Background: The pin nematode, belonging to the genus Paratylenchus, parasitizes higher plants, often causing reduced or inhibited root tip development. Methods: Pin nematodes were isolated from the roots and rhizosphere of blueberry plants and subsequently identified as representatives of Paratylenchus projectus based on morphological characteristics and molecular barcoding. The P. projectus draft genome was sequenced using the Illumina platform. Results: Phylogenetic analysis based on 18S, 28S and ITS rRNA placed this species in highly supported clades alongside other P. projectus specimens. The draft genome of P. projectus was sequenced and assembled, representing the first genomic data for both the genus Paratylenchus and the family Tylenchulidae. The assembled genome, though fragmented, had a total length of 191.36 Mb and an estimated genome size of 64.9 Mb. Protein-coding genes were predicted using four different databases, with particular focus on carbohydrate-active enzymes from the GH5 and GH18 families. The recovered GH5 genes were distributed among three distinct clades: one forming a basal group relative to other nematodes, one as a sister clade to the fungivorous nematode Aphelenchus avenae and one nested within a fungal clade. The GH18 chitinase genes were grouped into two clades: one closely related to sedentary plant-parasitic nematodes of the genera Heterodera and Globodera and the other closely related to the fungivorous nematode Ditylenchus. Conclusions: The draft genome of Paratylenchus projectus was sequenced and assembled, representing the first genomic data for both the genus Paratylenchus and the family Tylenchulidae to our knowledge. Graphical

In order to increase nutrient input and alleviate the poor growth of blueberry (Vaccinium corymbosum L.) in neutral soil with strong nitrification, the application of nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) as an enhanced efficiency fertilizer is a strategy to reduce nitrogen (N) loss and improve N supply. However, few studies have systematically investigated the effect of DMPP application on blueberry and its soil condition in detail so far. In this study, a pot experiment was conducted to elucidate the effect of DMPP at four gradient levels including 0.5% (w/w applied-N) DMPP (DL), 1% DMPP (DM), 2% DMPP (DH), and no DMPP (CK) on the dynamics of soil mineral N (NH₄⁺-N and NO₃⁻-N), soil chemical properties, as well as the agronomic characteristics and physiological indexes of blueberry plants in the neutral soil–blueberry system. The addition of DMPP significantly increased the retention of soil ammonium nitrogen and the content of total mineral nitrogen. qPCR analysis showed that DMPP inhibited the ammoxidation process mainly by reducing the abundance of the ammonia-oxidizing bacteria (AOB) amoA gene rather than the ammonia-oxidizing archaea (AOA) amoA gene. No significant inhibitory effect of DMPP was observed for the nitrite dehydrogenase gene nxrA and nitrite reductase gene nirS. Soil NH₄⁺-N and available phosphorus content were both enhanced with the DMPP application rates both in bulk and rhizosphere soil. Applying 1% DMPP to the neutral soil for blueberry was sufficient to safely inhibit soil nitrification, not only increasing ammonium nitrogen content by 10.42% and 26.79%, but also enhancing available phosphorus content by 9.19% and 22.41% compared with CK in bulk and rhizosphere soil, respectively. Moreover, 1% DMPP addition increased the nitrogen and phosphorus concentration of blueberry leaves by 12.17% and 26.42%, respectively, compared with CK. The total branch length and the dry weight of blueberry plant were also increased by 16.8% and 33.1%, respectively. These results provide valuable agronomic information for the application of DMPP in blueberry cultivation. Fertilization applied with 1% DMPP has great economic potential to improve both nitrogen and phosphorus absorption of blueberry so as to promote the vegetative growth of blueberry.

The fruit ripening season for the rabbiteye blueberry often coincides with periods of heavy rainfall in central–eastern China. The use of rain shelters to protect fruit from rainfall damage has increased worldwide due to global climate anomalies. However, the effects of rain-shelter cultivation on the photosynthesis and fruit characteristics of the rabbiteye blueberry have not yet been fully explored. In the present study, 4-year-old container-grown rabbiteye blueberry plants were covered with polyethylene (PE) film from the berry coloration stage until fruit were harvested for three consecutive years in Nanjing, China. The results showed that rain-shelter cultivation did not affect the air temperature and relative humidity, but significantly reduced the photosynthetically active radiation and UV radiation reaching the canopy zone. However, the rain shelter conditions did not significantly decrease the net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (E) of the rabbiteye blueberry leaves. Additionally, the fruit yield and berry weight of blueberries cultivated under the rain shelter were not significantly affected. Furthermore, no significant differences were observed in total soluble solids, acidity, and total flavonoids content between fruits grown under the rain shelter and in the open field in all experimental years, but a significant decrease in total polyphenols and anthocyanins content was observed in fruits grown under the rain shelter in years with less rainfall. Our results suggest that simple rain shelter cultivation did not noticeably affect the photosynthesis and fruit yield of container-grown rabbiteye blueberry in rainy areas of central–eastern China, but its effects on the fruit quality vary depending on rainfall during the fruit ripening period.

This study evaluated the effects of the preharvest application of 0.2 g/L gibberellin A3 (GA₃) or 0.02 g/L forchlorfenuron (CPPU) at full bloom on postharvest storability and defense responses in ‘Brightwell’ blueberry. After ripening, berries were inoculated in vitro with a defined mixture of postharvest fungal pathogens. Fruit quality attributes and physio-logical indices were monitored during storage, and LC-MS metabolomics was performed to characterize treatment-associated metabolic alterations.GA₃-treated fruit exhibited higher antioxidant capacity and a lower decay incidence than CPPU-treated and control fruit. Metabolomic profiling showed that GA₃ was associated with the accumulation of specific polyphenols, coinciding with enhanced resistance to postharvest pathogens. In parallel, GA₃ treatment modulated glycerolipid metabolism and mitigated membrane lipid peroxidation, as indicated by reduced malondialdehyde levels, while enhancing enzymatic (superoxide dismutase and ascorbate peroxidase) and non-enzymatic (poly-phenol) antioxidant defenses. Overall, these results suggest that preharvest GA₃ application can improve blueberry storability by coordinating redox homeostasis and lipid-related metabolic remodeling.

Corolla abscission is an important agronomic trait that affects fruit quality and disease susceptibility in blueberry. However, the underlying molecular mechanisms remain poorly understood. This study aimed to investigate the molecular and physiological factors associated with corolla abscission by comparing two blueberry cultivars with contrasting corolla abscission characteristics: the caducous 'Magica' ('F6') and the persistent 'Eureka-Sunrise' ('L25'). Cytological analysis revealed distinct structural differences in the abscission zone (AZ) between the two cultivars. In 'F6', cell separation occurred after full bloom, whereas AZ cells in 'L25' remained intact and gradually resembled adjacent tissues. To explore the molecular basis of these differences, transcriptome analysis was performed at three developmental stages. Differential expression and enrichment analyses indicated that genes related to plant hormone signaling, cell wall organization, and oxidative stress response were consistently involved. Weighted gene co-expression network analysis further identified modules associated with cultivar-specific traits, with genes related to ethylene and abscisic acid pathways showing higher expression in 'F6', while those associated with auxin metabolism and stress-related processes were more active in 'L25'. To validate these findings, the activities of cell wall-related enzymes were measured. Polygalacturonase activity increased at the stage corresponding to abscission initiation in 'F6', while remaining relatively low in 'L25'. In addition, cellulase activity was consistently higher in 'F6' than in 'L25'. These results indicate that corolla abscission in blueberry is associated with coordinated changes in hormone-related pathways and cell wall modification. Differences in the regulation of these processes between cultivars may contribute to variation in abscission behavior.