Improving nitrogen use efficiency (NUE) is essential for sustainable wheat production, given the global demand for high-yielding and environmentally resilient crop varieties. NUE is a complex trait governed by multiple genetic, physiological, and environmental factors. This review synthesizes recent advances in the genetic dissection of NUE in wheat, focusing on quantitative trait loci (QTL) mapping, genome-wide association studies (GWAS), and transcriptome analyses. Furthermore, novel approaches such as protein turnover quantification, epigenetic regulation, NIR-based quality prediction, and genomic selection optimization are discussed as emerging strategies to enhance NUE. Key genes identified include nitrate transporters (NRT1, NRT2), nitrogen assimilation enzymes (GS, GOGAT), transcription factors (NLPs, WRKYs, NACs), and signal transduction components (SnRK, CIPK). Integrative studies combining genomics, transcriptomics, and machine learning offer new insights into the dynamic regulation of NUE. This review highlights the importance of multi-layered breeding approaches and provides valuable genetic resources and methodological frameworks for future wheat NUE improvement programs.

In this study, we constructed a reference transcriptome database for the special crops Codonopsis lanceolata (known as “deodeok” in Korean) and Ixeridium dentata (known as “sseumbagwi” in Korean). The reference transcriptome sequence based on PacBio Iso-Seq technology was rapidly analyzed using various programs on a supercomputer at the Rural Development Administration to determine homologous gene searches, domain searches, and metabolic pathway-related information. Transcriptome information was organized into a single file database (DB) with a simple user interface using Microsoft Access, enabling efficient access and management of transcriptome sequences and functional prediction information. The deodeok reference transcriptome DB included 49,677 transcriptome sequences, whereas the sseumbagwi reference transcriptome DB included 73,757 transcriptome sequences. These reference transcriptome DBs can be utilized for various genomic analyses, such as gene discovery, gene expression analysis, inter-and intraspecies comparisons, and marker development, with particular potential for use in secondary metabolite research. The reference transcriptome DBs constructed in this study are expected to contribute to enhancing the agricultural value and industrial applicability of deodeok and sseumbagwi.

Sybeans have been grown by plant breeding for decades. As soybeans have very limited genetic variation, it is difficult for soybean breeders to find new genetic resources for abiotic stressors. Recently, soybeans have been exposed to flooding stress from intensive summer rainfall owing to climate change. Glycine soja, a wild soybean, is known to have greater genetic variation and greater resistance to a variety of biotic and abiotic stresses than ordinary soybeans. In this study, high-throughput transcriptome analysis was performed using flood-treated Glycine soja. Differentially expressed genes (DEGs) were analyzed using reads mapped to reference sequences, and gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed using selected DEGs. In addition, RT-qPCR analysis was performed to further analyze the expression of specific candidate genes. Several novel genes that could explain various mechanisms related to water stress were identified as related transcripts and adaptation mechanisms through cell wall expansion, alcoholic fermentation under anaerobic conditions, and structural changes. In addition, most of the isoflavonoid daidzein pathway genes exhibited upregulated expression under flooding stress. Interestingly, expression of the DIR (dirigent protein 1-like) gene, which is known to decrease in response to flooding stress in soybeans (Glycine max), was upregulated in Glycine soja. The expression of DIR revealed that DIR may play a key role in conferring flooding stress resistance in Glycine soja. This study provides useful information regarding the genes and comprehensive adaptation mechanisms related to flooding stress tolerance that can be utilized for cultivated soybeans through the Korean wild soybean.

Globally, wheat (Triticum aestivum) is a major food crop for humans with no regional restrictions. However, it is still difficult for Korea to achieve self-sufficiency owing to production limitations. Moreover, food security is unstable owing to the unpredictable climate and unstable international economy. Pre-harvest sprouting (PHS) is among the factors that occurs frequently due to irregular climates, and damages the value of wheat. In this study, RNA-seq was conducted on PHS-treated samples (for Korean representative cultivar ‘keumgang’) and PHS-resistant mutation line ‘Jeonju 377ho’. Gene functional annotation and DEGs analysis were performed using 234,131,980 mapped reads. Associated transcripts were analyzed using Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and were mainly used to search for genes associated with ATP synthesis and starch and sucrose metabolism related to seed germination and seed dormancy. Candidate DEGs were compressed through cluster set analysis, and gene expression was conducted to search for genes related to seed germination and dormancy to explain them in greater detail based on biological and chemical mechanisms.

Flooding stress causes a significant reduction in soybean yield. The development of flood-tolerant cultivars is an effective way to minimize yield loss due to flooding. Information on candidate genes for flooding tolerance is useful for developing tolerant lines. The
objective
of this study was to identify potential candidate genes for flooding tolerance in soybean by integrating the results of a quantitative trait locus analysis and RNA sequencing. A total of 19 genes showed good amplification in capillary electrophoresis and were further analyzed through a reverse transcription quantitative polymerase chain reaction (qRT-PCR); two of these genes showed differential expression among tolerant and susceptible lines. The expression of Glyma.12g030900 and Glyma.10g050300 in leaf and root tissues, respectively, was higher in several tolerant lines than in the susceptible lines under flooding stress. The chlorophyll index of the tolerant lines was also consistently higher than that of the susceptible lines over two years, supporting the qRT-PCR results. This study provides useful information on flooding tolerance in soybeans.