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Background: As an important forage in arid and semi-arid regions, Agropyron cristatum provides livestock with exceptionally high nutritional value. Additionally, A. cristatum exhibits outstanding genetic characteristics to endure drought and disease. Therefore, rich genetic diversity serves as a cornerstone for the improvement of major food crops. The purposes of this study were to systematically describe mitogenome of A.cristatum and preliminarily analyze its internal variations. Result: The A. cristatum mitogenome was a single-ring molecular structure of 381,065 bp that comprised 52 genes, including 35 protein-coding, 3 rRNA and 14 tRNA genes. Among these, two pseudoprotein-coding genes and multiple copies of tRNA genes were observed. A total of 320 repetitive sequences was found to cover more than 10% of the mitogenome (105 simple sequences, 185 dispersed and 30 tandem repeats), which led to a large number of fragment rearrangements in the mitogenome of A. cristatum. Leucine was the most frequent amino acid (n = 1087,10.8%) in the protein-coding genes of A. cristatum mitogenome, and the highest usage codon was ATG (initiation codon). The number of A/T changes at the third base of the codon was much higher than that of G/C. Among 23 PCGs, the range of Pi values is from 0.0021 to 0.0539, with an average of 0.013. Additionally, 81 RNA editing sites were predicted, which were considerably fewer than those reported in other plant mitogenomes. Most of the RNA editing site base positions were concentrated at the first and second codon bases, which were C to T transitions. Moreover, we identified 95 sequence fragments (total length of 34, 343 bp) that were transferred from the chloroplast to mitochondria genes, introns, and intergenic regions. The stability of the tRNA genes was maintained during this process. Selection pressure analysis of 23 protein-coding genes shared by 15 Poaceae plants, showed that most genes were subjected to purifying selection during evolution, whereas rps4, cob, mttB, and ccmB underwent positive selection in different plants. Finally, a phylogenetic tree was constructed based on 22 plant mitogenomes, which showed that Agropyron plants have a high degree of independent heritability in Triticeae. Conclusion: The findings of this study provide new data for a better understanding of A. cristatum genes, and demonstrate that mitogenomes are suitable for the study of plant classifications, such as those of Agropyron. Moreover, it provides a reference for further exploration of the phylogenetic relationships within Agropyron species, and establishes a theoretical basis for the subsequent development and utilization of A. cristatum plant germplasm resources. [ABSTRACT FROM AUTHOR]

Abstract Background As an important forage in arid and semi-arid regions, Agropyron cristatum provides livestock with exceptionally high nutritional value. Additionally, A. cristatum exhibits outstanding genetic characteristics to endure drought and disease. Therefore, rich genetic diversity serves as a cornerstone for the improvement of major food crops. The purposes of this study were to systematically describe mitogenome of A.cristatum and preliminarily analyze its internal variations. Result The A. cristatum mitogenome was a single-ring molecular structure of 381,065 bp that comprised 52 genes, including 35 protein-coding, 3 rRNA and 14 tRNA genes. Among these, two pseudoprotein-coding genes and multiple copies of tRNA genes were observed. A total of 320 repetitive sequences was found to cover more than 10% of the mitogenome (105 simple sequences, 185 dispersed and 30 tandem repeats), which led to a large number of fragment rearrangements in the mitogenome of A. cristatum. Leucine was the most frequent amino acid (n = 1087,10.8%) in the protein-coding genes of A. cristatum mitogenome, and the highest usage codon was ATG (initiation codon). The number of A/T changes at the third base of the codon was much higher than that of G/C. Among 23 PCGs, the range of Pi values is from 0.0021 to 0.0539, with an average of 0.013. Additionally, 81 RNA editing sites were predicted, which were considerably fewer than those reported in other plant mitogenomes. Most of the RNA editing site base positions were concentrated at the first and second codon bases, which were C to T transitions. Moreover, we identified 95 sequence fragments (total length of 34, 343 bp) that were transferred from the chloroplast to mitochondria genes, introns, and intergenic regions. The stability of the tRNA genes was maintained during this process. Selection pressure analysis of 23 protein-coding genes shared by 15 Poaceae plants, showed that most genes were subjected to purifying selection during evolution, whereas rps4, cob, mttB, and ccmB underwent positive selection in different plants. Finally, a phylogenetic tree was constructed based on 22 plant mitogenomes, which showed that Agropyron plants have a high degree of independent heritability in Triticeae. Conclusion The findings of this study provide new data for a better understanding of A. cristatum genes, and demonstrate that mitogenomes are suitable for the study of plant classifications, such as those of Agropyron. Moreover, it provides a reference for further exploration of the phylogenetic relationships within Agropyron species, and establishes a theoretical basis for the subsequent development and utilization of A. cristatum plant germplasm resources.

Understanding the mechanisms underlying viable seed production of perennial bunchgrasses is critical to improving restoration and conservation success in Great Basin sagebrush steppe rangelands. We studied the effects of pre‐ and post‐anthesis flag‐leaf removal and post‐anthesis seed‐head shading on reproductive effort in two important rangeland restoration species, the exotic crested wheatgrass (Agropyron cristatum) and native squirreltail (Elymus elymoides). Flag‐leaf removal had distinct, species‐specific effects on seed filling. Pre‐anthesis flag‐leaf removal in crested wheatgrass reduced the proportion of filled seeds, while post‐anthesis removal did not. In contrast, squirreltail increased filled seed proportions regardless of flag‐leaf removal timing. Neither flag‐leaf removal treatment affected seed quality, as quantified by seed‐specific mass (in grams per square meter), which significantly reduced with seed‐head shading in both species. Seed‐head shading reduced total propagule production (unfilled + filled seeds) in crested wheatgrass but increased it in squirreltail, possibly due to our shading method protecting from seed‐head herbivory or high‐light stress. Flag‐leaf removal in the squirreltail also induced a negative shading effect on filled seed area, mass, and specific mass. These findings suggest flag leaves can modulate reproductive effort outside of seed provisioning, either by maintaining pre‐fertilized seed viability, as in crested wheatgrass, or acting as a competitive sink to the fully emerged seed‐head, as in squirreltail. Moreover, this study demonstrates photosynthetic activity by the seed‐head itself is critical to the expression of seed quality traits important to seedling establishment success of semiarid perennial bunchgrasses. [ABSTRACT FROM AUTHOR]

Abstract Understanding the mechanisms underlying viable seed production of perennial bunchgrasses is critical to improving restoration and conservation success in Great Basin sagebrush steppe rangelands. We studied the effects of pre‐ and post‐anthesis flag‐leaf removal and post‐anthesis seed‐head shading on reproductive effort in two important rangeland restoration species, the exotic crested wheatgrass (Agropyron cristatum) and native squirreltail (Elymus elymoides). Flag‐leaf removal had distinct, species‐specific effects on seed filling. Pre‐anthesis flag‐leaf removal in crested wheatgrass reduced the proportion of filled seeds, while post‐anthesis removal did not. In contrast, squirreltail increased filled seed proportions regardless of flag‐leaf removal timing. Neither flag‐leaf removal treatment affected seed quality, as quantified by seed‐specific mass (in grams per square meter), which significantly reduced with seed‐head shading in both species. Seed‐head shading reduced total propagule production (unfilled + filled seeds) in crested wheatgrass but increased it in squirreltail, possibly due to our shading method protecting from seed‐head herbivory or high‐light stress. Flag‐leaf removal in the squirreltail also induced a negative shading effect on filled seed area, mass, and specific mass. These findings suggest flag leaves can modulate reproductive effort outside of seed provisioning, either by maintaining pre‐fertilized seed viability, as in crested wheatgrass, or acting as a competitive sink to the fully emerged seed‐head, as in squirreltail. Moreover, this study demonstrates photosynthetic activity by the seed‐head itself is critical to the expression of seed quality traits important to seedling establishment success of semiarid perennial bunchgrasses.

Agropyron cristatum (2n = 4x = 28, PPPP), which harbours many high-yield and disease-resistance genes, is a promising donor for wheat improvement. Narrow genetic diversity and the trade-off between grain weight and grain number have become bottlenecks for increasing grain yield in wheat. In this study, a novel translocation line, WAT650l, was derived from the chromosome 6P addition line 4844–12, which can simultaneously increase both grain number per spike (GNS) and thousand-grain weight (TGW). Cytological analysis and molecular marker analysis revealed that WAT650l was a 5BL·5BS-6PL (bin 12–17) translocation line. Assessment of agronomic traits and analysis of the BC4F2 and BC5F2 populations suggested that the 6PL terminal chromosome segment in WAT650l resulted in increased grain number per spike (average increased by 14.07 grains), thousand-grain weight (average increased by 4.31 g), flag leaf length, plant height, spikelet number per spike and kernel number per spikelet during the two growing seasons of 2020–2021 and 2021–2022. Additionally, the increased GNS locus and high-TGW locus of WAT650l were mapped to the bins 16–17 and 12–13, respectively, on chromosome 6PL by genetic population analysis of three translocation lines. In summary, we provide a valuable germplasm resource for broadening the genetic base of wheat and overcoming the negative relationship between GNS and TGW in wheat breeding.

Wide hybridization is a strategy for broadening the genetic basis of wheat. Because an efficient method for inducing wheat–alien chromosome translocations will allow producing useful germplasm, it is desirable to discover new genes that induce chromosomal variation. In this study, chromosome 5P from A. cristatum was shown to induce many types of chromosomal structural variation in a common wheat background, including nonhomoeologous chromosome translocations, as revealed by genomic in situ hybridization, fluorescence in situ hybridization, and DNA marker analysis. Aberrant meiosis was associated with chromosomal structural variation, and aberrant meiotic behavior was observed in wheat–A. cristatum 5P monosomic and disomic addition lines, suggesting that the effect of chromosome 5P was independent of the number of chromosome 5P copies. Chromosome 5P disturbed homologous chromosome pairing at pachytene stage in a common wheat background, resulting in a high frequency of univalent formation and reduced crossing over. Thirteen genes involved in DNA repair or chromatin remodeling, including RAD52-like and MSH6 genes, were differentially expressed (upregulated) in wheat–A. cristatum 5P addition lines according to transcriptome analysis, implicating chromosome 5P in the process of meiotic double-strand break repair. These findings provide a new, efficient tool for inducing wheat–alien chromosome translocations and producing new germplasm.

Wild relatives of wheat are essential gene pools for broadening the genetic basis of wheat. Chromosome rearrangements and genomic variation in alien chromosomes are widespread. Knowledge of the genetic variation between alien homologous chromosomes is valuable for discovering and utilizing alien genes. In this study, we found that 5113 and II-30-5, two wheat–A. cristatum 6P addition lines, exhibited considerable differences in heading date, grain number per spike, and grain weight. Genome resequencing and transcriptome analysis revealed significant differences in the 6P chromosomes of the two addition lines, including 143,511 single-nucleotide polymorphisms, 62,103 insertion/deletion polymorphisms, and 757 differentially expressed genes. Intriguingly, genomic variations were mainly distributed in the middle of the chromosome arms and the proximal centromere region. GO and KEGG analyses of the variant genes and differentially expressed genes showed the enrichment of genes involved in the circadian rhythm, carbon metabolism, carbon fixation, and lipid metabolism, suggesting that the differential genes on the 6P chromosome are closely related to the phenotypic differences. For example, the photosynthesis-related genes PsbA, PsbT, and YCF48 were upregulated in II-30-5 compared with 5113. ACS and FabG are related to carbon fixation and fatty acid biosynthesis, respectively, and both carried modification variations and were upregulated in 5113 relative to II-30-5. Therefore, this study provides important guidance for cloning desirable genes from alien homologous chromosomes and for their effective utilization in wheat improvement. [ABSTRACT FROM AUTHOR]

Agropyron cristatum (P genome) is a Triticeae species from the wheat tertiary gene pool which has economic importance as forage and also displays traits beneficial to wheat. Resistance to leaf rust was previously mapped to the short arm of chromosome 1P (1PS) in A. cristatum by the development of a compensating Robertsonian translocation involving chromosome arm 1PS and the long arm of wheat chromosome 1B (1BL). In this study, chromosome arm 1PS was engineered using the ph1b mutation to induce 1BS/1PS homoeologous recombination and to obtain new translocations with shortened fragments of chromosome arm 1PS. Two translocations with different alien fragment sizes were identified by genomic in situ hybridization, wheat 1BS- and 1PS-specific molecular markers and gene-specific markers for glutenin, Glu-B3 and gliadin Gli-B1 seed storage protein. One translocation (called type 1) replaces a proximal segment of 1PS chromatin, and the other (called type 2) replaces a distal 1PS segment and introduces the Glu-B3 and Gli-B1 wheat storage protein loci. Six specific EST-STS markers for chromosome arm 1PS amplified PCR products in the recombinant type 2 translocation line. Resistance analysis showed that the type 2 translocation was highly resistant to a virulent race of leaf rust pathogen. The new wheat–A. cristatum translocations obtained yield material with seedling plant resistance to leaf rust and seed storage protein loci. [ABSTRACT FROM AUTHOR]

Agropyron cristatum (L.) Gaertn. (2n = 4x = 28, PPPP), which is a wild relative of common wheat and has a P genome, has many excellent characteristics (for example, it is disease-resistant, stress-resistant, and high yielding) and has important utilization values for the genetic improvement of wheat. In this study, the wheat–A. cristatum 3P addition line I-27 and 3P(3B) substitution line I-15 were identified for the first time via in situ hybridization (ISH) and specific molecular marker (EST-STS) from wheat–A. cristatum-derived lines, which are a representative and important material for the utilization of the excellent genes from the A. cristatum chromosome 3P for wheat genetic improvement. In terms of agronomic traits, the tiller number and spike length of the 3P addition line I-27 were significantly higher than those of Fukuhokomugi. The spike length and spikelet number per spike of the 3P substitution line I-15 were significantly greater than those of Fukuho. Additionally, the wheat–A. cristatum 3P substitution line I-15 was resistant to wheat leaf rust. The generation of the 3P addition line I-27 and the 3P substitution line I-15 was essential for the transfer of the excellent genes of the A. cristatum 3P chromosome into common wheat, and resulted in the wheat–A. cristatum addition line containing a complete set of genetic research materials, laying the foundation for comparative studies of the P genome and subsequent fine mapping. [ABSTRACT FROM AUTHOR]

As one of the serious diseases of wheat, powdery mildew (Blumeria graminis f. sp. tritici) is a long-term threat to wheat production. Therefore, it is of great significance to explore new powdery mildew-resistant genes for breeding. The wild relative species of wheat provide gene resources for resistance to powdery mildew breeding. Agropyron cristatum (2n = 4x = 28, genomes PPPP) is an important wild relative of wheat, carrying excellent genes for high yield, disease resistance, and stress resistance, which can be used for wheat improvement. To understand the molecular mechanism of powdery mildew resistance in the wheat-A. cristatum translocation line WAT2020-17-6, transcriptome sequencing was performed, and the resistance genes were analyzed by weighted gene co-expression network analysis (WGCNA). In the results, 42,845 differentially expressed genes were identified and divided into 18 modules, of which six modules were highly correlated with powdery mildew resistance. Gene ontology (GO) enrichment analysis showed that the six interested modules related to powdery mildew resistance were significantly enriched in N-methyltransferase activity, autophagy, mRNA splicing via spliceosome, chloroplast envelope, and AMP binding. The candidate hub genes of the interested modules were further identified, and their regulatory relationships were analyzed based on co-expression data. The temporal expression pattern of the 12 hub genes was verified within 96 h after powdery mildew inoculation by RT-PCR assay. In this study, we preliminarily explained the resistance mechanism of the wheat-A. cristatum translocation lines and obtained the hub candidate genes, which laid a foundation in the exploration of resistance genes in A. cristatum for powdery mildew-resistant breeding in wheat. [ABSTRACT FROM AUTHOR]

Fluorescence in situ hybridization (FISH) is a basic tool that is widely used in cytogenetic research. The detection efficiency of conventional FISH is limited due to its time-consuming nature. Oligonucleotide (oligo) probes with fluorescent labels have been applied in non-denaturing FISH (ND-FISH) assays, which greatly streamline experimental processes and save costs and time. Agropyron cristatum, which contains one basic genome, "P," is a vital wild relative for wheat improvement. However, oligo probes for detecting P-genome chromosomes based on ND-FISH assays have not been reported. In this study, according to the distribution of transposable elements (TEs) in Triticeae genomes, 94 oligo probes were designed based on three types of A. cristatum sequences. ND-FISH validation showed that 12 single oligo probes generated a stable and obvious hybridization signal on whole P chromosomes in the wheat background. To improve signal intensity, mixed probes (Oligo-pAc) were prepared by using the 12 successful probes and validated in the diploid accession A. cristatum Z1842, a small segmental translocation line and six allopolyploid wild relatives containing the P genome. The signals of Oligo-pAc covered the entire chromosomes of A. cristatum and were more intense than those of single probes. The results indicate that Oligo-pAc can replace conventional genomic in situ hybridization (GISH) probes to identify P chromosomes or segments in non-P-genome backgrounds. Finally, we provide a rapid and efficient method specifically for detecting P chromosomes in wheat backgrounds by combining the Oligo-pAc probe with the Oligo-pSc119.2–1 and Oligo-pTa535-1 probes, which can replace conventional sequential GISH/FISH assays. Altogether, we developed a set of oligo probes based on the ND-FISH assays to identify P-genome chromosomes, which can promote utilization of A. cristatum in wheat improvement programs. [ABSTRACT FROM AUTHOR]

Wheat leaf rust (caused by Puccinia triticina Erikss.) is among the major diseases of common wheat. The lack of resistance genes to leaf rust has limited the development of wheat cultivars. Wheat–Agropyron cristatum (A. cristatum) 2P addition line II-9-3 has been shown to provide broad-spectrum immunity to leaf rust. To identify the specific A. cristatum resistance genes and related regulatory pathways in II-9-3, we conducted a comparative transcriptome analysis of inoculated and uninoculated leaves of the resistant addition line II-9-3 and the susceptible cultivar Fukuhokomugi (Fukuho). The results showed that there were 66 A. cristatum differentially expressed genes (DEGs) and 1389 wheat DEGs in II-9-3 during P. triticina infection. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment and gene set enrichment analysis (GSEA) revealed that the DEGs of II-9-3 were associated with plant–pathogen interaction, MAPK signaling pathway–plant, plant hormone signal transduction, glutathione metabolism, and phenylpropanoid biosynthesis. Furthermore, many defense-related A. cristatum genes, such as two NLR genes, seven receptor kinase-encoding genes, and four transcription factor-encoding genes, were identified. Our results indicated that the key step of resistance to leaf rust involves, firstly, the gene expression of chromosome 2P upstream of the immune pathway and, secondly, the effect of chromosome 2P on the co-expression of wheat genes in II-9-3. The disease resistance regulatory pathways and related genes in the addition line II-9-3 thus could play a critical role in the effective utilization of innovative resources for leaf rust resistance in wheat breeding. [ABSTRACT FROM AUTHOR]

Crested wheatgrass (Agropyron cristatum), a wild relative of wheat, is an attractive source of genes and alleles for their improvement. Its wider use is hampered by limited knowledge of its complex genome. In this work, individual chromosomes were purified by flow sorting, and DNA shotgun sequencing was performed. The annotation of chromosome-specific sequences characterized the DNA-repeat content and led to the identification of genic sequences. Among them, genic sequences homologous to genes conferring plant disease resistance and involved in plant tolerance to biotic and abiotic stress were identified. Genes belonging to the important groups for breeders involved in different functional categories were found. The analysis of the DNA-repeat content identified a new LTR element, Agrocen, which is enriched in centromeric regions. The colocalization of the element with the centromeric histone H3 variant CENH3 suggested its functional role in the grass centromere. Finally, 159 polymorphic simple-sequence-repeat (SSR) markers were identified, with 72 of them being chromosome- or chromosome-arm-specific, 16 mapping to more than one chromosome, and 71 mapping to all the Agropyron chromosomes. The markers were used to characterize orthologous relationships between A. cristatum and common wheat that will facilitate the introgression breeding of wheat using A. cristatum. [ABSTRACT FROM AUTHOR]

Agropyroncristatum (L.) Gaertn. (2n = 28, PPPP), a relative of wheat, carries desirable genes associated with high yield, disease resistance, and stress resistance, which is an important resource for wheat genetic improvement. The long arm of A. cristatum chromosome 2P carries favorable genes conferring powdery mildew and leaf rust resistance, and two wheat–A. cristatum 2P translocation lines, 2PT3 and 2PT5, with a large segment of 2P chromatin were obtained. In this study, 2PT3 and 2PT5 translocation lines with powdery mildew and leaf rust resistance genes were used to induce translocations of different chromosomal sizes via ionizing radiation. According to cytological characterization, 10 of those plants were new wheat–A. cristatum 2P small-chromosome segment translocation lines with reduced 2P chromatin, and 6 plants represented introgression lines without visible 2P chromosomal fragments. Moreover, four lines were resistant to both powdery mildew and leaf rust, while two lines were resistant only to leaf rust. [ABSTRACT FROM AUTHOR]

As an important wheat wild relative, the P genome of Agropyron cristatum (L.) Gaertn. (2 n = 4 x = 28) is very valuable for wheat improvement. A complete set of wheat- A. cristatum disomic addition lines is the basis for studying the genetic behavior of alien homoeologous chromosomes and exploring and utilizing the excellent genes. In this study, a wheat- A. cristatum derivative II-11-1 was proven to contain a pair of 5P chromosomes and a pair of 2P chromosomes with 42 wheat chromosomes by analyzing the fluorescence in situ hybridization (FISH) and expressed sequence tag (EST) markers. Additionally, cytological identification and field investigation showed that the 5P chromosome can weaken the homologous pairing of wheat chromosomes and promote the pairing between homoeologous chromosomes. This provides new materials for studying the mechanism of the alien gene affecting the homologous chromosome pairing and promoting the homoeologous pairing of wheat. In addition, chromosomal structural variants have been identified in the progeny of II-11-1. Therefore, the novel 5P addition line might be used as an important genetic material to widen the genetic resources of wheat. [ABSTRACT FROM AUTHOR]

As an important wheat wild relative, the P genome of Agropyron cristatum (L.) Gaertn. (2n = 4x = 28) is very valuable for wheat improvement. A complete set of wheat-A. cristatum disomic addition lines is the basis for studying the genetic behavior of alien homoeologous chromosomes and exploring and utilizing the excellent genes. In this study, a wheat-A. cristatum derivative II-11-1 was proven to contain a pair of 5P chromosomes and a pair of 2P chromosomes with 42 wheat chromosomes by analyzing the fluorescence in situ hybridization (FISH) and expressed sequence tag (EST) markers. Additionally, cytological identification and field investigation showed that the 5P chromosome can weaken the homologous pairing of wheat chromosomes and promote the pairing between homoeologous chromosomes. This provides new materials for studying the mechanism of the alien gene affecting the homologous chromosome pairing and promoting the homoeologous pairing of wheat. In addition, chromosomal structural variants have been identified in the progeny of II-11-1. Therefore, the novel 5P addition line might be used as an important genetic material to widen the genetic resources of wheat.

Agropyron cristatum (P genome) is a Triticeae species from the wheat tertiary gene pool which has economic importance as forage and also displays traits beneficial to wheat. Resistance to leaf rust was previously mapped to the short arm of chromosome 1P (1PS) in A. cristatum by the development of a compensating Robertsonian translocation involving chromosome arm 1PS and the long arm of wheat chromosome 1B (1BL). In this study, chromosome arm 1PS was engineered using the ph1b mutation to induce 1BS/1PS homoeologous recombination and to obtain new translocations with shortened fragments of chromosome arm 1PS. Two translocations with different alien fragment sizes were identified by genomic in situ hybridization, wheat 1BS- and 1PS-specific molecular markers and gene-specific markers for glutenin, Glu-B3 and gliadin Gli-B1 seed storage protein. One translocation (called type 1) replaces a proximal segment of 1PS chromatin, and the other (called type 2) replaces a distal 1PS segment and introduces the Glu-B3 and Gli-B1 wheat storage protein loci. Six specific EST-STS markers for chromosome arm 1PS amplified PCR products in the recombinant type 2 translocation line. Resistance analysis showed that the type 2 translocation was highly resistant to a virulent race of leaf rust pathogen. The new wheat–A. cristatum translocations obtained yield material with seedling plant resistance to leaf rust and seed storage protein loci.

As one of the serious diseases of wheat, powdery mildew (Blumeria graminis f. sp. tritici) is a long-term threat to wheat production. Therefore, it is of great significance to explore new powdery mildew-resistant genes for breeding. The wild relative species of wheat provide gene resources for resistance to powdery mildew breeding. Agropyron cristatum (2n = 4x = 28, genomes PPPP) is an important wild relative of wheat, carrying excellent genes for high yield, disease resistance, and stress resistance, which can be used for wheat improvement. To understand the molecular mechanism of powdery mildew resistance in the wheat-A. cristatum translocation line WAT2020-17-6, transcriptome sequencing was performed, and the resistance genes were analyzed by weighted gene co-expression network analysis (WGCNA). In the results, 42,845 differentially expressed genes were identified and divided into 18 modules, of which six modules were highly correlated with powdery mildew resistance. Gene ontology (GO) enrichment analysis showed that the six interested modules related to powdery mildew resistance were significantly enriched in N-methyltransferase activity, autophagy, mRNA splicing via spliceosome, chloroplast envelope, and AMP binding. The candidate hub genes of the interested modules were further identified, and their regulatory relationships were analyzed based on co-expression data. The temporal expression pattern of the 12 hub genes was verified within 96 h after powdery mildew inoculation by RT-PCR assay. In this study, we preliminarily explained the resistance mechanism of the wheat-A. cristatum translocation lines and obtained the hub candidate genes, which laid a foundation in the exploration of resistance genes in A. cristatum for powdery mildew-resistant breeding in wheat.

Abstract Background Agropyron cristatum (L.) Gaertn. (2n = 4x = 28; genomes PPPP) is a wild relative of common wheat (Triticum aestivum L.) and provides many desirable genetic resources for wheat improvement. However, there is still a lack of reference genome and transcriptome information for A. cristatum, which severely impedes functional and molecular breeding studies. Results Single-molecule long-read sequencing technology from Pacific Biosciences (PacBio) was used to sequence full-length cDNA from a mixture of leaves, roots, stems and caryopses and constructed the first full-length transcriptome dataset of A. cristatum, which comprised 44,372 transcripts. As expected, the PacBio transcripts were generally longer and more complete than the transcripts assembled via the Illumina sequencing platform in previous studies. By analyzing RNA-Seq data, we identified tissue-enriched transcripts and assessed their GO term enrichment; the results indicated that tissue-enriched transcripts were enriched for particular molecular functions that varied by tissue. We identified 3398 novel and 1352 A. cristatum-specific transcripts compared with the wheat gene model set. To better apply this A. cristatum transcriptome, the A. cristatum transcripts were integrated with the wheat genome as a reference sequence to try to identify candidate A. cristatum transcripts associated with thousand-grain weight in a wheat-A. cristatum translocation line, Pubing 3035. Conclusions Full-length transcriptome sequences were used in our study. The present study not only provides comprehensive transcriptomic insights and information for A. cristatum but also proposes a new method for exploring the functional genes of wheat relatives under a wheat genetic background. The sequence data have been deposited in the NCBI under BioProject accession number PRJNA534411.

Agropyron cristatum (L.) Gaertn. (2n = 4x = 28, PPPP), one of the most important wild relatives of wheat, harbors many desirable genes for wheat genetic improvement. Development of wheat-A. cristatum translocation lines with superior agronomic traits facilitates wheat genetic improvement. In this study, 5106-DS was identified to be a wheat-A. cristatum 6P (6D) disomic substitution line using cytogenetic identification and molecular markers analysis, which displayed higher thousand-grain weight than its wheat parent Triticum aestivum cv. Fukuhokomugi (2n = 6x = 42, AABBDD). Analysis of its backcross populations indicated that there might be genes conferring increased grain weight and width on the chromosome 6P of 5106-DS. In the backcross population, we found three plants as Robertsonian translocation lines, created by chromosome centric breakage-fusion. Among them, there are one T6DS·6PL and two T6PS·6DL Robertsonian translocation lines. Additionally, the centromeres of these three translocation lines were determined to be fused centromeres of 6D and 6P using the probes pAcCR1 and pCCS1. The development of Robertsonian translocation lines would promote the utilization of A. cristatum chromosome 6P in wheat improvement. [ABSTRACT FROM AUTHOR]

To study of forage quantity and quality traits of eleven accessions of two varieties (subspecies) of Elymus hispidus var. hispidus and Elymus hispidus var. ١i٦٦osus and six accessions of Agropyron cristatum were carried out in two separate experiments using randomized complete block design with three replications in Khorasan-e-Razavi Agricultural and Natural Resources Research and Education Center. The seeds of the above accessions were sown in greenhouse conditions at a temperature of 20 ±2 ° C, and 5 of them were planted in each plastic pot, and after full establishment, the seedlings were transferred to the main soil. To fully establish the seedlings in the main field and ensure the purity of the accessions, the first year of the project was considered as the year of establishment. The comparison between the varieties of E. hispidus showed that the villosus variety had higher forage yield, number of spikes, and spike length compared to hispidus. In contrast, the percentage of plant establishment was higher in the hispidus variety. hr terms of forage quality, there is no difference between the E. hispidus accessions. In ١illosus variety, Chahar-Tagh accession due to high total dry matter (DM) yield (7732 kg ha-1), high dry matter digestibility (DMD) (43.6%), high soluble carbohydrates (8.8%), and consequently low acid detergent fiber (43.7%) was superior to other accessions. In species A.cristatum 1727 accession had the lowest height, the lowest forage yield, and the highest number of spikes. Among the accessions of A. cristatum, the highest and lowest annual dry matter yield of 12974 and 5692 kg ha-1 per year was achieved in 208 and 1727 accessions, respectively. Accessions 208 originating in Isfahan also had a significant percentage of digestibility and protein. In general, the results of this study showed that the accessions of the villosus variety, as well as the 208 accession, were superior to other accessions. [ABSTRACT FROM AUTHOR]

Salinity, which is more common in semi-arid and arid areas, is increasing every day with climate change, poor quality irrigation water, and soil structure. High salt concentration restricts plant production and causes productivity loss in agriculture. To sustain agriculture in saline soils, the determination of plant species resistant to salinity comes into prominence in areas with salinity problems. For this reason, the research was performed to determine the nutrients (Ca, Mg, P, S, B, Cu, Fe, Mn, and Zn) accumulating at aboveground and underground parts of the three different Agropyron species, namely Agropyron cristatum, A.desertorum and A. elongatum (Syn. Elymus elongatus) under different salt concentrations (control, 5, 10 and 15 EC dS m-1NaCl). A. cristatum, A.desertorum, and A. elongatumspecies, which are quality forage crops grown in drought and salinity conditions, were determined to Ca content 1.03%, 1.01%, and 1.49% respectively, and Mg content. 0.13%, 0.11% and 0.20% respectively. As salt concentrations increased, Ca, Mg, Cu, Fe, Mn, and Zn in the aboveground organ has increased compared to the control treatment but decreased in the underground organs. Ca and Mg content of the aboveground organs of A. elongatum grown at 10 EC dS m-1NaCl increased by 204% and 98%, respectively, compared to the control. Fe content of the wheatgrassspecies in saline conditions was found quite high, and an average of 788 mg kg-1 of Fe was found in underground organswhile this value was as 430mg kg-1 in aboveground organs. The results showed that A. elongatum had more nutrient elements in both underground and aboveground parts of the crop by comparison to the other two Agropyron speciesunder increased salinity levels. [ABSTRACT FROM AUTHOR]

Flowering time is important in the adaptation of crop plants to different environments and impacts the economic value of agricultural crops. Wheatgrass is a perennial Triticeae species and one of the most important grasses for pasture and forage in temperate regions of the world. Late heading is of interest in forage crop breeding programmes. Increasing the time to heading by molecular means may be facilitated by the identification and characterization of floral genes. In addition, the characterization of orthologous genes in wheatgrass is useful for establishing genetic relationships between grasses. In this study, we characterized a wheatgrass orthologue of the hexaploid wheat VRN‐A1 gene involved in the vernalization response. High sequence similarity of this gene, designated VRN‐P1, to both VRN‐A1 and VRN‐H1 and its localization on the 5PL chromosome arm in Agropyron cristatum indicated that VRN‐P1 is orthologous to VRN1 from wheat and barley. VRN‐P1 retains the VRN1 exon/intron organization and encodes a MADS‐box transcription factor. Phylogenetic and amino acid analyses confirmed that the isolated sequence represents VRN1. Furthermore, phylogenetic analysis of the deduced protein sequence revealed an intimate genetic relationship between VRN‐P1 and VRN1 from Triticeae species. [ABSTRACT FROM AUTHOR]

Agropyron cristatum (L.) Gaertn. (A. cristatum), which is an important wild relative of wheat (Triticum aestivum L.), exhibits multiple agronomic traits that are valuable for the genetic improvement of wheat. II-30-5 is derived from the BC3F1 progeny between wheat cv. Fukuhokomugi (Fukuho) and A. cristatum (2n = 4x = 28, PPPP). In this study, II-30-5 was proven to be a novel wheat-A. cristatum disomic 6P addition line by cytogenetics and A. cristatum expressed sequence tag-sequence-tagged site (EST-STS) markers. II-30-5 possessed several elite agronomic traits, such as good plant type, erect leaf position, short flag leaf, high thousand-grain weight, and high resistance to powdery mildew and leaf rust. Chromosomal rearrangements led to multiple addition lines in the same group of homologous group. Evaluation of the agronomic traits of different 6P addition lines showed that different 6P addition lines contain specific traits. In the same homologous group, the production of multiple addition lines increases the types of genetic variation for wheat improvement. [ABSTRACT FROM AUTHOR]

Agropyron cristatum, a wild relative of common wheat (Triticum aestivum L.), provides many desirable genetic resources for wheat improvement, such as tolerance to cold, drought, and disease. To transfer and utilize these desirable genes, in this study, two wheat-A. cristatum derivatives II-13 and II-23 were identified and analyzed. We found that the number of root tip cell chromosomes was 44 in both II-13 and II-23, but there were four and six P genome chromosomes in II-13 and II-23, respectively, based on genomic in situ hybridization (GISH). The chromosome configurations of II-13 and II-23 were both 2n=22II by the meiotic analysis of pollen mother cells (PMCs) at metaphase I, indicating that there were two and three pairs of P chromosomes in II-13 and II-23, respectively. Notably, wheat chromosome 7D was absent in derivative line II-13 while II-23 lacked chromosomes 4B and 7A based on SSR analysis combining fluorescence in situ hybridization (FISH) analysis with pAs1 and pSc119.2 as probes. Chromosomes 2P and 7P were detected in both II-13 and II-23. Another pair of P genome chromosomes in II-23 was determined to be 4P based on expressed-sequences tags-sequence tagged sites (EST-STS) markers specific to A. cristatum and FISH with probes pAcTRT1 and pAcpCR2. Overall, these results suggest that II-13 was a 7P (7D) substitution line with one pair of additional 2P chromosomes and II-23 was a multiple 4P (4B), 7P (7A) substitution line with one pair of additional 2P chromosomes. Moreover, we obtained six alien disomic addition lines and five alien disomic substitution lines by backcrossing. These new materials will allow desirable genes from A. cristatum to be used in common wheat.

The sucrose non-fermenting-1 related protein kinase 2 (SnRK2) family plays an important role in the response to abiotic stress. To characterize the function of the SnRK2 gene from Agropyron cristatum in stress protection, we cloned the complete coding sequence of the AcSnRK2.11 gene from A. cristatum and generated AcSnRK2.11-overexpressing tobacco lines. The open reading frame of AcSnRK2.11 was 1083 bp in length and encoded a polypeptide of 360 amino acid residues. The sequence analysis results showed that AcSnRK2.11 contained conserved domains typified in SnRK2 protein kinases. Subcellular localization analysis showed that AcSnRK2.11 was located in the nucleus. AcSnRK2.11 was constitutively expressed in all of the examined tissues, and its transcription was induced by cold, dehydration, and salt stress, but not by abscisic acid treatment. Overexpression of the AcSnRK2.11 gene conferred freezing tolerance in yeast. AcSnRK2.11-overexpressing tobacco lines showed higher tolerance to freezing stress than did wild-type (WT) based on higher survival rates, lower malondialdehyde content and increased relative water content retention, chlorophyll yields, superoxide dismutase activities, reactive oxygen species content, peroxidase levels, and soluble carbohydrates under low-temperature conditions. The transcripts of NtDREB1, NtDREB2, NtERD10A, NtERD10B, NtERD10C, NtERD10D, NtMnSOD, NtCDPK15, and NtMPK9 in AcSnRK2.11-overexpressing tobacco lines were more abundant than in WT plants under low-temperature stress. These results suggest that AcSnRK2.11 may function as a regulatory factor associated with a cold-response pathway and could be used in plant breeding for cold resistance. [ABSTRACT FROM AUTHOR]

Heavy metals and polycyclic aromatic hydrocarbons (PAHs) co-contamination in the soil is widespread. Phytoremediation is often used to remediate co-contaminated soil, but few studies focused on the effects of nickel on the dissipation and uptake of pyrene in phytoremediation. The dissipation of pyrene, the uptake, and distribution of pyrene in Agropyron cristatum L. (A. cristatum) were investigated in this study in the presence of nickel. The pyrene removal rate in single pyrene-contaminated soil with A. cristatum cultivation (48.97%) was the highest, which was higher than that of the co-contamination (47.88%). This was due to the high soil microbial activity and high dissolved organic matter (DOM) contents. In single pyrene-contaminated soil, pyrene was mainly accumulated in the soluble fraction in shoots and on the cell wall in roots of A. cristatuma. Besides, nickel could promote the adsorption of pyrene on the cell wall. Pyrene in A. cristatum could be transported through the apoplast and symplast, and the pyrene contents in the symplast were 2–3 times that of the apoplast. The uptake of pyrene by A. cristatum included both active absorption and passive transportation. Active absorption involved H+ transport and energy conversion processes, and passive transport was associated with water protein channels. [ABSTRACT FROM AUTHOR]

Background: Agropyron cristatum (L.) Gaertn. (2n = 4x = 28; genomes PPPP) is a wild relative of common wheat (Triticum aestivum L.) and provides many desirable genetic resources for wheat improvement. However, there is still a lack of reference genome and transcriptome information for A. cristatum, which severely impedes functional and molecular breeding studies. Results: Single-molecule long-read sequencing technology from Pacific Biosciences (PacBio) was used to sequence full-length cDNA from a mixture of leaves, roots, stems and caryopses and constructed the first full-length transcriptome dataset of A. cristatum, which comprised 44,372 transcripts. As expected, the PacBio transcripts were generally longer and more complete than the transcripts assembled via the Illumina sequencing platform in previous studies. By analyzing RNA-Seq data, we identified tissue-enriched transcripts and assessed their GO term enrichment; the results indicated that tissue-enriched transcripts were enriched for particular molecular functions that varied by tissue. We identified 3398 novel and 1352 A. cristatum-specific transcripts compared with the wheat gene model set. To better apply this A. cristatum transcriptome, the A. cristatum transcripts were integrated with the wheat genome as a reference sequence to try to identify candidate A. cristatum transcripts associated with thousand-grain weight in a wheat-A. cristatum translocation line, Pubing 3035. Conclusions: Full-length transcriptome sequences were used in our study. The present study not only provides comprehensive transcriptomic insights and information for A. cristatum but also proposes a new method for exploring the functional genes of wheat relatives under a wheat genetic background. The sequence data have been deposited in the NCBI under BioProject accession number PRJNA534411. [ABSTRACT FROM AUTHOR]

Crested wheatgrass (Agropyron cristatum L. Gaertn., genome P), included in the Triticeae tribe (family Poaceae), is one of the most important grasses in temperate regions. It has been valued as a donor of important agronomic traits for wheat improvement, including tolerance to cold, drought, and high salinity, as well as resistance to leaf rust, stripe rust, and powdery mildew. For successful incorporation of beneficial alleles into wheat, it is essential that recombination between wheat and A. cristatum chromosomes occurs. In this work, we analysed chromosome associations during meiosis in wheat lines carrying chromosome introgressions from A. cristatum chromosomes 5P and 6P in the presence and absence of Ph1 locus using fluorescence in situ hybridisation. The results showed that the Ph1 locus does not affect chromosome associations between A. cristatum and wheat chromosomes because there were no interspecific chromosome associations; therefore, no recombination between chromosomes from wheat and Agropyron were observed in the absence of the Ph1 locus. The 5P and 6P A. cristatum chromosomes do not have a suppressor effect on the Ph1 locus. Wheat univalents in metaphase I suggest that Agropyron chromosomes might carry genes having a role in wheat homologous chromosome associations. Putative effect of the Agropyron genes on wheat chromosome associations does not interact with the Ph1 locus.

Wildfire size and frequency have increased in the western United States since the 1950s, but it is unclear how seeding treatments have altered fire regimes in arid steppe systems. We analyzed how the number of fires since 1955 and the fire return interval and frequency between 1995 and 2015 responded to seeding treatments, anthropogenic features, and abiotic landscape variables in Wyoming big sagebrush ecosystems. Arid sites had more fires than mesic sites and fire return intervals were shortest on locations first treated between 1975 and 2000. Sites drill seeded before the most recent fire had fewer, less frequent fires with longer fire return intervals (15–20 years) than aerially seeded sites (intervals of 5–8 years). The response of fire regime variables at unseeded sites fell between those of aerial and drill seeding. Increased moisture availability resulted in decreased fire frequency between 1994 and 2014 and the total number of fires since 1955 on sites with unseeded and aerially pre-fire seeding, but fire regimes did not change when drill seeded. Greater annual grass biomass likely contributed to frequent fires in the arid region. In Wyoming big sagebrush steppe, drill seeding treatments reduced wildfire risk relative to aerial seeded or unseeded sites.

Key message: An enhanced-grain number per spike locus from Agropyron cristatum 6PL was mapped onto 6PL (0.27–0.51) via deletion mapping, and its effect was further verified by evaluating a newly created translocation line. Agropyron cristatum (2n = 4x = 28, PPPP) is an important wild relative of common wheat and carries many desirable yield-related traits. The wheat-A. cristatum 6P disomic addition line 4844-12 exhibited high grain number per spike (GNS), high spikelet number per spike (SNS), and high kernel number per spikelet (KNS). In this study, five A. cristatum 6P deletion lines, five wheat-A. cristatum 6P translocation lines, and genetic populations of these lines were used to map the enhanced-GNS locus from A. cristatum chromosome 6P, which were genotyped via genomic in situ hybridization, fluorescence in situ hybridization, or molecular markers. According to the evaluation of the agronomic traits in four growing seasons (2014–2015, 2015–2016, 2016–2017, and 2017–2018), we found that the deletion lines and the translocation lines carrying the long arm of A. cristatum chromosome 6P (6PL) exhibited high GNS, SNS, and KNS, and the enhanced-GNS locus was ultimately mapped onto 6PL (0.27–0.51). To verify the localization results, we created a new translocation line WAT650a (T5BL•5BS-6PL) that carried 6PL (0.35–0.42); this line exhibited higher GNS and SNS than the recipient parent Fukuhokomugi (Fukuho). Collectively, the enhanced-GNS locus of A. cristatum 6PL can be important for improving yield traits in common wheat; the translocation lines with the enhanced-GNS locus can serve as novel and valuable germplasm resources for wheat breeding. [ABSTRACT FROM AUTHOR]

Abstract PAHs affect the uptake of heavy metal by plants. The uptake pathway, distribution and detoxification of nickel (Ni) in Agropyron cristatum L. (A. cristatum) were investigated in the presence of pyrene in this study. Most of Ni was adsorbed on the cell wall in the insoluble phosphate (57.31–72.18%) form and pectate and protein integrated (38.27–38.98%) form. Ni was transferred to the organelle (from 37.84% to 40.52%) in the presence of pyrene. The concentration of Ni in A. cristatum decreased by 27.42%; it was affected by the ATP production inhibitor and 29.49% by the P-type ATPase inhibitor. The results indicated that the uptake of Ni related closely to the synthesis and decomposition of ATP and was an active uptake process. Contents of phytochelatins (PCs) in A. cristatum in Ni contaminated soils increased by 19.97%, and an additional 4.13% increase occurred in the presence of pyrene when compared to single Ni contamination. The content of malic acid in A. cristatum was the highest for 262.78 mg g−1 in shoots and 46.81 mg g−1 in roots with Ni contamination. Besides, acetic acid in shoots and roots increased by 40.25% and 102.63% with Ni contamination, and by 61.59% and 185.71% with Ni-pyrene co-contamination. This study preliminarily explored the inhibitory mechanism of pyrene on plant uptake of Ni. Highlights • Ni was mainly accumulated on the cell wall of A.cristatum. • Most Ni was found dominant in 1 M Nacl and 2% HAc extractable fractions. • The uptake of Ni by A.cristatum was inhibited by pyrene. • Contents of PCs and specific organic acids in A.cristatum increased by Ni. • The absorption of Ni by A.cristatum was related to the ATP. [ABSTRACT FROM AUTHOR]

The P genome of Agropyron cristatum Gaertn. contains many desirable genes that can be utilized as genetic resources to improve wheat. In this research, we used both the gametocidal chromosome 2Cc and the pairing homologous gene (Ph1b) mutant to induce structural aberrations and translocations between wheat and the 4P, 5P, and 6P genome chromosomes. By using the two approaches, a total of 19 wheat-A. cristatum translocations have been identified, in which 13 were induced by the Triticum aestivum cv. Chinese Spring (CS) ph1b mutant (CS ph1b) and six were induced by gametocidal chromosome 2Cc from Aegilops cylindrica Host. The wheat-4P, -5P and -6P A. cristatum translocations were characterized by in situ hybridization and by a set of conserved orthologous set (COS) molecular markers. The aberrations included centromeric translocations, terminal translocations, dicentric translocations, and deletions. The average induction frequency of chromosome structural aberrations was 10.9% using gametocidal 2Cc chromosome and 8.8% using ph1b mutant. The highest frequency obtained was for chromosome 4P using both approaches. All the wheat-A. cristatum translocation lines obtained were valuable for identifying A. cristatum chromosome 4P, 5P, and 6P related genes. In addition, these lines provided genetic resources and new germplasm accessions for the genetic improvement of wheat.

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 135,554 bp 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 (800 bp), which primarily contained the rpl 23 (non-reciprocally translocated from IRs) and acc D genes, was detected between rbc L gene and psa I gene within LSC region. The deletion of the acc D and translocated rpl 23 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. [ABSTRACT FROM AUTHOR]

Weeds in reclamations interfere with success by: 1) competing with desirable species seeded during revegetation; 2) preventing recolonization of reclamations by native species; and 3) reducing the integrity of landscapes by expanding from reclamations into adjacent, intact areas. In the Bakken oilfield of western North Dakota, dispersed reclamation activity and increased traffic may provide many opportunities for weeds to spread. To determine the potential for disturbance and reclamation to increase resident weed populations and introduce new weed species, we tracked twenty-one weed (non-native/ruderal/invasive) species over a four-year period after the installation of a 1.8 km livestock water pipeline and subsequent land reclamation on a historic ranch in western North Dakota. We included areas of historic (early 20th century homestead) and recent (prairie dog town) landscape disturbances and tracked weed frequency and density in the disturbed pipeline and in the directly adjacent intact prairie. Most of the weeds in the pipeline were non-persistent populations of naturalized species. Our data show that although naturalized weeds may respond positively to disturbance, they can quickly return to pre-disturbance levels. However, disturbance may have resulted in the introduction of one new noxious weed, Hyoscyamus niger (black henbane). Agropyron cristatum (crested wheatgrass), an invasive, non-native perennial grass that reduces native plant diversity and forage value, was also introduced. This study demonstrates the importance of prevention of weed dispersal during disturbance and reclamation, contamination-free seed sources, and post-reclamation follow up to control any weeds that may have been introduced as a result of pipeline development. [ABSTRACT FROM AUTHOR]

Crested wheatgrass (Agropyron cristatum L.) breeding programs aim to develop later maturing cultivars for extending early spring grazing inWestern Canada. Plant maturity is a complex genetic trait, and little is known about genes associated with late maturity in this species. An attempt was made using RNA-Seq to profile the transcriptome of crested wheatgrass maturity and to analyze differentially expressed genes (DEGs) between early and late maturing lines. Three cDNA libraries for each line were generated by sampling leaves at the stem elongation stage, spikes at the boot and anthesis stages. A total of 75,218,230 and 74,015,092 clean sequence reads were obtained for early and late maturing lines, respectively. De novo assembly of all sequence reads generated 401,587 transcripts with a mean length of 546 bp and N50 length of 691 bp. Out of 13,133 DEGs detected, 22, 17, and eight flowering related DEGs were identified for the three stages, respectively. Twelve DEGs, including nine flowering related DEGs at the stem elongation stage were further confirmed by qRT-PCR. The analysis of homologous genes of the photoperiod pathway revealed their lower expression in the late maturing line at the stem elongation stage, suggesting that their differential expression contributed to late maturity in crested wheatgrass. [ABSTRACT FROM AUTHOR]

Agropyron cristatum exhibits resistance to Blumeria graminis f. sp. tritici. Disomic and ditelosomic chromosome addition lines of A. cristatum in ‘Chinese Spring’ wheat were utilized to determine which A. cristatum chromosomes carry resistance gene(s). Resistance is conferred by gene(s) on chromosome arms 2PL and 6PL. The availability of molecular markers capable of detecting these chromosome arms in a wheat background would be very useful for marker-assisted introgression of 2PL and 6PL chromatin into common wheat. With this aim, 170 wheat conserved orthologous set (COS) markers (92 and 78 from wheat homoeologous groups 2 and 6 respectively) were assessed for their utility in A. cristatum. A total of 116 (68.2%) COS markers successfully amplified product in A. cristatum and 46 (40.0%) of these markers were polymorphic between A. cristatum and common wheat. From marker loci mapping on wheat homoeologous group 2 chromosomes, 23 markers (34.9%) were polymorphic between A. cristatum and common wheat and from them 13 markers were assigned to chromosome arm 2PL and six markers were mapped to chromosome 4P of A. cristatum showing that this chromosome is related to wheat homoeologous group 2. From marker loci mapping on wheat homoeologous group 6 chromosomes, 23 (46.0%) markers were polymorphic between A. cristatum and common wheat and from them 17 markers were located on chromosome 6P, six of them were mapped to chromosome arm 6PS and five to chromosome arm 6PL, respectively. The specific COS markers allocated on the long arms of chromosomes 2P and 6P may have a role in marker-assisted screening in wheat breeding for powdery mildew disease resistance. [ABSTRACT FROM AUTHOR]

Concerns about wildlife habitat quality in western North America has stimulated interest in diversifying Agropyron cristatum (crested wheatgrass) stands. Four main obstacles make it difficult to establish native forbs in stands of A. cristatum. First, adult A. cristatum plants are fierce competitors with native seedlings. Second, A. cristatum seedlings emerging from a long-lived seedbank can crowd out native species. Third, A. cristatum control may facilitate secondary invaders rather than the desired native species. Fourth, potential soil modification by A. cristatum may impede establishment of diverse native plant species. A "bridge species' that is compatible with A. cristatum control and improves conditions for native species establishment could facilitate A. cristatum stand diversification. We compared native forb growth in soils of former A. cristatum stands preconditioned by A. cristatum, Bromus tectorum (cheatgrass), and Onobrychis viciifolia (sainfoin), a glyphosate-tolerant legume. Soils preconditioned by O. viciifolia had the greatest P and K availability. Although total plant biomass was similar among treatments, native forbs had greater root colonization by arbuscular mycorrhizal (AM) fungi, less root colonization by non-AM fungal, and lower root-shoot ratios when grown in O. viciifolia-conditioned soils, suggesting improved soil microbe and nutrient conditions for native forb establishment. We conclude that O. viciifolia may be a useful bridge species for improving soil conditions while allowing for weed control during restoration of A. cristatum stands. [ABSTRACT FROM AUTHOR]

Semi-arid rangelands are important carbon (C) pools at global scales. However, the degree of net C storage or release in water-limited systems is a function of precipitation amount and timing, as well as plant community composition. In northern latitudes of western North America, C storage in cold-desert ecosystems could increase with boosts in wintertime precipitation, in which climate models predict, due to increases in wintertime soil water storage that enhance summertime productivity. However, there are few long-term, manipulative field-based studies investigating how rangelands will respond to altered precipitation amount or timing. We measured aboveground C pools and fluxes at leaf, soil, and ecosystem scales over a single growing season in plots that had 200 mm of supplemental precipitation added in either winter or summer for the past 21 years, in shrub- and exotic-bunchgrass-dominated garden plots. At our cold-desert site (298 mm precipitation during the study year), we hypothesized that increased winter precipitation would stimulate the aboveground C uptake and storage relative to ambient conditions, especially in plots containing shrubs. Our hypotheses were generally supported: ecosystem C uptake and long-term biomass accumulation were greater in winter- and summer-irrigated plots compared to control plots in both vegetation communities. However, substantial increases in the aboveground biomass occurred only in winter-irrigated plots that contained shrubs. Our findings suggest that increases in winter precipitation will enhance C storage of this widespread ecosystem, and moreso in shrub- compared to grass-dominated communities. [ABSTRACT FROM AUTHOR]