The Chinese white pear (Pyrus bretschneideri) is an economically significant fruit crop worldwide. Previous versions of the P. bretschneideri genome assembly contain numerous gaps and unanchored genetic regions. Here, we generated two high-quality, gap-free genome assemblies for 'Dangshansu' (DS; 503.92 Mb) and 'Lianglizaosu' (ZS; 509.01 Mb), each anchored to 17 chromosomes, achieving a benchmarking universal single-copy ortholog completeness score of nearly 99.0%. Our genome-wide association studies explored the associations between genetic variations and stone cell traits, revealing a significant association peak on DS chromosome 3 and identifying a novel non-tandem CCCH-type zinc finger gene, designated PbdsZF. Through genetic transformation, we verified the pivotal role of PbdsZF in regulation of both lignin biosynthesis and stone cell formation, as it transcriptionally activates multiple genes involved in these processes. By binding to the CT-rich motifs CT1 (CTTTTTTCT) and CT2 (CTCTTTTT), PbdsZF significantly influences the transcription of genes essential for lignin production, underscoring its regulatory importance in plant lignin metabolism. Our study illuminates the complex biology of fruit development and delineates the gene regulatory networks that influence stone cell and lignocellulose formation, thereby enriching genetic resources and laying the groundwork for the molecular breeding of perennial trees.

Camellia oleifera Abel., recognized as a significant oil plant, is of immense potential health and economic value. Due to the self-incompatibility of C. oleifera, pollination relies on cross-pollination from other flowers. Additionally, the asynchronous flowering periods of individual plants result in low fruit set and yield, which limits the broader cultivation and utilization of this species. The study investigated the dynamic changes and regulatory patterns of different tissues within flower buds from flower bud development to flowering, employing a multi-faceted approach that included cellular dissection, analysis of hormone content, and transcriptome analysis. This study demonstrates that ABA and SA, rather than GA3, IAA, ZT, acts as potentially effective endogenous agents to promote flowering in the later stages of flower development, which is a critical period for the maturation of pollen and embryo sacs; while ZT plays a more significant role in the early stages of flower bud development. Transcriptome analysis indicated that C.oleifera primarily regulates the late stages of flower bud development via regulating genes involved in starch and sucrose metabolism in petals, monoterpene synthesis and ABC transporters in pistils and stamens. WGCNA identified four key modules associated with the development of stamens and pistils in the late stage of C.oleifera flower buds, and also screened out key core genes, including CoBMY7/8, CoTPP6/10, and CoG8H7/11, which are involved in the regulation of flowering time. These findings enhance our understanding of the developmental changes in stamens, pistils, and petals during the flower bud development of C. oleifera. Moreover, they provide a foundation for manipulating flowering time and improving fruit set by regulating the expression of key genes in future studies.

Kiwifruits (Actinidia chinensis) are among the most widely planted fruit in Jiangxi Province, China. Infected kiwifruits of the cultivars 'Hongyang' and 'Jinyan' were obtained from a commercial orchard in Fengxin county, Jiangxi Province (28°67' N; 115°42' E) from September to November 2022. The 1200 kiwifruits were collected from cold storage (cold stored for 3 months at 2°C), and moved to room temperatures (15 to 20°C), approximately 20% had symptoms of postharvest soft rot 7 days later. The infected fruits had brown or dark gray spots on the peel. Most were round or oval, with a diameter of approximately 1~3 cm. The pulp was milky white, and there was a waterlogged ring at the junction of decay. The pathogen was isolated by removing several small pieces (3×3 mm) of infected tissue from the diseased kiwifruits, which were sterilized with 75% ethanol for 30 s, dipped in 1% NaClO for 1 min, and rinsed three times with sterile distilled water. These pieces were transferred onto potato dextrose agar (PDA) and incubated for 5 days at 28°C, 75% relative humidity (RH), separated, and repurified. Eight unidentified isolates with similar morphology were obtained on PDA (D3-1 to D3-8). These isolates had abundant aerial fluffy mycelia. The colonies were white during the early stage of culture and turned light purple in the later stage. The mycelia grew 5.8 mm day-1 (n=5) on average and produced abundant conidia 10 days later. The microconidia were solitary, transparent, ovoid, with 0 to 1 septa, and 3.6 to 11.2 × 1.6 to 3.5 µm (average 6.5 × 2.9 µm, n = 50). The macroconidia were sickle-shaped, slender and slightly curved, with 3 to 5 septa, and 22.3 to 53.9 × 2.6 to 5.4 µm (average 39.5 × 4.3 µm, n = 50). Chlamydospores were absent. The morphological characteristics enabled the identification of the pathogen as Fusarium spp. (Leslie and Summerell, 2006). Isolate D3-2 was further confirmed, and the primers ITS1/ITS4 (White et al. 1990), 5F2/7CR and EF1/EF2 (O'Donnell et al. 2022) were used to amplify the internal transcribed spacer (ITS) region, RNA polymerase II largest subunit (RPB2) gene and translation elongation factor-1 alpha regions (TEF-1α). The ITS (accession no. PP077075), RPB2 (PP566653) and TEF-1α (PP566654) sequences shared 99.62 to 100% identities with ITS (ON564593.1), RPB2 (ON734380.1) and TEF-1α (ON697186.1) of F. fujikuroi from NCBI, respectively. Thus, the pathogen was identified as F. fujikuroi based on morphological and molecular characteristics. Each of the three isolates was inoculated on surface-disinfected (75% ethanol, 5 min) disease-free kiwifruits of cv. 'Jinyan' and 'Hongyang'. The six kiwifruits were pierced by a sterile inoculation needle and inoculated with 20 μl spore suspension (1×10⁶ spores/ml), and six kiwifruits were treated with spore suspension without any wounds, four control fruits were inoculated with sterile distilled water. All the fruits were sealed in a storage box, kept at an RH of 90%-95%, and incubated at a constant temperature of 28°C for 5 days. After 3 days, the fruit rotted at the inoculation site, and after 5 days, the lesions gradually increased, and the symptoms were the same as those of the original sample. The control fruits remained disease-free. The pathogenicity tests were repeated three times. Koch's postulates were completed by reisolating the fungus from infected kiwifruits, which was identified as F. fujikuroi by sequencing. Although F. solani (Yang et al. 2018) and F. acuminatum (Wang et al. 2015) have been previously reported to rot kiwifruits in China, this is the first report of F. fujikuroi causing postharvest rot on kiwifruits in China. This discovery can alert agronomists to prevent and control this pathogen.

Rapid softening limits the postharvest life of kiwifruit, but how thidiazuron (TDZ) affects the accompanying transcriptional changes remains unclear. We in