Sorghum ( Sorghum bicolor L.) is a vital global crop often cultivated in waterlogging-prone regions. However, its productivity is severely limited by waterlogging stress, which inhibits growth and significantly reduces yields. To address this, we investigated the physiological and molecular mechanisms of waterlogging tolerance by comparing a tolerant variety ‘S208’ with a sensitive one ‘S015’. After 12 days of waterlogging, ‘S208’ exhibited markedly less reduction in plant height, stem thickness, and leaf area. It also developed more and longer adventitious roots and, after 6 days, formed a significantly higher proportion of aerenchyma Physiological assays revealed that the activities of key anaerobic respiratory enzymes, including pyruvate decarboxylase (PDC), lactate dehydrogenase (LDH), and alcohol dehydrogenase (ADH), were consistently higher in ‘S208’. Transcriptomic analysis 24 hours post-waterlogging identified differentially expressed genes (DEGs) enriched in energy metabolism, hormone regulation, and cell wall modification. Weighted gene co-expression network analysis (WGCNA) further highlighted the predominant regulatory roles of AP2/ERF, BHLH and WRKY transcription factor families. Our finding demonstrate that the superior waterlogging tolerance of ‘S208’ is atrributed to integrated morphological, phsiological, and transcriptional adaptations, providing valuable insights for breeding resilient sorghum varieties.

Drought stress during sorghum emergence significantly affects seedling establishment, adversely affecting both emergence and population growth. This study investigates drought tolerance mechanisms during sorghum germination by analyzing physiological changes and transcriptomic data from two lines: W069 (drought tolerant) and W040 (drought sensitive). Under drought conditions, a phenotypic analysis revealed that W069 exhibited longer shoots and roots than W040. Additionally, physiological data indicated higher osmotic substance and lower malondialdehyde levels in W069. Using Kyoto Encyclopedia of Genes and Genome analyses, we identified three key pathways (starch and sucrose metabolism, phenylpropanoid biosynthesis, and phytohormone signaling) as pivotal in the drought response during seed germination in sorghum plants. Expression profiling revealed that most drought tolerance-related genes in the three key pathways were expressed at higher levels in the drought-tolerant cultivar W069, possibly explaining its greater stress tolerance. These findings enhance our understanding of drought-responsive gene networks in sorghum seed germination, offering potential target genes and strategies for enhancing drought tolerance in this crop.

Background/Objectives: Cyclic nucleotide-gated channel (CNGC) genes play crucial roles in plant growth, development, and stress responses, yet their functions in sorghum remain poorly understood. Methods: This study systematically analyzed sorghum CNGC genes through genome-wide identification, encompassing chromosomal mapping, phylogenetic relationships, gene structure, cis-acting elements, miRNA regulation, and GO/KEGG annotation. Results: A total of 23 sorghum CNGC genes were identified and classified into five subclasses (I–IV-b), exhibiting high evolutionary conservation with rice and maize. Promoter and miRNA analyses revealed multi-level regulation involving light, hormones (ABA, JA), and stress response elements. Several SbCNGC genes were predicted to be regulated by multiple miRNAs. Expression profiling and qRT-PCR validation indicated that most SbCNGC genes responded to both high-temperature and low-temperature stress. Expression analysis revealed tissue specificity and stress-induced transcriptional responses. Notably, SbCNGC1 remains consistently upregulated under both cold and heat stress, suggesting a potential key role in Ca²⁺-mediated signaling. Conclusions: This study systematically characterizes SbCNGC genes for the first time, reveals their potential role in abiotic stress tolerance, and provides a valuable resource for sorghum functional genomics and molecular breeding.