The spikelet number per spike (SNS) contributes greatly to grain yield in wheat. Identifying various genes that control wheat SNS is vital for yield improvement. This study used a recombinant inbred ...line population genotyped by the Wheat55K single-nucleotide polymorphism array to identify two major and stably expressed quantitative trait loci (QTLs) for SNS. One of them (QSns.sau-2SY-2D.1) was reported previously, while the other (QSns.sau-2SY-7A) was newly detected and further analyzed in this study. QSns.sau-2SY-7A had a high LOD value ranging from 4.46 to 16.00 and explained 10.21–40.78％ of the phenotypic variances. QSns.sau-2SY-7A was flanked by the markers AX-110518554 and AX-110094527 in a 4.75-cM interval on chromosome arm 7AL. The contributions and interactions of both major QTLs were further analyzed and discussed. The effect of QSns.sau-2SY-7A was successfully validated by developing a tightly linked kompetitive allele specific PCR marker in an F2:3 population and a panel of 101 high-generation breeding wheat lines. Furthermore, several genes including the previously reported WHEAT ORTHOLOG OF APO1 (WAPO1), an ortholog of the rice gene ABERRANT PANICLE ORGANIZATION 1 (APO1) related to SNS, were predicted in the interval of QSns.sau-2SY-7A. In summary, these results revealed the genetic basis of the multi-spikelet genotype of wheat line 20828 and will facilitate subsequent fine mapping and breeding utilization of the major QTLs.
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.
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 F
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.
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.
Many observational studies assessed the association between obesity and risk of hip fracture in adults, but reported controversial results. Our goal was to evaluate the association between obesity ...and risk of hip fracture in adults by conducting a meta-analysis of prospective cohort studies.
Three databases, PubMed, Embase and Web of Science, were searched through May 2012 to identify eligible cohort studies. Either a fixed- or a random-effects model was used to calculate the pooled relative risk (RR) with its 95% confidence interval (95%CI).
Fifteen prospective cohort studies involving a total 3,126,313 participants were finally included into this meta-analysis. Overall, adults with obesity compared with the normal weight group had a significantly decreased risk of hip fracture (RR: 0.66, 95% CI 0.57 to 0.77, P<0.001). Meta-analyses by the adjusted status of RRs also suggested adults with obesity compared with the reference group had a significantly decreased risk of hip fracture (adjusted RR: 0.48, 95% CI 0.39 to 0.58, P<0.001; unadjusted RR: 0.66, 95% CI 0.56 to 0.78, P<0.001). Subgroup analyses by gender suggested individuals with obesity had a significantly decreased risk for developing hip fracture compared with the reference group in both men (RR 0.54, 95% CI 0.48 to 0.60, P<0.001) and women (RR 0.70, 95% CI 0.58 to 0.84, P<0.001). No evidence of publication bias was observed in this meta-analysis.
This meta-analysis of prospective cohort studies suggests that obesity significantly decreases the risk of hip fracture in adults, and obesity is probably a protective factor of hip fracture in adults.
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.
The electron transfer mechanism in the process of peroxymonosulfate (PMS) activation using heterojunction catalyst was controversial. In this work, magnetic heterojunction Cu
2
O/CoFe
2
O
4
(CC) was ...first synthesized to activate PMS. An innovative reaction mechanism based on built-in electric field-driven electron migration from Cu
2
O to CoFe
2
O
4
and effective magnetic moment of CC for enhancing PMS activation was proposed. Meanwhile, the CC/PMS system was used for efficient removal of antibiotic tetracycline (TC). Under optimal conditions, 98.0% TC could be removed using CC/PMS catalytic system after only 30 min. The catalytic activity was higher than that of Cu
2
O/PMS and CoFe
2
O
4
/PMS. Meanwhile, the impact of solution pH on TC removal was insignificant, suggesting the pH-insensitive PMS activation ability of CC. Besides, the coexisting inorganic ions in the environment, such as HCO
3
−
, H
2
PO
4
−
, NO
3
−
, Cl
−
and humic acid (HA) as representative of natural organic matter, did not inhibit TC removal in CC/PMS system. Furthermore, CC/PMS system exhibited excellent reusability with more than 94.0% TC removal after the 5th reuse. Electron paramagnetic resonance (EPR) tests and quenching experiments showed that O
2
·
−
and
1
O
2
played vital roles in TC removal. The intermediate products and corresponding toxicity assessment revealed that this catalytic system could reduce TC toxicity. This work provided new insights into the PMS activation mechanism using heterogeneous magnetic catalysts, including transition metal oxide.
Graphical abstract
The level and pattern of nucleotide variation in duplicate gene provide important information on the evolutionary history of polyploids and divergent process between homoeologous loci within ...lineages. Kengyilia is a group of allohexaploid species with the StYP genomic constitutions in the wheat tribe. To investigate the evolutionary dynamics of the Pgk1 gene in Kengyilia and its diploid relatives, three copies of Pgk1 homoeologues were isolated from all sampled hexaploid Kengyilia species and analyzed with the Pgk1 sequences from 47 diploid taxa representing 18 basic genomes in Triticeae. Sequence diversity patterns and genealogical analysis suggested that (1) Kengyilia species from the Central Asia and the Qinghai-Tibetan plateau have independent origins with geographically differentiated P genome donors and diverged levels of nucleotide diversity at Pgk1 locus; (2) a relatively long-time sweep event has allowed the Pgk1 gene within Agropyron to adapt to cold climate triggered by the recent uplifts of the Qinghai-Tibetan Plateau; (3) sweep event and population expansion might result in the difference in the d(N)/d(S) value of the Pgk1 gene in allopatric Agropyron populations, and this difference may be genetically transmitted to Kengyilia lineages via independent polyploidization events; (4) an 83 bp MITE element insertion has shaped the Pgk1 loci in the P genome lineage with different geographical regions; (5) the St and P genomes in Kengyilia were donated by Pseudoroegneria and Agropyron, respectively, and the Y genome is closely related to the Xp genome of Peridictyon sanctum. The interplay of evolutionary forces involving diverged natural selection, population expansion, and transposable events in geographically differentiated P genome donors could attribute to geographical differentiation of Kengyilia species via independent origins.
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.
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
,
,
,
,
,
,
, and
in Triticeae had evolved toward size reduction largely because of pseudogenes elimination events and length deletion fragments in intergenic. The
/
complex,
,
,
,
, and
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
N-
C and
E-
L 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.
Display omitted
•The progenitors of six basic genomes constitute most maternal donor of Triticeae polyploids.•The Ee, Eb and V genome donor contributed cytoplasm genome to Pseudoroegneria ...species.•The Ee/Eb/V cytoplasm lineages of the St-containing polyploids are derived from Pseudoroegneria via polyploidization.•Genetic heterogeneity might associate with the richness of the polyploids.
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.
Single- and low- copy genes are less likely subject to concerted evolution, thus making themselves ideal tools for studying the origin and evolution of polyploid taxa. Leymus is a polyploid genus ...with a diverse array of morphology, ecology and distribution in Triticeae. The genomic constitution of Leymus was assigned as NsXm, where Ns was presumed to be originated from Psathyrostachys, while Xm represented a genome of unknown origin. In addition, little is known about the evolutionary history of Leymus. Here, we investigate the phylogenetic relationship, genome donor, and evolutionary history of Leymus based on a single-copy nuclear Acc1 gene.
Two homoeologues of the Acc1 gene were isolated from nearly all the sampled Leymus species using allele-specific primer and were analyzed with those from 35 diploid taxa representing 18 basic genomes in Triticeae. Sequence diversity patterns and genealogical analysis suggested that (1) Leymus is closely related to Psathyrostachys, Agropyron, and Eremopyrum; (2) Psathyrostachys juncea is an ancestral Ns-genome donor of Leymus species; (3) the Xm genome in Leymus may be originated from an ancestral lineage of Agropyron and Eremopyrum triticeum; (4) the Acc1 sequences of Leymus species from the Qinghai-Tibetan plateau are evolutionarily distinct; (5) North America Leymus species might originate from colonization via the Bering land bridge; (6) Leymus originated about 11-12MYA in Eurasia, and adaptive radiation might have occurred in Leymus during the period of 3.7-4.3 MYA and 1.7-2.1 MYA.
Leymus species have allopolyploid origin. It is hypothesized that the adaptive radiation of Leymus species might have been triggered by the recent upliftings of the Qinghai-Tibetan plateau and subsequent climatic oscillations. Adaptive radiation may have promoted the rapid speciation, as well as the fixation of unique morphological characters in Leymus. Our results shed new light on our understanding of the origin of Xm genome, the polyploidization events and evolutionary history of Leymus that could account for the rich diversity and ecological adaptation of Leymus species.
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