Peanut (Arachis hypogaea L.) is a globally important oilseed cash crop, yet its limited genetic diversity and unique reproductive biology present persistent challenges for conventional crossbreeding. Traditional breeding approaches are often time-consuming and inadequate, mitigating the pace of cultivar development. Essential for double fertilization and programmed cell death (PCD), DUF679 membrane proteins (DMPs) represent a membrane protein family unique to plants. In the present study, a comprehensive analysis of the DMP gene family in peanuts was conducted, which included the identification of 21 family members. Based on phylogenetic analysis, these genes were segregated into five distinct clades (I–V), with AhDMP8A, AhDMP8B, AhDMP9A, and AhDMP9B in clade IV exhibiting high homology with known haploid induction genes. These four candidates also displayed significantly elevated expression in floral tissues compared to other organs, supporting their candidacy for haploid induction in peanuts. Subcellular localization prediction, confirmed through co-localization assays, demonstrated that AhDMPs primarily localize to the plasma membrane, consistent with their proposed roles in the reproductive signaling process. Furthermore, chromosomal mapping and synteny analyses revealed that the expansion of the AhDMP gene family is largely driven by whole-genome duplication (WGD) and segmental duplication events, reflecting the evolutionary dynamics of the tetraploid peanut genome. Collectively, these findings establish a foundational understanding of the AhDMP gene family and highlight promising targets for future applications in haploid induction-based breeding strategies in peanuts.

The cultivated peanut (Arachis hypogaea L.) is an important oilseed and economic crop worldwide, with seed protein content being a key target for quality improvement. The Sugars Will Eventually be Exported Transporter (SWEET) gene family encodes sugar transporters that play crucial roles in plant growth and development, stress tolerance, pathogen interactions, and seed filling. In this study, 43 AhSWEET genes were identified in the cultivated peanut genome and classified into four phylogenetic clades. Members within the same clade generally show similar exon-intron structures and conserved motif compositions, suggesting evolutionary conservation within subgroups. Promoter cis-regulatory elements analysis indicated that AhSWEET genes contain multiple elements associated with light response, hormone signaling, stress response, and growth and development, implying their potential involvement in diverse biological processes. Subcellular localization predictions indicated that most AhSWEET proteins are likely localized to the plasma membrane, consistent with their putative roles in transmembrane sugar transport. This was further supported by transient expression analysis of selected AhSWEET-eGFP fusion proteins in Nicotiana benthamiana leaves. Comparative phylogenetic and synteny analyses reveal that AhSWEET5, AhSWEET21, AhSWEET27, and AhSWEET43 are closely related to soybean GmSWEET10a and GmSWEET10b, which are known to regulate seed size and storage-compound accumulation. Transcriptome data and quantitative reverse transcriptase PCR analysis showed that these candidate genes are preferentially expressed in seed-related tissues, particularly the testa and embryo, suggesting possible sugar allocation during peanut seed development. Overall, this study provides a systematic characterization of the AhSWEET gene family and identifies several candidate genes for future functional studies aimed at improving peanut seed quality, including protein accumulation.