Seed priming, a valuable seed pretreatment method widely employed in agricultural production, counteracts the decline in seed vigor attributed to aging and deterioration. However, PEG priming effectively enhances the vigor of aged soybean seeds. In this study, “TONGDOU13” soybean seeds were subjected to PEG-6000 priming at varying concentrations (10%, 20%, 30%, 40%) for three different durations (12 h, 24 h, 36 h). The results showed that a 24 h priming with 30% PEG-6000 significantly enhances the vigor of aged soybean seeds. To elucidate the mechanism underlying the heightened vigor resulting from PEG-6000 priming, we employed transcriptome sequencing and physiological–biochemical tests. Transcriptome sequencing analysis showed the significant down-regulation of carbon metabolism-related genes post PEG-6000 priming, which facilitated energetically efficient germination. Five peroxidase-encoding genes displayed significant up-regulation, promoting the conversion of coumaryl alcohol to hydroxy-phenyl lignin, a probable catalyst for augmented seed vigor. SOD and GST genes were significantly up-regulated, enhancing the scavenging ability of reactive oxygen species (ROS). The concurrent up-regulation of brassinolide (BR) and auxin (IAA) signals countered ABA signaling, thereby promoting aged seed germination. Further investigation included the measurements of antioxidant enzyme activity, hormone levels, and lignin content. Notably, primed aged seeds exhibited enhanced ROS scavenging ability, and increased lignin, BR, and IAA contents. Therefore, PEG priming may improve aged soybean seed vigor through the co-regulation of carbon metabolism, ROS scavenging, hormone signaling, and lignin synthesis. This study will be vital for preserving germplasm resources and reutilizing aged soybean seeds.

Long-term fertilization profoundly influences soil biochemical processes and microbial functionality, yet the coupling mechanisms between soil enzyme activities and functional genes in nutrient cycling remain unclear. This study investigated the effects of different fertilization regimes—nitrogen alone (N), nitrogen–phosphorus–potassium fertilizer (NPK), organic fertilizer (M), and combined organic–inorganic fertilizer (MNPK)—on soil properties, enzyme activities, N- and P-cycling-related functional gene abundances, and faba bean (Vicia faba L.) yield in a 45-year ongoing field experiment in subtropical eastern China. Results showed that long-term fertilization significantly affected soil pH, electrical conductivity, nutrient contents, and crop yield. Organic fertilizer addition (M and MNPK) markedly improved soil organic matter, total and available nutrients, and enhanced faba bean grain yield by 75.07–92.79% compared with NPK, whereas NPK had limited benefits on total and available soil nutrients compared with N-only application. Soil enzyme activity analysis revealed that the MNPK treatment achieved the highest urease and neutral protease activities, while acid and alkaline protease activities responded inconsistently. Phosphorus-related enzymes (acid, neutral, and alkaline phosphatases) were strongly stimulated by organic inputs, reflecting enhanced P mineralization potential. Functional gene analysis showed that N-fixation and assimilatory nitrate reduction genes increased under M and MNPK, while N assimilation, N mineralization, anammox, nitrification, denitrification, and dissimilatory nitrate reduction genes were enriched under N treatment. Phosphate uptake and transport genes were upregulated under NPK, M, and MNPK, whereas inorganic P solubilization genes were highest under N. Significant positive correlations were observed among soil enzyme activities, nutrient contents, and faba bean yield, whereas acid and alkaline protease activities showed opposite trends. The relative abundances of N- and P-cycling functional genes exhibited distinct yet coordinated relationships with soil fertility indicators and enzyme activities. These findings provide mechanistic insights into the long-term regulation of soil–microbe interactions and nutrient cycling, offering a scientific basis for sustainable fertilization strategies in agroecosystems.

Large areas of tidal flats were previously developed into aquaculture ponds and were recently encouraged to be converted into paddy fields to fulfill food and economic needs in China. However, the influences of short-term rice cultivation at the reclaimed aquaculture ponds on soil chemical properties and bacterial communities are poorly understood. To address this issue, we collected mineral soil samples at 0–20 and 20–40 cm depths from non-cultivated soils and paddy fields after being reclaimed from aquaculture ponds in Nantong, China, and identified soil bacterial communities using high-throughput sequencing. The results suggested that rice cultivation significantly increased the accumulation of total soil carbon (TC) and dissolved organic carbon (WSOC). The pH, ammonium (NH₄⁺), nitrate (NO₃⁻) and available phosphorus (AP) varied with the reclamation duration but did not show a unanimous tendency. Proteobacteria, Acidobacteria, Bacteroidetes, Chloroflexi and Planctomycetes dominated the bacterial community in both non-cultivated and cultivated soils after reclamation regardless of cultivation ages and soil depth. The variations in the diversity and composition of the soil microbial community were mainly associated with electrical conductivity (EC), WSOC, TC, NH₄⁺ and NO₃⁻ in non-cultivated and cultivated lands. Here, we found that short-term rice cultivation at the reclaimed aquaculture ponds strongly influenced soil bacterial communities and chemical properties, especially in the 0–20 cm depth, in the coastal regions.