Search

SUMMARY: A chromosome‐specific painting technique has been developed which combines the most recent approaches of the companion disciplines of molecular cytogenetics and genome research. We developed seven oligonucleotide (oligo) pools derivd from single‐copy sequences on chromosomes 1 to 7 of barley (Hordeum vulgare L.) and corresponding collinear regions of wheat (Triticum aestivum L.). The seven groups of pooled oligos comprised between 10 986 and 12 496 45‐bp monomers, and these then produced stable fluorescence in situ hybridization (FISH) signals on chromosomes of each linkage group of wheat and barley. The pooled oligo probes were applied to high‐throughput karyotyping of the chromosomes of other Triticeae species in the genera Secale, Aegilops, Thinopyrum, and Dasypyrum, and the study also extended to some wheat‐alien amphiploids and derived lines. We demonstrated that a complete set of whole‐chromosome oligo painting probes facilitated the study of inter‐species chromosome homologous relationships and visualized non‐homologous chromosomal rearrangements in Triticeae species and some wheat‐alien species derivatives. When combined with other non‐denaturing FISH procedures using tandem‐repeat oligos, the newly developed oligo painting techniques provide an efficient tool for the study of chromosome structure, organization, and evolution among any wild Triticeae species with non‐sequenced genomes. Significance Statement: We developed seven oligonucleotide pools based on single‐copy sequences on seven chromosomes of barley (Hordeum vulgare L.) and corresponding collinear regions of wheat (Triticum aestivum L.). The approach has greatly improved the resolution of chromosome identification for high‐throughput karyotyping of representative wild Triticeae species and the probes enable to characterize chromosome rearrangements for wheat‐alien transfer and evolutionary studies. [ABSTRACT FROM AUTHOR]

During thermal exposure, the sintering process of the plasma-sprayed thermal barrier coatings (PS-TBCs) presents significant two-stage kinetics, as reported in the Part I. As a companion study, this part aims to reveal the mechanism responsible for the ultrafast sintering kinetics when initially exposed, since the initial short stage (stage-I) often finishes most increment of the mechanical and thermal properties. A detailed examination of the pore healing behavior was carried out, based on the experimental result in Part I that the dominant structural change at the stage-I is the significant healing at intersplat pore tips. Results show that the smooth splat surface, which made up the wedge-shaped intersplat pores, changed to a rough surface with multiscale convexs after high-temperature thermal exposure. Moreover, the multiscale roughening is highly sensitive to various orientations of the columnar grains inside the splats. Subsequently, multipoint connection between the counter-surfaces of the intersplat pores was formed by the bridging of multiscale convexs. This multiscale multipoint connection between pore surfaces significantly accelerated the healing of intersplat pores, which can be dominantly responsible for the ultrafast sintering kinetics at the stage-I. This comprehensive sintering mechanism could offer some positive suggestions toward prolonging the thermal-insulating effect of TBCs. [ABSTRACT FROM AUTHOR]

Main conclusion : New molecular markers were developed for targeting Thinopyrum intermedium 1St#2 chromosome, and novel FISH probe representing the terminal repeats was produced for identification of Thinopyrum chromosomes. Thinopyrum intermedium has been used as a valuable resource for improving the disease resistance and yield potential of wheat. A wheat- Th. intermedium ssp. trichophorum chromosome 1St#2 substitution and translocation has displayed superior grain protein and wet gluten content. With the aim to develop a number of chromosome 1St#2 specific molecular and cytogenetic markers, a high throughput, low-cost specific-locus amplified fragment sequencing (SLAF-seq) technology was used to compare the sequences between a wheat- Thinopyrum 1St#2 (1D) substitution and the related species Pseudoroegneria spicata (St genome, 2 n = 14). A total of 5142 polymorphic fragments were analyzed and 359 different SLAF markers for 1St#2 were predicted. Thirty-seven specific molecular markers were validated by PCR from 50 randomly selected SLAFs. Meanwhile, the distribution of transposable elements (TEs) at the family level between wheat and St genomes was compared using the SLAFs. A new oligo-nucleotide probe named Oligo-pSt122 from high SLAF reads was produced for fluorescence in situ hybridization (FISH), and was observed to hybridize to the terminal region of 1St#L and also onto the terminal heterochromatic region of Th. intermedium genomes. The genome-wide markers and repetitive based probe Oligo-pSt122 will be valuable for identifying Thinopyrum chromosome segments in wheat backgrounds. [ABSTRACT FROM AUTHOR]

Main conclusion: New wheat- Secale africanum chromosome 5R substitution and translocation lines were developed and identified by fluorescence in situ hybridization and molecular markers, and chromosome 5R specific genes responsible for grain hardness were isolated. The wild species, Secale africanum Stapf. (genome RR), serves as a valuable germplasm resource for increasing the diversity of cultivated rye ( S. cereale L., genome RR) and providing novel genes for wheat improvement. In the current study, fluorescence in situ hybridization (FISH) and molecular markers were applied to characterize new wheat- S. africanum chromosome 5R derivatives. Labeled rye genomic DNA (GISH) and the Oligo-probes pSc119.2 and pTa535 (FISH) were used to study a wheat- S. africanum amphiploid and a disomic 5R (5D) substitution, and to identify a T5DL.5RS translocation line and 5RS and 5RL isotelosome lines. Twenty-one molecular markers were mapped to chromosome 5R arms which will facilitate future rapid identification of 5R introgressions in wheat backgrounds. Comparative analysis of the molecular markers mapped on 5R with homoeologous regions in wheat confirmed a deletion on the chromosome T5DL.5RS, which suggests that the wheat- S. africanum Robertsonian translocation involving homologous group 5 may not be fully compensating. Complete coding sequences at the paralogous puroindoline-a ( Pina) and grain softness protein gene ( Gsp- 1) loci from S. africanum were cloned and localized onto the short arm of chromosome 5R. The S. africanum chromosome 5R substitution and translocation lines showed a reduction in the hardness index, which may be associated with the S. africanum- specific Pina and Gsp- 1 gene sequences. The present study reports the production of novel wheat- S. africanum chromosome 5R stripe rust resistant derivatives and new rye-specific molecular markers, which may find application in future use of wild Secale genome resources for grain quality studies and disease resistance breeding. [ABSTRACT FROM AUTHOR]

The synthetic aperture radar interferometry (InSAR) technique is an effective means to monitor ground deformation with high spatial resolution over large areas. However, it is still difficult to obtain the spatially continuous deformation map due to SAR decorrelation or SAR distortion, which greatly limits the usage of the InSAR deformation map, especially for spatiotemporal characterizing and mechanism inversion. Some conventional methods (e.g., spatial interpolation) rely only on the deformation measurements without considering the influence factors, leading to the inaccuracy of the deformation prediction. So, we propose a multifactor-based machine learning model, namely the K-RFR model, that combines K-means clustering and random forest regression algorithm to reconstruct a continuous deformation map, where the influence factors on ground deformation are considered, such as land use, geological engineering, and under groundwater extraction. We take the city of Xi'an, China, as the study area where SBAS-InSAR was used to obtain the ground deformation maps from 2012 to 2015. Fourteen influence factors are employed, including confined water level, change of confined water, phreatic water level, change of phreatic water, rainfall, ground fissures, stratigraphic lithology, landform, hydrogeology, engineering geology, type of land use, soil type, GDP, and DEM, where the K-means clustering method is used to reduce the influence of spatial heterogeneity. The study area is divided into three homogeneous regions and modeled independently, where the mean squared errors of region I–III are 2.9 mm, 2.3 mm, and 3.9 mm, respectively, and the mean absolute errors are 2.5 mm, 1.0 mm, and 2.8 mm, respectively. Finally, the continuous ground deformation maps of Xi'an from 2012 to 2015 are reconstructed. We compared the new method with two interpolation methods. Results show that the correlation coefficient between prediction and InSAR measurements of the new model is 0.94, whereas the ordinary Kriging method is 0.69, and the IDW method is only 0.63. This study provides an effective means to predict the continuous surface deformation over a large area. [ABSTRACT FROM AUTHOR]