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The role of lncRNA and circRNA in wheat grain development is still unclear. The objectives of this study were to characterize the lncRNA and circRNA in the wheat grain development and to construct the interaction network among lncRNA, circRNA, and their target miRNA to propose a lncRNA–circRNA–miRNA module related to wheat grain development. Full transcriptome sequencing on two wheat varieties (Annong 0942 and Anke 2005) with significant differences in 1000-grain weight at 10 d (days after pollination), 20 d, and 30 d of grain development were conducted. We detected 650, 736, and 609 differentially expressed lncRNA genes, and 769, 1054, and 1062 differentially expressed circRNA genes in the grains of 10 days, 20 days and 30 days after pollination between Annong 0942 and Anke 2005, respectively. An analysis of the lncRNA–miRNA and circRNA–miRNA targeting networks reveals that circRNAs exhibit a more complex and extensive interaction network in the development of cereal grains and the formation of grain shape. Central to these interactions are tae-miR1177, tae-miR1128, and tae-miR1130b-3p. In contrast, lncRNA genes only form a singular network centered around tae-miR1133 and tae-miR5175-5p when comparing between varieties. Further analysis is conducted on the underlying genes of all target miRNAs, we identified TaNF-YB1 targeted by tae-miR1122a and TaTGW-7B targeted by miR1130a as two pivotal regulatory genes in the development of wheat grains. The quantitative real-time PCR (qRT-PCR) and dual-luciferase reporter assays confirmed the target regulatory relationships between miR1130a-TaTGW-7B and miR1122a-TaNF-YB1. We propose a network of circRNA and miRNA-mediated gene regulation in the development of wheat grains. [ABSTRACT FROM AUTHOR]

Wheat grain development is an important biological process to determine grain yield and quality, which is controlled by the interplay of genetic, epigenetic, and environmental factors. Wheat grain development has been extensively characterized at the phenotypic and genetic levels. The advent of innovative molecular technologies allows us to characterize genes, proteins, and regulatory factors involved in wheat grain development, which have enhanced our understanding of the wheat seed development process. However, wheat is an allohexaploid with a large genome size, the molecular mechanisms underlying the wheat grain development have not been well understood as those in diploids. Understanding grain development, and how it is regulated, is of fundamental importance for improving grain yield and quality through conventional breeding or genetic engineering. Herein, we review the current discoveries on the molecular mechanisms underlying wheat grain development. Notably, only a handful of genes that control wheat grain development have, thus far, been well characterized, their interplay underlying the grain development remains elusive. The synergistic network-integrated genomics and epigenetics underlying wheat grain development and how the subgenome divergence dynamically and precisely regulates wheat grain development are unknown. [ABSTRACT FROM AUTHOR]

The article presents Origins and chromosome differentiation of Thinopyrum elongatum revealed by PepC and Pgk1 genes and ND-FISH. Topics discussed include Thinopyrum elongatum is an important gene pool for wheat genetic improvement; and in this study, we used single-copy nuclear genes and non-denaturing fluorescence in situ hybridization (NDFISH) to characterize genome constitution and chromosome differentiation in Th. elongatum.

In common wheat, stem strength is one of the key factors for lodging resistance, which is influenced by lignin content. Cinnamyl alcohol dehydrogenase (CAD) is a vital enzyme in the pathway of lignin biosynthesis. Cloning and marker development of the CAD gene could be helpful for lodging resistance breeding. In this study, the full-length genomic DNA sequence of CAD gene in wheat was cloned by using homologous strategy. A marker 5-f2r2 was developed based on CAD sequence and used to genotype 258 wheat lines. Four haplotype combinations of CAD genes were identified in 258 wheat lines. Correction analyses among the CAD gene expression, CAD activity, and stem strength indicated significant positive correlation between CAD gene expression and CAD activity, between wheat CAD activity and wheat stem strength. The haplotype combination B is significantly associated with the lower enzyme activity and weak stem strength, which was supported by the level of CAD gene expression. The CAD activity and stem strength of wheat could be distinguished to some extent using this pair of specific primer 5-f2r2 designed in this study, indicating that the sequence targeted site (STS) marker 5-f2r2 could be used in marker assistant selection (MAS) breeding. [ABSTRACT FROM AUTHOR]

Background and objectives: Genetic diversity of high‐molecular‐weight (HMW) glutenin subunits is often used for wheat improvement because of its correlation with end‐use quality of wheat. The objectives were (a) to characterize and analyze the HMW‐GS composition of common wheat, (b) determine the diversity of high‐molecular‐weight glutenin subunits, and (c) elucidate the distribution characteristics of wheat good‐quality subunit and quality classification. Findings: The results revealed a total of 15 different alleles (3 at Glu‐A1, 8 at Glu‐B1, and 4 at Glu‐D1) and 35 allele combinations. Glu‐A1c (57.92%), Glu‐A1a (62.94%), Glu‐A1c (55.86%) appeared to be the most frequent alleles at Glu‐A1 in Hebei, Henan, and Sichuan provinces, respectively. The Glu‐B1c was the most common allele at the Glu‐B1 locus in all three provinces, with frequencies of 48.75%, 55.24%, and 29.66%, respectively. Glu‐D1a (66.25%), Glu‐D1d (53.85%), Glu‐D1a (55.17%) at the Glu‐D1 locus appeared to be the common alleles in Hebei, Henan, and Sichuan provinces, respectively. Cluster analysis based on allelic similarity of Glu‐1 loci classified the 528 wheat cultivars into two major categories. Conclusions: These results indicated that the HMW glutenin allele compositions are not optimal for the current varieties in these provinces. A high level of quality improvement may be implemented by increasing the frequencies of Glu‐A1a (1) or Glu‐A1b (2*), Glu‐B1i (17 + 18), Glu‐D1d (5 + 10). Significance and novelty: Our results revealed clear directions for wheat quality improvement in these provinces. [ABSTRACT FROM AUTHOR]

Bread wheat (AABBDD) originated from the diploid progenitor Triticum urartu (AA), a relative of Aegilops speltoides (BB), and Ae. tauschii (DD). The DREB1 transcriptional factor plays key regulatory role in low-temperature tolerance. The modern breeding strategies resulted in serious decrease of the agricultural biodiversity, which led to a loss of elite genes underlying abiotic stress tolerance in crops. However, knowledge of this gene’s natural diversity is largely unknown in the genome donor species of wheat. We characterized the dehydration response element binding protein 1 (DREB1) gene-diversity pattern in Ae. speltoides, Ae. tauschii, T. monococcum and T. urartu. The highest nucleotide diversity value was detected in Ae. speltoides, followed by Ae. tauschii and T. monococcum. The lowest nucleotide diversity value was observed in T. urartu. Nucleotide diversity and haplotype data might suggest no reduction of nucleotide diversity during T. monococcum domestication. Alignment of the 68 DREB1 sequences found a large-size (70 bp) insertion/deletion in the accession PI486264 of Ae. speltoides, which was different from the copy of sequences from other accessions of Ae. speltoides, suggesting a likely existence of two different ancestral Ae. speltoides forms. Implication of sequences variation of Ae. speltoides on origination of B genome in wheat was discussed. [ABSTRACT FROM AUTHOR]

Genetic variation in the allotetraploid grass Elymus alaskanus complex was assessed using microsatellites in seven populations from Canada, Greenland, and the U.S.A. Microsatellite variation was compared with allozyme and RAPD variation. Our results indicated that E. alaskanus was highly homozygous but also highly variable. The polymorphic loci ranged from 50 to 100% with a mean of 78.6%, and the mean number of allele per locus was 3.14. Average expected heterozygosity value (HE, gene diversity) varied across populations and ranged from 0.244 to 0.651 with mean of 0.414. The mean value of HE across Canadian populations (0.517) was significantly higher than that across populations in Greenland (0.367). The correlation between allozyme and microsatellite gene diversity value (HE) showed a high positive correlation (r = 0.68), but between RAPD and microsatellite showed a low positive correlation (r = 0.08). Populations were highly differentiated, with 38% of variation among populations. Interpopulation genetic distance showed no association with geographic distance between the population sites of origin. A Hardy-Weinberg exact test for all loci and all populations reveals a significant heterozygote deficiency. Possible explanations for heterozygote deficiency are discussed. [ABSTRACT FROM AUTHOR]