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Plant transcription factors (TFs), such as basic helix-loop-helix (bHLH) and AT-rich zinc-binding proteins (PLATZ), play critical roles in regulating the expression of developmental genes in cereals. We identified the bHLH protein TaPGS1 (T. aestivum Positive Regulator of Grain Size 1) specifically expressed in the seeds at 5-20 days post-anthesis in wheat. TaPGS1 was ectopically overexpressed (OE) in wheat and rice, leading to increased grain weight (up to 13.81% in wheat and 18.55% in rice lines) and grain size. Carbohydrate and total protein levels also increased. Scanning electron microscopy results indicated that the starch granules in the endosperm of TaPGS1 OE wheat and rice lines were smaller and tightly embedded in a proteinaceous matrix. Furthermore, TaPGS1 was bound directly to the E-box motif at the promoter of the PLATZ TF genes TaFl3 and OsFl3 and positively regulated their expression in wheat and rice. In rice, the OsFl3 CRISPR/Cas9 knockout lines showed reduced average thousand-grain weight, grain width, and grain length in rice. Our results reveal that TaPGS1 functions as a valuable trait-associated gene for improving cereal grain yield.

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a global threat to wheat production. Aegilops tauschii, one of the wheat progenitors, carries the YrAS2388 locus for resistance to Pst on chromosome 4DS. We reveal that YrAS2388 encodes a typical nucleotide oligomerization domain-like receptor (NLR). The Pst-resistant allele YrAS2388R has duplicated 3' untranslated regions and is characterized by alternative splicing in the nucleotide-binding domain. Mutation of the YrAS2388R allele disrupts its resistance to Pst in synthetic hexaploid wheat; transgenic plants with YrAS2388R show resistance to eleven Pst races in common wheat and one race of P. striiformis f. sp. hordei in barley. The YrAS2388R allele occurs only in Ae. tauschii and the Ae. tauschii-derived synthetic wheat; it is absent in 100% (n = 461) of common wheat lines tested. The cloning of YrAS2388R will facilitate breeding for stripe rust resistance in wheat and other Triticeae species.

The basic leucine zipper (bZIP) family of genes encode transcription factors that play key roles in plant growth and development. In this study, a total of 92 HvbZIP genes were identified and compared with previous studies using recently released barley genome data. Two novel genes were characterized in this study, and some misannotated and duplicated genes from previous studies have been corrected. Phylogenetic analysis results showed that 92 HvbZIP genes were classified into 10 groups and three unknown groups. The gene structure and motif distribution of the three unknown groups implied that the genes of the three groups may be functionally different. Expression profiling indicated that the HvbZIP genes exhibited different patterns of spatial and temporal expression. Using qRT-PCR, more than 10 HvbZIP genes were identified with expression patterns similar to those of starch synthase genes in barley. Yeast one-hybrid analysis revealed that two of the HvbZIP genes exhibited in vitro binding activity to the promoter of HvAGP-S. The two HvbZIP genes may be candidate genes for further study to explore the mechanism by which they regulate the synthesis of barley starch. Key words: barley, basic leucine zipper, transcription factors, gene interaction, starch synthesis. La famille de genes qui presentent un domaine de glissiere a leucines basique (bZIP) code pour des facteurs de transcription qui jouent des roles cles dans la croissance et le developpement des plantes. Dans ce travail, les auteurs ont identifie un total de 92 genes HvbZIP grace aux plus recentes donnees genomiques chez l'orge et ils les comparent a ceux rapportes precedemment. Deux genes inedits sont rapportes dans ce travail et certaines erreurs d'annotation ou cas de duplication de genes rapportes anterieurement font l'objet ici d'une correction. Une analyse phylogenetique a montre que les 92 genes HvbZIP appartiennent a 10 groupes connus et trois groupes inconnus. La structure des genes et la distribution des motifs au sein de ces trois groupes inconnus suggerent que les genes qui en font partie pourraient avoir des fonctions differentes. Une analyse de l'expression genique indique que les genes HvbZIP presentent differents modes d'expression tant au niveau spatial que temporel. A laide de la qRT-PCR, les auteurs ont identifie plus de 10 genes HvbZIP affichant une expression semblable a celle des genes codant pour lamidon synthase chez l'orge. Une analyse 'un hybride' chez la levure a revele que deux des genes HvbZIP presentaient une activite de liaison in vitro avec le promoteur du gene HvAGP-S. Ces deux genes constituent des candidats pour des etudes futures, pour explorer le mecanisme par lequel ils regulent la synthese de l'amidon chez lorge. [Traduit par la Redaction] Mots-cles : orge, glissiere a leucines basique, facteurs de transcription, interaction genique, synthese de l'amidon., Introduction Transcription factors (TFs) play key roles in the regulation of gene transcription by binding to cis-acting elements of their target genes. Basic region/leucine zipper (bZIP) TFs are one of [...]

Whole-genome scans with large number of genetic markers provide the opportunity to investigate local adaptation in natural populations and identify candidate genes under positive selection. In the present study, adaptation genetic differentiation associated with solar radiation was investigated using 695 polymorphic SNP markers in wild emmer wheat originated in a micro-site at Yehudiyya, Israel. The test involved two solar radiation niches: (1) sun, in-between trees; and (2) shade, under tree canopy, separated apart by a distance of 2-4 m. Analysis of molecular variance showed a small (0.53%) but significant portion of overall variation between the sun and shade micro-niches, indicating a non-ignorable genetic differentiation between sun and shade habitats. Fifty SNP markers showed a medium (0.05 ≤ FST ≤ 0.15) or high genetic differentiation (FST > 0.15). A total of 21 outlier loci under positive selection were identified by using four different FST -outlier testing algorithms. The markers and genome locations under positive selection are consistent with the known patterns of selection. These results suggested that genetic differentiation between sun and shade habitats is substantial, radiation-associated, and therefore ecologically determined. Hence, the results of this study reflected effects of natural selection through solar radiation on EST-related SNP genetic diversity, resulting presumably in different adaptive complexes at a micro-scale divergence. The present work highlights the evolutionary theory and application significance of solar radiation-driven natural selection in wheat improvement.

Deployment of cultivars with genetic resistance is an effective approach to control the diseases of powdery mildew (PM) and yellow rust (YR). Chinese wheat cultivar XK0106 exhibits high levels of resistance to both diseases, while cultivar E07901 has partial, adult plant resistance (APR). The aim of this study was to map resistance loci derived from the two cultivars and analyze their effects against PM and YR in a range of environments. A doubled haploid population (388 lines) was used to develop a framework map consisting of 117 SSR markers, while a much higher density map using the 90K Illumina iSelect SNP array was produced with a subset of 80 randomly selected lines. Seedling resistance was characterized against a range of PM and YR isolates, while field scores in multiple environments were used to characterize APR. Composite interval mapping (CIM) of seedling PM scores identified two QTLs (QPm.haas-6A and QPm.haas-2A), the former being located at the Pm21 locus. These QTLs were also significant in field scores, as were Qpm.haas-3A and QPm.haas-5A. QYr.haas-1B-1 and QYr.haas-2A were identified in field scores of YR and were located at the Yr24/26 and Yr17 chromosomal regions respectively. A second 1B QTL, QYr.haas-1B-2 was also identified. QPm.haas-2A and QYr.haas-1B-2 are likely to be new QTLs that have not been previously identified. Effects of the QTLs were further investigated in multiple environments through the testing of selected lines predicted to contain various QTL combinations. Significant additive interactions between the PM QTLs highlighted the ability to pyramid these loci to provide higher level of resistance. Interactions between the YR QTLs gave insights into the pathogen populations in the different locations as well as showing genetic interactions between these loci.

SUMMARY: Pre‐harvest sprouting (PHS) is a significant threat to global food security due to its association with losses in both yield and quality. Among the genes involved in PHS resistance in wheat, PHS‐3D (TaMyb10‐D) plays a crucial role. Here, we characterized the sequence variations of TaMyb10 genes in 416 bread wheat and 302 Aegilops tauschii accessions. Within TaMyb10‐A sequences, we identified a deletion ranging from 214 to 305 bp in the signal and amino acid coding region, present in 61.3% of the accessions. Similarly, 79.3% of the TaMyb10‐B sequences within the third exon region exhibited a 19 bp deletion. Additionally, 40.8% of the accessions lacked the 2.4 Mb fragment (in/del mutations) on Chr3D, where TaMyb10‐D/PHS‐3D was located. Interestingly, the geographical distribution of accessions showed little correlation with the divergence of TaMyb10. TaMyb10‐A‐IIIDele, TaMyb10‐B‐IVDele, and TaMyb10‐D‐VDele genotypes were prevalent in wheat populations across continents. Despite their structural variations, the five distinct protein types exhibited comparable ability to bind the promoters of downstream genes in the flavonoid and ABA pathways, such as CHS, DFR, and NCED. Furthermore, the combination of TaMyb10 homologs was significantly associated with grain color and germination percentages. Accessions exclusively harboring TaMyb10‐D displayed red seed color and reduced germination percentages, indicating the predominant role of TaMyb10‐D compared to TaMyb10‐A and TaMyb10‐B. This comprehensive investigation enhances our understanding of the structural variations and functional divergence of TaMyb10, providing valuable insights and resources for improving PHS resistance in wheat. Significance Statement: TaPHS‐3D (TaMyb10‐D) plays a crucial role among the genes implicated in pre‐harvest sprouting resistance in wheat. Our study revealed a significant correlation between the combination of TaMyb10 homologs, grain color, and germination. Notably, TaMyb10‐D exhibited a more substantial functional impact than TaMyb10‐A and TaMyb10‐B. These findings deepen our understanding of the structural variations and functional distinctions within TaMyb10, providing valuable insights and resources for improving PHS resistance in wheat. [ABSTRACT FROM AUTHOR]

Statistical network analysis primarily focuses on inferring the parameters of an observed network. In many applications, especially in the social sciences, the observed data is the groups formed by individual subjects. In these applications, the network is itself a parameter of a statistical model. Zhao and Weko propose a model-based approach, called the hub model, to infer implicit networks from grouping behavior. The hub model assumes that each member of the group is brought together by a member of the group called the hub. The set of members which can serve as a hub is called the hub set. The hub model belongs to the family of Bernoulli mixture models. Identifiability of Bernoulli mixture model parameters is a notoriously difficult problem. This article proves identifiability of the hub model parameters and estimation consistency under mild conditions. Furthermore, this article generalizes the hub model by introducing a model component that allows hubless groups in which individual nodes spontaneously appear independent of any other individual. We refer to this additional component as the null component. The new model bridges the gap between the hub model and the degenerate case of the mixture model—the Bernoulli product. Identifiability and consistency are also proved for the new model. In addition, a penalized likelihood approach is proposed to estimate the hub set when it is unknown. for this article are available online. [ABSTRACT FROM AUTHOR]