Yuansong Xiao

A field experiment was conducted to explore how long-term integrated organic or inorganic fertilization influences soil bacterial communities in dryland farming systems. High-throughput amplicon sequencing was applied to profile bacterial composition and diversity under six treatments—no fertilizer (T0), chemical fertilizer alone (T1), and chemical fertilizer combined with cattle manure (T2), sheep manure (T3), bio-organic fertilizer (T4), or potassium fulvate (T5)—and to pinpoint the major environmental determinants. The results showed that combined fertilization markedly elevated soil nutrient levels, with cattle manure (T2) and sheep manure (T3) exhibiting the strongest effects. The bacterial community was dominated by Actinomycetota, Pseudomonadota, and Chloroflexota. Relative abundances of Pseudomonadota and Bacteroidota increased under combined fertilization, whereas Actinomycetota declined—particularly in T2 and T3. At the genus level, Nocardioides, KD4-96, and Subgroup 6 were predominant. Moreover, T2 and T3 significantly raised the Simpson index relative to T1. Redundancy analysis revealed that soil organic matter (p = 0.002) and pH (p = 0.03) were strongly associated with variation in bacterial community composition. Collectively, long-term combined organic-inorganic fertilization with different organic amendments effectively enhances soil fertility and bacterial community structure, offering a promising approach for nutrient management in the dryland farming regions of the Ningxia Hui Autonomous Region, northwestern China.

Adventitious root (AR) formation is critical for the vegetative propagation of peach rootstocks. While miRNAs are known to regulate AR development, the role of specific miRNAs and target genes in peach rootstocks remains poorly understand. In this study, we profiled the miRNAome of ‘GF677’ peach rootstock during indole-3-butyric acid (IBA)-induced AR formation. Samples were collected at key four time points (2 h, 2, 10, and 17 days) based on the dynamic changes in endogenous auxin and root morphogenesis. A total of 188 miRNAs were identified, including 60 novel miRNAs. There were 28, 45, 59, 18, 30, and 14 differentially expressed miRNAs (DEMs) in the following six comparison groups of libraries: 2 h vs. 2 d, 2 h vs. 10 d, 2 h vs. 17 d, 2 d vs. 10 d, 2 d vs. 17 d, and 10 d vs. 17 d, respectively. KEGG pathway enrichment indicated that the target genes of DEMs were predominantly associated with signal transduction and metabolism. Specifically, the plant hormone signaling and starch and sucrose metabolism pathways were enriched across all the six comparison groups, while each group exhibited a unique enriched pathway. Additionally, the functional validation of miR319, a DEM, through transgenic analysis in Arabidopsis revealed its regulatory role in AR development. Collectively, this study provides the first insights into the role of miRNAs in peach adventitious rooting, laying a theoretical foundation for improving the vegetative propagation of peach rootstock.

The grain-level heterogeneity of fruit morphological characteristics significantly determines their sensory performance and intrinsic quality, providing a quantitative basis for commercial grading. This study utilized “Liuyuehong” soft-seeded pomegranate (Punica granatum L.) as experimental material. Fruits were classified into three size grades based on individual fresh weight: large (107–125 g), medium (74–92 g), and small (47–67 g). Fresh weights of whole fruits, exocarp, and outer seed coat were measured for each grade, followed by analysis of key quality indicators, including seed count, 100-seed weight, Brix degrees, pH, single-seed dimensions, vitamin C content, and edible fraction. Subsequently, correlation analysis, principal component analysis (PCA), and the entropy weight-TOPSIS method were employed to evaluate the integrated quality of different fruit grades comprehensively. The results indicate that the fruit morphological characteristics of “Liuyuehong” soft-seed pomegranate have a significant impact on its sensory and physicochemical qualities. (1) Large and medium fruits are superior to small fruits in terms of single fruit size, exocarp color uniformity, seed color, and mouthfeel, with large fruits having the highest comprehensive evaluation score (0.7). (2) Mouthfeel is correlated with the number of seeds in the fruit; the number of seeds in large and small fruits shows a significant negative correlation with Brix degrees (p < 0.05). (3) Small fruits exhibit greater individual variation within the group, with outliers and a tendency for late maturation. In conclusion, the fruit morphological characteristics of “Liuyuehong” soft-seed pomegranate significantly affect seed maturity and quantity, thereby determining the fruit’s sensory quality and physicochemical properties. The results indicate that fruits with a single- weight below 70 g commonly exhibit delayed development. It is therefore recommended to raise the lower threshold for commercial grading to above 75 g to enhance overall fruit quality and market consistency.

Summary: Root development is crucial for the growth and yield of horticultural crops. Hydrogen sulfide (H₂S), an important gasotransmitter, has been shown to regulate lateral root (LR) formation in plants, including peach (Prunus persica). However, its specific regulatory mechanism remains largely unclear. Here, we show that the energy/metabolic sensor SUCROSE NON‐FERMENTING RELATED KINASE 1 (SnRK1) mediates the control of peach LR growth by H₂S. PpSnRK1 activity in peach roots is enhanced with H₂S to promote LR generation. Cys419, Cys430 and Cys505 residues in the catalytic α‐subunit of PpSnRK1 are modified by H₂S persulfidation. Reduced persulfidation inhibits the H₂S‐induced PpSnRK1 activity. Mutating Cys419 and Cys430 of PpSnRK1α severely impedes H₂S‐promoted LR formation. LATERAL ORGAN BOUNDARIES DOMAIN 16 (LBD16) is a transcription factor essential for LR initiation. Further evidence shows that PpSnRK1α interacts with PpLBD16 in the nucleus, thereby enhancing the transcription of LR development‐related genes PpCNGC1 (CYCLIC NUCLEOTIDE‐GATED ION CHANNEL 1) and PpEXPB2 (EXPANSIN‐B2). In peach roots, transcription of these two genes is markedly up‐regulated by H₂S‐induced PpSnRK1 activity. Silencing of PpLBD16, PpEXPB2 or PpCNGC1 significantly reduces exogenous H₂S‐induced LR formation. In situ hybridization analysis shows that they are strongly expressed in peach LR primordia along with PpSnRK1α. Our data reveal an interaction between H₂S signal and SnRK1 kinase, providing mechanistic insights into the shaping of agronomically important root systems.

Salt stress is one of the main abiotic stresses that affects peach growth. Hydrogen sulfide has an important role in regulating plant resistance to salt stress. However, the mechanism by which hydrogen sulfide regulates salt stress resistance is currently unclear in peach. Here, we investigated the mechanism by which hydrogen sulfide alleviates salt stress in peach trees. In our study, exogenous hydrogen sulfide enhances the activity of antioxidant enzymes and reduces the accumulation of reactive oxygen species, thereby mitigating salt stress damage to seedlings. Moreover, transcriptome analysis was carried out and an encoding allene oxide synthase gene (AOS), PpAOS3, which is highly responsive to hydrogen sulfide, was found. Overexpression of PpAOS3 increased the root length and jasmonic acid (JA) content and attenuated growth inhibition under salt stress in Arabidopsis. NBT and Evans staining showed that Arabidopsis overexpressing PpAOS3 reduces O²⁻ accumulation and cell death under salt stress. Additionally, transcriptome analysis revealed that 10 genes encoding oxidoreductase were upregulated after hydrogen sulfide treatment. RT-qPCR was also performed which showed that these genes were upregulated to different degrees after hydrogen sulfide treatment. In conclusion, a hydrogen-sulfide-mediated PpAOS3-JA module significantly contributes to salt resistance in peach. These results can serve as a theoretical basis for utilizing hydrogen sulfide to improve the salt tolerance of peach.

Appropriate calcium treatments help maintain the appearance, nutritional quality, and postharvest quality of apples, reducing losses during storage. This study investigated the effects of different calcium preparations on the fresh-cut quality and ultrastructure of ‘Starkrimson’ apples. The treatments included control (CK), calcium chloride (T1), sorbitol-chelated calcium (T2), and calcium nitrate (T3). The results demonstrated that sorbitol-chelated calcium significantly inhibited the decline in fresh-cut firmness and pectin content while reducing the increase in cellulose content and minimizing ultrastructural damage. Apples treated with sorbitol-chelated calcium maintained the best fresh-cut hardness and soluble pectin contents, which were 35.71% and 15.42% higher than that of CK on the 12th day, and the cellulose was 27.08% lower than that of CK. Under transmission electron microscopy, the pulp cell surface in the T2 group remained intact, with no bending or deformation, and the middle lamella was well preserved. Additionally, T2 treatment promoted the expression of aroma-related genes during fruit storage. Sorbitol-chelated calcium effectively preserved color and significantly reduced the browning and microbial spoilage of fresh-cut apples, particularly postharvest pathogen growth. The study demonstrates that sorbitol-chelated calcium preserves fresh-cut apple quality by reinforcing cell wall integrity through calcium-mediated crosslinking, suppressing pectin degradation and cellulose accumulation, and activating aroma-related genes (AAT1, AAT2, LOX) to enhance volatile synthesis, thereby reducing microbial spoilage and enzymatic browning during storage.

Nitrogen critically regulates peach yield formation and fruit quality development through multifaceted physiological mechanisms. In peach production, the problems of large nitrogen input and low Nitrogen Use Efficiency (NUE) are more prominent. Therefore, mining key genes for efficient nitrogen utilization in peach is crucial for improving NUE and reducing nitrogen use. Integrated transcriptomic profiling of peach rootstock 'Shannong-1' under low-nitrogen (0.1 mM) treatment identified the MADS-box transcription factor PpAGL24. Functional characterization revealed that PpAGL24 modulates root system architecture and coordinates nitrogen uptake-assimilation pathways, suggesting its pivotal role in enhancing NUE. PpAGL24 expressed in peach roots and overexpressed in Arabidopsis thaliana both resulted in an increased number of lateral roots and higher nitrogen content. Transcriptome sequencing of PpAGL24-overexpressing peach roots revealed its putative regulatory network governing 'lateral root development', 'nitrate assimilation', and 'nitrogen metabolism', suggesting its hierarchical coordination in root developmental plasticity and nitrogen remodeling. Dual-luciferase and yeast one-hybrid assays showed that PpAGL24 can activate the transcription of the nitrite reductase-encoding gene PpNiR1. This study reveals a new mechanism by which the MADS-box transcription factor PpAGL24 regulates root growth and nitrogen assimilation in peach trees by modulating the PpNiR1 gene, which provides theoretical support for the improvement of NUE and the reduction of nitrogen inputs in peach orchards.

Background/Objectives: The sucrose non-fermentation-related kinase 1 (SnRK1) protein complex in plants plays an important role in energy metabolism, anabolism, growth, and stress resistance. SnRK1 is a heterotrimeric complex. The SnRK1 complex is mainly composed of α, β, βγ, and γ subunits. Studies on plant SnRK1 have primarily focused on the functional α subunit, with the β regulatory subunit remaining relatively unexplored. The present study aimed to elucidate the evolutionary relationship, structural prediction, and interaction with the core α subunit of peach SnRK1β3 (PpSnRK1) subunit. Methods: Bioinformatics analysis of PpSnRK1 was performed through software and website. We produced transgenic tomato plants overexpressing PpSnRK1 (OEPpSnRK1). Transcriptome analysis was performed on OEPpSnRK1 tomatoes. We mainly tested the growth index and drought resistance of transgenic tomato plants. Results: The results showed that PpSnRK1 has a 354 bp encoded protein sequence (cds), which is mainly located in the nucleus and cell membrane. Phylogenetic tree analysis showed that PpSnRK1β3 has similar domains to other woody plants. Transcriptome analysis of OEPpSnRK1β3 showed that PpSnRK1β3 is widely involved in biosynthetic and metabolic processes. Functional analyses of these transgenic plants revealed prolonged growth periods, enhanced growth potential, improved photosynthetic activity, and superior drought stress tolerance. Conclusions: The study findings provide insight into the function of the PpSnRK1 subunit and its potential role in regulating plant growth and drought responses. This comprehensive analysis of PpSnRK1 will contribute to further enhancing our understanding of the plant SnRK1 protein complex.