The PIF7 gene is a member of the bHLH family, playing a pivotal role in plant germination. However, its roles in tea plants (Camellia sinensis) remain largely unexplored. In this study, we cloned the phytochrome-interacting factor gene CsPIF7 to elucidate its role in the germination of tea plants. Subcellular localization analysis demonstrated that CsPIF7 was localized in the nucleus. Yeast one-hybrid and dual-luciferase reporter assays demonstrated that CsPIF7 directly bound to a specific region (7-321 bp) of the CsEXP promoter, thereby repressing the expression of CsEXP. These findings suggest that CsPIF7 may modulate the germination of tea plants by inhibiting the expression of CsEXP. Quantitative real-time PCR results showed that both CsPIF7 and CsEXP exhibited high expression levels in tea buds, with different expression patterns in response to abscisic acid (ABA) treatment. Furthermore, both CsPIF7 and CsEXP were upregulated under cold stress at 4 ℃, indicating their involvement in the cold response of tea plants. Taken together, these results suggest that CsPIF7 regulates CsEXP expression in an ABA-dependent manner, thereby influencing the germination of tea plants. This study provides both theoretical and experimental insights into the molecular mechanisms governing the germination of tea plants, laying the groundwork for further exploring the role of PIF7 in plant development and stress responses.
Camellia sinensis/metabolism* ; Gene Expression Regulation, Plant ; Plant Proteins/metabolism* ; Abscisic Acid/pharmacology* ; Germination/genetics* ; Basic Helix-Loop-Helix Transcription Factors/metabolism* ; Promoter Regions, Genetic ; Cold Temperature

Gelsemium elegans, a vine plant of Loganiaceae, has both medicinal and forage values. However, it is susceptible to low temperatures during growth. Exploring low temperature response genes is of great significance for cold resistance breeding of G. elegans. Ethylene response factors (ERFs) are the transcription factors of the AP2/ERF superfamily and play a crucial role in plant stress response. In this study, based on the unigene GeERF involved in the response to low temperature stress in the transcriptome of G. elegans, a full-length cDNA sequence of the transcription factor GeERF4B-1 was cloned from the leaves of G. elegans by reverse transcription-polymerase chain reaction (RT-PCR). Bioinformatics analysis showed that GeERF4B-1 had an open reading frame of 759 bp, encoding a protein composed of 252 amino acid residues and with a relative molecular weight of 27 kDa. The deduced protein was predicted to be an unstable, alkaline, and hydrophilic protein. The phylogenetic tree showed that GeERF4B-1 was in the same clade as the B-4 subfamily of the ERF family. The results of the subcellular localization experiment revealed that GeERF4B-1 was located in the nucleus. Real time quantitative PCR (RT-qPCR) analysis indicated that GeERF4B-1 was expressed in the root, stem, and leaf of G. elegans, with the highest expression level in the root. Compared with the control, the treatments with a low temperature (4 ℃), methyl jasmonate (MeJA), and abscisic acid (ABA) up-regulated the expression level of GeERF4B-1, which reached the peak at 24-48 h. This result revealed that GeERF4B-1 actively responded to low temperature, MeJA, and ABA stresses. However, both sodium chloride (NaCl) and drought treatments down-regulated the expression of GeERF4B-1. In addition, a prokaryotic expression vector of GeERF4B-1 was constructed, and a fusion protein of approximately 52 kDa was yielded after induced expression. The results of the plate stress assay showed that compared with the control, the prokaryotic strain expressing GeERF4B-1 demonstrated enhanced tolerance to low temperatures and sensitivity to salt and mannitol stresses. This study provides theoretical references and potential genetic resources for breeding G. elegans varieties with stress resistance.
Transcription Factors/metabolism* ; Plant Proteins/metabolism* ; Gelsemium/metabolism* ; Acetates/pharmacology* ; Gene Expression Regulation, Plant ; Phylogeny ; Cold Temperature ; Amino Acid Sequence ; Cyclopentanes/metabolism* ; Oxylipins/metabolism* ; Stress, Physiological/genetics* ; Abscisic Acid/metabolism* ; Cloning, Molecular

Ganoderma lucidum is a mushroom widely used for its edible and medicinal properties. Primary bioactive constituents of G. lucidum are ganoderic triterpenoids (GTs), which exhibit important pharmacological activity. Abscisic acid (ABA), a plant hormone, is associated with plant growth, development, and stress responses. ABA can also affect the growth, metabolism, and physiological activities of different fungi and participates in the regulation of the tetracyclic triterpenes of some plants. Our findings indicated that ABA treatment promoted GT accumulation by regulating the gene expression levels (squalene synthase (sqs), 3-hydroxy-3-methylglutaryl-CoA reductase (hmgr), and lanosterol synthase (ls)), and also activated cytosolic Ca²⁺ channels. Furthermore, under ABA mediation, exogenous Ca²⁺ donors and inhibitors directly affected the cytosolic Ca²⁺ concentration and related gene expression in Ca²⁺ signaling. Our study also revealed that ABA-mediated cytosolic Ca²⁺ played a crucial regulatory role in GT biosynthesis, accompanied by antioxidant defense modulation with increasing superoxide dismutase (SOD) activity and ascorbate peroxidase (APX) activity, and the resistance ability of O₂^•- and glutathione (GSH) contents.
Reishi/metabolism* ; Triterpenes/metabolism* ; Abscisic Acid/metabolism* ; Antioxidants/metabolism*

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*

Glutamate receptor-like (GLR) is an important class of Ca²⁺ channel proteins, playing important roles in plant growth and development as well as in response to biotic and abiotic stresses. In this paper, we performed genome-wide identification of banana GLR gene family based on banana genomic data. Moreover, we analyzed the basic physicochemical properties, gene structure, conserved motifs, promoter cis-acting elements, evolutionary relationships, and used real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) to verify the expression patterns of some GLR family members under low temperature of 4 ℃ and different hormone treatments. The results showed that there were 19 MaGLR family members in Musa acuminata, 16 MbGLR family members in Musa balbisiana and 14 MiGLR family members in Musa itinerans. Most of the members were stable proteins and had signal peptides, all of them had 3-6 transmembrane structures. Prediction of subcellular localization indicated that all of them were localized on the plasma membrane and irregularly distributed on the chromosome. Phylogenetic analysis revealed that banana GLRs could be divided into 3 subclades. The results of promoter cis-acting elements and transcription factor binding site prediction showed that there were multiple hormone- and stress-related response elements and 18 TFBS in banana GLR. RT-qPCR analysis showed that MaGLR1.1 and MaGLR3.5 responded positively to low temperature stress and were significantly expressed in abscisic acid/methyl jasmonate treatments. In conclusion, the results of this study suggest that GLR, a highly conserved family of ion channels, may play an important role in the growth and development process and stress resistance of banana.
Musa/metabolism* ; Phylogeny ; Abscisic Acid/metabolism* ; Temperature ; Stress, Physiological/genetics* ; Hormones/metabolism* ; Gene Expression Regulation, Plant ; Plant Proteins/metabolism* ; Gene Expression Profiling

Iron (Fe) is an important trace element involved in many important plant physiological and metabolic processes such as photosynthesis, respiration and nitrogen metabolism. Plants maintain iron homeostasis through absorption, transporting, storage and redistribution of iron. Iron metabolism is strictly regulated in plants. Iron regulatory transcription factors and iron transporters constitute the regulatory network of plant iron absorption and transport in plants. Ferritin and iron transporter jointly regulate the response to excess iron in plants. In recent years, important progress has been made in understanding how abscisic acid (ABA) regulates iron metabolism in plants. ABA may be used as a signal to regulate the absorption, transportation and reuse of Fe, or to relieve the symptoms of iron stress by regulating the oxidative stress responses in plants. In order to gain deeper insights into the crosstalk of ABA and iron metabolism in plants, this review summarized the mechanisms of iron absorption and transport and metabolic regulatory network in plants, as well as the mechanisms of ABA in regulating iron metabolism. The relationship between ABA and FER-like iron deficiency-induced transcription factor (FIT), iron-regulated transporter 1 (IRT1), and oxidative stress of iron deficiency were highlighted, and future research directions were prospected.
Abscisic Acid/metabolism* ; Gene Expression Regulation, Plant ; Homeostasis ; Iron/metabolism* ; Plants/metabolism* ; Transcription Factors/metabolism*

Seed vigor is a key factor affecting seed quality. The mechanical drying process exerts a significant influence on rice seed vigor. The initial moisture content (IMC) and drying temperature are considered the main factors affecting rice seed vigor through mechanical drying. This study aimed to determine the optimum drying temperature for rice seeds according to the IMC, and elucidate the mechanisms mediating the effects of drying temperature and IMC on seed vigor. Rice seeds with three different IMCs (20%, 25%, and 30%) were dried to the target moisture content (14%) at four different drying temperatures. The results showed that the drying temperature and IMC had significant effects on the drying performance and vigor of the rice seeds. The upper limits of drying temperature for rice seeds with 20%, 25%, and 30% IMCs were 45, 42, and 38 °C, respectively. The drying rate and seed temperature increased significantly with increasing drying temperature. The drying temperature, drying rate, and seed temperature showed extremely significant negative correlations with germination energy (GE), germination rate, germination index (GI), and vigor index (VI). A high IMC and drying temperature probably induced a massive accumulation of hydrogen peroxide (H₂O₂) and superoxide anions in the seeds, enhanced superoxide dismutase (SOD) and catalase (CAT) activity, and increased the abscisic acid (ABA) content. In the early stage of seed germination, the IMC and drying temperature regulated seed germination through the metabolism of H₂O₂, gibberellin acid (GA), ABA, and α-amylase. These results indicate that the metabolism of reactive oxygen species (ROS), antioxidant enzymes, GA, ABA, and α-amylase might be involved in the mediation of the effects of drying temperature on seed vigor. The results of this study provide a theoretical basis and technical guidance for the mechanical drying of rice seeds.
Abscisic Acid/metabolism* ; Antioxidants/pharmacology* ; Catalase/metabolism* ; Gene Expression Regulation, Plant/drug effects* ; Germination ; Gibberellins/metabolism* ; Hydrogen Peroxide/chemistry* ; Malondialdehyde/chemistry* ; Oryza/metabolism* ; Oxygen/chemistry* ; Plant Proteins/genetics* ; Reactive Oxygen Species ; Seeds/metabolism* ; Superoxide Dismutase/metabolism* ; Superoxides/chemistry* ; Temperature ; Weather ; alpha-Amylases/metabolism*

In plants, lipoxygenases (LOXs) play a crucial role in biotic and abiotic stresses. In our previous study, five 13-LOX genes of oriental melon were regulated by abiotic stress but it is unclear whether the 9-LOX is involved in biotic and abiotic stresses. The promoter analysis revealed that CmLOX09 (type of 9-LOX) has hormone elements, signal substances, and stress elements. We analyzed the expression of CmLOX09 and its downstream genes-CmHPL and CmAOS-in the leaves of four-leaf stage seedlings of the oriental melon cultivar "Yumeiren" under wound, hormone, and signal substances. CmLOX09, CmHPL, and CmAOS were all induced by wounding. CmLOX09 was induced by auxin (indole acetic acid, IAA) and gibberellins (GA₃); however, CmHPL and CmAOS showed differential responses to IAA and GA₃. CmLOX09, CmHPL, and CmAOS were all induced by hydrogen peroxide (H₂O₂) and methyl jasmonate (MeJA), while being inhibited by abscisic acid (ABA) and salicylic acid (SA). CmLOX09, CmHPL, and CmAOS were all induced by the powdery mildew pathogen Podosphaera xanthii. The content of 2-hexynol and 2-hexenal in leaves after MeJA treatment was significantly higher than that in the control. After infection with P. xanthii, the diseased leaves of the oriental melon were divided into four levels-levels 1, 2, 3, and 4. The content of jasmonic acid (JA) in the leaves of levels 1 and 3 was significantly higher than that in the level 0 leaves. In summary, the results suggested that CmLOX09 might play a positive role in the response to MeJA through the hydroperoxide lyase (HPL) pathway to produce C6 alcohols and aldehydes, and in the response to P. xanthii through the allene oxide synthase (AOS) pathway to form JA.
Abscisic Acid ; Acetates/chemistry* ; Aldehyde-Lyases/metabolism* ; Aldehydes/chemistry* ; Cucurbitaceae/genetics* ; Cyclopentanes/chemistry* ; Cytochrome P-450 Enzyme System/metabolism* ; Gene Expression Profiling ; Gene Expression Regulation, Plant ; Hormones/metabolism* ; Hydrogen Peroxide/metabolism* ; Intramolecular Oxidoreductases/metabolism* ; Lipoxygenase/metabolism* ; Oxylipins/chemistry* ; Plant Leaves/genetics* ; Plant Proteins/metabolism* ; Promoter Regions, Genetic ; Salicylic Acid/chemistry* ; Seedlings/metabolism* ; Signal Transduction ; Stress, Physiological ; Transgenes

To investigate roles of nitric oxide (NO) signal in accumulations of phenolic acids in abscisic.acid (ABA)-induced Salvia miltiorrhiza hairy roots, S. miltiorrhiza hairy roots were treated with different concentrations of sodium nitroprusside (SNP)-an exogenous NO donor, for 6 days, and contents of phenolic acids in the hairy roots are determined. Then with treatment of ABA and NO scavenger (2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylimidazoline-1- oxyl-3-oxide, c-PTIO) or NO synthase inhibitor (NG-nitro-L-arginine methyl ester, L-NAME), contents of phenolic acids and expression levels of three key genes involved in phenolic acids biosynthesis were detected. Phenolic acids production in S. miltiorrhiza hairy roots was most significantly improved by 100 µmoL/L SNP. Contents of RA and salvianolic acid B increased by 3 and 4 folds. ABA significantly improved transcript levels of PAL (phenylalanine ammonia lyase), TAT (tyrosine aminotransferase) and RAS (rosmarinic acid synthase), and increased phenolic acids accumulations. However, with treatments of ABA+c-PTIO or ABA+L-NAME, accumulations of phenolic acids and expression levels of the three key genes were significantly inhibited. Both NO and ABA can increase accumulations of phenolic acids in S. miltiorrhiza hairy roots. NO signal probably mediates the ABA-induced phenolic acids production.
Abscisic Acid ; pharmacology ; Benzofurans ; metabolism ; Free Radical Scavengers ; pharmacology ; Hydroxybenzoates ; metabolism ; Nitric Oxide ; metabolism ; Phenylalanine Ammonia-Lyase ; metabolism ; Plant Roots ; metabolism ; Salvia miltiorrhiza ; metabolism ; Tyrosine Transaminase ; metabolism

Drought stress exerts a considerable effect on growth, physiology and secondary metabolisms of the medicinal plants. It could inhabit the growth of the medicinal plants but promote secretion of secondary metabolites. Other researches indicated that the medicinal plants could depend on the ABA signaling pathway and secreting osmotic substances to resist the drought stress and reduce the damage by it. The article concludes the changes in growth, physiology, secondary metabolisms and response mechanisms of medicinal plants to drought stress that provides a theoretical basis for exploring the relationship between medicinal plants and drought stress.
Abscisic Acid ; metabolism ; Droughts ; Plant Proteins ; genetics ; metabolism ; Plants, Medicinal ; genetics ; growth & development ; metabolism ; Signal Transduction ; Water ; metabolism