Currently, the widely used active form of plant elicitor peptide 1 (PEP1) from Arabidopsis thaliana is composed of 23 amino acids, hereafter AtPEP1^(1–23), serving as an immune elicitor. The relatively less conserved N-terminal region in AtPEP family indicates that the amino acids in this region may be unrelated to the function and activity of AtPEP peptides. Consequently, we conducted an investigation to determine the necessity of the nonconserved amino acids in AtPEP1^(1–23) peptide for its functional properties. By assessing the primary root growth and the burst of reactive oxygen species (ROS), we discovered that the first eight N-terminal amino acids of AtPEP1^(1–23) are not crucial for its functionality, whereas the conserved C-terminal aspartic acid plays a significant role in its functionality. In this study, we identified a truncated peptide, AtPEP1^(9–23), which exhibits comparable activity to AtPEP1^(1–23) in inhibiting primary root growth and inducing ROS burst. Additionally, the truncated peptide AtPEP1^(13–23) shows similar ability to induce ROS burst as AtPEP1^(1–23), but its inhibitory effect on primary roots is significantly reduced. These findings are significant as they provide a novel approach to explore and understand the functionality of the AtPEP1^(1–23) peptide. Moreover, exogenous application of AtPEP1^(13–23) may enhance plant resistance to pathogens without affecting their growth and development. Therefore, AtPEP1^(13–23) holds promise for development as a potentially applicable biopesticides.

Winter rapeseed is a high-oil crop that exhibits significant sensitivity to low temperatures, leading to a substantial reduction in production. Hence, it is of great significance to elucidate the genomic genetic mechanism of strong freezing-resistant winter rapeseed to improve their freezing-resistant traits. In this study, global transcriptome expression profiles of the freezing-resistant cultivar NTS57 (NS) under freezing stress were obtained for the years 2015, 2016, and 2017 by RNA sequencing (RNA-seq). Most differentially expressed genes (DEGs) were involved in the plant hormone signal transduction, alpha-linolenic acid metabolism, protein processing, glutathione metabolism, and plant-pathogen interaction pathways. Antioxidant enzyme activities and lipid peroxidation levels were significantly positively and negatively correlated with overwintering rate (OWR), respectively. After freezing treatment, the formation of freezing resistance of NS was attributed to the increase in antioxidant enzyme activities and content of osmotic regulation substances, as well as the decrease in lipid peroxidation level. Furthermore, quantitative reverse transcription polymerase chain reaction (qRT-PCR) and phenotypic verification indicated that heat stress transcription factor A2 (HSFA2) and 17.6 kDa class II heat shock protein (HSP17.6) participated in the response to freezing stress. This study will further refine the regulatory network of plants against freezing stress and help to screen candidate genes for improving plant freezing resistance.

Histone deacetylases (HDACs) are key epigenetic enzymes governing lysine deacetylation. This modification is tightly coupled to cellular redox homeostasis and antioxidant signaling in plants. Plant HDACs are grouped into three subfamilies: RPD3/HDA1, SIR2, and plant-specific HD2. HDACs target both histone residues (e.g., H3K9 and H4K5) and a broad set of non-histone substrates (e.g., transcription factors and metabolic enzymes). Via coordinated chromatin remodeling and non-histone protein modification, HDACs integrate phytohormone signals, reactive oxygen species (ROS) bursts and NAD⁺ metabolic fluctuations to orchestrate plant abiotic stress responses, balancing antioxidant defense, redox equilibrium and normal growth. This review systematically sorts the divergent stress-response traits, substrate preferences and bidirectional regulatory logic of the three HDAC subfamilies; integrates chromatin-dependent and transcription factor-centered transcriptional branches; and summarizes crosstalk rules between HDAC-mediated deacetylation and other epigenetic marks. We further hierarchically clarify current research bottlenecks spanning basic mechanism dissection, multi-crop validation and field breeding transformation and propose targeted stratified research directions. We further construct a complete regulatory cascade linking environmental stimuli, ROS/ABA/NAD⁺ signals, HDAC activity and downstream antioxidant/stress gene expression, filling gaps in previous reviews that overlook redox-dependent HDAC functions. This mechanistic framework delivers integrated epigenetic and redox theoretical references for breeding stress-tolerant crops with reinforced antioxidant capacity.

Brassica rapa is widely cultivated in alpine and cold mountainous regions due to its strong cold tolerance. However, lodging severely limits its yield and quality. This study integrated agronomic traits, stem microstructure, and transcriptomic profiles to explore the mechanism of lodging resistance by comparing a resistant cultivar (Ganyou 3064, GY) and a susceptible cultivar (Tianyou 2022, TY) across four developmental stages (full flowering, final flowering, podding, and maturity). At the four growth stages, the stem breaking strength of GY was 1.71, 1.93, 1.88, and 1.88 times that of TY, respectively. Compared with TY, the gravity center height of GY was decreased by 25.04%, 16.6%, 11.18%, and 8.98% at these four stages, respectively. Similarly, the lodging index of GY was decreased by 65.94%, 55.08%, 56.06%, and 55.63% compared with TY, respectively. Biochemical and anatomical analyses revealed that compared with TY, the lignin content of GY increased by 1.93%, 2.7%, 3.05%, and 3.42% at the four stages, while the cellulose content increased by 92.75%, 45.32%, 44.4%, and 49.92%, respectively. Meanwhile, the epidermal thickness, cortical thickness, vascular bundle length, vascular bundle area, and vascular bundle density of GY were also significantly increased. Transcriptomic and KEGG pathway analyses revealed a predictive defense mechanism of GY. At the final flowering stage, GY showed pre-activation of hormone and MAPK signal transduction, as well as phenylpropanoid biosynthesis; it shifted to energy supply and sustained cell wall reinforcement at the podding stage. In addition, upregulated genes in phenylpropanoid biosynthesis (such as PAL3, CCoAOMT, and CAD9) indicated that enhanced stem lignification is a key molecular determinant of lodging resistance. In summary, GY enhances its lodging resistance through coordinated morphological and transcriptional regulation. This study is the first to integrate the lodging characteristics of Brassica rapa, offering valuable candidate genes and phenotypic markers for molecular breeding.