Strawberry (Fragaria × ananassa) is an economically important crop in Zhejiang, China. In the autumn of 2021, crown necrobiosis and angular leaf spot was observed in commercial strawberry fields (c...

Soil salinity severely constrains strawberry production by disrupting ion homeostasis and provoking oxidative injury. This study investigated whether soluble silicon (Si) and activated carbon (AC) act to enhance salt tolerance in strawberry (Fragaria × ananassa). Under NaCl stress, plants showed pronounced growth inhibition, increased Na⁺ accumulation and a deteriorated K⁺/Na⁺ balance, accompanied by elevated reactive oxygen species (ROS) and lipid peroxidation. In contrast, combined AC + Si treatment consistently provided the strongest protection, improving seedling vigor and survival. Relative to NaCl alone, AC + Si increased shoot and root fresh weight by 67.5% and 78.5%, reduced shoot Na⁺ by 59.1%, and lowered shoot H₂O₂ and MDA by 62.6% and 66.5%, respectively, indicating marked improvement in ion–redox homeostasis. Beyond plant responses, AC-containing treatments alleviated salt-induced increases in soil electrical conductivity, coinciding with a clear restructuring of the rhizosphere bacterial community and enrichment of putatively beneficial taxa. Transcriptome profiling further supported coordinated reprogramming of ion transport, redox control and stress-responsive signaling pathways under the AC + Si regime. Collectively, the results indicated that Si and AC co-application enhances strawberry salt tolerance through an integrated soil–plant–microbiome mechanism that stabilizes ion homeostasis and reinforces redox homeostasis.

Strawberry Fusarium wilt, caused by Fusarium spp., is one of the most devastating diseases threatening the Chinese strawberry industry. In this study, 64 representative Fusarium strains were isolated from diseased crowns and petioles of strawberry plants cultivated in six key production areas across Zhejiang Province, where disease incidence ranged from 30 to 50% from July to December. Morphological characterization, multilocus phylogenetic analysis, and pathogenicity tests identified these strains as three distinct species: Fusarium oxysporum f. sp. fragariae (Fof) (48 strains, 75%) in the F. oxysporum species complex, F. luffae (9 strains, 14.06%) in the F. incarnatum-equiseti species complex, and F. commune (7 strains, 10.94%) in the F. nisikadoi species complex. Among these species, Fof was dominant, with the fastest colony growth at temperatures above 28°C. Pathogenicity tests revealed that Fof isolates resulted in the highest disease severity, followed by F. commune. This study presents the first report of Fof as a causal agent of strawberry Fusarium wilt in Zhejiang, China, and of F. luffae causing Fusarium wilt of strawberry worldwide. The identification and pathogenicity characterization of Fusarium species causing strawberry wilt provides valuable information for the effective management of the disease in China.

In the winter of 2022, circular or irregular leaf spots were observed on strawberry (Fragaria × ananassa) planted in commercial fields (cultivar 'xuetu', 'mengzhifu') in Yinzhou, Ningbo, Zhejiang, China (N29°48'48″, E121°39'47″), with disease incidence ranging from 10 to 15% in a field approximately 0.67 ha in size. The estimated crop loss associated with this disease was ~10%. Symptoms included circular or irregular lesions with brown halos and wheel marks, which eventually developed into leaf blight and petiole decay, but spore masses were seldom found on the leaf surface. In severe cases, leaves withered and abscissed. To isolate the causal agent, ten diseased leaves from ten different plants were collected, surface-sterilized with 75% ethanol for 50 s, rinsed twice with sterile distilled water, cut into small pieces (0.5 cm × 0.5 cm), and plated on potato dextrose agar (PDA), then incubated at 25°C in darkness for 5 days. Isolates , which displayed one kind of colony morphology were consistently obtained from each of the ten samples, and 58 single-conidium isolates with the same colony morphology were obtained. The isolation frequency was 58 of 60 samples. The colonies that grew on PDA produced white mycelia, which sporulated after 1 week, producing typical Botrytis-like gray spores. Three isolates (NBCM-1, NBCM-2, NBCM-3) were selected for identification and pathogenicity assays. Conidia were round to ellipsoid, 9.2 to 14.3 μm long (n=50), and 6.4 to 9.2 μm wide (n=50). Sclerotia were not observed on PDA. Based on these characteristics, the pathogen was tentatively identified as Botrytis cinerea (Zhang 2001). PCR was conducted for each of the three isolates to amplify the G3PDH, HSP60, RPB2, NEP1, and NEP2 genes, which are typically used for molecular identification of Botrytis species (Staats et al. 2005; Liu et al. 2016). The resulting amplicons were sequenced, and the sequences were processed using BLAST in the National Center for Biotechnology Information. Sequences of the three isolates were deposited in GenBank (accession nos. OR052082 to OR052086, OR493405 to OR493414). BLASTn analyses showed that isolates were 99 to 100% identical to B.cinerea reported causing leaf spot on strawberry in California; accession numbers MK919496 (G3PDH, 883/883 bp), MK919494 (HSP60, 992/992 bp), and MK919495 (RPB2, 1081/1081 bp). The resulting concatenated data set of G3PDH-HSP60-RPB2-NEP1-NEP2 was used to conduct a multilocus phylogenetic analysis (MLSA) using the maximum likelihood method. The MLSA tree indicated that the three isolates belonged to Botrytis cinerea. To test for pathogenicity, three 1-month-old strawberry (cultivar 'xuetu') plants were inoculated with each isolate (NBCM-1, NBCM-2, NBCM-3). A noninoculated control (sterile water only) was also included. The strawberry plants were inoculated by spraying with conidia suspension (1.0 × 105/ml) until run-off. Inoculations with sterile water served as controls. All plants were kept at 28/25°C (day/night), under a 12:12-h light/dark photoperiod. All plants were covered with transparent plastic bags to maintain humidity for the first 48 h, after which the bags were removed. After 4 to 7 days, leaf spot symptoms similar to those observed in the field were observed in all inoculated plants, while the controls remained healthy. The experiment was repeated three times. The pathogen was reisolated from the inoculated leaves and again identified as B. cinerea, with the same methodology used for the initial identification. Leaf spot caused by B. cinerea on strawberry was recently reported in California (Mansouripour and Holmes 2020) and Florida (Marin and Peres 2022). To our knowledge, this is the first report of B. cinerea causing leaf spot on strawberry in China. The pathogen is also the causal agent of Botrytis fruit rot on strawberry. Given the high variability of this pathogen (Marin and Peres 2022), further studies on its occurrence, spread, management, and control are required. The identification of this pathogen provides a basis for further research on its management and control.

Soil salinity severely constrains strawberry production by disrupting ion homeostasis and provoking oxidative injury. Here, we investigated whether soluble silicon (Si) and activated carbon (AC) act synergistically to enhance salt tolerance in strawberry (Fragaria × ananassa). Under NaCl stress, plants showed pronounced growth inhibition, increased Na⁺ accumulation and a deteriorated K⁺/Na⁺ balance, accompanied by elevated reactive oxygen species (ROS) and lipid peroxidation. In contrast, combined Si and AC treatment consistently provided the strongest protection, improving seedling vigor and survival, limiting Na⁺ build-up while maintaining a higher K⁺/Na⁺ ratio, and attenuating oxidative damage as reflected by reduced ROS and MDA levels together with enhanced activities of antioxidant enzymes (SOD, POD and CAT). Beyond plant responses, AC-containing treatments alleviated salt-induced increases in soil electrical conductivity and improved soil nutrient availability, coinciding with a clear restructuring of the rhizosphere bacterial community and enrichment of putatively beneficial taxa. Transcriptome profiling further supported coordinated reprogramming of ion transport, redox control and stress-responsive signaling pathways under the Si+AC regime. Collectively, our results indicate that Si and AC co-application enhances strawberry salt tolerance through an integrated soil–plant–microbiome mechanism that stabilizes ion homeostasis and reinforces redox homeostasis.

FAR1/FHY3 transcription factors are key regulators of plant growth and development, but their identification and functions in strawberries (Fragaria × ananassa) remain largely unexplored. In this study, 47 FaFAR1/FHY3 genes in cultivated strawberries were systematically identified, which were categorized into six subfamilies and randomly distributed across 15 chromosomes, with segmental duplication as the main driver of the expansion of this gene family. Integration of phylogenetic relationships, gene structure, and conserved motif composition uncovered distinct divergences among the subfamilies. A cis-acting element analysis of promoters and gene expression profiles showed that these genes responded to various abiotic and biotic stresses, phytohormones, and far-red light signals, with FaFAR1-7 and FaFAR1-44 strongly responding to multiple stresses, including temperature, drought, and pathogen infection. Additionally, FaFAR1-12 and FaFAR1-18 exhibited positive correlations with anthocyanin accumulation and the expression of key anthocyanin biosynthesis genes during fruit development. Dual-luciferase reporter assays further confirmed that FaFAR1-12 and FaFAR1-18 significantly activated the promoters of key structural genes related to anthocyanin biosynthesis, indicating that these two TFs exert vital regulatory functions in anthocyanin accumulation during strawberry fruit development. This study comprehensively identifies and characterizes the FaFAR1/FHY3 genes in cultivated strawberries, laying a foundation for their functional analysis and for screening out the key regulatory genes for strawberry fruit quality improvement.