Background Transcription factors, including trihelix transcription factors, play vital roles in various growth and developmental processes and in abiotic stress responses in plants. The trihelix gene has been systematically studied in some dicots and monocots, including Arabidopsis, tomato, chrysanthemum, soybean, wheat, corn, rice, and buckwheat. However, there are no related studies on sorghum. Results In this study, a total of 40 sorghum trihelix (SbTH) genes were identified based on the sorghum genome, among which 34 were located in the nucleus, 5 in the chloroplast, 1 (SbTH38) in the cytoplasm, and 1 (SbTH23) in the extracellular membrane. Phylogenetic analysis of the SbTH genes and Arabidopsis and rice trihelix genes indicated that the genes were clustered into seven subfamilies: SIP1, GTγ, GT1, GT2, SH4, GTSb8, and orphan genes. The SbTH genes were located in nine chromosomes and none on chromosome 10. One pair of tandem duplication gene and seven pairs of segmental duplication genes were identified in the SbTH gene family. By qPCR, the expression of 14 SbTH members in different plant tissues and in plants exposed to six abiotic stresses at the seedling stage were quantified. Except for the leaves in which the genes were upregulated after only 2 h exposure to high temperature, the 12 SbTH genes were significantly upregulated in the stems of sorghum seedlings after 24 h under the other abiotic stress conditions. Among the selected genes, SbTH10/37/39 were significantly upregulated, whereas SbTH32 was significantly downregulated under different stress conditions. Conclusions In this study, we identified 40 trihelix genes in sorghum and found that gene duplication was the main force driving trihelix gene evolution in sorghum. The findings of our study serve as a basis for further investigation of the functions of SbTH genes and providing candidate genes for stress-resistant sorghum breeding programmes and increasing sorghum yield.

Background The basic leucine zipper (bZIP) transcription factor (TF) is one of the largest families of transcription factors (TFs). It is widely distributed and highly conserved in animals, plants, and microorganisms. Previous studies have shown that the bZIP TF family is involved in plant growth, development, and stress responses. The bZIP family has been studied in many plants; however, there is little research on the bZIP gene family in tobacco. Results In this study, 77 bZIPs were identified in tobacco and named NtbZIP01 through to NtbZIP77. These 77 genes were then divided into eleven subfamilies according to their homology with Arabidopsis thaliana. NtbZIPs were unevenly distributed across twenty-two tobacco chromosomes, and we found sixteen pairs of segmental duplication. We further studied the collinearity between these genes and related genes of six other species. Quantitative real-time polymerase chain reaction analysis identified that expression patterns of bZIPs differed, including in different organs and under various abiotic stresses. NtbZIP49 might be important in the development of flowers and fruits; NtbZIP18 might be an important regulator in abiotic stress. Conclusions In this study, the structures and functions of the bZIP family in tobacco were systematically explored. Many bZIPs may play vital roles in the regulation of organ development, growth, and responses to abiotic stresses. This research has great significance for the functional characterisation of the tobacco bZIP family and our understanding of the bZIP family in higher plants.

Background As transcription factors, the TCP genes are considered to be promising targets for crop enhancement for their responses to abiotic stresses. However, information on the systematic characterization and functional expression profiles under abiotic stress of TCPs in Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) is limited. Results In this study, we identified 26 FtTCPs and named them according to their position on the chromosomes. Phylogenetic tree, gene structure, duplication events, and cis-acting elements were further studied and syntenic analysis was conducted to explore the bioinformatic traits of the FtTCP gene family. Subsequently, 12 FtTCP genes were selected for expression analysis under cold, dark, heat, salt, UV, and waterlogging (WL) treatments by qRT-PCR. The spatio-temporal specificity, correlation analysis of gene expression levels and interaction network prediction revealed the potential function of FtTCP15 and FtTCP18 in response to abiotic stresses. Moreover, subcellular localization confirmed that FtTCP15 and FtTCP18 localized in the nucleus function as transcription factors. Conclusions In this research, 26 TCP genes were identified in Tartary buckwheat, and their structures and functions have been systematically explored. Our results reveal that the FtTCP15 and FtTCP18 have special cis-elements in response to abiotic stress and conserved nature in evolution, indicating they could be promising candidates for further functional verification under multiple abiotic stresses.

Background The trihelix family of transcription factors plays essential roles in the growth, development, and abiotic stress response of plants. Although several studies have been performed on the trihelix gene family in several dicots and monocots, this gene family is yet to be studied in Chenopodium quinoa (quinoa). Results In this study, 47 C. quinoa trihelix (CqTH) genes were in the quinoa genome. Phylogenetic analysis of the CqTH and trihelix genes from Arabidopsis thaliana and Beta vulgaris revealed that the genes were clustered into five subfamilies: SIP1, GTγ, GT1, GT2, and SH4. Additionally, synteny analysis revealed that the CqTH genes were located on 17 chromosomes, with the exception of chromosomes 8 and 11, and 23 pairs of segmental duplication genes were detected. Furthermore, expression patterns of 10 CqTH genes in different plant tissues and at different developmental stages under abiotic stress and phytohormone treatment were examined. Among the 10 genes, CqTH02, CqTH25, CqTH18, CqTH19, CqTH25, CqTH31, and CqTH36, were highly expressed in unripe achenes 21 d after flowering and in mature achenes compared with other plant tissues. Notably, the 10 CqTH genes were upregulated in UV-treated leaves, whereas CqTH36 was consistently upregulated in the leaves under all abiotic stress conditions. Conclusions The findings of this study suggest that gene duplication could be a major driver of trihelix gene evolution in quinoa. These findings could serve as a basis for future studies on the roles of CqTH transcription factors and present potential genetic markers for breeding stress-resistant and high-yielding quinoa varieties.

IntroductionThe transcription factor WRKY is widespread in the plant kingdom and plays a crucial role in diverse abiotic stress responses in plant species. Tritipyrum, an octoploid derived from an intergeneric cross between Triticum aestivum (AABBDD) and Thinopyrum elongatum (EE), is a valuable germplasm resource for introducing superior traits of Th. elongatum into T. aestivum. The recent release of the complete genome sequences of T. aestivum and Th. elongatum enabled us to investigate the organization and expression profiling of Tritipyrum WRKY genes across the entire genome.ResultsIn this study, 346 WRKY genes, from TtWRKY1 to TtWRKY346, were identified in Tritipyrum. The phylogenetic analysis grouped these genes into three subfamilies (I-III), and members of the same subfamilies shared a conserved motif composition. The 346 TtWRKY genes were dispersed unevenly across 28 chromosomes, with 218 duplicates. Analysis of synteny suggests that the WRKY gene family may have a common ancestor. Expression profiles derived from transcriptome data and qPCR demonstrated that 54 TtWRKY genes exhibited relatively high levels of expression across various salt stresses and recovery treatments. Tel1E01T143800 (TtWRKY256) is extremely sensitive to salt stress and is on the same evolutionary branch as the salt-tolerant A. thaliana genes AtWRKY25 and AtWRKY33. From 'Y1805', the novel AtWRKY25 was cloned. The Pearson correlation analysis identified 181 genes that were positively correlated (R>0.9) with the expression of TtWRKY256, and these genes were mainly enriched in metabolic processes, cellular processes, response to stimulus, biological regulation, and regulation of biological. Subcellular localization and qRT-PCR analysis revealed that TtWRKY256 was located in the nucleus and was highly expressed in roots, stems, and leaves under salt stress.DiscussionThe above results suggest that TtWRKY256 may be associated with salt stress tolerance in plants and may be a valuable alien gene for improving salt tolerance in wheat.

Urtica fissa E. Pritz is not only an important medicinal plant for rheumatism and cough relief, but it is also an important forage plant. In this study, the complete chloroplast genome of U. fissa was assembled for the first time and reported to be 146,837 base pairs (bp) long with a typical tetragonal structure and including a large single-copy of 79,657 bp, a small single-copy of 17,712 bp, and two inverted repeats of 24,734 bp each. It harbors 115 unique genes, including 70 protein-coding genes, 38 transfer RNA genes, and 7 ribosomal RNA genes. Phylogenetic analysis showed that U. fissa is closely related to Urtica lobatifolia . This study contributes to the understanding of the origin and evolution of U. fissa , as well as its genetic relationships with other species.

Helicoverpa assulta (Guenée), a moth species belonging to the Noctuidae (Lepidoptera) family, is a destructive agricultural pest that infests multiple cash crops. To assess differences in the gene expression profiles of different tissues in H. assulta, we analyzed the transcriptomes of two tissue types (midgut and hemocytes) using the Illumina Hiseq 2000 platform, on the basis of which we obtained 52076750 and 53404200 high-quality clean reads, respectively. De novo assembly yielded 46146 and 33707 unigenes from the midgut and hemocytes, respectively. After screening, we identified 23726 unigenes differentially expressed between the midgut and hemocytes. Taking the midgut as the control, we detected 7448 and 16278 unigenes that were up- and downregulated in hemocytes, respectively. Gene Ontology functional annotation divided the differentially expressed unigenes (DEUs) into three categories (biological process, cellular component, and molecular function) and 51 branches, whereas the Kyoto Encyclopedia of Genes and Genomes metabolic pathway annotation assigned the DEUs to six categories, mapping these to 258 pathways. In addition, we detected 224918 single-nucleotide polymorphic sites. Our findings based on transcriptome sequencing, data assembly, and functional gene annotation of two different tissues in H. assulta will provide a valuable reference for further excavation and study of functional genes in H. assulta.

Background Glutathione S-transferase (GST) is an antioxidant enzyme essential for cell protection because of its scavenging of reactive oxygen species accumulated under various stresses. Cold stress studies on the GST gene family have been conducted in several dicotyledonous and monocotyledonous plants, including Arabidopsis, rice, sweet potato, cantaloupe, and pumpkin. However, no relevant studies have been conducted on quinoa to date. Results In the present study, 59 GST (CqGST) genes were identified in the C. quinoa genome, among which 34 were located in the cytoplasm, 20 in the chloroplasts, and five in the ribosomes. Our phylogenetic analysis of CqGST and GST genes from Arabidopsis and rice showed that these genes were clustered into eight subfamilies, namely Tau, Phi, GHR, Zeta, Lambda, EF1B, DHER, and TCHQD. A total of 59 CqGSTs were located on 14 chromosomes, and none were located on chromosomes 00, 4, 9, 13, and 15. Eleven pairs of tandem-duplicated genes and 12 pairs of segmentally duplicated genes were identified in the CqGST gene family. The promoter region of each CqGST contained at least one cis-element associated with adversity. We selected 16 representative genes for fluorescence quantitative RT-PCR to verify gene expression and found that most of the CqGST genes were highly expressed in the roots and recovered for 3 h after different cold treatment times, indicating that the GST family plays an important role in quinoa cold stress. Conclusions In the present study, 59 GST genes were identified in quinoa, and gene duplication events were found to be the main drivers of GST gene family evolution in this species. Our results provide a basis for further studies on the function of GST genes in quinoa as well as a research basis for breeding quinoa in high-altitude cold regions, indicating the candidate genes for enhancing quinoa yield.