Actin-depolymerizing factors (ADFs) are important regulators of actin cytoskeleton dynamics and play critical roles in plant development and stress responses. However, the evolutionary patterns and functional diversity of the ADF gene family within the Brassica napus pangenome remain largely unexplored. In this study, we performed a comprehensive pangenome-scale analysis of ADF genes across eight B. napus genomes and identified 263 BnADFs, with gene numbers ranging from 27 to 36 among accessions. Orthology analysis grouped these genes into 21 orthologous clusters, which were classified into nine core, three soft-core, five shell, and four cloud groups, revealing a continuum of conservation across the pangenome. Core genes showed stronger signatures of purifying selection and more conserved gene structures, whereas dispensable genes exhibited greater structural variation and presence–absence polymorphism. Transposable element insertions and structural variants were frequently detected at ADF loci, suggesting that genome structural variation has contributed to the diversification of this gene family. Expression profiling revealed tissue-specific expression patterns and identified several BnADFs that were induced under salt stress, particularly in roots. Four representative genes were independently examined by qRT-PCR in Chuanyou 83 and showed salt-responsive transcription. Using the 2,311-accession population variation resource integrated in BnIR, sequence polymorphism analysis of these four candidate loci identified 144 variants and distinct major haplotypes, several of which were associated with differences in yield performance under salt–alkali conditions. Our results provide new insights into the evolutionary dynamics and functional diversification of BnADFs in the rapeseed pangenome. The favorable haplotypes identified here represent promising targets for the genetic improvement of salt-tolerant rapeseed cultivars.
Chilling stress is one of the major factors affecting the green period and turf quality of zoysiagrass (Zoysia spp.). However, the physiological and molecular mechanisms of differential chilling tolerance among zoysiagrass cultivars remain largely unexplored. The objectives of this study were to elucidate differences in chilling tolerance between the two cultivars through integrating physiological and transcriptomic analyses, and to investigate protective effects of exogenous chitosan on the sensitive one. The results showed that the chilling-tolerant cultivar ‘Nannong NT1’ suffered less injury than the sensitive ‘Nannong LG’ under chilling stress, as evidenced by lower electrolyte leakage, reduced reactive oxygen species (ROS) accumulation, and a higher recovery rate. Transcriptomic analyses further identified that ‘Nannong NT1’ specifically up-regulated carbohydrate and lipid metabolism, while concurrently down-regulating photosynthesis and carbon fixation. In contrast, ‘Nannong LG’ activated carotenoid and flavonoid biosynthesis, and repressed amino acid metabolism and protein export. Additionally, foliar application of chitosan (50 mg·L−¹) significantly alleviated chilling injury in ‘Nannong LG’ by enhancing chlorophyll content, relative water content, osmoprotectant accumulation, and recovery rate, while reducing electrolyte leakage and ROS accumulation. At the transcriptional level, chitosan specifically modulated the expression of several critical differentially expressed genes, such as ZsNAC2, ZsNAC3, ZsLecRLK1, ZsLecRLK2, and ZsBAM. These findings demonstrate that differential chilling tolerance was attributed to the divergent regulatory and metabolic strategies. Exogenous chitosan offers a complementary approach to enhance chilling tolerance in the sensitive cultivar in zoysiagrass.
Sesame (Sesamum indicum L.) is an important oilseed crop. The seed coat plays important roles in seed protection, maturation, and quality formation in sesame. However, its dynamic developmental process remains poorly understood. In this study, seed coat development was investigated using metabolomic, proteomic, and transcriptomic analyses. Morphological and histological observations showed a clear developmental progression from early structural formation (5–15 days after pollination, DAP), through structural consolidation (15–25 DAP), to maturation accompanied by extensive intracellular accumulation (25–40 DAP). Based on these developmental characteristics, seed coats collected at 10, 20, 30, and 40 DAP were selected for multi-omics analysis. Metabolomic analysis revealed dynamic metabolic changes, with lipid metabolism being prominent during the early development stage, whereas amino acid metabolism and secondary metabolite biosynthesis were associated with later developmental stages. Antioxidant-related pathways, particularly ascorbate and aldarate metabolism, were consistently enriched throughout seed coat development. Proteomic analysis showed that most differentially expressed proteins (DEPs) were downregulated, with enrichment patterns shifting from RNA processing and lipid biosynthesis at the early developmental stage to translation and redox metabolism at the middle developmental stage, and subsequently to energy metabolism and protein processing at the late developmental stage. Fatty acid biosynthesis was consistently enriched across all developmental stages. Transcriptomic analysis indicated that hormone signaling, carbon metabolism, and secondary metabolite biosynthesis were associated with seed coat development. Integrated metabolome-transcriptome and metabolome-proteome analyses showed glyoxylate and dicarboxylate metabolism as a metabolic pathway potentially associated with seed coat development. Furthermore, weighted gene co-expression network analysis (WGCNA) integrating transcriptomic and metabolomic data identified the green module (MEgreen), which contained candidate genes potentially associated with metabolic changes during seed coat development. This study provides an integrated multi-omics characterization of sesame seed coat development and reveals developmental stage-specific changes in metabolites, proteins, and transcripts. The identified candidate pathways and genes provide valuable resources for further investigating the molecular mechanisms underlying sesame seed coat development.
Exploiting allelopathic plants and elucidating their mechanisms of action are essential for sustainable weed management and the discovery of natural bioherbicides. This study investigated the allelopathic potency of Ranunculus testiculatus aqueous extract on seed germination, seedling biochemistry, and α-amylase activity, supported by hypothesis-generating molecular docking. Dose–response bioassays were conducted on Hordeum vulgare var. Sardari to determine the concentration causing 50
Low-temperature stress restricts plant growth, development, and geographical distribution. Kentucky bluegrass (Poa pratensis L.), a cool-season turfgrass, is susceptible to low-temperature events during winter, early spring, and late autumn, which can impair turf establishment and quality. To investigate the physiological and molecular responses associated with cold tolerance in Kentucky bluegrass, 20 accessions were evaluated at the germination stage under 7 °C and at the seedling stage under 0 °C, with 25 °C serving as the control. Based on comprehensive cold-tolerance evaluation, MD and XH were selected as representative cold-tolerant and cold-sensitive accessions, respectively. Compared with XH, MD maintained higher superoxide dismutase, peroxidase, and catalase activities, accumulated more soluble protein and proline, exhibited lower levels of H₂O₂, O₂·⁻, malondialdehyde, and relative electrical conductivity, and maintained more stable photosynthetic performance under low-temperature stress. Transcriptome profiling of MD and XH at 0, 24, and 48 h under 0 °C revealed distinct genotype-dependent transcriptional responses. Differentially expressed genes and genes within trait-associated co-expression modules were primarily enriched in plant hormone signal transduction, mitogen-activated protein kinase signaling, phenylpropanoid biosynthesis, starch and sucrose metabolism, and plant-pathogen interaction pathways. These results identify MD as a promising cold-tolerant germplasm and provide candidate genes and co-expression networks associated with cold tolerance, offering physiological and molecular resources for future genetic improvement of Kentucky bluegrass.
