The mechanism and therapeutic potential of lncRNA MIR497HG/miR-16-5p axis in breast cancer.

BACKGROUND: Breast cancer has become a major public health problem in the current society, and its incidence rate ranks the first among Chinese female malignant tumors. This paper once again confirmed the efficacy of lncRNA in tumor regulation by introducing the mechanism of the diagnosis of breast cancer by the MIR497HG/miR-16-5p axis. METHODS: The abnormal expression of MIR497HG in breast cancer was determined by RT-qPCR method, and the correlation between MIR497HG expression and clinicopathological characteristics of breast cancer patients was analyzed via Chi-square test. To understand the diagnostic potential of MIR497HG in breast cancer by drawing the receiver operating characteristic curve (ROC). The overexpressed MIR497HG (pcDNA3.1-MIR497HG) was designed and constructed to explore the regulation of elevated MIR497HG on biological function of BT549 and Hs 578T cells through Transwell assays. Additionally, the luciferase gene reporter assay and Pearson analysis evaluated the targeting relationship of MIR497HG to miR-16-5p. RESULTS: MIR497HG was decreased in breast cancer and had high diagnostic function, while elevated MIR497HG inhibited the migration and invasion of BT549 and Hs 578T cells. In terms of functional mechanism, miR-16-5p was the target of MIR497HG, and MIR497HG reversely regulated the miR-16-5p. miR-16-5p mimic reversed the effects of upregulated MIR497HG on cell biological function. CONCLUSIONS: In general, MIR497HG was decreased in breast cancer, and the MIR497HG/miR-16-5p axis regulated breast cancer tumorigenesis, providing effective insights for the diagnosis of patients.

Expression and Significance of LINC02418 in Breast Cancer.

Purpose: The complicated pathogenesis and poor prognosis of breast cancer have become a major difficulty in medical research. This study aims to explore new lncRNA as prognostic markers for breast cancer and explore their roles and molecular mechanisms to lay a foundation for the treatment of cancer patients. Patients and Methods: The expression of LINC02418 and miR-766-5p in breast cancer tissues and cells was first identified using polymerase chain reaction, and Pearson was used to examine the correlation between the two. The cancer cells activities under different transfection conditions were detected using the Transwell assay and CCK8 assay. The correlation between LINC02418 and patient prognosis was analyzed using multifactor Cox regression and Kaplan-Meier. Results: It was shown that LINC02418 expression was upregulated in breast cancer tissues and cells. There are significant differences in lymph node metastasis and TNM stage between high and low LINC02418 expression groups. The higher the expression of LINC02418, the higher the mortality rate of breast cancer patients. miR-766-5p expression was downregulated and negatively correlated with LINC02418. There are binding sites between LINC02418 and miR-766-5p; Transfection with miR-766-5p inhibitor boosted LINC02418 luciferase activity, but transfection with miR-766-5p mimic decreased it. Knockdown of LINC02418 promoted miR-766-5p expression and inhibited cancer progression, which was alleviated to some extent by transfection with miR-766-5p inhibitors. Conclusion: LINC02418 has the potential to serve as a poor prognostic marker for breast cancer and plays a pro-oncogenic role by targeting miR-766-5p.

Unlocking the potential of phenolated kraft lignin as a versatile feed additive.

Lignin, a renewable natural antioxidant and bacteriostat, holds promise as a versatile, cost-effective feed additive. However, traditional industrial lignin faces limitations, including low reactivity, poor uniformity, and unstable properties, necessitating chemical modification. Complex modification methods pose economic and toxicity challenges, so this study adopted a relatively simple alkali-catalyzed phenolization approach, using phenol, catechol, and pyrogallol to modify kraft lignin, and characterized the resulting products using various techniques. Subsequently, their antioxidant, antibacterial, adsorption properties for heavy metal ions and mycotoxins, growth-promoting properties, and antiviral abilities were assessed. The phenolation process led to lignin depolymerization and a notable increase in phenolic hydroxyl content, particularly in pyrogallol-phenolated lignin (Py-L), rising from 3.08 to 4.68 mmol/g. These modified lignins exhibited enhanced antioxidant activity, with over 99 % inhibition against E. coli and S. aureus, and remarkable adsorption capacities for heavy metal ions and mycotoxins. Importantly, Py-L improved the growth performance of mice and reduced influenza mortality. Furthermore, density functional theory calculations elucidated the mechanism behind the enhanced antioxidant properties. This study presents a promising avenue for developing versatile feed additives to address challenges related to animal feed antioxidant supplementation, bacterial control, and growth promotion.

Genome constitution and evolution of Elymus atratus (Poaceae: Triticeae) inferred from cytogenetic and phylogenetic analysis.

BACKGROUND: Elymus atratus (Nevski) Hand.-Mazz. is perennial hexaploid wheatgrass. It was assigned to the genus Elymus L. sensu stricto based on morphological characters. Its genome constitution has not been disentangled yet. OBJECTIVE: To identify the genome constitution and origin of E. atratus. METHODS: In this study, genomic in situ hybridization and fluorescence in situ hybridization, and phylogenetic analysis based on the Acc1, DMC1 and matK sequences were performed. RESULTS: Genomic in situ hybridization and fluorescence in situ hybridization results reveal that E. atratus 2n = 6x = 42 is composed of 14 St genome chromosomes, 14 H genome chromosomes, and 14 Y genome chromosomes including two H-Y type translocation chromosomes, suggesting that the genome formula of E. atratus is StStYYHH. The phylogenetic analysis based on Acc1 and DMC1 sequences not only shows that the Y genome originated in a separate diploid, but also suggests that Pseudoroegneria (St), Hordeum (H), and a diploid species with Y genome were the potential donors of E. atratus. Data from chloroplast DNA showed that the maternal donor of E. atratus contains the St genome. CONCLUSION: Elymus atratus is an allohexaploid species with StYH genome, which may have originated through the hybridization between an allotetraploid Roegneria (StY) species as the maternal donor and a diploid Hordeum (H) species as the paternal donor.

Roegneria yenchiana: A new species in the Triticeae (Poaceae) from the Hengduan Mountain region.

Roegneria yenchiana sp. nov. (Triticeae) is a new species collected from Shangri-la of Yunnan Province in China based on morphological, cytological, and molecular data. It is morphologically characterized by one spikelet per node, rectangular glums, awns flanked by two short mucros in lemmas, distinguished from other species of Roegneria. The genomic in situ hybridization results indicate that R. yenchiana is an allotetraploid, and its genomic constitution is StY. Phylogenetic analyses based on multiple loci suggested that R. yenchiana is closely related to Pseudoroegneria and Roegneria, and the Pseudoroegneria served as the maternal donors during its polyploid speciation.

Drivers of diversification in Linum (Linaceae) by means of chromosome evolution: correlations with biogeography, breeding system and habit.

BACKGROUND AND AIMS: Chromosome evolution leads to hybrid dysfunction and recombination patterns and has thus been proposed as a major driver of diversification in all branches of the tree of life, including flowering plants. In this study we used the genus Linum (flax species) to evaluate the effects of chromosomal evolution on diversification rates and on traits that are important for sexual reproduction. Linum is a useful study group because it has considerable reproductive polymorphism (heterostyly) and chromosomal variation (n = 6-36) and a complex pattern of biogeographical distribution. METHODS: We tested several traditional hypotheses of chromosomal evolution. We analysed changes in chromosome number across the phylogenetic tree (ChromEvol model) in combination with diversification rates (ChromoSSE model), biogeographical distribution, heterostyly and habit (ChromePlus model). KEY RESULTS: Chromosome number evolved across the Linum phylogeny from an estimated ancestral chromosome number of n = 9. While there were few apparent incidences of cladogenesis through chromosome evolution, we inferred up to five chromosomal speciation events. Chromosome evolution was not related to heterostyly but did show significant relationships with habit and geographical range. Polyploidy was negatively correlated with perennial habit, as expected from the relative commonness of perennial woodiness and absence of perennial clonality in the genus. The colonization of new areas was linked to genome rearrangements (polyploidy and dysploidy), which could be associated with speciation events during the colonization process. CONCLUSIONS: Chromosome evolution is a key trait in some clades of the Linum phylogeny. Chromosome evolution directly impacts speciation and indirectly influences biogeographical processes and important plant traits.

Study on Synthesizing Isobornyl Acetate/Isoborneol from Camphene Using α-Hydroxyl Carboxylic Acid Composite Catalyst.

This study examined the preparation of isobornyl acetate/isoborneol from camphene using an α-hydroxyl carboxylic acid (HCA) composite catalyst. Through the study of the influencing factors, it was found that HCA and boric acid exhibited significant synergistic catalysis. Under optimal conditions, when tartaric acid-boric acid was used as the catalyst, the conversion of camphene and the gas chromatography (GC) content and selectivity of isobornyl acetate were 92.9%, 88.5%, and 95.3%, respectively. With the increase in the ratio of water to acetic acid, the GC content and selectivity of isobornol in the product increased, but the conversion of camphene decreased. The yield of isobornol was increased by adding ethyl acetate or titanium sulfate/zirconium sulfate to form a ternary composite catalyst. When a ternary complex of titanium sulfate, tartaric acid, and boric acid was used as the catalyst, the GC content of isobornol in the product reached 55.6%. Under solvent-free conditions, mandelic acid-boric acid could catalyze the hydration reaction of camphene, the GC content of isoborneol in the product reached 26.1%, and the selectivity of isoborneol was 55.9%. The HCA-boric acid composite catalyst can use aqueous acetic acid as a raw material, which is also beneficial for the reuse of the catalyst.

Comparative physiological and root transcriptome analysis of two annual ryegrass cultivars under drought stress.

Annual ryegrass is a widely cultivated forage grass with rapid growth and high productivity. However, drought is one of the abiotic stresses affecting ryegrass growth and quality. In this study, we compared the physiological and transcriptome responses of Chuansi No.1 (drought-tolerant, DT) and Double Barrel (drought-sensitive, DS) under drought stress simulated by PEG-6000 for 7 days. The results showed that Chuansi No. 1 had stronger physiological and biochemical parameters such as root properties, water content, osmotic adjustment ability and antioxidant ability. In addition, RNA-seq was used to elucidate the molecular mechanism of root drought resistance. We identified 8588 differentially expressed genes related to drought tolerance in root, which were mainly enriched in oxidation-reduction process, carbohydrate metabolic process, apoplast, arginine and proline metabolism, and phenylpropanoid biosynthesis pathways. The expression levels of DEGs were consistent with physiological changes of ryegrass under drought stress. We found that genes related to sucrose and starch synthesis, root development, osmotic adjustment, ABA signal regulation and specifically up-regulated transcription factors such as WRKY41, WRKY51, ERF7, ERF109, ERF110, NAC43, NAC68, bHLH162 and bHLH148 in Chuansi No. 1 may be the reason for its higher drought tolerance. This study revealed the underlying physiological and molecular mechanisms of root response to drought stress in ryegrass and provided some new candidate genes for breeding rye drought tolerant varieties.

Evolutionary patterns of plastome resolve multiple origins of the Ns-containing polyploid species in Triticeae.

Tracing evolutionary history proves challenging for polyploid groups that have evolved rapidly, especially if an ancestor of a polyploid is extinct. The Ns-containing polyploids are recognized as the NsXm and StHNsXm genomic constitutions in Triticeae. The Ns originated from Psathyrostachys, while the Xm represented a genome of unknown origin. Here, we use genetic information in plastome to trace the complex lineage history of the Ns-containing polyploid species by sampling 26 polyploids and 90 diploid taxa representing 23 basic genomes in Triticeae. Phylogenetic reconstruction, cluster plot of genetic distance matrix, and migration event demonstrated that (1) the Ns plastome originated from different Psathyrostachys species, and the Xm plastome may originate from an ancestral lineage of Henrardia, Agropyron, and Eremopyrum; (2) the Ns, Xm, and St genome donors separately served as the maternal parents during the speciation of the Ns-containing polyploid species, resulting in a maternal haplotype polymorphism; (3) North AmericanLeymusspecies might originate from colonization during late Miocene via the Bering land bridge and were the paternal donor of the StHNsXm genome Pascopyrum species. Our results shed new light on our understanding of the rich diversity and ecological adaptation of the Ns-containing polyploid species.

Biosystematics studies on Elymus breviaristatus and Elymus sinosubmuticus (Poaceae: Triticeae).

BACKGROUND: Elymus breviaristatus and Elymus sinosubmuticus are perennial herbs, not only morphologically similar but also sympatric distribution. The genome composition of E. sinosubmuticus has not been reported, and the relationship between E. sinosubmuticus and E. breviaristatus is still controversial. We performed artificial hybridization, genomic in situ hybridization, and phylogenetic analyses to clarify whether the two taxa were the same species. RESULTS: The high frequency bivalent (with an average of 20.62 bivalents per cell) at metaphase I of pollen mother cells of the artificial hybrids of E. breviaristatus (StYH) × E. sinosubmuticus was observed. It illustrated that E. sinosubmuticus was closely related to E. breviaristatus. Based on genomic in situ hybridization results, we confirmed that E. sinosubmuticus was an allohexaploid, and the genomic constitution was StYH. Phylogenetic analysis results also supported that this species contained St, Y, and H genomes. In their F1 hybrids, pollen activity was 53.90%, and the seed setting rate was 22.46%. Those indicated that the relationship between E. sinosubmuticus and E. breviaristatus is intersubspecific rather than interspecific, and it is reasonable to treated E. sinosubmuticus as the subspecies of E. breviaristatus. CONCLUSIONS: In all, the genomic constitutions of E. sinosubmuticus and E. breviaristatus were StYH, and they are species in the genus Campeiostachys. Because E. breviaristatus was treated as Campeistachys breviaristata, Elymus sinosubmuticus should be renamed Campeiostachys breviaristata (Keng) Y. H. Zhou, H. Q. Zhang et C. R. Yang subsp. sinosubmuticus (S. L. Chen) Y. H. Zhou, H. Q. Zhang et L. Tan.

Synthesis of Terpineol from Alpha-Pinene Catalyzed by α-Hydroxy Acids.

We report the use of five alpha-hydroxy acids (citric, tartaric, mandelic, lactic and glycolic acids) as catalysts in the synthesis of terpineol from alpha-pinene. The study found that the hydration rate of pinene was slow when only catalyzed by alpha-hydroxyl acids. Ternary composite catalysts, composed of AHAs, phosphoric acid, and acetic acid, had a good catalytic performance. The reaction step was hydrolysis of the intermediate terpinyl acetate, which yielded terpineol. The optimal reaction conditions were as follows: alpha-pinene, acetic acid, water, citric acid, and phosphoric acid, at a mass ratio of 1:2.5:1:(0.1-0.05):0.05, a reaction temperature of 70 °C, and a reaction time of 12-15 h. The conversion of alpha-pinene was 96%, the content of alpha-terpineol was 46.9%, and the selectivity of alpha-terpineol was 48.1%. In addition, the catalytic performance of monolayer graphene oxide and its composite catalyst with citric acid was studied, with acetic acid used as an additive.

Confirmation of Natural Hybridization between Kengyilia (StStYYPP) and Campeiostachys (StStYYHH) (Triticeae: Poaceae) Based on Morphological and Molecular Cytogenetic Analyses.

Natural hybridization has been frequently observed in Triticeae; however, few studies have investigated the origin of natural intergeneric Triticeae hybrids. In the present study, we discovered three putative hybrid Triticeae plants in the Western Sichuan Plateau of China. Morphologically, the putative hybrids were intermediate between Kengyilia melanthera (2n = 6x = 42; StStYYPP) and Campeiostachys dahurica var. tangutorum (2n = 6x = 42; StStYYHH) with greater plant height and tiller number. Cytological analyses demonstrated that the hybrids were hexaploid with 42 chromosomes (2n = 6x = 42). At metaphase I, 12.10-12.58 bivalents and 13.81-14.18 univalents per cell were observed in the hybrid plants. Genomic in situ hybridization demonstrated that the hybrids had StStYYHP genomes. Phylogenetic analysis of Acc1 sequences indicated that the hybrids were closely related to K. melanthera and C. dahurica var. tangutorum. Our morphological, cytological, and molecular analyses indicate that these hexaploid natural hybrid plants may be hybrids of K. melanthera and C. dahurica var. tangutorum.

Variation in Plastome Sizes Accompanied by Evolutionary History in Monogenomic Triticeae (Poaceae: Triticeae).

To investigate the pattern of chloroplast genome variation in Triticeae, we comprehensively analyzed the indels in protein-coding genes and intergenic sequence, gene loss/pseudonization, intron variation, expansion/contraction in inverted repeat regions, and the relationship between sequence characteristics and chloroplast genome size in 34 monogenomic Triticeae plants. Ancestral genome reconstruction suggests that major length variations occurred in four-stem branches of monogenomic Triticeae followed by independent changes in each genus. It was shown that the chloroplast genome sizes of monogenomic Triticeae were highly variable. The chloroplast genome of Pseudoroegneria, Dasypyrum, Lophopyrum, Thinopyrum, Eremopyrum, Agropyron, Australopyrum, and Henradia in Triticeae had evolved toward size reduction largely because of pseudogenes elimination events and length deletion fragments in intergenic. The Aegilops/Triticum complex, Taeniatherum, Secale, Crithopsis, Herteranthelium, and Hordeum in Triticeae had a larger chloroplast genome size. The large size variation in major lineages and their subclades are most likely consequences of adaptive processes since these variations were significantly correlated with divergence time and historical climatic changes. We also found that several intergenic regions, such as petN-trnC and psbE-petL containing unique genetic information, which can be used as important tools to identify the maternal relationship among Triticeae species. Our results contribute to the novel knowledge of plastid genome evolution in Triticeae.

Genome-Wide Survey and Expression Analysis of the KT/HAK/KUP Family in Brassica napus and Its Potential Roles in the Response to K+ Deficiency.

The KT/HAK/KUP (HAK) family is the largest potassium (K+) transporter family in plants, which plays key roles in K+ uptake and homeostasis, stress resistance, and root and embryo development. However, the HAK family has not yet been characterized in Brassica napus. In this study, 40 putative B. napus HAK genes (BnaHAKs) are identified and divided into four groups (Groups I-III and V) on the basis of phylogenetic analysis. Gene structure analysis revealed 10 conserved intron insertion sites across different groups. Collinearity analysis demonstrated that both allopolyploidization and small-scale duplication events contributed to the large expansion of BnaHAKs. Transcription factor (TF)-binding network construction, cis-element analysis, and microRNA prediction revealed that the expression of BnaHAKs is regulated by multiple factors. Analysis of RNA-sequencing data further revealed extensive expression profiles of the BnaHAKs in groups II, III, and V, with limited expression in group I. Compared with group I, most of the BnaHAKs in groups II, III, and V were more upregulated by hormone induction based on RNA-sequencing data. Reverse transcription-quantitative polymerase reaction analysis revealed that the expression of eight BnaHAKs of groups I and V was markedly upregulated under K+-deficiency treatment. Collectively, our results provide valuable information and key candidate genes for further functional studies of BnaHAKs.

Preliminary structure and bioactivities of polysaccharide SMWP-U&E isolated from Salvia miltiorrhiza Bunge Residue.

The fractional polysaccharide SMWP-U&E was isolated from Salvia miltiorrhiza residue. SMWP-U&E consists of 91.40% carbohydrates and has an average molecular weight of 5.07 × 105 Da. The polysaccharides are mainly composed of arabinose (Ara), fructose (Fru), mannose (Man), glucose (Glc), and galactose (Gal), and their mole percentages are 3.72%, 4.11%, 6.18%, 32.08% and 53.91%, respectively. When effected on weaned piglets, 1.5 g/kg SMWP-U&E supplementation significantly increased the villus height to crypt depth ratio in ileum. PCR-denaturing gradient gel electrophoresis and qRT-PCR results indicated that SMWP-U&E supplementation could change the density of intestinal microbiota and the populations of Lactobacillus and Escherichia coli in jejunum, ileum, caecum, and colon. The supplementation also increased contents of IgA, IgG, IgM, IL-2, IFN-γ, and IL-10; promoted T-AOC and SOD activities; and reduced MDA level in the serum. These findings suggest that SMWP-U&E improves digestion and nutrient absorption in weaned piglets, exerts beneficial effects on intestinal morphology and microflora, and enhances the immune and antioxidant capabilities in mode of weaned piglets. Thus, SMWP-U&E exhibits potential as a new type of plant-derived additive and novel prebiotics.

Evolutionary patterns of plastome uncover diploid-polyploid maternal relationships in Triticeae.

To investigate the diploid-polyploid relationships and the role of maternal progenitors in establishment of polyploid richness in Triticeae, 35 polyploids representing almost all genomic constitutions together with 48 diploid taxa representing 20 basic genomes in the tribe were analyzed. Phylogenomic reconstruction, genetic distance matrix, and nucleotide diversity patterns of plastome sequences indicated that (1) The maternal donor of the annual polyploid species with the U- and D-genome are related to extant Ae. umbellulata and Ae. tauschii, respectively. The maternal donor to the annual polyploid species with the S-, G-, and B-genome originated from the species of Sitopsis section of the genus Aegilops. The annual species with the Xe-containing polyploids were donated by Eremopyrum as the female parent; (2) Pseudoroegneria and Psathyrostachys were the maternal donor of perennial species with the St- and Ns-containing polyploids, respectively; (3) The Lophopyrum, Thinopyrum and Dasypyrum genomes contributed cytoplasm genome to Pseudoroegneria species as a result of incomplete lineage sorting and/or chloroplast captures, and these lineages were genetically transmitted to the St-containing polyploid species via polyploidization; (4) There is a reticulate relationship among the St-containing polyploid species. It can be suggested that genetic heterogeneity might associate with the richness of the polyploids in Triticeae.

Properties of Rigid Polyurethane Foam Modified by Tung Oil-Based Polyol and Flame-Retardant Particles.

Although tung oil is renewable, with an abundant production and low price in China, and it is used to synthesize different polyols for rigid polyurethane foam (RPUF), it remains a challenge to improve the properties of RPUF by redesigning the formula. Therefore, we propose four novel compounds to strengthen the properties of RPUF, such as the catalyst-free synthesis of tung oil-based polyol (PTOK), aluminum phosphate micro-capsule (AM), silica micro-capsule (SiM), and grafted epoxidized monoglyceride of tung oil on the surface of SiO2 (SiE), which were designed and introduced into the RPUF. Because of the PTOK with a catalytic function, the foaming process of some RPUF samples was catalyst-free. The results show that the incorporation of AM, SiM, and SiE, respectively, endow RPUF with a better thermal stability at a high temperature, and the T5%, Tmax1, and Tmax2 of RPUF appeared to be reduced, however, the Tmax3 and residue rate at 800 °C were improved, which may have a positive effect on the extension of the rescue time in case of fire, and the limiting oxygen index (LOI) value was increased to 22.6%. The formula, containing 25% PTOK made the RPUF environment-friendly. The results were obtained by comparing the pore size and mechanical properties of the RPUF-the AM had a better dispersion in the foam, and the foam obtained a better mechanical, thermal, and flame retardancy.

Chemical composition, antimicrobial activity and antioxidant activity of Litsea cubeba essential oils in different months.

In this study, the chemical composition, antimicrobial and antioxidant activities of Litsea cubeba essential oils extracted in different months were analysed. Results showed that the essential oil contents of fruits collected in June, July and August were 3.47%, 5.02% and 5.64%, respectively, and contained 13, 17 and 17 components, respectively. Neral and geranial were the main components and accounted for 54.76%. The essential oil extracted from fruits collected in July had the highest antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Salmonella typhimurium, and it was the most effective based on the OH· scavenging activity test. The essential oil extracted from fruits collected in August was the most effective based on the test for DPPH· scavenging activity and ferric reducing antioxidant power. Considering the contents, chemical compositions and antimicrobial and antioxidant activities, the appropriate harvest time for L. cubeba essential oils is from July to August.

Extraction and antioxidant activities of polysaccharides from roots of Arctium lappa L.

Polysaccharides were extracted from the roots of Arctium lappa L. (ALPs) using response surface methodology with ultrasonication. A central composition design was used to optimize extraction parameters by maximizing the polysaccharide extraction yield. The modified optimal conditions were as follows: water to raw material ratio of 31 mL/g, ultrasonic power of 158 W, extraction time of 83 min, and extraction temperature of 50 °C. Furthermore, fractions of ALP40-1, ALP60-1, and ALP80-1 were obtained for chemical and antioxidant activity analyses after purification. Results indicated that the three fractions had a molecular weight of 218, 178, and 60 kDa, respectively, and were composed of mannose, glucose, fructose, and galactose. ALP60-1 exhibited strong scavenging activities on 1,1­diphenyl­2­picryhydrazyl, hydroxyl, and superoxide radicals. These results demonstrate that ultrasonic-assisted extraction is a very effective method for extracting ALPs, and ALP60-1 is a potential novel natural antioxidant. However, further structure elucidation and in vivo experiments are required.

Complete structure and variation of the chloroplast genome of Agropyron cristatum (L.) Gaertn.

Agropyron cristatum (L.) Gaertner, a perennial grass in the tribe Triticeae (Poaceae), is a wild relative of cereal crops that is suitable for genetic improvement. In this study, we first sequenced the complete chloroplast (cp) genome of Ag. cristatum using Hiseq4000 PE150. The Ag. cristatum chloroplast genome is 135,554bp in length, has a typical quadripartite structure and contains 76 protein-coding genes, 29 tRNA genes and four rRNA genes. The cp genome of Ag. cristatum was used for comparison with other seven Triticeae species. One large variable region (800bp), which primarily contained the rpl23 (non-reciprocally translocated from IRs) and accD genes, was detected between rbcL gene and psaI gene within LSC region. The deletion of the accD and translocated rpl23 genes in Ag. cristatum indicated an independent gene-loss events or an additional divergence in Triticeae. Analyses of the dn/ds ratio and K2-P's genetic distance for 76 protein-coding genes showed that genes with evolutionary divergence might suffer from the effect of sequence regional constraints or gene functional constraints in Triticeae species. Our research will generally contribute to the knowledge of plastid genome evolution in Triticeae.