The WUSCHEL-related homeobox (WOX) is a family of plant-specific transcription factors, with important functions, such as regulating the dynamic balance of division and differentiation of plant stem cells and plant organ development. We identified 14 distinct TaWOX genes in the wheat (Triticum aestivum L.) genome, based on a genome-wide scan approach. All of the genes under evaluation had positional homoeologs on subgenomes A, B and D except TaWUS and TaWOX14. Both TaWOX14a and TaWOX14d had a paralogous copy on the same genome due to tandem duplication events. A phylogenetic analysis revealed that TaWOX genes could be divided into three groups. We performed functional characterization of TaWOX genes based on the evolutionary relationships among the WOX gene families of wheat, rice (Oryza sativa L.), and Arabidopsis. An overexpression analysis of TaWUS in Arabidopsis revealed that it affected the development of outer floral whorl organs. The overexpression analysis of TaWOX9 in Arabidopsis revealed that it promoted the root development. In addition, we identified some interaction between the TaWUS and TaWOX9 proteins by screening wheat cDNA expression libraries, which informed directions for further research to determine the functions of TaWUS and TaWOX9. This study represents the first comprehensive data on members of the WOX gene family in wheat.

CLAVATA3/EMBRYO SURROUNDING REGION (CLE) peptides are post-translationally cleaved and modified peptides from their corresponding pre-propeptides. Although they are only 12 to 13 amino acids in length, they are important ligands involved in regulating cell proliferation and differentiation in plant shoots, roots, vasculature, and other tissues. They function by interacting with their corresponding receptors. CLE peptides have been studied in many plants, but not in wheat. We identified 104 TaCLE genes in the wheat genome based on a genome-wide scan approach. Most of these genes have homologous copies distributed on sub-genomes A, B, and D. A few genes are derived from tandem duplication and segmental duplication events. Phylogenetic analysis revealed that TaCLE genes can be divided into five different groups. We obtained functional characterization of the peptides based on the evolutionary relationships among the CLE peptide families of wheat, rice, and Arabidopsis, and expression pattern analysis. Using chemically synthesized peptides (TaCLE3p and TaCLE34p), we found that TaCLE3 and TaCLE34 play important roles in regulating wheat and Arabidopsis root development, and wheat stem development. Overexpression analysis of TaCLE3 in Arabidopsis revealed that TaCLE3 not only affects the development of roots and stems, but also affects the development of leaves and fruits. These data represent the first comprehensive information on TaCLE family members.

DUOII is a multi-ovary wheat (Triticum aestivum L.) line with two or three pistils and three stamens in each floret. The multi-ovary trait of DUOII is controlled by a dominant gene, whose expression can be suppressed by the heterogeneous cytoplasm of TeZhiI (TZI), a line with the nucleus of common wheat and the cytoplasm of Aegilops. Crosses between female DUOII plants and male TZI plants resulted in multi-ovary F1s; whereas, the reciprocal crosses resulted in mono-ovary F1s. Although the multi-ovary trait is inherited as single trait controlled by a dominant allele in lines with a Triticum cytoplasm, the mechanism by which the special heterogeneous cytoplasm suppresses the expression of multi-ovary is not well understood. Observing the developmental process, we found that the critical stage of additional pistil primordium development was when the young spikes were 2–6 mm long. Then, we compared the quantitative proteomic profiles of 2–6 mm long young spikes obtained from the reciprocal crosses between DUOII and TZI. A total of 90 differentially expressed proteins were identified and analyzed based on their biological functions. These proteins had obvious functional pathways mainly implicated in chloroplast metabolism, nuclear and cell division, plant respiration, protein metabolism, and flower development. Importantly, we identified two key proteins, Flowering Locus K Homology Domain and PEPPER, which are known to play an essential role in the specification of pistil organ identity. By drawing relationships between the 90 differentially expressed proteins, we found that these proteins revealed a complex network which is associated with multi-ovary gene expression under heterogeneous cytoplasmic suppression. Our proteomic analysis has identified certain differentially expressed proteins in 2–6 mm long young spikes, which was the critical stage of additional primordium development. This paper provided a universal proteomic profiling involved in the cytoplasmic suppression of wheat floral meristems; and our findings have laid a solid foundation for further mechanistic studies on the underlying mechanisms that control the heterogeneous cytoplasm-induced suppression of the nuclear multi-ovary gene in wheat.

Kinesin is a motor for microtubule-based motility. It plays a vital role in plant growth and development. The kinesin superfamily members are known mainly from Arabidopsis. Little research about kinesin superfamily has been conducted on hexploid wheat (Triticum aestivum L.). The functions of kinesins in wheat growth and development, regulation of cell division and response to stress are still unclear. In this study, we identified 155 kinesin (TaKIN) genes in wheat, which were divided into 10 families and some orphan genes via phylogenetic analysis. Less gene structural differences showed that TaKIN genes had redundant functions. The conserved domains of different family members were different, and some families might have some special functional domains. We found many cis-acting elements related to hormones (GA, Auxin, SA, MeJA), cell cycle and cell division in homeopathic elements of the TaKIN genes. Collinearity analysis showed that TaKIN genes were more conservative in monocotyledons. Expression level in different tissues at different stages suggested that TaKIN family may function during the whole growth and development process in wheat. It was worth noting there were quite different at gene expression level between physiological and heritable male sterile lines during the different stages of pollen development. The differential expression patterns of some TaKIN genes between male sterile line and maintainer line might be related to wheat male sterility. Furthermore, we also found TaKIN genes were involved in response to plant hormones and abiotic stress by stress assays. The result is useful for further exploration of the molecular mechanism of kinesin genes in wheat male sterility and provides important information concerning response to plant hormones and abiotic stress caused by kinesin genes.

Cadmium has been accumulating in the agricultural and ecological environment in recent years due to the release of industrial pollutants. Due to its high solubility, slow degradability and high toxicity, it is highly susceptible to occurring in agricultural fields. The presence of cadmium at low concentrations is harmful to plants. Heavy metal ATPases (HMAs) are proteins that can detoxify high concentrations of heavy metals through vacuole compartmentalization or exocytosis pathways. They have been extensively studied in plants. However, the cadmium transport function of HMAs in wheat has not been explored. In this study, a comprehensive and systematic investigation of HMA gene family members in wheat was conducted. A total of 28 putative TaHMAs were identified. Phylogenetically, these 28 putative TaHMAs were divided into two subgroups: Cu/Ag and Zn/Co/Cd/Pb. The gene structures and conserved motifs were consistent within the same branch and diverse in different branches. The TaHMA gene family is closely related to rice, B. distachyon and A. tauschii. GO analysis results suggest that TaHMAs may be involved in cation transport and membrane components. Protein interaction analysis results suggest that TaHMAs may interact with TaSOD to activate the SOD defense mechanism in wheat. Expression patterns exhibited tissue specificity. Finally, the expression patterns of TaHMAs were validated in the roots and leaves of wheat plants under cadmium stress. Our findings will be valuable for functional studies and applications of HMA gene family members in wheat.