The EPIDERMAL PATTERNING FACTOR (EPF) plays a crucial role in plant response to abiotic stress. While the EPF has been extensively studied in model plants such as Arabidopsis thaliana, there is a lack of research on identifying EPF genes in the whole sorghum genome and its response to drought stress. In this study, we employed bioinformatics tools to identify 12 EPF members in sorghum. Phylogenetic tree analysis revealed that SbEPFs can be categorized into four branches. Further examination of the gene structure and protein conservation motifs of EPF family members demonstrated the high conservation of the SbEPF sequence. The promoter region of SbEPFs was found to encompass cis-elements responsive to stress and plant hormones. Moreover, real-time fluorescence quantitative results indicated that the SbEPFs have a tissue-specific expression. Under drought stress treatment, most SbEPF members were significantly up-regulated, indicating their potential role in drought response. Our research findings establish a foundation for investigating the function of SbEPFs and offer candidate genes for stress-resistant breeding and enhanced production in sorghum.

Sorghum (Sorghum bicolor), the fifth most important cereal crop globally, serves as a staple food, animal feed, and a bioenergy source. Paclobutrazol-Resistance (PRE) genes play a pivotal role in the response to environmental stress, yet the understanding of their involvement in pest resistance remains limited. In the present study, a total of seven SbPRE genes were found within the sorghum BTx623 genome. Subsequently, their genomic location was studied, and they were distributed on four chromosomes. An analysis of cis-acting elements in SbPRE promoters revealed that various elements were associated with hormones and stress responses. Expression pattern analysis showed differentially tissue-specific expression profiles among SbPRE genes. The expression of some SbPRE genes can be induced by abiotic stress and aphid treatments. Furthermore, through phytohormones and transgenic analyses, we demonstrated that SbPRE4 improves sorghum resistance to aphids by accumulating jasmonic acids (JAs) in transgenic Arabidopsis, giving insights into the molecular and biological function of atypical basic helix-loop-helix (bHLH) transcription factors in sorghum pest resistance.

Sorghum seeds accumulate substantial amounts of condensed tannins (CTs), which are also referred to as proanthocyanidins (PAs), contributing to their characteristic astringent taste. Flavan-3-ol polymers, known as PAs, are sequestered within plant vacuoles and become catalytically activated via laccase enzymes. However, the biological roles and regulatory pathways of laccases in sorghum are still largely unclear. Here, integrated transcriptomic and metabolomic profiling of developing sorghum seeds identified 7942 differentially expressed genes between low- and high-CT lines, with Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment revealing flavonoid biosynthesis as a key pathway; weighted gene co-expression network analysis (WGCNA) further pinpointed SbLAC14 as a hub gene within the module most strongly correlated with CT content. We then examined its regulation by microRNA397 (SbmiR397-5p). Dual-luciferase assays confirmed the binding of SbmiR397-5p to SbLAC14 in co-transformed tobacco leaves. Overexpressing SbLAC14 in transgenic Arabidopsis significantly increased CT accumulation while decreasing catechin and epicatechin levels. Furthermore, transgenic plants overexpressing miR397 (OEmiR397-5p) exhibited reduced CT content, accompanied by a lightening of seed color. Conversely, transgenic lines overexpressing a miR397-insensitive laccase transcript exhibited a reversed phenotypic outcome. Our findings indicate that SbmiR397-5p negatively regulates the expression of SbLAC14 in relation to CT biosynthesis, identifying it as a potential target for manipulating CT metabolism in sorghum. Those results provide a genetic entry point for metabolic engineering and breeding efforts aimed at modulating grain phenolic profiles.

While previous reviews have largely focused on individual crops or single target-site mechanisms, the full-chain comparative landscape across major cereal crops remains unexplored. Here, we fill this critical gap by providing the first systematic, cross-crop comparative review that spans herbicide targets, resistance mechanisms, and breeding applications across four major cereals—rice, maize, wheat, and sorghum. Weed infestation is a serious constraint on crop production. Chemical weed control faces challenges such as herbicide resistance evolution and ecological risks. Developing herbicide-resistant varieties is a fundamental approach to achieve green and sustainable weed management. This review systematically summarizes research progress on herbicide resistance genes from three aspects: herbicide classification, resistance mechanisms, and crop breeding applications. It highlights key differences among four major cereal crops (rice, maize, wheat, and sorghum) in resistance-gene discovery and translational progress. Rice has the richest target-site resistance-gene resources. Maize leads in commercialization of transgenic herbicide resistance. Wheat focuses on endogenous precise editing due to genome complexity and regulatory constraints. Sorghum relies on specific mutations to serve cereal–legume intercropping systems. Based on this comparison, this review identifies the core trends in resistance breeding: from single-gene to multi-gene stacking, and from exogenous gene introduction to endogenous gene editing. It also points out common bottlenecks, including insufficient systematic mining of resistance-gene resources, lagging elucidation of non-target-site resistance regulatory networks, and strong genotype dependence in genetic transformation. Future efforts should focus on exploring broad-spectrum resistance genes, optimizing precise editing technologies, and developing sustainable resistance management strategies. This review provides a theoretical framework and practical references for molecular breeding of herbicide-resistant crops.