Jasmonic acid (JA), a plant endogenously synthesized lipid hormone, plays an important role in response to stress. This manuscript summarized the biosynthesis and metabolism of JA and its related regulatory mechanisms, as well as the signal transduction of JA. The mechanism and regulatory network of JA in plant response to biotic and abiotic stresses were systematically reviewed, with the latest advances highlighted. In addition, this review summarized the signal crosstalk between JA and other hormones in regulating plant resistance to various stresses. Finally, the problems to be solved in the study of plant stress resistance mediated by JA were discussed, and the application of new molecular biological technologies in regulating JA signaling to enhance crop resistance was prospected, with the aim to facilitate future research and application of plant stress resistance.
Signal Transduction ; Cyclopentanes ; Oxylipins ; Plant Growth Regulators

Abscisic acid, a plant hormone that inhibits growth, is a key factor in balancing plant endogenous hormones and regulating growth and metabolism. Abscisic acid can improve the drought resistance and salt tolerance of crops, reduce fruit browning, reduce the incidence rate of malaria and stimulate insulin secretion, so it has a broad application potential in agriculture and medicine. Compared with traditional plant extraction and chemical synthesis, abscisic acid synthesis by microorganisms is an economic and sustainable route. At present, a lot of progress has been made in the synthesis of abscisic acid by natural microorganisms such as Botrytis cinerea and Cercospora rosea, while the research on the synthesis of abscisic acid by engineered microorganisms is rarely reported. Saccharomyces cerevisiae, Yarrowia lipolytica and Escherichia coli are common hosts for heterologous synthesis of natural products due to their advantages of clear genetic background, easy operation and friendliness for industrial production. Therefore, the heterologous synthesis of abscisic acid by microorganisms is a more promising production method. The author reviews the research on the heterologous synthesis of abscisic acid by microorganisms from five aspects: selection of chassis cells, screening and expression enhancement of key enzymes, regulation of cofactors, enhancement of precursor supply and promotion of abscisic acid efflux. Finally, the future development direction of this field is prospected.
Abscisic Acid/metabolism* ; Plant Growth Regulators/metabolism* ; Plants/metabolism* ; Yarrowia/metabolism*

Uridine diphosphate glycosyltransferase(UGT) is a highly conserved protein in plants, which usually functions in secondary metabolic pathways. This study used the Hidden Markov Model(HMM) to screen out members of UGT gene family in the whole genome of Dendrobium officinale, and 44 UGT genes were identified. Bioinformatics was used to analyze the structure, phylogeny, and promoter region components of D. officinale genes. The results showed that UGT gene family could be divided into four subfamilies, and UGT gene structure was relatively conserved in each subfamily, with nine conserved domains. The upstream promoter region of UGT gene contained a variety of cis-acting elements related to plant hormones and environmental factors, indicating that UGT gene expression may be induced by plant hormones and external environmental factors. UGT gene expression in different tissues of D. officinale was compared, and UGT gene expression was found in all parts of D. officinale. It was speculated that UGT gene played an important role in many tissues of D. officinale. Through transcriptome analysis of D. officinale mycorrhizal symbiosis environment, low temperature stress, and phosphorus deficiency stress, this study found that only one gene was up-regulated in all three conditions. The results of this study can help understand the functions of UGT gene family in Orchidaceae plants and provide a basis for further study on the molecular regulation mechanism of polysaccharide metabolism pathway in D. officinale.
Dendrobium/genetics* ; Plant Growth Regulators ; Glycosyltransferases/metabolism* ; Gene Expression Profiling ; Mycorrhizae ; Phylogeny ; Plant Proteins/metabolism*

The study aimed to explore the effects of inoculation of Rhizophagus intraradices on the biomass, effective component content, and endogenous hormone content of Salvia miltiorrhiza through pot experiments. The number of leaves, plant height, dry weight of aboveground and underground parts, branch number, root number, root length, root diameter, and other biomass were mea-sured by weighing and counting methods. The content of salvianolic acid B, caffeic acid, rosmarinic acid, tanshinone Ⅰ, tanshinone Ⅱ_A, cryptotanshinone, and other effective components was determined by ultra-high performance liquid chromatography. The content of ABA and GA_3 was determined by triple quadrupole mass spectrometry. The correlations between biomass and effective components and between effective components and plant hormones ABA and GA_3 were analyzed. The results showed that R. intraradices significan-tly increased the aboveground dry weight, leaf number, and root number of S. miltiorrhiza by 0.24-0.65 times, respectively. The content of salvianolic acid B and rosmarinic acid in the aboveground part and the content of salvianolic acid B, caffeic acid, rosmarinic acid, tanshinone Ⅰ, and tanshinone Ⅱ_A in the underground part were significantly increased by 0.44-1.78 times, respectively. R. intraradices infection significantly increased the GA_3/ABA values of aboveground and underground parts by 3.82 and 76.47 times, respectively. The correlation analysis showed that caffeic acid, the effective component of the aboveground part, was significantly positively correlated with plant height, tanshinone Ⅱ_A, the effective component of the underground part, was significantly positively correlated with biomass root number, cryptotanshinone, and dry weight, while rosmarinic acid was significantly negatively correlated with dry weight. There were significant positive correlations between cryptotanshinone and ABA, tanshinone Ⅱ_A and ABA and GA_3, and caffeic acid and GA_3. In conclusion, R. intraradices can promote the accumulation of biomass and secondary metabolites of S. miltiorrhiza and regulate the balance between plant hormones ABA and GA_3, thereby promoting the growth of S. miltiorrhiza.
Salvia miltiorrhiza/chemistry* ; Plant Growth Regulators/analysis* ; Plant Roots/chemistry*

Aims: The main aim of the study was to evaluate some methods of application of Aspergillus niger AD1 and Trichoderma hamatum T-113 for enhancing the growth and yield of wheat var. Ibaa99 in pots and field conditions. Methodology and results: Plant growth-promoting fungi (PGPF) loaded with peat moss were used at a rate of 100, 150 and 200 mL pot-1 or m-2 in filed soil; seed treatment (coating) with fungi suspension 19 × 107, soil treatment and combination of all the three methods was employed in the study. Wheat seeds were sown in pots and field plots during 2018-2019, and data regarding various growth and yield attributes were recorded. In both pot and field trials, the results revealed that the best treatments for the desired plant growth and yield attributes were peat moss 150 mL alone or in combination with soil and seed treatments. The soil physicochemical parameters were also improved after inoculation with selected fungal isolates in different application methods compared with un-inoculated control treatment in both pot and field conditions. Conclusion, significance and impact of study The PGPF play a vital role represented phytoremediation, phytostimulation and bio-fertilization. The isolates of PGPF, which were applied with peat moss at 150 mL to the pot and in the field alone or combined with seed treatment and soil application, were significantly the best effective method for improving wheat attributes.
Aspergillus niger ; Trichoderma ; Plant Growth Regulators

Aims: Endophytic bacteria (EB) living inside plant tissues possess different beneficial traits including siderophore production and other plant growth-promoting (PGP) activities. Siderophore-producing EB promote host plant growth by secreting ferrum in iron-deficient conditions. This study screened 19 siderophore producers in vitro, isolated from upland rice roots grown in mountain farms of Tung Village, Nậm Có Commune, Mù Cang Chải District, Yên Bái Province, Vietnam, for PGP traits, including phosphate solubilisation, indole-3-acetic acid (IAA), ammonia, gelatinase, amylase and catalase production. Methodology and results: The bacteria were identified by Matrix assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-TOF MS). All 19 isolates were identified as genera Pseudomonas, Enterobacter, Pantoe, Bacillus, Burkholderia, Staphylococcus, Ralstonia and Cronotacter. The isolates produced catalase and ammonia. The amount of ammonia ranged from 60.74 ± 0.14 to 466.72 ± 0.18 mg/L. Out of the 19 siderophore producers, 17 (89.47%) were able to solubilise phosphate with solubilisation index (PSI) ranging from 1.12 ± 0.07 to 2.14 ± 0.15. The qualitative assays identified 12 isolates (63.15%) positive for IAA production with a tryptophan concentration of 5 mM, whereas 15 (78.94%) and 17 (89.47%) isolates were positive for gelatin and starch hydrolysis, respectively. Especially, 7 isolates were found to be positive for all tested assays in vitro including Pseudomonas rhodesiae (NC2), Enterobacter asburiae (NC50), Pantoea ananatis (NC63), Bacillus cereus (NC64), Burkholderia cenocepacia (NC110), Staphylococcus sciuri (NC112) and Ralstonia pickettii (NC122). Conclusion, significance and impact of study This study serves as crucial findings of multi-trait plant growth-promoting endophytic bacteria isolated from upland rice root in north-western Vietnam. The seven potential isolates positive for all tested assays could be effective PGP bacteria for bio-inoculants.
Oryza--microbiology ; Siderophores ; Plant Growth Regulators ; Vietnam

Saposhnikovia divaricata is a commonly used bulk medicinal plant. To explore the key enzyme genes and their expression in the biosynthesis of chromone and coumarin, the key active components, we carried out transcriptome sequencing(Illumina HiSeq) and bioinformatics analysis for the 1-year-old(S1) and 2-year-old(S2) plants of S. divaricata. A total of 40.8 Gb data was obtained. After the sequence assembly via Trinity, 110 732 transcripts and 86 233 unigenes were obtained, which were aligned and annotated with NR, Swiss-Prot, GO, KEGG, and PFAM. Daucus carota and S. divaricata had the highest sequence homology. KEGG pathway enrichment showed that the differentially expressed genes were mainly enriched in plant hormone signal transduction, phenylpropanoid biosynthesis, and flavonoid biosynthesis pathways. A total of 27 differentially expressed unigenes, including 13 enzyme genes, were identified in the pathways related to the synthesis of active ingredients in S. divaricata. Compared with S1 plant, S2 plant showed up-regulated expression of PAL, BGL, C4H, 4CL, CYP98A, CSE, REF, and CCoAOMT and down-regulated expression of CHS, CAD, and COMT. HCT and POD had both up-regulated and down-regulated unigenes. Among them, PAL, C4H, 4CL, BGL, and CHS can be used as candidate genes for the synthesis of the active ingredients in S. divaricata. The four key enzyme genes were verified by RT-qPCR, which showed the results consistent with transcriptome sequencing. This study enriches the genetic information of S. divaricata and provides support for the identification of candidate genes in the biosynthesis of secondary metabolites.
Apiaceae/genetics* ; Chromones ; Coumarins ; Flavonoids ; Gene Expression Profiling ; Gene Expression Regulation, Plant ; High-Throughput Nucleotide Sequencing/methods* ; Plant Growth Regulators ; Transcriptome

14-3-3 proteins are important proteins in plants, as they regulate plant growth and development and the response to biotic or abiotic stresses. In this study, a 14-3-3 gene(GenBank accession: OM683281) was screened from the cDNA library of the medicinal species Salvia miltiorrhiza by yeast two-hybrid and cloned. The open reading frame(ORF) was 780 bp, encoding 259 amino a cids. Bioinformatics analysis predicted that the protein was a non-transmembrane protein with the molecular formula of C_(1287)H_(2046)N_(346)O_(422)S_9, relative molecular weight of 29.4 kDa, and no signal peptide. Homologous sequence alignment and phylogenetic tree analysis proved that the protein belonged to 14-3-3 family and had close genetic relationship with the 14-3-3 proteins from Arabidopsis thaliana, Oryza sativa, and Nicotiana tabacum. The 14-3-3 gene was ligated to the prokaryotic expression vector pGEX-4 T-1 and then transformed into Escherichia coli BL21 for the expression of recombinant protein. Real-time fluorescent quantitative PCR showed that the expression of this gene was different among roots, stems, leaves, and flowers of S. miltiorrhiza. To be specific, the highest expression was found in leaves, followed by stems, and the lowest expression was detected in flowers. S. miltiorrhiza plants were treated with 15% PEG(simulation of drought), and hormones salicylic acid, methyl jasmonate, and ethephon, respectively, and the expression of 14-3-3 gene peaked at the early stage of induction. Therefore, the gene can quickly respond to abiotic stresses such as drought and plant hormone treatments such as salicylic acid, jasmonic acid, and ethylene. This study lays the foundation for revealing the molecular mechanism of 14-3-3 protein regulating tanshinone biosynthesis and responding to biotic and abiotic stresses.
14-3-3 Proteins/metabolism* ; Amino Acid Sequence ; Cloning, Molecular ; Ethylenes/metabolism* ; Gene Expression Regulation, Plant ; Hormones/metabolism* ; Phylogeny ; Plant Growth Regulators/pharmacology* ; Plant Proteins/metabolism* ; Recombinant Proteins/genetics* ; Salicylic Acid/metabolism* ; Salvia miltiorrhiza/metabolism*

Nitrogen fertilizers play an important role in the regulation of plant stress resistance. Impacts of nitrogen fertilizers on abiotic stress resistance and biotic stress resistance of Chinese materia medica(CMM) were summarized in this study. Adequate nitrogen application improves the abiotic stress resistance and weed resistance of CMM, however adverse effect appears when excess nitrogen is used. Generally, pest resistance decreases along with nitrogen deposition, while effects of nitrogen application on disease resistance vary with different diseases. Mechanisms underlying the impact of nitrogen fertilizers on plant stress resistance were also elucidated in this study from three aspects including physical defense mechanisms, biochemistry mechanisms and molecular defense mechanisms. Nitrogen availability modulates physical barrier of CMM like plant growth, formation of lignin and wax cuticle, and density of stomata. Growth of CMM promoted by nitrogen fertilizer may cause some decrease in pest resistance of CMM due to an increase in hiding places for pest along with plant growth. High ambient humidity caused by excessive plant growth facilitates the growth and development of CMM pathogen. Nitrogen application can also interfere with the accumulation of lignin in CMM which makes CMM more vulnerable to pest and pathogen attack. Stomatal closing delays due to nitrogen application is also a causal factor of increasing pathogen infection after nitrogen deposition. Biochemical defenses of plants are mainly achieved through nutrient elements, secondary metabolites, defense-related enzymes and proteins. Nutritional level of CMM and various antioxidant enzymes and resistance-related protein activities are elevated along with nitrogen deposition. These antioxidant enzymes can reduce the damage of reactive oxygen species content produced by plant in response to adversity and therefore enhance stress resistance of CMM. Researches showed that nitrogen application could also cause an increase in nitrogen-containing secondary metabolites content and a decrease in non-nitrogen-containing secondary metabolites content respectively. Nitrogen-mediated molecular defense mechanisms includes multiple plant hormones and nitric oxide signals. Plant hormones related to plant defense like salicylic acid, jasmonic acid and abscisic acid can be modulated by nitrogen application. Negative effect of nitrogen deposition was found on salicylic acid accumulation and the expression of related plant disease resistance genes. However, jasmonic acid level can be elevated by nitrogen. Nitric oxide signals constitute an important part of nitrogen mediated defense mechanisms. Nitric oxide signaling is related to many aspects of plant immunity. The roles of nitrogen fertilizers in CMM stress resistance are complex and may vary with different CMM varieties and environments. Further studies are urgently needed to provide a comprehensive understanding of how to improve stress resistance of CMM by using fertilizers.
Abscisic Acid ; China ; Materia Medica ; Nitrogen ; Plant Growth Regulators

Phytohormones play an important role at all stages of plant growth, influencing plant growth and development and regulating plant secondary metabolism, such as the synthesis of flavone, flavonol, anthocyanin, and other flavonoids. Flavonoids, a group of important secondary metabolites ubiquitous in plants, have antioxidative, anti-microbial, and anti-inflammatory activities and thus have a wide range of potential applications in Chinese medicine and food nutrition. With the development of biotechnology, phytohormones' regulation on flavonoids has become a research focus in recent years. This study reviewed the research progress on the mechanism of common phytohormones, such as abscisic acid, gibberellin, methyl jasmonate, and salicylic acid, in regulating flavonoid metabolism, and discussed the molecular mechanism of the synthesis and accumulation of flavonoids, aiming at clarifying the key role of phytohormones in modulating flavonoid metabolism. The result is of guiding significance for improving the content of flavonoids in plants through rational use of phytohormones and of reference value for exploring the mechanism of hormones in regulating flavonoid metabolism.
Abscisic Acid ; Flavonoids ; Gene Expression Regulation, Plant ; Gibberellins ; Plant Development ; Plant Growth Regulators