Soil salinity is a major abiotic stress limiting crop production globally. Oat (Avena sativa) is an annual cereal with a strong salt tolerance, a high yield, and nutritional quality, although the mechanisms underlying its salt stress response remain largely unknown. We examined the physiological and transcriptomic responses of A. sativa seedlings to salt stress in tolerant cultivar Qingyongjiu 195 and sensitive cultivar 709. Under salt stress, Qingyongjiu 195 maintained a higher photosynthetic efficiency, antioxidant enzymes activity, and leaf K⁺ accumulation but a lower Na⁺ uptake than 709. RNA-seq revealed 6616 differentially expressed genes (DEGs), including 4265 up- and 2351 downregulated. These were enriched in pathways like plant–pathogen interaction, phenylpropanoid biosynthesis, and MAPK signaling. We specifically highlight DEGs involved in photosynthesis (chlG, CP47 psbB, COX2, LHCB) and antioxidants (trxA, GroES). Qingyongjiu 195 also appeared to enhance K⁺ uptake via KAT1 and AKT2 and sequester Na⁺ in vacuoles via NHX2. Additionally, HKT restricted Na⁺ while promoting K⁺ transport to shoots, maintaining K⁺/Na⁺. The expression levels of CAX, ACA, CML, CaM, and CDPK in Qingyongjiu 195 were higher than those in 709. Oats regulated Ca²⁺ concentration through CAX and ACA after salt stress, decoded Ca²⁺ signals through CML, and then transferred Ca²⁺ signals to downstream receptors through the Ca²⁺ sensors CaM and CDPK, thereby activating K⁺/Na⁺ transporters, such as SOS1 and NHX, etc. Our results shed light on plant salt stress response mechanisms and provide transcriptomic resources for molecular breeding in improving salt tolerance in oats.

Background: Seed aging, a natural and inevitable process occurring during storage. Oats, an annual herb belonging to the Gramineae family and pooideae. In addition to being a healthy food, oats serve as ecological pastures, combating soil salinization and desertification. They also play a role in promoting grassland agriculture and supplementing winter livestock feed. However, the high lipid and fat derivatives contents of oat seeds make them susceptible to deterioration, as fat derivatives are prone to rancidity, affecting oat seed production, storage, development, and germplasm resource utilization. Comparative studies on the effects of aging on physiology and cytological structure in covered and naked oat seeds are limited. Thus, our study aimed to determine the mechanism underlying seed deterioration in artificially aged ‘LongYan No. 3’ (A. sativa) and ‘BaiYan No. 2’ (A. nuda) seeds, providing a basis for the physiological evaluation of oat seed aging and serving as a reference for scientifically safe storage and efficient utilization of oats. Results: In both oat varieties, superoxide dismutase and catalase activities in seeds showed increasing and decreasing trends, respectively. Variance analysis revealed significant differences and interaction in all measured indicators of oat seeds between the two varieties at different aging times. ‘LongYan No. 3’ seeds, aged for 24–96 h, exhibited a germination rate of < 30%, Conductivity, malondialdehyde, soluble sugar, and soluble protein levels increased more significantly than the ‘BaiYan No. 2’. With prolonged aging leading to cell membrane degradation, reactive oxygen species accumulation, disrupted antioxidant enzyme system, evident embryo cell swelling, and disordered cell arrangement, blocking the nutrient supply route. Simultaneously, severely concentrated chromatin in the nucleus, damaged mitochondrial structure, and impaired energy metabolism were noted, resulting in the loss of ‘LongYan No. 3’ seed vitality and value. Conversely, ‘BaiYan No. 2’ seeds showed a germination rate of 73.33% after 96 h of aging, consistently higher antioxidant enzyme activity during aging, normal embryonic cell shape, and existence of the endoplasmic reticulum. Conclusions: ROS accumulation and antioxidant enzyme system damage in aged oat seeds, nuclear chromatin condensation, mitochondrial structure damage, nucleic acid metabolism and respiration weakened, oat seed vigor decreased. ‘LongYan No. 3’ seeds were more severely damaged under artificial aging than ‘BaiYan No. 2’ seeds, highlighting their heightened susceptibility to aging effects.

Background: Drought is a significant condition that restricts vegetation growth on the Tibetan Plateau. Artemisia wellbyi is a unique semi-shrub-like herb in the family Compositae, which distributed in northern and northwest of Tibetan Plateau. It is a dominant species in the community that can well adapt to virous environment stress, such as drought and low temperature. Therefore, A. wellbyi. has a potential ecological value for soil and water conservation of drought areas. Understanding the molecular mechanisms of A. wellbyi. that defense drought stress can acquire the key genes for drought resistance breeding of A. wellbyi. and provide a theoretical basis for vegetation restoration of desertification area. However, they remain unclear. Thus, our study compared the transcriptomic characteristics of drought-tolerant “11” and drought-sensitive “6” material of A. wellbyi under drought stress. Results: A total of 4875 upregulated and 4381 downregulated differentially expressed genes (DEGs) were induced by drought in the tolerant material; however, only 1931 upregulated and 4174 downregulated DEGs were induced by drought in the sensitive material. The photosynthesis and transcriptional regulation differed significantly with respect to the DEGs number and expression level. We found that CDPKs (calmodulin-like domain protein kinases), SOS3 (salt overly sensitive3), MAPKs (mitogen-activated protein kinase cascades), RLKs (receptor like kinase), and LRR-RLKs (repeat leucine-rich receptor kinase) were firstly involved in response to drought stress in drought tolerant A. wellbyi. Positive regulation of genes associated with the metabolism of ABA (abscisic acid), ET (ethylene), and IAA (indole acetic acid) could play a crucial role in the interaction with other transcriptional regulatory factors, such as MYBs (v-myb avian myeloblastosis viral oncogene homolog), AP2/EREBPs (APETALA2/ethylene-responsive element binding protein family), WRKYs, and bHLHs (basic helix-loop-helix family members) and receptor kinases, and regulate downstream genes for defense against drought stress. In addition, HSP70 (heat shock protein70) and MYB73 were considered as the hub genes because of their strong association with other DEGs. Conclusions: Positive transcriptional regulation and negative regulation of photosynthesis could be associated with better growth performance under drought stress in the drought-tolerant material. In addition, the degradation of sucrose and starch in the tolerant A. wellbyi to alleviate osmotic stress and balance excess ROS. These results highlight the candidate genes that are involved in enhancing the performance of drought-tolerant A. wellbyi and provide a theoretical basis for improving the performance of drought-resistant A. wellbyi.

The Domain of unknown function 679 membrane protein (DMP) family, which is unique to plants, plays a crucial role in reproductive development, stress response and aging. A comprehensive study was conducted to identify the DMP gene members of oat (Avena sativa) and to investigate their structural features and tissue-specific expression profiles. Utilizing whole genome and transcriptome data, we analyzed the physicochemical properties, gene structure, cis-acting elements, phylogenetic relationships, conserved structural (CS) domains, CS motifs and expression patterns of the AsDMP family in A. sativa. The DMP family genes of A. sativa were distributed across 17 chromosomal scaffolds, encompassing a total of 33 members. Based on phylogenetic relationships, the AsDMP genes were classified into five distinct subfamilies. The gene structure also suggests that A. sativa may have undergone an intron loss event during its evolution. Covariance analysis indicates that genome-wide duplication and segmental duplication may be the major contributor to the expansion of the AsDMP gene family. Ka/Ks selective pressure analysis of the AsDMP gene family suggests that DMP gene pairs are generally conserved over evolutionary time. The upstream promoters of these genes contain several cis-acting elements, suggesting a potential role in abiotic stress responses and hormone induction. Transcriptome data revealed that the expression patterns of the DMP genes are involved in tissue and organ development. In this study, the AsDMP genes (AsDMP1, AsDMP19, and AsDMP22) were identified as potential regulators of seed senescence in A. sativa. These genes could serve as candidates for breeding studies focused on seed longevity and anti-aging germplasm in A. sativa. The study provides valuable insights into the regulatory mechanisms of the AsDMP gene family in the aging process of A. sativa germplasm and offers theoretical support for further function investigation into the functions of AsDMP genes and the molecular mechanisms underlying seed anti-aging. This study identified the AsDMP genes as being involved in the aging process of A. sativa seeds, marking the first report on the potential role of DMP genes in seed aging for A. sativa.

Background: The Domain of unknown function 679 membrane proteins (DMPs) family, as a green plant-specific membrane protein, plays an important role in plant reproductive development, stress response and aging. To identify the DMP gene members of oat (AsDMP) and to investigate their family structural features and tissue expression profile characteristics, a study was conducted. Based on the whole genome and transcriptome data, in this investigation, we have scrutinized the physicochemical properties, gene structure, cisacting elements, phylogenetic relationships, conserved structural (CS) domains, CS motifs and expression patterns of the AsDMP family of oat. Results The DMP family genes of oat were found distributed across 17 chromosomal scaffolds with 33 members. We could divide the AsDMP genes into five subfamilies based on phylogenetic relationships. The gene structure suggests that oats may have also undergone an intron loss event during evolution. Covariance analysis suggests that genome-wide duplication/segmental duplication may be the major contributor to the expansion of the AsDMP gene family. Ka/Ks selective pressure analysis of oat DMP gene family, suggests that DMP gene pairs tend to be conserved over evolutionary time. The upstream promoter of these genes containing several cis-acting elements indicates a plausible role in abiotic stress and hormone induction. Gene expression pattern according to transcriptome data revealed participation of the DMP genes in tissue and organ development. In this study, AsDMP genes (AsDMP1, AsDMP19, and AsDMP22) were identified as potentially regulating oat seed senescence, and can be used as candidate genes for seed longevity and anti-aging germplasm breeding studies in oat. The study provides valuable information on the regulatory mechanism of the AsDMP gene family in the aging process of oat germplasm, and also provides theoretical support for further function investigation in the oat DMP gene and the molecular mechanism of seed anti-aging. Conclusions In this study, we found that the AsDMP gene is involved in the aging process of oat seeds, which is the first report on the potential role of DMP genes in oat seeds.