Protein-protein interactions play a key role in cellular signaling, involved in various biological processes. Studies on these interactions are therefore crucial toward understanding the regulatory networks of cellular signaling. It is a standard practice that the protein-protein interactions identified by the yeast two-hybrid system should be independently confirmed by in vitro and in vivo approaches. Pull-down and co-immunoprecipitation (Co-IP) are routine approaches to detect protein-protein interactions. Pull-down assay is used to detect direct or physical interactions between proteins in vitro. In plant biology studies, one of the most convenient methods to detect protein-protein interactions is the transient expression of the target proteins in Nicotiana benthamiana leaves followed by the Co-IP assay. In this paper, we describe the principles and protocols for the GST tag-based pull-down assay and the Co-IP assay of proteins transiently expressed in N. benthamiana leaves, providing a reference for detecting plant protein-protein interactions.

Protein-Protein interactions play important roles in various eukaryotic biological processes. Compared to other techniques measuring protein-protein interactions in plants, the Luciferase Complementation Assay (LCA), based on Agrobacterium-mediated transient expression in Nicotiana benthamiana, is a simple, sensitive, reliable, highly quantitative and low background method that can be easily scaled up for high-throughput interactome studies. Here, we describe a protocol that includes two alternative data collection methods to qualitative and quantitative analyse luminescence or luminous intensity to detect protein-protein interactions in plant cells.

Tea (Camellia sinensis) is one of the most important beverage crops in the world. With the expanding cultivation area, the demand for tea seedlings is increasing. However, there are many problems with the traditional breeding method for tea plants using cuttings, such as low rooting rate, time consumption and difficulties to obtain materials. Therefore, optimizing the cutting method is of great importance for tea production. In this study, we first changed the culture medium to sponges and found that tea cuttings were able to generate new roots within 1 month on sponges, with rooting rate 32.2%. Second, we optimized the cutting materials by using fresh green tea branches in sponges, and the rooting potential of goung branch maintained with one bud and one leaf is better. In addition, we found that supplying rooting powder to sponges significantly promoted callus formation and new root generation from cuttings. In general, the most effective way was to apply 1.25 g∙L ^-1 rooting powder to cuttings for 48 h, for a rooting rate of 42.0%. We have established an effective rooting method for tea cuttings by optimizing the culture medium, cutting materials and adding optimal rooting powder. This method could shorten the rooting time, avoid the restriction of cutting materials, and thus effectively reduce the expense of tea cuttings, which has application prospects in tea production.

It is very important but usually difficult to extract high quality DNA from plants for molecular work since there exist a great deal of polysaccharides, hydroxybenzenes, esters and other secondary metabolities. In this paper we provide a simple modified CTAB (mCTAB) protocol for extracting plant DNA. The mCTAB method protocol includes 18 steps. (1) Weigh ca. 20 mg of dry plant tissue and ground into powder with sand using a mortar or a pestle. Remove the powder into a 2.0 mL microcentrifuge tube. (2) Add 1.0 mL pre-cooled buffer A (Table 2) to the tube, mix well and incubate the tube on ice for 15 min. Mix sample 2–3 times during incubation by inverting the tube. (3) Centrifuge the tube at 7 000 ×g for 10 min. Discard the supernatant liquid by pouring it out of the tube. (4) Repeat step 2 and 3 until the supernatant is not viscous. (5) Add 0.7 mL buffer B (Table 3), mix well and incubate at 65°C for 90–120 min. Mix the sample several times during incubation by inverting the tube. (6) Centrifuge at 10 000 ×g for 10 min, remove the supernatant to a new microcentrifuge tube. The precipitate is reusable from step 5 if necessary. (7) Add 0.7 mL CI (chloroform: isoamyl alcohol=24:1, v/v), mix it well for 10 min by inverting tube gently. (8) Centrifuge at 10 000 ×g, for 10 min, carefully remove the supernatant to a new 1.5 mL microcentrifuge tube. (9) Repeat step 7 and 8 until no precipitate appearing between the two layers of liquid after centrifuging. (10) Add 0.5 mL pre-cooled isopropanol, carefully mix well . Incubate at –20°C for 20 min. (11) Centrifuge at 10 000 ×g for 10 min, discard the supernatant, centrifuge the tube briefly to collect the remaining liquid and remove it by pipetting. (12) Add 0.1 mL RNase (100 mg·L^–1) and incubate at 37°C for 30–60 min. (13) Add 0.1 mL ddH₂O, 0.1 mL 5 mol·L^–1NaCl and 0.8 mL pre-cooled ethanol (95%), carefully mix well. (14) Centrifuge at 10 000 ×g for 10 min, discard the supernatant. (15) Add 0.5 mL 75% ethanol, re-suspend the pellet, centrifuge at 10 000 ×g for 2 min, discard the supernatant. (16) Repeat step 15. (17) Add 0.1 mL TE to dissolve DNA after ethanol has evaporated. (18) Estimate the concentration and the purity of the DNA solution. Store it at 4°C for immediate use, at –20°C for short time storage and –80°C for long time storage. We compared our protocol with four frequently used and commercially available kits. The result showed that our mCTAB method yielded much more DNA of high quality that is suitable for PCR amplification but with much lower cost.

Protein phosphorylation is one of the important protein posttranslational modifications that is involved in the regulation of most cellular processes in plants. Protein kinases catalyze the phosphorylation by transferring the phosphate group in ATP to the substrate proteins. The phosphate is usually covalently linked to the hydroxyl group of specific amino acid residues in the substrates by an ester bond. The mostly studied phosphorylation sites are serine, threonine, and tyrosine residues. Here, we present protocols and related tips for the in vitro and in vivo protein phosphorylation assays.

Domestication of wild plants was crucial for human settlement and the development of civilization, which arose independently in many different geographic areas on different wild species. However, these crops underwent variant domestication process displaying the ‘domestication syndrome’ with a common suite of traits. The systematical analysis of convergent selection at genome level may provide important information and genetic resources for crop breeding. Recently, a team led by Xiaohong Yang and Jiansheng Li from Chinese Agricultural University and Jianbing Yan from Huazhong Agricultural University reported the genetic basis of convergent selection between maize and rice at both single gene and whole genome levels. Particularly, they found the maize KRN2 and rice OsKRN2 genes experienced convergent selection and regulated grain number and yield in a similar pathway. Moreover, they identified a large number of orthologous gene pairs that underwent convergent selection during maize and rice evolution, which were enriched in certain pathways including starch metabolism, sugar and coenzyme synthesis. This significant work not only cloned KRN2/OsKRN2 orthologous gene pairs with great value in maize and rice breeding, but also revealed the convergent selection between maize and rice at the genome level, providing critical foundations for studying the molecular basis of domestication syndrome and their applications in breeding practices.

Chinese researchers in plant sciences published more original papers in international top journals and mainstream journals of plant science than last year, and made remarkable achievements in several areas. Research on the supramolecular structure and function of diatom photosynthetic membrane proteins was selected in the top 10 achievements in Chinese Sciences in 2019 and the top achievements of Chinese Life Sciences in 2019. Research on the structure and function of plant disease-resistant bodies was selected in the top 10 achievements of Chinese Life Sciences in 2019. In this review, we provide a commentary on the significant progress made by Chinese researchers in plant sciences this year.

Light is an important environmental factor that affects plant growth and development. Flowering is the most important event in higher plants. Plants perceive accurately changes in the surrounding light environments by photoreceptors, thus activating a series of signaling transduction processes and initiating flowering. Here, we summarized the current understanding of the structural characteristics and physiological functions of various photoreceptors in higher plants. We reviewed the molecular mechanisms of phytochromes, cryptochromes, and FKF1/ZTL/LKP2 in mediating signaling transduction and flowering time, including transcriptional and post-transcriptional regulation of CO and FT. Finally, we described the advances in photoreceptor-mediated-integration of light, temperature, and gibberellin signals in regulating flowering. Future directions in this area were also proposed.

Proximity labeling (PL), a recently developed technique to detect protein-protein interactions and subcellular structural proteomes in living cells, has been successfully applied in various animal and plant systems. Proximity labeling is conducted by fusing an engineered enzyme with catalytic activity to a protein of interest (bait protein). With the catalysis of the enzyme, small molecular substrates such as biotin are covalently linked to endogenous proximal proteins, which can be further enriched and analyzed to identify the interactome of the bait protein. TurboID, a biotin ligase produced by directed evolution, has the advantages of non-toxicity and high catalytic efficiency. Using TurboID-based proximity labeling to analyze proximal proteins of bait proteins, we can study transient or weak protein interactions, which helps to understand the complex biological processes occurring inside cells. Here, we describe methods and related tips for TurboID-based proximal labeling in Arabidopsis thaliana, and hope to provide a reference for studying plant protein-protein interactions.

Abscisic acid (ABA) plays a key role in the growth, development and stress condition of plants. The process of plant response to ABA is completed by signal recognition, transduction, and response cascades. The core ABA signaling pathway consists of receptor RCAR/PYR/PYLs, phosphatase PP2Cs, kinase SnRK2s, and transcription factors and ion channel proteins. Post-translational modifications (PTMs) of proteins such as phosphorylation, ubiquitination, small ubi- quitin-related modifier (SUMOylation) and redox modifications plays an important role in ABA signaling. This review focused on the role of modifications in the core ABA signaling pathway.

The ABC model was established in late 1980s to explain the genetic interactions between floral homeotic mutations. As the progress in flower developmental genetics, the ABC model was expanded to the ABCD model with the introduction of D class genes for ovary identity. More recently, a A-E model was proposed and will be discussed in this short review.

TDZ(N-phenyl-N’-1,2,3-thidiazol-5-yl-urea) is a substituted phenylurea compound and has emerged as a highly efficacious bioregulant of morphogenesis in the tissue culture of many plant species. Application of TDZ induces a diverse array of cultural responses ranging from induction of callus to formation of somatic embryos.TDZ exhibits the unique property of mimicking both auxin and cytokinin effects on growth and differentiation of cultured explants. The recent app roaches applied to study the morphogenic events initiated by TDZ are clearly beginning to reveal the details of a variety of underlying mechanisms. Various reports indicate that TDZ may act through modulation of the endogenous plant growth substances, or as a result of induced stress. The other possibilities include the modification in cell membranes, energy levels, nutrient uptake, or nutrient assimilation. In this review, several of these possibilities are presented and summarized in light of recently published studies on characterization of TDZ-induce dmorphogenic effects.

The plant can produce hairy roots after infection by Agrobacterium rhizogenes harboring Ri plasmids. Spinach (Spinacia oleracea) is a common edible vegetable, and its hairy root system has yet to be reported. In this study, A. rhizogenes LBA9402 was screened to be suitable for hairy root induction of spinach. The highest induction efficiency, 16%, was reached when the spinach stem was infected by LBA9402. Hairy roots grew vigorously on SH solid medium without exogenous hormones. The hairy roots of spinach were white and had enormous root hairs. The regeneration plant obtained from the callus redifferentiated from spinach hair roots; the rate of regeneration was 8%. In addition, Ri T-DNA and Ti T-DNA carrying rolB genes and GFP gene, respectively, were co-transferred into cells of spinach and produced transgenic hairy roots. PCR analysis and fluorescence microscopy assays showed rolB gene and GFP gene in the hairy roots of spinach and expressed stably; the rate of co-transformation was 50%.

Recent advances in genomics technologies have greatly accelerated the progress in both fundamental plant science and applied breeding research. Concurrently, high-throughput plant phenotyping is becoming widely adopted in the plant research, promising to alleviate the phenotypic bottleneck. Plant phenomics is a science that studies the growth, performance and composition of plants. It can effectively track the relationship among genotypes, environmental factors, and phenotypes. It is a key research field to break through the future crop research and application. In this paper, three stages of plant phenotypic analysis are discussed, that is, from the initial stage of manual measurement and counting and the assistant stage of specific measurement tools to the stage of high throughput phenomics. It is proposed that the development of plant phenotypic acquisition and analysis is driven by three important factors: phenotypic research facilities, phenotype acquisition technology and image analysis methods. Finally, the plant phenomic research is prospected.

Auxin is one of the most important plant hormones and plays a key role in regulating plant growth and development. In plants, early auxin responsive gene families, such as Aux/IAA (Auxin/Indole acetic acid repressors), GH3 (Gretchen Hagen3) and SAUR (Small Auxin up RNA), are rapidly induced and up-regulated by auxin treatment. Aux/IAA gene family is generally composed of four conserved domains. Domain I inhibits the expression of downstream genes in the auxin signaling pathway, and domain II is mainly regulated by Transport Inhibitor Response 1 (TIR1) in auxin signal transduction, thus affecting the stability of Aux/IAA. Domain III/IV regulates auxin signaling by interacting with Auxin Response Factor (ARF). Aux/IAA gene family has been reported to play an important role in organ development, root formation, stem elongation and leaf expansion in dicotyledonous Arabidopsis thaliana while in monocotyledonous rice (Oryza sativa) and wheat (Triticum aestivum), Aux/IAA mainly affects root development and plant architecture. However, the functions of most Aux/IAA genes remain unclear and need to further study. In this article, we reviewed the structure and function of Aux/IAA protein, and the auxin signal transduction pathway in Arabidopsis, cereal crops and other plants to provide clues for fully revealing the biofunction of the Aux/IAA gene family.

Genome-wide association study (GWAS) is a general approach for unraveling genetic variations associated with complex traits in both animals and plants. The development of high-throughput genotyping has greatly boosted the development and application of GWAS. GWAS is not only used to identify genes/loci contributing to specific traits from diversenatural populations with high-resolution genome-wide markers, it also systematically reveals the genetic architecture underlying complex traits. During recent years, GWAS has successfully detected a large number of QTLs and candidate genes associated with various traits in plants including Arabidopsis, rice, wheat, soybean and maize. All these findings provided candidate genes controlling the traits and theoretical basis for breeding of high-yield and high-quality varieties. Here we review the methods, the factors affecting the power, and a data analysis pipeline of GWAS to provide reference for relevant research.

Here we characterize three traditional woody oil crops, Camellia oleifera, Juglans regia, and Xanthoceras sorbifolium, and three emerging woody oil crops, Paeonia suffruticosa, Plukenetia volubilis, and Acer truncatum. We review the germplasm resources, fatty acid composition, active compounds and molecular biology of lipid synthesis and metabolism of these crops in detail. The description can help in planting the resources according to local conditions, exerting the advantage of special woody oils, and supplying the deficiency of the herb oil crops. It could increase the quantity of vegetable oil and improve nutrition awareness and health level by a return to nature and the protection of resources. Finally, we analyze the problems in use of the woody oil crops and suggest directions for further exploration.

S-nitrosylation is an important protein posttranslational modification, involved in covalently linking a nitric oxide (NO) molecule to the thiol group of a cysteine residue to generate S-nitrosothiols. S-nitrosylation regulates multiple biological processes by modulating protein activity, stability, subcellular localization and protein-protein interactions. The biotin-switch assay is one of the most-often used methods to detect and analyze protein S-nitrosylation. In principle, the free thiols in a target protein are first blocked, followed by reducing the S-nitrosothiols of the target protein to free thiols by ascorbate, which are subsequently labelled by biotin to form biotinylated proteins. The biotin-labelled sample was assayed by immunoblotting and mass spectrometry. Here, we present detailed experimental procedures for the in vitro and in vivo biotin-switch methods and give advice on key troubleshooting solutions.

Laccase belongs to the family of multicopper oxidases. In this review, the molecular structure, substrate specificity, catalytic mechanism and other physicochemical parameters of laccase are summarized. The role of laccase in plant cell wall formation and pathogen virulence are discussed. For applications, we pay special attention to the potential of laccase in bioremediation.

In the evolution of plants, the leaf is more sensitive and plastic to environmental change than other organs; environment change usually results in morphological and anatomical responses of the leaf, including morphology (length, width, thickness), surface (stomata, epidermis, attachment) and mesophyll (palisade, spongy, intercellur space, sclerified, vein). This review describes the above-mentioned adaptive characters of terrestrial plant leaves to alterations in environmental factors such as water, temperature, light and CO2 concentration and combined effects, and analyzes recent research, then indicates the emphasis and direction of future study.

Retrotransposons are a class of eukaryotic transposable elements, consisting of the long terminal repeat (LTR) and non-LTR retrotransposons. Retrotransposons are ubiquitous in the plant kingdom by high copy number and can be transmitted between generations by vertical transmission and between species by horizontal transmission. The same family retrotransposons presented highly heterogeneous populations in all higher plant genomes. Many of the plant retrotransposons are transcriptionally activated by various biotic and abiotic stress factors. Retrotransposons are used as molecular markers for their traits. S-SAP, IRAP, REMAP and RBIP are developed and will be applied widely in gene mapping, genetic biodiversity and phylogeny studies, and cultivar certification.

Reversible protein phosphorylation is a common mechanism regulating plant signaling pathways. Phosphorylation of key components in plant-pathogen interactions affects the activation of defense signaling. Many pathogens attack the plant immune system and enhance pathogenic toxicity by disturbing the phosphorylation status of defense regulators. In this review, we summarize the phosphorylation of regulators in plant defense responses and its regulating effect in plant immunity. Understanding the phosphorylation of key regulators in the plant-pathogen interaction may help to explore new mechanism of plant immune regulation. This review may provide support and a basis for studying new approaches of broad-spectrum disease resistance.

In this study, the chloroplast genomes from 19 species (11 genera) in Oleaceae were compared to reveal the general characteristics and structural variations. The chloroplast genome sizes in Oleaceae were 154-165 kb, and the differences were mainly caused by the length of large single-copy regions. The chloroplast genome sizes of 3 species from the genus Jasminum differed greatly from that for other species; in addition, the introns from the clpP and accD genes were lost in Jasminum. Synteny analyses showed several gene rearrangements in 3 Jasminum species that were probably caused by inversions. The boundary genes between IRb/small single copy (SSC) and SSC/IRa regions in 3 Jasminum species differed from others. Repeat sequences and simple sequence repeat detection demonstrated that Jasminum had significant differences in repeat number and repeat length as compared with other genera. On the basis of shared protein-coding genes among 19 species, Abeliophyllum distichum and Forsythia suspensa were the early-diverging clades in Oleaceae.

Plant science in China continued to maintain high-speed progress in 2017, with frequent remarkable achieve- ments and a steady increase in the number of original papers published in international top journals. Researchers in plant science in China have made brilliant achievements, such as the discovery of new broad-spectrum disease resistance mechanisms, the genetic basis and mechanism of rice broad-spectrum disease resistance, and the mechanism of Phytophthora infestation. Two achievements were included in the “Breakthrough of the year: The top 10 scientific achievements of life science in China in 2017”. Rice biology, evolution and genomics and hormone biology were highlighted. Also, academician Li Jiayang, who researches the molecular network of higher plants and metabolic pathway as well as rice design breeding, won first prize of National Natural Science in 2017 for his research "Molecular Mechanisms and Variety Design of High Yield and Quality Characters of Rice". This groundbreaking contribution with significant international impact marks the leading position of Chinese plant science in the international scientific frontier of this field. In this review, we give an overview of the significant progress made in plant science in China in 2017, review the latest findings and hot events in plant science in 2017, and share the great achievements made by Chinese scientists.

Plants have evolved numerous strategies to adapt to complex and changing surroundings. Plants have a wide range of systemic responses induced by local stresses to precisely regulate plant growth, development and adaptability to environments. Plant systemic responses induce whole-plant signaling transmission at first, called systemic signaling. When subjected to local stresses, plants trigger chemical molecules in local cells, such as biosynthesis and/or signaling transduction of the phytohormones jasmonic acid and methyl salicylate. Accompanied by a series of complex signal cascades, multiple signal components work together to activate the systemic response. In the past several years, pioneer studies demonstrated that phytohormones, small peptides and several types of RNAs are considered key components of slow-moving systemic signaling, and rapid systemic signals include reactive oxygen species, calcium signals and electrical signals. Plant systemic signaling is essential for plant growth, development and adaptation to the environment, and the precise transmission mechanism is worthy of further investigation. In this review, we describe the research progress in plant systemic signaling transmission and response to the environment and summarize several key systemic signal components and their transmission mechanism. Finally, the potential challenges of future research in this research field are discussed.

In order to adapt to various living environments, plants have gradually evolved a complex immune system against the infections caused by pathogens. The nucleotide-bounding leucine-rich repeat proteins (NLRs) act as typical resistance (R) proteins which commonly exist in plants and play an important role in regulating plant disease resistance. In this paper, the research progress of NLRs is reviewed from the aspects of NLR protein structures, signal transductions and regulations of plant disease resistance.

In 2020, the numbers of original research articles published by Chinese plant scientists in international multidisciplinary journals and mainstream plant science journals increased significantly compared with that in 2019, and important advances have been made in the fields of plant development, stress tolerance, crop biology, genomic phylogenetics and evolution. Among them, “Cloning, functional characterization and application in wheat breeding of the Fhb7 resistant gene to Fusarium head blight”, and “A new mechanism to improve the nitrogen-utilization efficiency in crops” were selected as two of the “Top Ten Advances in Life Sciences in China” in 2020. Here we summarize the achievements of plant science research in China in 2020, and briefly introduce 30 representative important research advances, so as to help readers understand the developmental trend of plant sciences in China, and conduct their future research to meet the national needs.

Cold (chilling or freezing) stress affects the growth and geographical distribution of plants, and it is one of the main factors that restricts crop yield and quality. Plants respond to cold signals by activating a series of effectors to adapt to cold stress. MAP protein kinase family plays a crucial role in plant response to environmental stresses, but it remains unclear whether they are directly involved in perception, transduction or/and networks in cold signaling. Recently, three research groups in China highlight the important role of MAP kinase in cold signaling transduction in Arabidopsis thaliana and rice, respectively. Low temperature activates MPK kinase that phosphorylates the ICE1 protein. Stability of ICE1 is controlled by MAP kinase mediated ICE phosphorylation, thus regulating freezing and chilling tolerance in plants. Their studies have advanced our understanding of the ICE1-mediated network of plant cold responses, which is an important breakthrough in the field. The outcome of these studies would provide a powerful theoretical basis for future molecular design breeding in crops.

The metabolome refers to all the low-molecular-weight metabolites present in an organism or cell in a particular physiological period. The term plant metabolomics is used for defining the technology of high-throughput, nonbiased analyses of the metabolome of plant extracts. Research into plant metabolomics has advanced greatly during recent years. This review introduces the definition, history and research approaches of plant metabolomics and gives several typical examples to elucidate the application of plant metabolomics.

Plant secondary cell walls (SCWs) contain cellulose, hemicellulose and lignin, which endow the cell walls with mechanical strength and hydrophobicity. This characteristic is very important for plant upright growth, water and nutrient transport, and resistance to biotic and abiotic stresses. In this review, we summarize the transcription factors regulating SCW biosynthesis and their regulatory mechanisms, including NAC transcription factors functioning as first-layer master switch, the AtMYB46/AtMYB83 and their downstream regulators serving as secondary-layer master switch, as well as the other transcription factors involved in the regulation of biosynthesis of the SCW. The future research contents and methods are also prospected in order to provide reference for further research on the transcriptional regulatory network of SCW biosynthesis.

Post-translational modification by small ubiquitin-related modifiers (SUMOs) is an important regulatory process to modulate protein function. This paper summarizes the SUMOylation pathway in plants; the pathway consists of SUMO molecules, a SUMO conjugation enzyme cascade and de-conjugation enzymes. Nascent SUMOs are processed by SUMO-specific proteases, then mature SUMOs are conjugated to substrate proteins by sequential action of three groups of enzymes: SUMO-activating enzymes (E1), SUMO-conjugating enzymes (E2) and SUMO-ligating enzymes (E3). SUMOylation can be reversed by SUMO-specific proteases. SUMO modification in plants is involved in flowering induction, hormone signaling, pathogen defense and stress response.

The chlorophyll fluorescence kinetics technique is referred to as a quick and nonintrusive probe in the studies of plant photosynthetic function. But there are irregularity and confusion in the nomenclature and interpretation of the parameters. In this paper we discuss the problems and try to solve them.

Plant plasma membrane H+ -ATPase was a P-type proton pump. The transmembrane electrochemical gradients generated by the enzyme was the primary force for the transmembrane transports. Researches indicated that the plasma membrane H+ -ATPase plays important roles in the growth and development in plants. It was called the "master enzyme" in plant cells; Great progress had been made about the biochemical character, gene expression and regulation, structure and function of the H+ -ATPase in recent years. In this article the biochemical character, molecular structure, regulatory mechanism and physiological roles of the plasma membrane H+ -ATPase were reviewed.

Terpenoids are the most abundant structural and quantitative compounds in plant secondary metabolites, and they play an important role in the interaction of plants with the external environment. Transcription factors have the function of regulating the expression level of genes in the secondary metabolic pathway and regulating the production of secondary metabolites. In the last decades, there are six major transcription factor families involved in the terpenoids biosynthesis (AP2/ERF, bHLH, MYB, NAC, WRKY and bZIP). In this study, we reviewed the structure characteristics, regulatory mode, and research advances of several important transcription factor families in the plant terpenoids biosynthesis, and hope to further enrich the regulatory network of terpenoids synthesis, and provide a reference for molecular breeding, high-quality cultivation and biological control in relevant to terpenoid biosynthesis.

The Arnon method is the most classical and common method for extracting and determining chlorophyll. De- spite many improvements to this method, severe problems remain, such as inaccurate test wavelength, wrong content formula, low extraction speed, large errors in results, and tedious operation process. We present a fast two-step extraction and determination method for chlorophyll. The first step is extracting chlorophyll with dimethyl sulfoxide (DMSO) at high temperature, then diluting the chlorophyll solution with 80% acetone. Chlorophyll content determined by this method can be completed within 3 h. The optimal experimental conditions for extraction and the accurate formula for chlorophyll content were obtained by analyzing extraction temperature, extraction time, dilution ratio and absorption spectroscopy. The merits and reliability of this method were tested with some typical plant materials. The method is described as follows: Cut the plant material into a 1 mm wide filament or small pieces and place 50-100 mg plant material into a 10 mL gradu- ated test tube with a stopper. Then add 2 mL DMSO into the test tube and dip the plant material into DMSO. Place the tubes into a 65°C incubator away from the light until all plant material turns white or transparent. As the liquid cools, add 8 mL 80% (v/v) acetone to dilute DMSO, mix well, then determine absorbance at 663.6 and 646.6 nm by spectrophoto- metry. Chlorophyll concentration can be calculated with the following formulas: C_a (mg∙L^-1)=12.27A_663.6-2.52A_646.6; C_b (mg∙L^-1)=20.10A_646.6-4.92A_663.6; C_T=C_a+C_b=7.35A_663.6+17.58A_646.6.

Plant root tips can sense the moisture gradient in soil and grow toward the higher water potential region. This unique response is called the hydrotropic response or hydrotropism. Hydrotropism plays a key role for plants to efficiently obtain water from soil. The root hydrotropic response has become one of the hot topics in plant biology. However, the detailed molecular mechanisms controlling the root hydrotropic response are poorly understood. Previous studies de- monstrated that MIZ1 and GNOM can positively regulate the hydrotropic response. Several phytohormones, light, ROS and Ca²⁺ were also thought to mediate the root hydrotropic response, but their detailed molecular mechanisms are not yet elucidated. This review highlights the research history and factors of hydrotropic response and identification and characterization of key regulators of hydrotropic response, to give a more comprehensive understanding of research progress in the plant hydrotropic response. We provide perspectives on possible future research directions.

Purple acid phosphatases (PAPs) are members of the metallo-phosphoesterase family identified from a wide range of plants. They are characterized by the presence of five conserved structure motifs and seven amino acid residues in the C-terminal. PAPs have mostly been studied for their potential involvement in phosphorus acquisition and redistribution because of their ability to catalyze the hydrolysis of activated phosphate esters and anhydrides under acidic conditions. Recent studies also showed that PAPs play important roles in modulating plant carbon metabolism, cell wall synthesis and pathogen resistance, etc. This review focuses on the structure, family members and regulatory factors of PAPs, with special emphasis on the recent progress of their biological functions, which will provide theoretical reference for further study of PAPs in plants.

Plants have evolved to maintain the dormancy of freshly harvested seeds, which ensures that seeds do not germinate until environmental conditions are optimal. Therefore, dormancy helps seeds spread over long distances to ensure the survival of species. The transition from dormancy to germination is crucial to plant survival and for promoting yield and quality in agricultural production. Seed dormancy and germination are precisely regulated by diverse endogenous hormones and light signals. Light cues regulate seed dormancy and germination by affecting abscisic acid/gibberellic acid biosynthesis and signals. In this review, we summarize the key roles of the hormone pathway and light signal transduction pathways in regulating seed dormancy and germination. We also discuss the interactions (crosstalk) between phytohormone signals and light signals in seed dormancy and germination, in order to apply reference for regulating seed dormancy and germination by using light and hormones in agricultural production.

Ubiquitin activating enzyme (E1), ubiquitin conjugating enzyme (E2) and ubiquitin protein ligase (E3) are the key enzymes of ubiquitin modification of substrate proteins. There are large amounts of genes encoding these ubiquitination enzymes in all eukaryotic genomes. Analyzing the biochemical characteristics and specificity of these enzymes and their substrate proteins is important for their functional study. Here we describe a simple and fast method for in vitro ubiquitination assay. In the presence of E1 and ubiquitin, E2 activity can be determined by detecting the DTT-sensitive thio-ester formation. The E3 activity of a putative protein as well as the E2-E3 or E3-substrate specificities can also be explored by in vitro ubiquitination assay. This system is mainiy based on proteins from Arabidopsis, which includes most varieties of Arabidopsis E2 proteins that are tested with several RING-finger type E3 ligases. This system facilitate not only the exploration of E3 activity in combination with various Arabidopsis E2 members but also the study of E2-RING E3 and RING E3-substrate specificities. This system is suitable for the ubiquitination assays of eukaryotic proteins, especially for plant proteins.