Heat shock protein 20 (HSP20) is a diverse and functionally important protein family that plays a crucial role in plants’ tolerance to various abiotic stresses. In this study, we systematically analyzed the structural and functional characteristics of the HSP20 gene family within the Zea pan-genome. By identifying 56 HSP20 pan-genes, we revealed the variation in the number of these genes across different maize inbreds or relatives. Among those 56 genes, only 31 are present in more than 52 inbreds or relatives. Further phylogenetic analysis classified these genes into four major groups (Class A, B, C, D) and explored their diversity in subcellular localization, physicochemical properties, and the terminal structures of those HSP20s. Through collinearity analysis and Ka/Ks ratio calculations, we found that most HSP20 genes underwent purifying selection during maize domestication, although a few genes showed signs of positive selection pressure. Additionally, expression analysis showed that several HSP20 genes were significantly upregulated under high temperatures, particularly in tassels and leaves. Co-expression network analysis revealed that HSP20 genes were significantly enriched in GO terms related to environmental stress responses, suggesting that HSP20 genes not only play key roles in heat stress but may also be involved in regulating various other biological processes, such as secondary metabolism and developmental processes. These findings expand our understanding of the functions of the maize HSP20 family and provide new insights for further research into maize’s response mechanisms to environmental stresses.

The Snf2 protein family is a group of ATP-dependent chromatin remodeling factors (CHRs) that play an essential role in gene expression regulation. In plants, Snf2 is involved in growth, development, as well as stress resistance. However, only a very limited number of experimentally validated Snf2 have been identified and reported, while the majority remaining undiscovered in most species . In this study, we predicted 3135 Snf2 proteins and 8398 chromatin remodeling complex (CRC) subunits in diverse plant species, and constructed the Plant Chromatin Remodeling Factors Database (PlantCHRs, http://www.functionalgenomics.cn/PlantCHRs/), which provide a comprehensive resource for researchers to access information about plant CHRs. We also developed an online tool capable of predicting CHRs and CRC subunits. Moreover, we investigated the distribution of Snf2 proteins in different species and observed a significant increase in the number of Snf2 proteins and the diversity of the Snf2 subfamily during the evolution, highlighting their evolutionary importance. By analyzing the expression patterns of the Snf2 genes in different tissues of maize and Arabidopsis, we found that the Snf2 proteins may show some conservation across different species in regulating plant growth and development. Over the all, we established a comprehensive database for plant CHRs, which will facilitate the researches on plant chromatin remodeling.

Sweet potato (Ipomoea batatas (L.) Lam) is an important food and energy crop. Soil salinization is a major abiotic stress that limits agricultural productivity and severely reduces yield of crops. Protein hydrolysates, as a class of natural biostimulants, have gained increasing attention for their potential to improve crop yield, quality and stress tolerance. This study investigated the effects of peptides from swine blood (PSB) on high salinity stress tolerance in sweet potato. Application of PSB promoted the growth of both aerial and underground parts of sweet potato under normal and high-salinity conditions. Further analysis revealed that, under high salinity stress, exogenous PSB up-regulated the expression of genes associated with stress responses, increased the accumulation of organic osmotic adjustment compounds such as free amino acids, promoted K⁺ uptake to elevate the K⁺/Na⁺ ratio, and enhanced the activity of key antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) involved in the reactive oxygen species-scavenging system. These biochemical responses contributed to maintaining cellular osmotic balance and redox homeostasis, protecting the cell membrane from damage while preserving its structural integrity and normal physiological functions, and improving photosynthetic efficiency, thereby enhancing high salinity stress tolerance in sweet potato. Thus, PSB holds significant potential as an effective natural biostimulant for sweet potato cultivation in saline soils.