Chrysanthemum × morifolium Ramat. is a famous perennial herb with medicinal, edible, and ornamental purposes, but the occurrence of plant diseases can reduce its value. A serious disease that caused leaf spots in C. morifolium appeared in 2022 in Tongxiang City, Zhejiang Province, China. The C. morifolium leaves with brown spots were collected and used for pathogen isolation. By completing Koch’s postulates, it was proven that the isolate had pathogenicity to infect C. morifolium. It was determined that the pathogen isolated from chrysanthemum leaves was Nigrospora oryzae, through morphology and a multilocus sequence analysis method using a combination of the internal transcribed spacer gene (ITS), beta-tubulin gene (TUB2), and translation elongation factor 1-alpha gene (TEF1-α). This is the first report of C. morifolium disease caused by N. oryzae in the world. Through dual culture assay on PDA plates, 12 strains of bacteria with antagonistic effects were selected from 231 strains from the C. morifolium phyllosphere, among which Bacillus siamensis D65 had the best inhibitory effect on N. oryzae growth. In addition, the components of a strain D65 fermentation broth were profiled by SPME-GC-Q-TOF analysis, providing a foundation for further application and research of biological control.

‘Hangju’ is a variety of Chrysanthemum × morifolium Ramat. with both edible and medicinal value, cultivated as a traditional Chinese medicine for four centuries. The cultivation of ‘Hangju’ is currently at risk due to waterlogging, yet there is a lack of comprehensive understanding regarding its response to waterlogging stress. This study compared the waterlogging-tolerant ‘Hangju’ variety Enhanced Waterlogging Tolerance (EWT) with the waterlogging-sensitive variety CK (‘zaoxiaoyangju’). EWT exhibited a more developed aeration tissue structure and demonstrated rapid growth regarding the adventitious roots following waterlogging. The time-course transcriptome analysis indicated that EWT could swiftly adjust the expression of the genes involved in the energy metabolism signaling pathways to acclimate to the waterlogged environment. Through WGCNA analysis, we identified Integrase-Type DNA-Binding Protein (CmTINY2) as a key factor in regulating the waterlogging tolerance in EWT. CmTINY2, a transcription factor belonging to the ethylene-responsive factor (ERF) subfamily III, operated within the nucleus and activated downstream gene expression. Its role in enhancing the waterlogging tolerance might be linked to the control of the stomatal aperture via the Ethylene-Responsive Element (ERE) gene. In summary, our research elucidated that the waterlogging tolerance displayed by EWT is a result of a combination of the morphological structure and molecular regulatory mechanisms. Furthermore, the study of the functions of CmTINY2 from ERF subfamily III also broadened our knowledge of the role of the ERF genes in the waterlogging signaling pathways.

Bletilla striata (Thunb. ex A. Murray) Rchb (known as baiji in Chinese), a herbal plant distributed mainly in China, has become a focus of scientific attention recently due to its medicinal value (He et al. 2017). In May 2023, blight symptoms on leaves and stems were observed approximately 60% of Bletilla striata in Hangzhou, Zhejiang, China (29.80° N, 119.67° E). Brown spots initially appear on the infected leaves, which gradually decay as the spots expand. The wilting is accompanied with fading and yellowing, and eventually leading to defoliation. The infected stem initially appears brown spots, which gradually decay as the spots expand, resulting in the death of the whole plant, affecting the yield and quality of the herbs ultimately. To isolate the pathogen, small symptomatic leaves and stems (5×5 mm) were surface-disinfected with 75% ethanol for 30 s and 1% NaClO for 2 min, then rinsed in distilled water 3 times. Subsequently, the disinfected tissues were placed on PDA and incubated at 27 ℃ for 3 days. A total of 8 fungal isolates with similar morphological characteristics were obtained. The colony by single-spore purification was light purple to dark purple with abundant aerial mycelium. Macroconidia were relatively slender with a curve, mainly three to five septate and measuring 24.34 to 54.64 μm (average 40.29 μm) × 3.59 to 5.45 μm (average 4.49 μm) (n=30). Microconidia appeared obovoid to pyriform, with sizes of 5.31 to 8.43 μm (average 7.12 μm) × 2.30 to 4.29 μm (average 3.22 μm) (n=30). The morphological characteristics were consistent with Fusarium annulatum (Yilmaz et al. 2021). To further confirm the isolate's identification, the genomic DNA of isolates were extracted and identified by phylogenetic analyses of multilocus sequences of the RNA polymerase largest subunit (rpb1, primers Fa and G2R), RNA polymerase second largest subunit (rpb2, primers 7cf and 11ar) and the translation elongation factor 1-alpha (tef1, primers EF1 and EF2) (O'Donnell et al. 2022). The sequences were deposited in GenBank (rpb1: OR493933, OR493934, OR753402; rpb2: OR753398, OR753399, OR753400; tef1: OR493935, OR493936, OR753401). BLAST searches of the rpb1, rpb2, and tef1 sequences revealed 99.83% (1775/1778 nt), 99.79% (957/959 nt), and 98.98% (678/685 nt) homology with those of Fusarium annulatum CBS:258.54 from New Caledonia (rpb1: MT010944; rpb2: MT010983; tef1: MT010994). To confirm pathogenicity, one-year-old B. striata leaves and stems were disinfected with 75% ethanol, wounded with a sterile syringe on 3 healthy leaves and stems, inoculated with 5 × 5 mm mycelial discs of strain BJ-L1 and BJ-S1, respectively. And the control were treated similarly except that they were inoculated with PDA discs. The experiment was replicated 3 times. After 5 days, all inoculated leaves and stems showed similar symptoms to those initially observed on infected plants. The same pathogen was re-isolated and identified by morphological characterization and molecular analysis, confirming Koch's postulates. Thus, the pathogen causing blight of B. striata was determined to be F. annulatum. To our knowledge, this is the first report of F. annulatum causing blight on B. striata in China. F. annulatum has a wide range of hosts and has been reported to infect a wide range of crops, fruits and vegetables (Bacon et al. 1991). This study provides the basis for further research on this disease and is important for the management of this disease and the improvement of the economic benefits of B. striata.

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.

Tetrastigma hemsleyanum (sanyeqing) is a valuable perennial medicinal plant in China, renowned for its extensive pharmacological properties and applications in traditional medicine. However, its cultivation is threatened by anthracnose disease. This study identified the causal Colletotrichum species responsible for the disease in Zhejiang province via morphological characterization and multilocus phylogenetic analyses ( ACT , CAL , CHS-1 , GAPDH , and ITS). The results revealed considerable diversity among these pathogens, with C. fructicola identified as a widely distributed species with relatively high virulence. To our knowledge, this is the first report of C. aenigma , C. siamense , C. plurivorum , C. sojae , and C. truncatum as causal agents of anthracnose on T. hemsleyanum . Pathogenicity of all species was confirmed, which fulfilled Koch’s postulates. Collectively, these findings clarify the pathogenic species associated with T. hemsleyanum anthracnose in Zhejiang and provide a theoretical foundation for the development of effective disease control strategies.

Efficacy of exogenous melatonin treatment of leaf spot disease on Gardenia jasminoides Eills caused by Aternaria alternata