Genome-wide analysis of glutathione S-transferase gene family in G. max

Single-Cell RNA-Sequencing of Soybean Reveals Transcriptional Changes and Antiviral Functions of GmGSTU23 and GmGSTU24 in Response to Soybean Mosaic Virus

Soybean mosaic virus (SMV) stands as a prominent and widespread threat to soybean (Glycine max L. Merr.), the foremost legume crop globally. Attaining a thorough comprehension of the alterations in the transcriptional network of soybeans in response to SMV infection is imperative for a profound insight into the mechanisms of viral pathogenicity and host resistance. In this investigation, we isolated 50 294 protoplasts from the newly developed leaves of soybean plants subjected to both SMV infection and mock inoculation. Subsequently, we utilized single-cell RNA sequencing (scRNA-seq) to construct the transcriptional landscape at a single-cell resolution. Nineteen distinct cell clusters were identified based on the transcriptomic profiles of scRNA-seq. The annotation of three cell types-epidermal cells, mesophyll cells, and vascular cells-was established based on the expression of orthologs to reported marker genes in Arabidopsis thaliana. The differentially expressed genes between the SMV- and mock-inoculated samples were analyzed for different cell types. Our investigation delved deeper into the tau class of glutathione S-transferases (GSTUs), known for their significant contributions to plant responses against abiotic and biotic stress. A total of 57 GSTU genes were identified by a thorough genome-wide investigation in the soybean genome G. max Wm82.a4.v1. Two specific candidates, GmGSTU23 and GmGSTU24, exhibited distinct upregulation in all three cell types in response to SMV infection, prompting their selection for further research. The transient overexpression of GmGSTU23 or GmGSTU24 in Nicotiana benthamiana resulted in the inhibition of SMV infection, indicating the antiviral function of soybean GSTU proteins.

Genome-Wide Identification of Glutathione S-Transferase Genes in Eggplant (Solanum melongena L.) Reveals Their Potential Role in Anthocyanin Accumulation on the Fruit Peel

Anthocyanins are ubiquitous pigments derived from the phenylpropanoid compound conferring red, purple and blue pigmentations to various organs of horticultural crops. The metabolism of flavonoids in the cytoplasm leads to the biosynthesis of anthocyanin, which is then conveyed to the vacuoles for storage by plant glutathione S-transferases (GST). Although GST is important for transporting anthocyanin in plants, its identification and characterization in eggplant (Solanum melongena L.) remains obscure. In this study, a total of 40 GST genes were obtained in the eggplant genome and classified into seven distinct chief groups based on the evolutionary relationship with Arabidopsis thaliana GST genes. The seven subgroups of eggplant GST genes (SmGST) comprise: dehydroascorbate reductase (DHAR), elongation factor 1Bγ (EF1Bγ), Zeta (Z), Theta(T), Phi(F), Tau(U) and tetra-chlorohydroquinone dehalogenase TCHQD. The 40 GST genes were unevenly distributed throughout the 10 eggplant chromosomes and were predominantly located in the cytoplasm. Structural gene analysis showed similarity in exons and introns within a GST subgroup. Six pairs of both tandem and segmental duplications have been identified, making them the primary factors contributing to the evolution of the SmGST. Light-related cis-regulatory elements were dominant, followed by stress-related and hormone-responsive elements. The syntenic analysis of orthologous genes indicated that eggplant, Arabidopsis and tomato (Solanum lycopersicum L.) counterpart genes seemed to be derived from a common ancestry. RNA-seq data analyses showed high expression of 13 SmGST genes with SmGSTF1 being glaringly upregulated on the peel of purple eggplant but showed no or low expression on eggplant varieties with green or white peel. Subsequently, SmGSTF1 had a strong positive correlation with anthocyanin content and with anthocyanin structural genes like SmUFGT (r = 0.9), SmANS (r = 0.85), SmF3H (r = 0.82) and SmCHI2 (r = 0.7). The suppression of SmGSTF1 through virus-induced gene silencing (VIGs) resulted in a decrease in anthocyanin on the infiltrated fruit surface. In a nutshell, results from this study established that SmGSTF1 has the potential of anthocyanin accumulation in eggplant peel and offers viable candidate genes for the improvement of purple eggplant. The comprehensive studies of the SmGST family genes provide the foundation for deciphering molecular investigations into the functional analysis of SmGST genes in eggplant.

Isolation and characterization of glutathione S-transferase genes and their transcripts in Saccharina japonica (Laminariales, Phaeophyceae) during development and under abiotic stress

BACKGROUND

Glutathione S-transferase (GST) is a crucial enzyme for metabolism, detoxification, and stress resistance in organisms. Many GSTs have been identified in seaweeds, but the isolation and functional analysis of GSTs in Saccharina japonica have not been completed.

RESULT

In this study, a total of 32 SjGST genes, localized on 10 scaffolds and 6 contigs, were identified and categorized into three groups. Most of these SjGSTs were presumed to be distributed in the cytoplasm. Tandem duplication had a significant influence on the expansion of the SjGST gene family. Functional analysis of cis-acting elements in the promoter regions demonstrated that SjGSTs enhance the stress resistance of the kelp. Quantitative real-time PCR tests confirmed that SjGSTs positively influence S. japonica sporophytes under stress from low salinity, drought, and high temperature. Recombinant yeast tests further affirmed the role of SjGSTs in stress resistance; SjGSTs improved the growth rate of recombinant yeast under 1.5 M NaCl or 8 mM H2O2. Analysis of biochemical parameters indicated that the optimum temperatures for SjGST20 and SjGST22 were 20 °C, and the optimum pH values were 7.0 and 8.0 for SjGST20 and SjGST22, respectively. The Km values for the substrate 1-chloro-2,4-dinitrobenzene (CDNB) were 2.706 mM and 0.674 mM and were 6.146 mM and 3.559 mM for the substrate glutathione (GSH) for SjGST20 and SjGST22, respectively.

CONCLUSION

SjGSTs are important stress resistant genes in S. japonica. This research results will enhance our understanding the function of GSTs in brown seaweeds, and explained its functional roles in stress resistance in marine environments.

The regulation of glutathione s-transferases by gibberellic acid application in salt treated maize leaves

Plant hormones and antioxidant system changes occur during plants' exposure to stress conditions. Although the interactions of some plant hormones (abscisic acid, salicylic acid, jasmonic acid, nitric oxide, and ethylene) with the glutathione s-transferase (GST) enzyme, which is one of the antioxidant enzymes, have already been reported, the influence of gibberellic acid (GA3) on this enzyme under saline conditions has not yet been reported. Plant material for the experiments was obtained from M14G144 cultivar of maize (Zea mays L.) plants grown as a soil culture in growth chambers at 22 °C, 65-70% moisture, 16-h light/8-h dark conditions, and with full strength Hoagland solution for 8 days under controlled growth conditions. Then, the plants were exposed to salt stress (350 mM NaCl and 100, 300, and 500 ppm GA3) simultaneously. In maize leaves, GA3 treatment alleviated the physiological parameters under salt stress. Specifically, the treatments with 100 and 500 ppm of GA3 were able to trigger GST enzyme and isoenzyme activities as well as hydrogen sulfide accumulation and anthocyanin content, although the lowest malondialdehyde, hydrogen peroxide, and superoxide radical content were under the treatment of 300 ppm of GA3. Besides this, GST gene expression levels were found to be upregulated between 1.5 and fourfold higher in all the plants treated with GA3 at different concentrations in proportion to salt stress. These results first indicated that the reason for the changes in GA3-treated plants was the stimulating role of this hormone to maintain GST regulation in maize plants.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-022-01269-2.

Computational insights into diverse aspects of glutathione S-transferase gene family in Papaver somniferum

Plant glutathione S-transferases are an ancient protein superfamily having antioxidant activity. These proteins are primarily involved in diverse plant functions such as plant growth and development, secondary metabolism, signaling pathways and defense against biotic and abiotic stresses. The current study aimed to comprehensively identify and characterize the GST gene family in the medicinally important crop Papaver somniferum. A total of 93 GST proteins were identified belonging to eight GST classes and found to be majorly localized in the cytoplasm. All GST genes were found on eleven opium chromosomes. Gene duplication analysis showed segmental duplication as a key factor for opium GST gene family expansion under strong purifying selection. Phylogenetic analysis with gymnosperm, angiosperm and bryophyte revealed the evolution of GSTs earlier than their division into separate groups and also prior to the divergence of monocot and dicot. The secondary structure prediction showed the dominance of α-helices indicative of PsomGSTs as structurally stable and elastic proteins. Gene architecture showed the conservation of number of exons across the classes. MEME analysis revealed only a few class specific and many across class conserved motifs. Ser was found to be the active site residue of tau, phi, theta and zeta class and Cys was catalytic residue of DHAR, lambda and GHR class. Promoter analyses identified many cis-acting regulatory elements related to hormonal, cellular, stress and light response functions. Ser was the key phosphorylation site. Only three glycosylation sites were found across the 93 PsomGSTs. 3D structure prediction was also performed and was validated. Interactome analyses revealed the correlation of PsomGSTs with glutathione metabolizing proteins. Gene enrichment analysis and KEGG pathway analyzed the involvement of PsomGSTs in three major pathways i.e. glutathione metabolism, tyrosine metabolism and ascorbate metabolism. The outcome revealed high model quality of PsomGSTs. The results of the current study will be of potential significance to understand the functional and structural importance of the GST gene family in opium, a medicinally important crop.

Genome-wide identification and characterization of glutathione S-transferase gene family in Musa acuminata L. AAA group and gaining an insight to their role in banana fruit development

Glutathione S-transferases are a multifunctional protein superfamily that is involved in diverse plant functions such as defense mechanisms, signaling, stress response, secondary metabolism, and plant growth and development. Although the banana whole-genome sequence is available, the distribution of GST genes on banana chromosomes, their subcellular localization, gene structure, their evolutionary relation with each other, conserved motifs, and their roles in banana are still unknown. A total of 62 full-length GST genes with the canonical thioredoxin fold have been identified belonging to nine GST classes, namely tau, phi, theta, zeta, lambda, DHAR, EF1G, GHR, and TCHQD. The 62 GST genes were distributed into 11 banana chromosomes. All the MaGSTs were majorly localized in the cytoplasm. Gene architecture showed the conservation of exon numbers in individual GST classes. Multiple Em for Motif Elicitation analyses revealed few class-specific motifs and many motifs were found in all the GST classes. Multiple sequence alignment of banana GST amino acid sequences with rice, Arabidopsis, and soybean sequences revealed the Ser and Cys as conserved catalytic residues. Gene duplication analyses showed the tandem duplication as a driving force for GST gene family expansion in banana. Cis-regulatory element analysis showed the dominance of light-responsive element followed by stress- and hormone-responsive elements. Expression profiling analyses were also done by RNA-seq data. It was observed that MaGSTs are involved in various stages of fruit development. MaGSTU1 was highly upregulated. The comprehensive and organized studies of MaGST gene family provide groundwork for further functional analysis of MaGST genes in banana at molecular level and further for plant breeding approaches.

Genome-wide analysis of the Glutathione S-Transferase family in wild Medicago ruthenica and drought-tolerant breeding application of MruGSTU39 gene in cultivated alfalfa

Transformation of MruGSTU39 in M. ruthenica and alfalfa enhanced growth and survival of transgenic plants by up-regulating GST and glutathione peroxidase activity to detoxify ROS under drought stress. Glutathione S-transferases (GSTs) are ubiquitous supergene family which play crucial roles in detoxification of reactive oxygen species (ROS). Despite studies on GSTs, few studies have focused on them in perennial, wild plant species with high tolerance to environmental stress. Here, we identified 66 MruGST genes from the genome of Medicago ruthenica, a perennial legume species native to temperate grasslands with high tolerance to environmental stress. These genes were divided into eight classes based on their conserved domains, phylogenetic tree and gene structure, with the tau class being the most numerous. Duplication analysis revealed that GST family in M. ruthenica was expanded by segmental and tandem duplication. Several drought-responsive MruGSTs were identified by transcriptomic analyses. Of them, expression of MruGSTU39 was up-regulated much more in a tolerant accession by drought stress. Transformation of MruGSTU39 in M. ruthenica and alfalfa (Medicago sativa) enhanced growth and survival of transgenic seedlings than their wild-type counterparts under drought. We demonstrated that MruGSTU39 can detoxify ROS to reduce its damage to membrane by up-regulating activities of GST and glutathione peroxidase. Our findings provide full-scale knowledge on GST family in the wild legume M. ruthenica with high tolerance to drought, and highlight improvement tolerance of legume forages to drought using genomic information of M. ruthenica.

Identification and characterization of the novel genes encoding glutathione S-transferases in Mytilus galloprovincialis

The superfamily of glutathione S-transferases (GST) plays an essential role in the xenobiotic metabolism, binding compounds to the glutathione, and is like a cell protector during the influence of various negative external factors. Nevertheless, there are very few works devoted to the investigation of these genes in marine invertebrates. Up to this time, only three classes of cytosolic GSTs for one of the leading commercial molluscs Mytilus galloprovincialis were described. We sequenced the whole transcriptome from the gill tissues and, using bioinformatic analysis, detected ten classes of glutathione S-transferases, which are expressed in the mussel M. galloprovincialis. For the first time, two subfamilies were described: mitochondrial GST (kappa class) and microsomal (MAPEG), as well as five classes of the family of cytosolic GSTs (mu, omega, rho, tau, theta). Omega and sigma GST classes might be rapidly regulated genes due to the lack of introns and this assumption was confirmed by the investigation of short-term hypoxia on M. galloprovincialis. Seven new classes of GST revealed a greater gene variety of this detoxifying enzyme in mussels than expected. The obtained nucleotide sequences are necessary for future investigations of GSTs expression in response to various external factors (pollution, oxygen starvation, infection, etc.).