Salt stress is a major threat to crop quality and yield. Most experiments on salt stress-related genes have been conducted at the laboratory or greenhouse scale. Consequently, there is a lack of research demonstrating the merit of exploring these genes in field crops. Here, we found that the R2R3-MYB transcription factor SiMYB19 from foxtail millet is expressed mainly in the roots and is induced by various abiotic stressors such as salt, drought, low nitrogen, and abscisic acid. SiMYB19 is tentatively localized to the nucleus and activates transcription. It enhances salt tolerance in transgenic rice at the germination and seedling stages. SiMYB19 overexpression increased shoot height, grain yield, and salt tolerance in field- and salt pond-grown transgenic rice. SiMYB19 overexpression promotes abscisic acid (ABA) accumulation in transgenic rice and upregulates the ABA synthesis gene OsNCED3 and the ABA signal transduction pathway-related genes OsPK1 and OsABF2. Thus, SiMYB19 improves salt tolerance in transgenic rice by regulating ABA synthesis and signal transduction. Using rice heterologous expression analysis, the present study introduced a novel candidate gene for improving salt tolerance and increasing yield in crops grown in saline-alkali soil.

Nitrogen plays a crucial role in wheat growth and development. Here, we analyzed the tolerance of wheat strains XM26 and LM23 to low-nitrogen stress using a chlorate sensitivity experiment. Subsequently, we performed transcriptome analyses of both varieties exposed to low-nitrogen (LN) and normal (CK) treatments. Compared with those under CK treatment, 3534 differentially expressed genes (DEGs) were detected in XM26 in roots and shoots under LN treatment (p < 0.05, and |log2FC| > 1). A total of 3584 DEGs were detected in LM23. A total of 3306 DEGs, including 863 DEGs in roots and 2443 DEGs in shoots, were specifically expressed in XM26 or showed huge differences between XM26 and LM23 (log2FC ratio > 3). These were selected for gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses. The calcium-mediated plant–pathogen interaction, MAPK signaling, and phosphatidylinositol signaling pathways were enriched in XM26 but not in LM23. We also verified the expression of important genes involved in these pathways in the two varieties using qRT-PCR. A total of 156 transcription factors were identified among the DEGs, and their expression patterns were different between the two varieties. Our findings suggest that calcium-related pathways play different roles in the two varieties, eliciting different tolerances to low-nitrogen stress.

Nitrogen crucially impacts foxtail millet (Setaria italica) growth and development. Uncovering low nitrogen (LN) tolerance genes and mechanisms is vital for breeding high nitrogen use efficiency varieties. In this study, the LN tolerance of 50 foxtail millet genotypes was assessed through field trials and seedling hydroponic experiments. Subsequently, transcriptome analysis was performed on one highly sensitive genotype, named Maotigu, and on one highly tolerant genotype, named Dahuanggu, under LN (0.1 mmol/L) and control (5 mmol/L) conditions in seedling hydroponic experiments. Compared to the control treatment, 823 differentially expressed genes (DEGs) (350 upregulated, 473 downregulated) were identified in the roots of Dahuanggu, while 2427 DEGs (1703 upregulated, 724 downregulated) were detected in Maotigu under LN treatment. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that a total of 3134 DEGs were associated with pathways including plant–pathogen interaction, amino sugar and nucleotide sugar metabolism, nitrogen metabolism, and others. A total of 116 DEGs were commonly identified between Dahuanggu and Maotigu, involving pathways like plant–pathogen interaction, galactose metabolism, and flavone and flavonol biosynthesis. The 28 of 116 DEGs showed opposite expression patterns between Dahuanggu and Maotigu; the expression of 18 genes was further validated using qRT-PCR. These offer valuable insights into the molecular mechanisms underlying LN stress responses in foxtail millet.