First Report of Postharvest Fruit Rot in Persimmon ( <i>Diospyros kaki</i> ) Caused by <i>Mucor inaequisporus</i> in China

Persimmon (Diospyros kaki) is a woody tree species belonging to the Ebenaceae family, originated in China (Li 2013). It has important commercial and nutritional value. In October 2025, soft rot of persimmon fruits was observed in the Fruit Market of Tianjin (39.08° N; 117.11° E), China. The skin of the infected fruit faded in color, and the internal flesh shrank and rotted, producing a fermented alcoholic odor. The incidence ranged from 75 to 80%. Voucher specimens collected in October 2025 were deposited in the Plant Disease Laboratory of Tianjin Agricultural University under accession number PATAU251018. To identify the causal agent of this disease, the margins of the infected fruits were cut into small pieces of 0.5 × 0.5 cm, disinfested in 1% sodium hypo-chlorite for 2 min and soaked in 75% ethanol for 30 s, then rinsed three times with sterile water, and placed on potato dextrose agar (PDA), followed by incubation at 28°C. After 24 h of incubation, white mycelia emerged around the tissues. Strain purification was subsequently performed via the hyphal tip transfer method on PDA medium, followed by incubation at 28°C. On PDA, the colonies were initially white and entirely filled the 90‑mm Petri dish within 3 days. The aerial mycelia were dense and the color became golden yellow. Sporangiospores were hyaline, and had two shapes, spherical (2.3 to 4.5× 4.6 to 8.0 µm) (n = 30) or oval (2.5 to 5.8 × 5.0 to 12.7 µm) (n = 30). Sporangia were yellow, globose or subglobose, measured 45.6 to 112.3 µm (n = 30) in diameter. To further identify the fungus, the total genomic DNA was extracted from the strain using the CTAB method (Aboul-Maaty and Oraby 2019). The internal transcribed spacer (ITS) and mtSSU region were amplified by the primers ITS1/ITS4 and MS1/MS2 (White et al. 1990), respectively. The sequences obtained by polymerase chain reaction were sequenced, and the sequences were deposited in GenBank with accession numbers PX973470 for ITS and PX973559 for mtSSSU. Using BLASTn, the sequences of ITS showed 99.83% identity to Mucor inaequisporus (MN539629) and the sequences of mtSSU showed 99.33% identity to Mucor inaequisporus (BK073525). Phylogenetic trees were performed using the neighbor-joining method of MEGA 11 based on the sequences of ITS and mtSSU. Phylogenetic trees indicated that isolates are M. inaequisporus. For Koch’s postulates, the isolated pathogens were tested for pathogenicity on healthy persimmons. Seven fruits were surface-disinfected with 75% alcohol, rinsed three times with sterile water, and air-dried. A 0.3 × 0.3 cm wound was created at the bottom of each persimmon, and the wound was inoculated with a 5-mm mycelial plug of M. inaequisporus that had been cultured on PDA for 3 days. Sterile water served as a control. The test was repeated three times. All fruits were placed in a constant temperature incubator at 25°C with a relative humidity of 60%. At 3 days after inoculation, all inoculated fruits showed symptoms of discoloration, rot, and a fermented alcoholic odor began to appear. After 4 days, yellow mycelia began to appear on the surface of persimmon, the fermented alcoholic odor became heavier. Control fruits remained healthy. The fungus was reisolated from symptomatic tissues and identified as M. inaequisporus by morphological characteristics and molecular characterization. M. inaequisporus has been reported to cause persimmon rot in South Korea (Lee and Jung 2020), plum and strawberry rot in China (Pan et al. 2025;Ren et al. 2023). However, M. inaequisporus has not been previously reported as a persimmon pathogen in China. To our knowledge, this is the first report of M. inaequisporus causing postharvest fruit rot of persimmon in China. These findings can improve our understanding of the ecology of M. inaequisporus and provide a theoretical basis for the development of control strategies against M. inaequisporus infection in persimmon.