured by qRT-PCR (Real-time quantitative reverse transcription PCR) technology, the result showed that AArBDH1 was differentially expressed in different tissues and leaves at different development stages, and highly expressed in stem and 30 days old leaves. The results of enzyme reactions using borneol as substrate and NAD⁺ as coenzyme showed that AArBDH1 could catalyze the dehydrogenation of borneol to camphor. The study provides a theoretical basis and gene resources for further analyzing the accumulating regularity of borneol in A. argyi leaves and improving the content of borneol in A. argyi leaves through molecular biology method.

Aluminum (Al) is one of the common metal contaminants in acidic soils. To reveal the effects of exogenous organic acids on the physiological characteristics and root DNA damage of Helianthus tuberosus under Al stress, we aimed to improve the Al tolerance of Helianthus tuberosus and promote safe production in Al-contaminated areas. The effects of exogenous organic acids on the physiological response and DNA damage of Helianthus tuberosus at various periods (7, 14, and 21 d) under Al stress were investigated by setting low, medium and high (0, 350 and 700 µmol·L^-1) Al concentration treatments and applying 0, 30, 60 and 90 µmol·L^-1 compound organic acids, respectively. The results showed that Al stress inhibits root elongation and root vitality, severely inhibited the photosynthetic and antioxidant systems of Helianthus tuberosus, and the DNA damage in the root system increased with the increase of Al concentration. In contrast, the application of 60 µmol·L^-1 compound organic acid effectively alleviated Al stress. 60 μmol/L compound organic acid improved the activity of the antioxidant system, maximum photochemical efficiency and organic acid secretion in root tips, citric acid with secretion 2 times (Xuzhou) and 0.75 times (Ziyang) than the control, reduced root tip aluminium content and improved root vitality. Besides, Xuzhou Helianthus tuberosus and Ziyang Helianthus tuberosus oliver tail moment decreased by 51.53% and 35.10%, and compound organic acid reduced the DNA trailing phenomenon and repaired DNA breaks to a greater extent. In conclusion, high concentration of Al cause serious damage to Helianthus tuberosus and difficult to mitigate. 60 µmol·L^-1 compound organic acid could enhance the Helianthus tuberosus physiological response under low aluminum stress, reduce DNA damage and improve the stress resistance. The alleviation effect was better in Ziyang Helianthus tuberosus. This study reveals the regulatory role of exogenous organic acids on the physiological response of chrysanthemum under Al stress, and provides a theoretical basis for the Helianthus tuberosus and production of other cash crops in the acid-aluminium areas of southern China.

Plasma membrane (PM) proteins are important components of cell membranes and play important roles in material transport, ion exchange, signal transduction, and metabolism process. Their movements in the PM are in response to the developmental cues and environmental stimuli. Studying the regulatory mechanism of PM protein movement is crucial for a better understanding of the development and the adaptation to environment of plants. In the recent years, the rapid development of microscopic technologies enables us to move one step closer to reveal the regulatory mechanism of PM protein dynamics. In this paper, we systematically summarized PM protein dynamics and the factors affecting it. We also provided an introduction to commonly-used microscopic imaging techniques for PM protein dynamics research. This review will provide new insights into further investigation of biological significance of PM proteins.

Riboflavin is the precursor of FMN and FAD that serve as indispensable cofactor to maintain normal metabolism, which plays pivotal roles in mitochondrial electron transport chain, citric acid cycle, β-oxidation of fatty acids, branched-chain amino acid catabolism, redox homeostasis, chromatin remodeling, DNA repair, apoptosis and secondary metabolite biosynthesis. Riboflavin defect will cause metabolic disorders and a series of defective phenotypes, and death in the severe cases. Among the living organisms, microorganisms and plants can de novo synthesize riboflavin, but humans and animals only obtain it from food. At present, the regulation of riboflavin biosynthesis in microorganisms has been clearly studied, but the mechanism of riboflavin transport and metabolism in plants is still not clear. Therefore, isolating riboflavin deficient mutants is of great significance for analyzing the molecular mechanisms of riboflavin biosynthesis, transport, and metabolism in plants and the effect of riboflavin on plant growth and development. In this paper, we firstly review riboflavin biosynthetic pathway and key enzymes, and then the processes of riboflavin involved in plant growth and development in detail, and finally give prospects for plant riboflavin research.

Pinoresinol–lariciresinol reductases (PLR) are key enzymes involved in the lignan biosynthesis in plants, which convert pinoresinol to lariciresinol and then to secoisolariciresinol. PLR are NADPH-dependent reductases with substrate stereoselectivity. The catalytic products of PLR are source of different types of 8-8′ lignans, and the substrate selectivity directly determines the skeleton types of lignans, such as furano, dibenzylbutane, dibenzylbutyrolactone and aryltetrahydronaphthalene lignans. Therefore, the catalytic and expression characteristics of PLR play an important role in the composition and biodiversity of lignans in plants. This paper reviewed the research progress in the important role of PLR in lignans biosynthesis, as well as its enantioselectivity and catalytic mechanism, thus to lay the foundation for further study on the biological function and catalytic mechanism of PLR gene, and point out the direction for the precise biosynthesis of different types of lignans enantiomers through synthetic biology or plant secondary metabolic engineering.