Superoxide dismutases (SODs) are crucial in safeguarding plants against reactive oxygen species (ROS) toxicity caused by abiotic or biotic factors. Although recent research has revealed the involvement of the SOD gene family in plant biological processes, the understanding of the SOD gene family in peanut remains inadequate. This study comprehensively characterizes the SOD gene family in the peanut genome. A total of 25 AhSOD genes were identified and subsequently categorized into three subfamilies: sixteen AhCSDs, six AhFSDs, and three AhMSDs according to the phylogenetic tree. A comprehensive analysis revealed that the AhSOD genes underwent segmental duplications. The majority of AhSOD genes exhibited conserved exon–intron and motif structures within the same subfamily. The examination of cis-acting elements within the promoter regions of SOD genes revealed that the expression of AhSOD was subject to regulation by plant hormones, as well as responses to defense and stress. RNA-seq analysis showed expression diversity of AhSOD genes in various tissues and cold, drought, and salt stresses. Furthermore, the regulation of AhSOD gene expression is anticipated to involve numerous transcription factors. The gene ontology annotation results validate the role of AhSOD genes in various stress stimuli, SOD activity, reactive oxygen species metabolic processes, and cellular oxidant detoxification processes. This investigation serves as the initial genome-wide analysis of the AhSOD gene family, providing a basis for comprehending the function of the AhSOD gene family and enhancing plant tolerance to cold, drought, and salt stresses.

High oleic acid peanut (HOAP) is extensively embraced in China because of its high nutritional value and enhanced oxidative stability. However, its dissemination has been severely constrained in high altitude and high latitude areas due to chilling stress during sowing, resulting in significant yield loss in these regions. Despite the lack of understanding of the molecular mechanisms underlying low temperature germination (LTG) in HOAP, discovering the quantitative trait loci (QTL) that confer this trait will undoubtedly benefit breeding efforts. In the present study, we identified putative genomic regions and single nucleotide polymorphisms (SNPs) that govern LTG tolerance of HOAP in an F₂ population derived from the cross of chilling-tolerant YH65 and chilling-sensitive FL14 using bulk segregant analysis (BSA). Analysis of ΔSNP-index and Euclidean distance (ED) value association pinpointed the overlapped region to a 2.29 Mb interval on chromosome A05. The candidate interval showed that 122 genes were significantly related to response to abiotic stress and plant–pathogen interaction. Furthermore, an SNP site associated with LTG tolerance was discovered. The SNP site was employed as a Kompetitive Allele Specific PCR (KASP) marker and validated in a universal peanut panel. These findings may provide valuable insight into the molecular mechanism underpinning LTG tolerance and facilitate marker-assisted selective breeding in HOAP.

Peanut is a vital cash crop globally, and enhancing its seed protein content is essential for nutritional security. However, the genetic basis of seed protein content in peanut remains unclear. In this study, bulked segregant analysis combined with next-generation sequencing (BSA-Seq) was employed to isolate a candidate gene, AhSPC, associated with peanut seed protein content. Its function was then characterized in Arabidopsis thaliana through CRISPR/Cas9-mediated gene knockout and overexpression analysis. Gene editing of the homologous gene in Arabidopsis significantly reduced seed protein content in six lines, while two lines showed no obvious change. Overexpression of the AhSPC gene in Arabidopsis led to an increase in seed protein content in three transgenic lines, but some lines showed no significant change, or even a decrease. These inconsistent results might be attributed to functional redundancy, epigenetic modifications, resource competition, or feedback regulation mechanisms within the protein synthesis pathway. This study provides insights into the molecular mechanisms of peanut seed protein content regulation and offers a potential genetic target for molecular breeding.

Peanut (Arachis hypogaea L.) is a globally vital oil and cash crop. However, frequent cold stress severely compromises its yield stability. To address this challenge, we conducted quantitative trait locus (QTL) mapping for two cold tolerance-associated traits, namely relative emergence rate (RER) and relative emergence index (REI), across four distinct environments using a recombinant inbred line (RIL) population derived from the cold-tolerant landrace Silihong and cold-sensitive cultivar Jinonghei 3. Two core QTLs associated with cold tolerance were detected, including qRER6 stable across all environments with PVE of 4.91–5.15% and a co-localized QTL qRER18.1/qREI18.2 on chromosome 18 that governs both target traits with PVE of 14.56–14.71% and 10.34%. Through integrated analysis of QTL mapping and Weighted gene co-expression network analysis (WGCNA), Arahy.657RUG was identified as a candidate cold tolerance gene and designated Ahcold18. Differential expression analysis and heterologous overexpression in Arabidopsis thaliana under freezing stress (−9 °C) showed that Ahcold18 enhances plant survival under low-temperature stress, suggesting a general role in cold tolerance that warrants further investigation in the context of peanut chilling tolerance. A gene-based KASP marker (KASP-2374669), developed from variant sites within Ahcold18, showed preliminary association with RER and REI in the RIL population; however, further validation in diverse germplasm is required to confirm its utility for marker-assisted selection. This study provides a critical genetic resource and a precise technical tool for marker-assisted breeding of cultivated peanut with cold tolerance.