WRKYs is a unique family of transcription factors (TFs) in plants, and belongs to the typical multifunctional regulator. It is involved in the regulation of multiple signaling pathways. This type of transcription factor is characterized to contain about 60 highly conservative amino acids as the WRKY domain, and usually also has the Cys2His2 or Cys2His-Cys zinc finger structure. WRKYs can directly bind to the W-box sequence ((T)(T) TGAC (C/T)) in the promoter region of the downstream target gene, and activate or inhibit the transcription of the target genes by interacting with the target protein. They may up-regulate the expression of stress-related genes through integrating signal pathways mediated by abscisic acid (ABA) and reactive oxygen species (ROS), thus playing a vital role in regulating plant response to abiotic stresses. This review summarizes the advances in research on the structure and classification, regulatory approach of WRKYs, and the molecular mechanisms of WRKYs involved in response to drought and salt stresses, and prospects future research directions, with the aim to provide a theoretical support for the genetic improvement of crop in response to abiotic stresses.
Transcription Factors/genetics* ; Abscisic Acid ; Amino Acids ; Droughts ; Stress, Physiological/genetics*

Galactinol synthase (GolS) genes play important roles in plant response to abiotic stress. In this research, the plant expression vector of soybean GmGolS2-2 gene was constructed and transformed into tobacco to study the drought tolerance of transgenic tobacco. A GmGolS2-2 gene with 975 bp coding sequence was cloned from soybean leaves by reverse transcription-polymerase chain reaction (RT-PCR). GmGolS2-2 was linked to the plant expression vector pRI101 by restriction enzyme sites Nde Ⅰ and EcoR Ⅰ, and transformed into tobacco by leaf disc method. Genomic DNA PCR and real-time PCR showed that three GmGolS2-2 transgenic tobacco plants were obtained. The growth status of GmGolS2-2 transgenic tobacco under drought stress was better than that of wild-type tobacco. After drought stress treatment, the electrolyte leakage and malondialdehyde content of transgenic tobacco were lower than those of wild-type tobacco, but the proline content and soluble sugar content were higher than those of wild-type tobacco. The results of real-time PCR showed that the heterologous expression of GmGolS2-2 increased the expression of stress-related genes NtERD10C and NtAQP1 in transgenic tobacco. The above results indicated that GmGolS2-2 improved drought resistance of transgenic tobacco.
Drought Resistance ; Tobacco/genetics* ; Soybeans/genetics* ; Plant Proteins/metabolism* ; Plants, Genetically Modified/genetics* ; Stress, Physiological/genetics* ; Droughts ; Gene Expression Regulation, Plant

To explore the changes and the reaction mechanisms between soil microecological environment and the content of secon-dary metabolites of plants under water deficit, this study carried out a pot experiment on the 3-leaf stage seedlings of Rheum officinale to analyze their response mechanism under different drought gradients(normal water supply, mild, moderate, and severe drought). The results indicated that the content of flavonoids, phenols, terpenoids, and alkaloids in the root of R. officinale varied greatly under drought stresses. Under mild drought stress, the content of substances mentioned above was comparatively high, and the content of rutin, emodin, gallic acid, and(+)-catechin hydrate in the root significantly increased. The content of rutin, emodin, and gallic acid under severe drought stress was significantly lower than that under normal water supply. The number of species, Shannon diversity index, richness index, and Simpson index of bacteria in the rhizosphere soil were significantly higher than those in blank soil, and the number of microbial species and richness index decreased significantly with the aggravation of drought stresses. In the context of water deficit, Cyanophyta, Firmicutes, Actinobacteria, Chloroflexi, Gemmatimonadetes, Streptomyces, and Actinomyces were the dominant bacteria in the rhizosphere of R. officinale. The relative content of rutin and emodin in the root of R. officinale was positively correlated with the relative abundance of Cyanophyta and Firmicutes, and the relative content of(+)-catechin hydrate and(-)-epicatechin gallate was positively correlated with the relative abundance of Bacteroidetes and Firmicutes. In conclusion, appropriate drought stress can increase the content of secondary metabolites of R. officinale from physiological induction and the increase in the association with beneficial microbe.
Rhizosphere ; Rheum ; Droughts ; Soil ; Catechin ; Emodin ; Bacteria/metabolism* ; Water/metabolism* ; Firmicutes ; Soil Microbiology

Heat stress transcription factors (Hsf) family is one of the most important transcription factor families in plants, and plays an important role in the growth and development of plants when encountering abiotic stresses such as heat, drought, and heavy metals. In this study, 20 SpbHsf genes were identified from the full-length transcriptome database of Setcreasea purpurea, and the structure and function of the Hsf gene family were analyzed using bioinformatics tools and qRT-PCR. The results showed that all SpbHsf proteins were hydrophilic. There were 12 SpbHsf proteins located in the nucleus, and the content of α-helix and random coil in the secondary structure of all SpbHsf proteins was high. The SpbHsf genes are divided into three subfamilies, each of which contains unique conserved motifs. All SpbHsf proteins contain DBD and HR-A/B domains. Phylogenetic analysis showed that OsHsf in Oryza sativa protein had the highest homology with SpbHsf protein. All the 20 SpbHsf genes were expressed in the root tissues of S. purpurea. Among them, 8 were significantly up-regulated while 8 were significantly down-regulated under Cu²⁺ stress. This study may help better understand the function and expression pattern of the S. purpurea Hsf gene family.
Droughts ; Gene Expression Regulation, Plant ; Heat Shock Transcription Factors/metabolism* ; Humans ; Phylogeny ; Plant Proteins/metabolism*

Galactinol synthase (GolS) is a key enzyme in the biosynthetic pathway of raffinose family oligosaccharides (RFOs) and plays an important role in plant responses to abiotic stresses. However, the molecular characteristics of the GolS family members in soybean was not well-known. In this study, six members of GmGolS gene family were genome-widely identified, and their physicochemical properties, chromosomal localization, evolutionary relationship, gene structure, conserved motifs, secondary structure, tertiary structure, tissue-specific expression patterns and the expression levels under salt and drought stresses were analyzed. The results showed that six soybean GolS genes were unevenly distributed on four chromosomes, the range of the isoelectric points of six GmGolS proteins was 5.45-6.08, the molecular weight range was 37 567.07-38 817.59 Da, and the number of amino acids was 324-339 aa. The results of subcellular localization showed that 4 proteins were located in the chloroplast, and 2 proteins in the cytoplasm. Phylogenetic tree analysis showed that the members of the soybean GolS gene family were closely adjacent to each other, and were evolutionarily conservative. Six gene members contain 3 or 4 exons. Prediction of secondary and tertiary structures showed that the spatial structure of proteins of all family members was mainly composed of α-helix and random coil structure, with less β-turn and extended chain structure. Tissue-specific expression analysis showed that six GmGolS members expressed to variable degrees in seeds, roots, root hairs, flowers, stems, pods, nodules and leaves. Expression analysis based on qRT-PCR showed that all GmGolS genes showed different degrees of up-regulated expression under salt and drought treatment, indicating that these genes may be related to the response of plants to salt-tolerance and drought-resistance. These results may facilitate subsequent functional analysis of soybean GolS genes.
Droughts ; Soybeans/genetics* ; Phylogeny ; Plant Proteins/metabolism* ; Stress, Physiological/genetics* ; Plants/metabolism* ; Gene Expression Regulation, Plant

The NAC(NAM/ATAF/CUC) transcription factors are members of the largest transcriptional gene family in plants and play an essential role in the response of plants to drought stress. To identify the number and function of the NAC gene family in Carthamus tinctorius, the present study adopted bioinformatics methods to identify NAC gene family members based on the whole genome data of C. tinctorius, and analyzed their physicochemical properties, chromosomal location, phylogenetic relationship, gene structure, conserved domain, and conserved motif. Meanwhile, the real-time fluorescence-based quantitative RT-PCR(qRT-PCR) was used to analyze the transcription level of four NAC genes under drought stress in different time. The results showed that C. tinctorius contained 87 NAC genes unevenly distributed on 11 chromosomes, while no NAC gene was found on chromosome 12. The encoded proteins were 103-974 amino acids and the number of CDS ranged from 3 to 9. According to the phylogenetic relationships, 87 NAC genes were clustered into17 subfamilies. The analysis of conserved domains and motifs revealed that most of the genes contained five conserved subdomains, A-E and motif2 was the most conserved among NAC genes. The expression pattern analysis showed that the transcription levels of four NAC genes related to drought resistance were all up-regulated after drought stress treatment for different time, suggesting that these four NAC genes may be related to drought resistance of C. tinctorius. This study is expected to provide a theoretical basis for further functional analysis of NAC transcription factors in C. tinctorius and references for the cultivation of drought-tolerant C. tinctorius varieties.
Droughts ; Carthamus tinctorius/genetics* ; Gene Expression Regulation, Plant ; Plant Proteins/metabolism* ; Phylogeny ; Transcription Factors/metabolism* ; Stress, Physiological/genetics* ; Multigene Family

Lipids are important components of living organisms that participate in and regulate a variety of life activities. Lipids in plants also play important physiological functions in response to a variety of abiotic stresses (e.g. salt stress, drought stress, temperature stress). However, most research on lipids focused on animal cells and medical fields, while the functions of lipids in plants were overlooked. With the rapid development of "omics" technologies and biotechnology, the lipidomics has received much attention in recent years because it can reveal the composition and function of lipids in a deep and comprehensive way. This review summarizes the recent advances in the functions and classification of lipids, the development of lipidomics technology, and the responses of plant lipids against drought stress, salt stress and temperature stress. In addition, challenges and prospects were proposed for future lipidomics research and further exploration of the physiological functions of lipids in plant stress resistance.
Droughts ; Gene Expression Regulation, Plant ; Lipids ; Plants ; Stress, Physiological

With the constant change of global climate, plants are often affected by multiple abiotic stresses such as heat stress, drought stress, cold stress and saline-alkali stress. Heat shock transcription factors (HSFs) are a class of transcription factors widely existing in plants to respond to a variety of abiotic stresses. In this article, we review and summarize the structure, signal regulation mechanism of HSFs and some research in plants like Arabidopsis thaliana, tomato, rice and soybean, to provide reference for further elucidating the role of HSFs in the stress regulation network.
Arabidopsis/metabolism* ; Droughts ; Gene Expression Regulation, Plant ; Heat Shock Transcription Factors/genetics* ; Plant Proteins/genetics* ; Stress, Physiological ; Transcription Factors/metabolism*

Six month old Cinnamomum cassia seedlings were used to simulate drought stress with polyethylene glycol(PEG 6000). The physiological indicators(osmotic substances, antioxidant enzymes, etc.) and chemical components of seedlings under different drought levels and the correlation between the two were studied. The results showed that the chlorophyll content and relative water content decreased gradually with the increase of PGE 6000(0, 5%, 10%, 15%) concentration and time(3, 5, 7 d), while the soluble protein content, soluble sugar content and catalase(CAT) activity increased, but the rising rate slowed down with the time. The activities of peroxidase(POD), superoxide dismutase(SOD), malondialdehyde(MDA) and proline content increased at first and then decreased. The content of coumarin, cinnamaldehyde, cinnamic acid and dimethoxycinnamaldehyde decreased, while the content of cinnamyl alcohol continued to increase.Under drought stress, the fluorescence signals of reactive oxygen species and no contents in roots of C. cassia seedlings were significantly stronger than those of the control.Further correlation analysis showed that coumarin content, di-methoxycinnamaldehyde content and osmoregulation substance content were significantly negatively correlated(P<0.05), cinnamic acid content was significantly negatively correlated with POD and SOD activities(P<0.01).It was found that C. cassia seedlings showed a certain degree of drought tolerance under short-term or mild drought stress, but if the drought exceeded a certain degree, the physiological metabolism of the seedlings would be unbalanced.
Catalase ; Cinnamomum aromaticum ; Droughts ; Malondialdehyde ; Seedlings ; Stress, Physiological ; Superoxide Dismutase

Dehydration-responsive element binding proteins (DREBs) are an important class of transcription factors related to plant stress tolerance. Ammopiptanthus mongolicus is an evergreen broadleaf shrub endemic to desert areas of northwest China, and it has a very high tolerance to harsh environments. In order to reveal the functions and mechanisms of the AmDREB1F gene from this species in enduring abiotic stresses, we performed subcellular localization test, expression pattern analysis, and stress tolerance evaluation of transgenic Arabidopsis harboring this gene. The protein encoded by AmDREB1F was localized in the nucleus. In laboratory-cultured A. mongolicus seedlings, the expression of AmDREB1F was induced significantly by cold and drought but very slightly by salt and heat stresses, and undetectable upon ABA treatment. In leaves of naturally growing shrubs in the wild, the expression levels of the AmDREB1F gene were much higher during the late autumn, winter and early spring than in other seasons. Moreover, the expression was abundant in roots and immature pods rather than other organs of the shrubs. Constitutive expression of AmDREB1F in Arabidopsis induced the expression of several DREB-regulated stress-responsive genes and improved the tolerance of transgenic lines to drought, high salinity and low temperature as well as oxidative stress. The constitutive expression also caused growth retardation of the transgenics, which could be eliminated by the application of gibberellin 3. Stress-inducible expression of AmDREB1F also enhanced the tolerance of transgenic Arabidopsis to all of the four stresses mentioned above, without affecting its growth and development. These results suggest that AmDREB1F gene may play positive regulatory roles in response to abiotic stresses through the ABA-independent signaling pathways.
Arabidopsis/metabolism* ; Droughts ; Ectopic Gene Expression ; Fabaceae/genetics* ; Gene Expression Regulation, Plant ; Plant Proteins/metabolism* ; Plants, Genetically Modified/genetics* ; Stress, Physiological/genetics*