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.

Tandospirone prevents stress-induced anxiety-like behavior and visceral hypersensitivity by suppressing theta oscillation enhancement via 5-HT1A receptors in the anterior cingulate cortex in rats.

Tandospirone, a third-generation of antianxiety agent with fewer side effects, has been widely used in the treatment of anxiety. Moreover, it is interesting that tandospirone has been found to relieve gastrointestinal symptoms in patients with refractory irritable bowel syndrome who also have psychological dysfunctions. However, the underlying mechanism remains unclear. In this study, using a visceral hypersensitivity rat model induced by chronic water avoidance stress to mimic the symptoms of irritable bowel syndrome, we found that tandospirone relieved anxiety-like behavior and visceral hypersensitivity induced by stress. Meanwhile, stressed rats had increased 5-HT concentration, less 5-HT1A receptor expression, and enhanced theta oscillations in the anterior cingulate cortex (ACC). Furthermore, the power of the theta band in ACC is positively correlated with the level of visceral sensitivity. Activation of 5-HT1A receptors by its agonist, 8-OH-DPAT, to compensate for their effect in ACC reduced the enhancement of theta oscillations in ACC slices in stressed rats, whereas 5-HT1A receptor antagonist, WAY100135, facilitates theta oscillations in slices of normal rats. Tandospirone reduced the enhancement of theta band power in ACC in vitro and in vivo, thus alleviating anxiety-like behavior and visceral hypersensitivity through 5-HT1A receptors in stressed rats. These results suggest a novel mechanism by which tandospirone activates 5-HT1A receptors to relieve stress-induced anxiety and visceral hypersensitivity by suppressing theta oscillation enhancement in ACC.

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.

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.

Hypoxia facilitates the proliferation of colorectal cancer cells by inducing cancer-associated fibroblast-derived IL6.

Colorectal cancer (CRC) is the most common malignancy worldwide, and its underlying molecular mechanisms remain largely unexplored. Accumulating evidences indicate cancer-associated fibroblasts (CAFs), abundant stromal cell population in the tumor microenvironment, play a key role in tumor development. Herein, we have successfully isolated CAFs and paired normal fibroblasts (NFs) from colorectal cancer tissues (n=10). By using a multiplex cytokine profiling assay, we have identified IL-6 as a major cytokine released by CAFs. Co-culturing of CAFs with CRC cell lines HCT116 or SW480 increases IL-6 release, and the secretion by CAFs can be further enhanced under hypoxia. By using the CCK-8 assay, we have found that HCT116 or SW480 cells treated with culture medium from CAFs, IL-6, or hypoxia showed a significant cell growth compared to control cells (p<0.01). Mechanistically, we have found that hypoxia could enhance the effect of the IL-6/STAT3 signaling on CRC cells, in part, through HIF-1a targeting PKM2. In conclusion, our data clearly proposes the interconnected mechanisms for constitutive activation of STAT3 signal by CAFs-derived IL-6 under hypoxia in colorectal cancer. The pharmacological inhibition of STAT3, PKM2, or HIF-1α can significantly reduce the oncogenic effect of IL-6, providing a potential therapeutic target for CRC patients.

Blood gas analysis of healthy people in Diqing Tibetan Autonomous Prefecture in Yunnan Province.

BACKGROUND: To investigate the reference value of blood gas analysis and related factors in healthy adults in Diqing Tibetan Autonomous Prefecture in Yunnan Province. METHODS: From August 24, 2018 to August 11, 2020, healthy people between the ages of 18 and 70 years were observed at the Physical Examination Center of People's Hospital of Diqing Tibetan Autonomous Prefecture in Yunnan province. Participant information and clinical characteristics were collected. Blood gas analyzer was used to measure PH value, arterial partial oxygen pressure (PaO2), arterial partial pressure of carbon dioxide (PaCO2), arterial oxygen saturation (SaO2), acidity (pH), actual bicarbonate (AB) and residual base (BE). The participants' basic and blood gas indicator data were analyzed, and the blood gas reference values and related factors were analyzed using chi-squared tests, Mann-Whitney-Wilcoxon Test, and Spearman's correlation analysis. RESULTS: A total of 1,218 eligible health examination participants were included. They had an average age of 40 [31-47] years, and males accounted for 51.0%. In terms of blood gas reference values, the average pH value was moderate, and the values of PaO2, SaO2, PaCO2, AB, and BE were low. PaO2 was basically matched with the estimated value of the domestic model formula. These indexes were found to be correlated with social demographic characteristics such as sex, age, and smoking history. CONCLUSIONS: The correlations between the indexes and social demographic characteristics may be helpful in the prediction of blood gas analysis results in clinical practice. For men, middle-aged and elderly people, or adults with a history of active smoking/biofuel exposure, blood gas PaO2 and PaCO2 should be monitored to facilitate the early intervention of respiratory failure. The PaO2 data basically matched the estimated values of the domestic model formula, suggesting that other regions in the Prefecture could use comprehensive epidemiological data and model methods to guide clinical work.

Medication adherence among patients with chronic obstructive pulmonary disease treated in a primary general hospital during the COVID-19 pandemic.

BACKGROUND: The objective of this study was to investigate medication adherence and the associated influencing factors in patients with chronic obstructive pulmonary disease (COPD) who were treated in a primary general hospital in Shanghai China during the 2019 novel coronavirus (COVID-19) pandemic. METHODS: From March to April 2020, all of the COPD patients treated in our department in the last 7 years were interviewed by telephone. The basic patient data and each questionnaire item were collected, and influencing factors were analyzed by the Chi-square test, U test, and univariate and multivariate logistic regression analyses. RESULTS: A total of 191 patients with COPD were queried, and 84 (44.0%) valid questionnaires were obtained. Among them, individuals with group B symptoms were most represented (45.2%); 53.6% had Medical Research Council (MRC) dyspnea levels of 2 or above. Chronic obstructive pulmonary disease assessment test (CAT) had an average of 9 [3, 13], and 52.4% of patients used two-drug combination therapy. Medication adherence was both good in ordinary times and over the past 2 months of the pandemic, and 88.8% of patients had no acute exacerbation during the pandemic. The CAT scores of male patients <70 years old, and patients with general outpatient follow-up and regular gargling were reduced (P<0.05). Drug combination and doctor's supervision were favorable factors affecting medication adherence during the 2 months of the pandemic, while possible depression was an unfavorable factor (P<0.05). CONCLUSIONS: During the pandemic, medication adherence in patients with COPD was similar to that in regular times, and was significantly related to drug combination, doctor's supervision, and accompanying mood disorders. An effective way to improve patient adherence and disease control could be strengthening follow-up education and diagnosing and treating depression and other complications.

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.

MicroRNA-9 functions as a tumor suppressor and enhances radio-sensitivity in radio-resistant A549 cells by targeting neuropilin 1.

Radiotherapy is commonly used to treat lung cancer but may not kill all cancer cells, which may be attributed to the radiotherapy resistance that often occurs in non-small cell lung cancer (NSCLC). At present, the molecular mechanism of radio-resistance remains unclear. Neuropilin 1 (NRP1), a co-receptor for vascular endothelial growth factor (VEGF), was demonstrated to be associated with radio-resistance of NSCLC cells via the VEGF-phosphoinositide 3-kinase-nuclear factor-κB pathway in our previous study. It was hypothesized that certain microRNAs (miRs) may serve crucial functions in radio-sensitivity by regulating NRP1. Bioinformatics predicted that NRP1 was a potential target of miR-9, and this was validated by luciferase reporter assays. Functionally, miR-9-transfected A549 cells exhibited a decreased proliferation rate, increased apoptosis rate and attenuated migratory and invasive abilities. Additionally, a high expression of miR-9 also significantly enhanced the radio-sensitivity of A549 cells in vitro and in vivo. These data improve understanding of the mechanisms of cell radio-resistance, and suggest that miR-9 may be a molecular target for the prediction of radio-sensitivity in NSCLC.

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.

Phylogeny and maternal donors of Elytrigia Desv. sensu lato (Triticeae; Poaceae) inferred from nuclear internal-transcribed spacer and trnL-F sequences.

BACKGROUND: Elytrigia Desv. is a genus with a varied array of morphology, cytology, ecology, and distribution in Triticeae. Classification and systematic position of Elytrigia remain controversial. We used nuclear internal-transcribed spacer (nrITS) sequences and chloroplast trnL-F region to study the relationships of phylogenetic and maternal genome donor of Elytrigia Desv. sensu lato. RESULTS: (1) E, F, P, St, and W genomes bear close relationship with one another and are distant from H and Ns genomes. Ee and Eb are homoeologous. (2) In ESt genome species, E genome is the origin of diploid Elytrigia species with E genome, St genome is the origin of Pseudoroegneria. (3) Diploid species Et. elongata were differentiated. (4) Et. stipifolia and Et. varnensis sequences are diverse based on nrITS data. (5) Et. lolioides contains St and H genomes and belongs to Elymus s. l. (6) E genome diploid species in Elytrigia serve as maternal donors of E genome for Et. nodosa (PI547344), Et. farcta, Et. pontica, Et. pycnantha, Et. scirpea, and Et. scythica. At least two species act as maternal donor of allopolyploids (ESt and EStP genomes). CONCLUSIONS: Our results suggested that Elytrigia s. l. species contain different genomes, which should be divided into different genera. However, the genomes of Elytrigia species had close relationships with one another. Diploid species were differentiated, because of introgression and different geographical sources. The results also suggested that the same species and the same genomes of different species have different maternal donor. Further study of molecular biology and cytology could facilitate the evaluation of our results of phylogenetic in a more specific and accurate way.

Contrasting evolutionary patterns of multiple loci uncover new aspects in the genome origin and evolutionary history of Leymus (Triticeae; Poaceae).

Leymus Hochst. (Triticeae: Poaceae), a group of allopolyploid species with the NsXm genomes, is a perennial genus with diversity in morphology, cytology, ecology, and distribution in the Triticeae. To investigate the genome origin and evolutionary history of Leymus, three unlinked low-copy nuclear genes (Acc1, Pgk1, and GBSSI) and three chloroplast regions (trnL-F, matK, and rbcL) of 32 Leymus species were analyzed with those of 36 diploid species representing 18 basic genomes in the Triticeae. The phylogenetic relationships were reconstructed using Bayesian inference, Maximum parsimony, and NeighborNet methods. A time-calibrated phylogeny was generated to estimate the evolutionary history of Leymus. The results suggest that reticulate evolution has occurred in Leymus species, with several distinct progenitors contributing to the Leymus. The molecular data in resolution of the Xm-genome lineage resulted in two apparently contradictory results, with one placing the Xm-genome lineage as closely related to the P/F genome and the other splitting the Xm-genome lineage as sister to the Ns-genome donor. Our results suggested that (1) the Ns genome of Leymus was donated by Psathyrostachys, and additional Ns-containing alleles may be introgressed into some Leymus polyploids by recurrent hybridization; (2) The phylogenetic incongruence regarding the resolution of the Xm-genome lineage suggested that the Xm genome of Leymus was closely related to the P genome of Agropyron; (3) Both Ns- and Xm-genome lineages served as the maternal donor during the speciation of Leymus species; (4) The Pseudoroegneria, Lophopyrum and Australopyrum genomes contributed to some Leymus species.

Cytogenetic study and stripe rust response of the derivatives from a wheat - Thinopyrum intermedium - Psathyrostachys huashanica trigeneric hybrid.

To transfer multiple desirable alien genes into common wheat, we previously reported a new trigeneric hybrid synthesized by crossing a wheat - Thinopyrum intermedium partial amphiploid with wheat - Psathyrostachys huashanica amphiploid. Here, the meiotic behavior, chromosome constitution, and stripe rust resistance of F5 derivatives from the wheat - Th. intermedium - P. huashanica trigeneric hybrid were studied. Cytological analysis indicated the F5 progenies had chromosome numbers of 42-50 (average 44.96). The mean meiotic configuration was 1.28 univalents, 21.74 bivalents, 0.04 trivalents, and 0.02 tetravalents per pollen mother cell. In 2n = 42 lines, the average pairing configuration was 0.05 I + 19.91 II (ring) + 1.06 II (rod) + 0.003 IV, suggesting these lines were cytologically stable. Most lines with 2n = 43, 44, 46, 48, or 50, bearing a high frequency of univalents or multivalents, showed abnormal meiotic behavior. Genomic in situ hybridization karyotyping results revealed that 25 lines contained 1-7 Th. intermedium chromosomes, but no P. huashanica chromosomes were found among the 27 self-pollinated progenies. At meiosis, univalents (1-5) possessing Th. intermedium hybridization signals were detected in 19 lines. Bivalents (1-3) expressing fluorescence signals were observed in 12 lines. Importantly, 21 lines harbored wheat - Th. intermedium chromosomal translocations with various alien translocation types. Additionally, two homozygous lines, K13-668-10 and K13-682-12, possessed a pair of wheat - Th. intermedium small fragmental translocations. Compared with the recurrent parent Zhong 3, most lines showed high resistance to the stripe rust (Puccinia striiformis f. sp. tritici) pathogens prevalent in China, including race V26/Gui22. This paper reports a highly efficient technical method for inducing alien translocation between wheat and Th. intermedium by trigeneric hybridization. These lines might be potentially valuable germplasm resources for further wheat improvement.

Genome origin, historical hybridization and genetic differentiation in Anthosachne australasica (Triticeae; Poaceae), inferred from chloroplast rbcL, trnH-psbA and nuclear Acc1 gene sequences.

BACKGROUND AND AIMS: Anthosachne Steudel is a group of allopolyploid species that was derived from hexaploidization between the Asian StY genome Roegneria entity and the Australasia W genome Australopyrum species. Polyploidization and apomixis contribute to taxonomic complexity in Anthosachne Here, a study is presented on the phylogeny and evolutionary history of Anthosachne australasica The aims are to demonstrate the process of polyploidization events and to explore the differentiation patterns of the St genome following geographic isolation. METHODS: Chloroplast rbcL and trnH-psbA and nuclear Acc1 gene sequences of 60 Anthosachne taxa and nine Roegneria species were analysed with those of 33 diploid taxa representing 20 basic genomes in Triticeae. The phylogenetic relationships were reconstructed. A time-calibrated phylogeny was generated to estimate the evolutionary history of A. australasica Nucleotide diversity patterns were used to assess the divergence within A. australasica and between Anthosachne and its putative progenitors. KEY RESULTS: Three homoeologous copies of the Acc1 sequences from Anthosachne were grouped with the Acc1 sequences from Roegneria, Pseudoroegneria, Australopyrum, Dasypyrum and Peridictyon The chloroplast sequences of Anthosachne were clustered with those from Roegneria and Pseudoroegneria Divergence time for Anthosachne was dated to 4·66 million years ago (MYA). The level of nucleotide diversity in Australasian Anthosachne was higher than that in continental Roegneria A low level of genetic differentiation within the A. australasica complex was found. CONCLUSIONS: Anthosachne originated from historical hybridization between Australopyrum species and a Roegneria entity colonized from Asia to Australasia via South-east Asia during the late Miocene. The St lineage served as the maternal donor during the speciation of Anthosachne A contrasting pattern of population genetic structure exists in the A. australasica complex. Greater diversity in island Anthosachne compared with continental Roegneria might be associated with mutation, polyploidization, apomixis and expansion. It is reasonable to consider that A. australasica var. scabra and A. australasica var. plurinervisa should be included in the A. australasica complex.

Cytogenetic Behavior of Trigeneric Hybrid Progeny Involving Wheat, Rye and Psathyrostachys huashanica.

Trigeneric hybrids are commonly used as bridges to transfer genes from some wild species to cultivated wheat and to measure the genomic interaction between donor species. We previously reported that trigeneric germplasms were produced by crossing wheat-Psathyrostachys huashanica amphiploids (PHW-SA, 2n = 8x = 56, AABBDDNsNs) with hexaploid triticale (Zhongsi 828, 2n = 6x = 42, AABBRR). In the present study, chromosome pairing behavior and the genome constitution of the F4 progenies of wheat-rye-P. huashanica trigeneric hybrids were studied. Cytological analysis showed that the chromosome number of F4 progenies ranged from 39 to 46, and 57.5% of them had 42 chromosomes. The mean meiotic configuration of F4 lines was 1.71 univalents, 20.26 bivalents, 0.04 trivalents, and 0.001 quadrivalents per pollen mother cell. Among the lines with 2n = 42, the average pairing configuration was 1.21 univalents, 16.22 ring bivalents, 4.16 rod bivalents, and 0.01 trivalents. This result indicated that these lines were cytologically stable. Other lines with 2n = 39, 40, 41, 43, 44, 45, and 46, bearing a high number of univalents or multivalents, showed abnormal meiotic behavior. Genomic in situ hybridization (GISH) revealed that all F4 lines had 11-14 rye chromosomes, but no P. huashanica chromosomes. The complete set of 14 rye chromosomes was found in 19 lines. At meiosis, GISH detected 1-6 univalents with hybridization signals of rye in 13 lines. Bivalents with fluorescence signals were identified in each line, ranging from 3 to 7. A quadrivalent with hybridization signals was observed in only 1 line, K13-714-8. Lagging chromosomes, chromosome bridges, micronuclei, and chromosome fragments hybridizing with the probe were not discovered in any of the lines. These results inferred that the behavior of rye chromosomes was normal during meiosis. In addition, 21 lines of 2n = 42 (91.3%) with 12 or 14 rye chromosomes, always contained 6 or 7 bivalents bearing fluorescence signals. This suggested that the rye chromosomes exhibiting complete pairing in these lines were cytologically stable during meiosis and may therefore be considered as new hexaploid triticales. Thus, these lines might be potential materials for further hexaploid triticale improvement.

Characterization of wheat - Psathyrostachys huashanica small segment translocation line with enhanced kernels per spike and stripe rust resistance.

Psathyrostachys huashanica Keng (2n = 2x = 14, NsNs), a distant wild relative of common wheat, possesses rich potentially valuable traits, such as disease resistance and more spikelets and kernels per spike, that could be useful for wheat genetic improvement. Development of wheat - P. huashanica translocation lines will facilitate its practical utilization in wheat breeding. In the present study, a wheat - P. huashanica small segmental translocation line, K-13-835-3, was isolated and characterized from the BC1F5 population of a cross between wheat - P. huashanica amphiploid PHW-SA and wheat cultivar CN16. Cytological studies showed that the mean chromosome configuration of K-13-835-3 at meiosis was 2n = 42 = 0.10 I + 19.43 II (ring) + 1.52 II (rod). GISH analyses indicated that chromosome composition of K-13-835-3 included 40 wheat chromosomes and a pair of wheat - P. huashanica translocation chromosomes. FISH results demonstrated that the small segment from an unidentified P. huashanica chromosome was translocated into wheat chromosome arm 5DS, proximal to the centromere region of 5DS. Compared with the cultivar wheat parent CN16, K-13-835-3 was highly resistant to stripe rust pathogens prevalent in China. Furthermore, spikelets and kernels per spike in K-13-835-3 were significantly higher than those of CN16 in two growing seasons. These results suggest that the desirable genes from P. huashanica were successfully transferred into CN16 background. This translocation line could be used as novel germplasm for high-yield and, eventually, resistant cultivar breeding.

[Characteristics of Microbial Community in Each Compartment of ABR ANAMMOX Reactor Based on High-throughput Sequencing].

In order to investigate the characteristics of microbial community in each compartment of ABR anammox reactor, a five-compartment ABR reactor was used to analyze the microbial community by Miseq High-throughput Sequencing during the steady operational process. The results indicated that the denitrifying bacteria coexisted in the reactor, such as Proteobacteria, Planctomycete, and Nitrospirae bacteria, and the percentages of these three microbial populations in the sludge were 11.66%-20.28%, 2.18%-7.94% and 0.19%-6.30%, respectively. In addition, there were four dominant genera in the phylum Proteobacteria:Rhodoplanes, Dok59, Rubrivivax and Bdellovibrio. Furthermore, Candidatus brocadia and Candidatus kuenenia were the main genera in the phylum Planctomycete. The color of sludge in the five compartments, in turn, varied from red to black. In addition, the biodiversity index of Chao, ACE, Shannon and Simpson indicated that the richness and diversity of microbial community increased gradually, and at the same time, the relative abundance of Proteobacteria increased while that of Planctomycetes gradually decreased. The above conclusion was consistent with the laws of substrate degradation and enrichment of functional microorganisms.