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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.

Background: Fusarium head blight (FHB) significantly impacts wheat yield and quality. Understanding the intricate interaction mechanisms between Fusarium graminearum (the main pathogen of FHB) and wheat is crucial for developing effective strategies to manage and this disease. Our previous studies had shown that the absence of the cell wall mannoprotein FgCWM1, located at the outermost layer of the cell wall, led to a decrease in the pathogenicity of F. graminearum and induced the accumulation of salicylic acid (SA) in wheat. Hence, we propose that FgCWM1 may play a role in interacting between F. graminearum and wheat, as its physical location facilitates interaction effects. Results: In this study, we have identified that the C-terminal region of NADH dehydrogenase [ubiquinone] 1 alpha subcomplex subunit 9 (NDUFA9) could interact with FgCWM1 through the yeast two-hybrid assay. The interaction was further confirmed through the combination of Co-IP and BiFC analyses. Consistently, the results of subcellular localization indicated that TaNDUFA9 was localized in the cytoplasm adjacent to the cell membrane and chloroplasts. The protein was also detected to be associated with mitochondria and positively regulated complex I activity. The loss-of-function mutant of TaNDUFA9 exhibited a delay in flowering, decreased seed setting rate, and reduced pollen fertility. However, it exhibited elevated levels of SA and increased resistance to FHB caused by F. graminearum infection. Meanwhile, inoculation with the FgCWM1 deletion mutant strain led to increased synthesis of SA in wheat. Conclusions: These findings suggest that TaNDUFA9 inhibits SA synthesis and FHB resistance in wheat. FgCWM1 enhances this inhibition by interacting with the C-terminal region of TaNDUFA9, ultimately facilitating F. graminearum infection in wheat. This study provides new insights into the interaction mechanism between F. graminearum and wheat. TaNDUFA9 could serve as a target gene for enhancing wheat resistance to FHB. [ABSTRACT FROM AUTHOR]

Chloroplasts are key players in photosynthesis and immunity against microbial pathogens. However, the precise and timely regulatory mechanisms governing the control of photosynthesis-associated nuclear genes (PhANGs) expression in plant immunity remain largely unknown. Here we report that TaPIR1, a Pst-induced RING-finger E3 ubiquitin ligase, negatively regulates Pst resistance by specifically interacting with TaHRP1, an atypical transcription factor histidine-rich protein. TaPIR1 ubiquitinates the lysine residues K131 and K136 in TaHRP1 to regulate its stability. TaHRP1 directly binds to the TaHRP1-binding site elements within the PhANGs promoter to activate their transcription via the histidine-rich domain of TaHRP1. PhANGs expression induces the production of chloroplast-derived ROS. Although knocking out TaHRP1 reduces Pst resistance, TaHRP1 overexpression contributes to photosynthesis, and chloroplast-derived ROS production, and improves disease resistance. TaPIR1 expression inhibits the downstream activation of TaHRP1 and TaHRP1-induced ROS accumulation in chloroplasts. Overall, we show that the TaPIR1-mediated ubiquitination and degradation of TaHRP1 alters PhANGs expression to disrupt chloroplast function, thereby increasing plant susceptibility to Pst. Wheat E3 ubiquitin ligase TaPIR1-mediated ubiquitination and degradation of an atypical transcription factor TaHRP1 alters PhANGs expression to disrupt chloroplast function and ROS accumulation, increasing plant susceptibility to wheat stripe rust. [ABSTRACT FROM AUTHOR]

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 [...]

Background: Wheat grain endosperm is mainly composed of proteins and starch. The contents and the overall composition of seed storage proteins (SSP) markedly affect the processing quality of wheat flour. Polyploidization results in duplicated chromosomes, and the genomes are often unstable and may result in a large number of gene losses and gene rearrangements. However, the instability of the genome itself, as well as the large number of duplicated genes generated during polyploidy, is an important driving force for genetic innovation. In this study, we compared the differences in starch and SSP, and analyzed the transcriptome and metabolome among Aegilops sharonensis (R7), durum wheat (Z636) and amphidiploid (Z636×R7) to reveal the effects of polyploidization on the synthesis of seed reserve polymers. Results: The total starch and amylose content of Z636×R7 was significantly higher than R7 and lower than Z636. The gliadin and glutenin contents of Z636×R7 were higher than those in Z636 and R7. Through transcriptome analysis, there were 21,037, 2197, 15,090 differentially expressed genes (DEGs) in the three comparison groups of R7 vs Z636, Z636 vs Z636×R7, and Z636×R7 vs R7, respectively, which were mainly enriched in carbon metabolism and amino acid biosynthesis pathways. Transcriptome data and qRT-PCR were combined to analyze the expression levels of genes related to storage polymers. It was found that the expression levels of some starch synthase genes, namely AGP-L, AGP-S and GBSSI in Z636×R7 were higher than in R7 and among the 17 DEGs related to storage proteins, the expression levels of 14 genes in R7 were lower than those in Z636 and Z636×R7. According to the classification analysis of all differential metabolites, most belonged to carboxylic acids and derivatives, and fatty acyls were enriched in the biosynthesis of unsaturated fatty acids, niacin and nicotinamide metabolism, one-carbon pool by folate, etc. Conclusion: After allopolyploidization, the expression of genes related to starch synthesis was down-regulated in Z636×R7, and the process of starch synthesis was inhibited, resulting in delayed starch accumulation and prolongation of the seed development process. Therefore, at the same development time point, the starch accumulation of Z636×R7 lagged behind that of Z636. In this study, the expression of the GSe2 gene in Z636×R7 was higher than that of the two parents, which was beneficial to protein synthesis, and increased the protein content. These results eventually led to changes in the synthesis of seed reserve polymers. The current study provided a basis for a greater in-depth understanding of the mechanism of wheat allopolyploid formation and its stable preservation, and also promoted the effective exploitation of high-value alleles. [ABSTRACT FROM AUTHOR]

In our previous work, a novel high-molecular-weight glutenin subunit (HMW-GS) with an extremely large molecular weight from Aegilops sharonensis was identified that may contribute to excellent wheat (Triticum aestivum) processing quality and increased dough strength, and we further generated HMW-GS homozygous lines by crossing. In this study, we crossed the HMW-GS homozygous line 66-17-52 with 'Chinese Spring' Phl mutant CS phlb to induce chromosome recombination between wheat and Ae. sharonensis. SDS-PAGE was used to identify 19 derived [F.sub.2] lines with the HMW-GSs of Ae sharonensis. The results of non-denaturing fluorescence in situ hybridization (ND-FISH) indicated that lines 6-1 and 6-7 possessed a substitution of both 5D chromosomes by a pair of 1[S.sup.sh] chromosomes. Further verification by newly developed 1[S.sup.sh]-specific chromosome markers showed that these two lines amplified the expected fragment. Thus, it was concluded that lines 6-1 and 6-7 are 1[S.sup.sh](5D) chromosome substitution lines. The 1[S.sup.sh](5D) chromosome substitution lines, possessing alien subunits with satisfactory quality-associated structural features of large repetitive domains and increased number of subunits, may have great potential in strengthening the viscosity and elasticity of dough made from wheat flour. Therefore, these substitution lines can be used for wheat quality improvement and further production of 1[S.sup.sh] translocation lines. Key words: Aegilops sharonensis, substitution line, Ph gene mutant, high-molecular-weight glutenin subunits, molecular markers. Dans leurs travaux precedents, les auteurs ont identifie une nouvelle sous-unite de glutenine de masse moleculaire elevee (HMW-GS) de tres grande masse chez l'Aegilops sharonensis, laquelle pourrait contribuer a produire un ble (Triticum aestivum) dote de meilleures proprietes pour la transformation et d'une meilleure resistance de la pate. Les auteurs ont egalement genere des lignees homozygotes HMW-GS par la voie de croisements. Dans ce travail, les auteurs ont croise la lignee homozygote 66-17-52 avec le mutant Ph1 de Chinese Spring (CS ph1b) pour produire des recombinants chromosomiques entre le ble et l'Ae. sharonensis. Des gels SDS-PAGE ont ete employes pour identifier 19 descendants [F.sub.2] porteurs de HMW-GS de l'Ae. sharonensis. Les resultats d'hybridations in situ en fluorescence en conditions non-denaturantes (ND-FISH) ont revele que les lignees 6-1 et 6-7 presentent une substitution des deux chromosomes 5D par une paire de chromosomes 1[S.sup.sh]. Des analyses additionnelles realisees au moyen de marqueurs specifiques du chromosome 1[S.sup.sh] nouvellement mis au point ont montre que les fragments attendus ont ete obtenus chez ces deux lignees. Les auteurs concluent donc que les lignees 6-1 et 6-7 sont des lignees de substitution 1[S.sup.sh](5D). Ces lignees de substitution chromosomique 1[S.sup.sh](5D) possedent des sous-unites d'origine interspecifique qui presentent des caracteristiques structurales associees a une meilleure qualite, soit la presence de grands domaines repetes et un nombre accru de sous-unites. Celles-ci permettront possiblement d'accroitre la viscosite et l'elasticite de la pate preparee a partir de farine de ble. Ainsi, ces lignees de substitution pourront servir a ameliorer la qualite du ble panifiable ainsi que pour la production de lignees de translocation 1[S.sup.sh]. [Traduit par la Redaction] Mots-cles : Aegilops sharonensis, lignee de substitution, mutant du gene Ph, sous-unites de glutenine de masse moleculaire elevee, marqueurs moleculaires., Introduction High-molecular-weight glutenin subunits (HMW-GSs) are essential in the determination of dough viscosity and elasticity in wheat flour processing (Shewry et al. 2003). HMW-GSs are encoded by the Glu-1 loci, [...]

A completely developed and vigorous root system can provide a stable platform for aboveground plant organs. To identify loci controlling root traits that could be used in wheat (Triticum aestivum L.) breeding, 199 recombinant inbred lines were used to measure and analyze eight root traits. A total of 18 quantitative trait loci (QTL) located on chromosomes 1A, 2A, 2B, 2D, 4B, 4D, 6A, 7A, and 7B were identified. The phenotypic variation explained by these 18 QTL ranged from 3.27% to 11.75%, and the logarithm of odds scores ranged from 2.50 to 6.58. A comparison of physical intervals indicated several new QTL for root traits were identified. In addition, significant correlations between root and agronomic traits were detected and discussed. The results presented in this study, along with those of previous reports, suggest that chromosomes 2 and 7 likely play important roles in the growth and development of wheat roots. Keywords: Triticum aestivum L., recombinant inbred lines, root traits, quantitative trait loci, correlation. Un systeme racinaire bien developpe et vigoureux peut servir d'assise stable aux organes aeriens de la plante. Afin d'identifier des locus contr[delta]lant des caracteres racinaires utiles en amelioration genetique chez le ble (Triticum aestivum L.), 199 lignees recombinantes fixees ont ete employees pour mesurer et analyser huit caracteres racinaires. Au total, 18 QTL, situes sur les chromosomes 1A, 2A, 2B, 2D, 4B, 4D, 6A, 7A et 7B, ont ete identifies. La variation phenotypique expliquee par ces QTL variait entre 3,27 et 11,75%, et les scores LOD variaient entre 2,50 et 6,58. Une comparaison des intervalles physiques a suggere que plusieurs QTL inedits pour des caracteres racinaires ont ete identifies. De plus, des correlations significatives entre des caracteres racinaires et agronomiques ont ete detectees et sont discutees. Les resultats presentes dans cette etude, avec ceux rapportes anterieurement, suggerent que les chromosomes 2 et 7 jouent des roles importants dans la croissance et le developpement des racines chez le ble. [Traduit par la Redaction] Mots-cles: Triticum aestivum L., lignees recombinantes fixees, caracteres racinaires, locus de caracteres quantitatifs, correlation., Introduction Common wheat (Triticum aestivum L.) is an important food crop planted worldwide (Ray et al. 2013). The development of high-yielding wheat varieties with good quality is essential in wheat [...]