Gamma rays as a type of ionizing radiation constitute a physical mutagen that induces mutations and could be effectively used in plant breeding. To compare the effects of gamma and ionizing irradiation according to exposure time in common wheat (Keumgang, IT 213100), seeds were exposed to ⁶⁰Co gamma rays at different dose rates. To evaluate the amount of free radical content, we used electron spin resonance spectroscopy. Significantly more free radicals were generated in the case of long-term compared with short-term gamma-ray exposure at the same dose of radiation. Under short-term exposure, shoot and root lengths were slightly reduced compared with those of the controls, whereas long-term exposure caused severe growth inhibition. The expression of antioxidant-related and DNA-repair-related genes was significantly decreased under long-term gamma-ray exposure. Long-term exposure caused higher radiosensitivity than short-term exposure. The results of this study could help plant breeders select an effective mutagenic induction dose rate in wheat.

Genes of the F-box family play specific roles in protein degradation by post-translational modification in several biological processes, including flowering, the regulation of circadian rhythms, photomorphogenesis, seed development, leaf senescence, and hormone signaling. F-box genes have not been previously investigated on a genome-wide scale; however, the establishment of the wheat (Triticum aestivum L.) reference genome sequence enabled a genome-based examination of the F-box genes to be conducted in the present study. In total, 1796 F-box genes were detected in the wheat genome and classified into various subgroups based on their functional C-terminal domain. The F-box genes were distributed among 21 chromosomes and most showed high sequence homology with F-box genes located on the homoeologous chromosomes because of allohexaploidy in the wheat genome. Additionally, a synteny analysis of wheat F-box genes was conducted in rice and Brachypodium distachyon. Transcriptome analysis during various wheat developmental stages and expression analysis by quantitative real-time PCR revealed that some F-box genes were specifically expressed in the vegetative and/or seed developmental stages. A genome-based examination and classification of F-box genes provide an opportunity to elucidate the biological functions of F-box genes in wheat.

U-box E3 ligase genes play specific roles in protein degradation by post-translational modification in plant signaling pathways, developmental stages, and stress responses; however, little is known about U-box E3 genes in wheat. We identified 213 U-box E3 genes in wheat based on U-box and other functional domains in their genome sequences. The U-box E3 genes were distributed among 21 chromosomes and most showed high sequence homology with homoeologous U-box E3 genes. Synteny analysis of wheat U-box E3 genes was conducted with other plant species such as Brachypodium distachyon, barley, rice, Triricum uratu, and Aegilops tauschii. A total of 209 RNA-seq samples representing 22 tissue types, from grain, root, leaf, and spike samples across multiple time points, were analyzed for clustering of U-box E3 gene expression during developmental stages, and the genes responded differently in various tissues and developmental stages. In addition, expression analysis of U-box E3 genes under abiotic stress, including drought, heat, and both heat and drought, and cold conditions, was conducted to provide information on U-box E3 gene expression under specific stress conditions. This analysis of U-box E3 genes could provide valuable information to elucidate biological functions for a better understanding of U-box E3 genes in wheat.

Plant U-box E3 ubiquitin ligase (PUB) is involved in various environmental stress conditions. However, the molecular mechanism of U-box proteins in response to abiotic stress in wheat remains unknown. In this study, two U-box E3 ligase genes (TaPUB2 and TaPUB3), which are highly expressed in response to adverse abiotic stresses, were isolated from common wheat, and their cellular functions were characterized under drought stress. Transient expression assay revealed that TaPUB2 was localized in the cytoplasm and Golgi apparatus, whereas TaPUB3 was expressed only in the Golgi apparatus in wheat protoplasts. Additionally, TaPUB2 and TaPUB3 underwent self-ubiquitination. Moreover, TaPUB2/TaPUB3 heterodimer was identified in yeast and the cytoplasm of wheat protoplasts using a pull-down assay and bimolecular fluorescence complementation analysis. Heterogeneous overexpression of TaPUB2 and TaPUB3 conferred tolerance to drought stress. Taken together, these results implied that the heterodimeric form of U-box E3 ubiquitin ligases (TaPUB2/TaPUB3) responded to abiotic stress and roles as a positive regulator of drought stress tolerance.

Lentinula edodes is an edible mushroom that is rich in polysaccharides, glucan, and lentinan. It is famous for its earthy, sweet, umami flavor, and is used in various foods all over the world. Although Lentinula edodes does not carry out photosynthesis with light, its fruit body development is regulated by light. In this study, we analyzed the morphological changes of L. edodes strain Sanjo701ho and identified the global gene expression patterns using EdgeR of fruit body development under blue light. The phenotype analysis under different light sources revealed that the pileus diameter grew, while the stipe length was suppressed under blue light. To understand the changes in the transcriptome under different light sources in L. edodes, gene set enrichment analysis (GSEA), KOG functional categories, and KEGG pathways were used and compared to the no-light condition. Lignocellulose, CAZyme, and transcription factor classified DEGs (differentially expressed genes) were identified to better understand the significant DEGs affected by light sources in the synthesis, metabolism, and recognition of complex carbohydrates. Six glycoside hydrolases (GHs), four auxiliary activities (AAs), three carbohydrate esterases (CEs), and glycosyltransferases (GTs) were identified as upregulated in the CAZyme DEGs. Furthermore, four β-glucosidase, one glucose oxidase, and one multicopper oxidase-related gene for lignocellulolytic genes were upregulated in the blue light condition, and AT_hook transcription factor, CBFD_NFYB_HMF transcription factor, HMG_box transcription factor, and fungal specific transcription factor were upregulated in the blue light condition. This study helps us understand fruit body development in mushroom-breeding programs.

F-box proteins are substrate recognition components of the Skp1-Cullin-F-box (SCF) complex, which performs many important biological functions including the degradation of numerous proteins via the ubiquitin–26S proteasome system. In this study, we isolated the gene encoding the F-box/LRR-repeat (FBXL) protein from wheat (Triticum aestivum L.) seedlings and validated that the TaFBXL protein is a component of the SCF complex. Yeast two-hybrid assays revealed that TaFBXL interacts with the wheat glycosylphosphatidylinositol-anchored protein (TaGPI-AP). The green fluorescent protein (GFP) fusion protein of TaFBXL was detected in the nucleus and plasma membrane, whereas that of TaGPI-AP was observed in the cytosol and probably also plasma membrane. yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays revealed that TaFBXL specifically interacts with TaGPI-AP in the nucleus and plasma membrane, and TaGPI-AP is targeted by TaFBXL for degradation via the 26S proteasome system. In addition, TaFBXL and TaGPI-AP showed antagonistic expression patterns upon treatment with indole-3-acetic acid (IAA), and the level of TaGPI-AP was higher in tobacco leaves treated with both MG132 (proteasome inhibitor) and IAA than in leaves treated with either MG132 or IAA. Taken together, our data suggest that TaFBXL regulates the TaGPI-AP protein level in response to exogenous auxin application.