The mycotoxin fumonisin is known to be harmful to humans and animals, and thus it is desirable to reduce fumonisin content in crop products. We explored the functions of several genes that function in fumonisin biosynthesis (FUM1, FUM6, FUM8, FUM19, and FUM21) in Fusarium proliferatum and found that deletion of FUM1, FUM6, FUM8, or FUM21 results in a severe reduction in fumonisin biosynthesis, while loss of FUM19 does not. In addition, fumonisin-deficient strains display significantly decreased pathogenicity. Co-cultivation of the ΔFUM1, ΔFUM6, ΔFUM8, and ΔFUM19 mutants restores fumonisin synthesis. However, co-cultivation was unable to restore fumonisin synthesis in the ΔFUM21 strain. The relative expression levels of three key FUM genes (FUM1, FUM6, and FUM8) differed significantly in each mutant strain; notably, the expression levels of these three genes were significantly down-regulated in the ΔFUM21 strain. Taken together, our results demonstrate that FUM1, FUM6, FUM8, and FUM21 are essential for fumonisin synthesis, and FUM19 is non-essential. Partial mutants lost the ability to synthesize fumonisin, the co-culture of the mutants was able to restore fumonisin biosynthesis. While the pathogenicity of F. proliferatum is affected by many factors, inhibition of the synthesis of the mycotoxin fumonisin will weaken the pathogenicity of rice spikelet rot disease (RSRD).

Polygonatum cyrtonema Hua is a perennial herb of the Asparagaceae family that is used for both dietary and medicinal purposes in China. In September 2019, a new leaf spot disease on Polygonatum cyrtonema was detected and is currently widespread in Huaihua, Hunan Province, China. Pathogenic fungi were isolated and purified from samples of diseased tissue that were collected for morphological and molecular phylogenetic studies. The pathogen was identified using multilocus (ITS, TEF-1, and TUB2) phylogenies, as well as morphological characters, and was found to be clustered but separately divergent from species of Pestalotiopsis. However, there were significant morphological differences between the pathogen and similar species. The pathogen was finally identified as a new species that was designated Pestalotiopsis xuefengensis. This is the first report of Pestalotiopsis xuefengensis serving as the causal agent of gray leaf spot on Polygonatum cyrtonema. This study will provide useful information for the diagnosis and management of this disease.

Polygonatum cyrtonema Hua, a perennial plant of the Asparagaceae family, is an important herb in Chinese medicine and is mainly grown in the Chinese provinces of Guizhou, Hunan, Yunnan, Anhui, and Zhejiang (Chen et al. 2021). In June 2021, a new case of leaf spot disease was detected in an 80 m2 plantation of P. cyrtonema on Xuefeng Mountain, Huaihua City, Hunan Province (27°17'30″N, 110°24'20″E). It infected almost 40% of the total planted area. Initially, irregular light brown spots appeared on the leaves, gradually turning dark brown and coalescing to form large necrotic areas, after which the affected plant turned yellow and eventually died. Ten disease samples were collected from ten plants in the plantation area. The leading edge of necrotic tissues were rinsed with sterile water and then disinfected with 3% hydrogen peroxide for 30 s, followed by 75% ethanol for 90 s, and rinsed three times with sterile water. Samples were then placed on water agar plates and incubated in the dark in a constant temperature incubator at 28 ℃ for 3-5 days. After mycelial growth was observed in the media, the hyphae were transferred to potato dextrose agar plates and incubated for 3-5 days at 28 ℃ in the dark. Ultimately, 12 purified fungal isolates were obtained, some of which were morphologically similar, including 10 that were Alternaria (83.3% isolation rate). Three representative isolates (HJYB1, HJYB2, and HJYB3) were selected for further study. The initial colonies were grayish green with white fluffy mycelia on the surface and a prominent white rim, which became brown with dense, cottony aerial mycelia as the colonies matured. The conidia were obpyriform or ellipsoidal, pale to dark brown, with 0-4 transverse and 0-3 longitudinal septa, some with a short cylindrical beak at the tip. They measured 11.826-28.873 × 6.231-26.018 μm (n = 100). To further confirm the identity of the isolates, their rDNA internal transcribed spacer region (ITS), β-microtubulin (TUB2) and translation elongation factor-1 (TEF-1) genes were amplified and sequenced using the ITS4/ITS5, TUB2F/R and EF-526F/1567R primers, respectively (Hong et al. 2006). The sequences were submitted to GenBank (ITS: OR513924, OR513964, OR519874; TUB2: OR526928, OR533421, OR526929; TEF: OR526926, OR533420, OR526927). A concatenated phylogenetic tree of the three genes showed that the isolate clustered significantly with Alternaria alternata. Based on morphological identification and phylogenetic tree analysis, the isolate was identified as A. alternata. We carried out pathogenicity tests on four uniformly growing P. cyrtonema plants. Three of these plants were used as experimental plants and one as a control. For each plant, three young leaves were selected and inoculated with 6 × 6 mm PDA blocks, while sterile PDA blocks were used as controls. The treated plants were subjected to 10 days of stable temperature in a climatic chamber set at 28°C, 80% constant relative humidity and 12 hours of light per day. The pathogenic lesions appeared and the pathogens re-isolated from the diseased leaves showed similar morphological characteristics to representative isolates and were confirmed as A. alternata by DNA sequencing, thus fulfilling Koch's postulates. A. alternata is the major causal agent of leaf spot on P. sibiricum (Zou et al. 2023) and Agrimonia pilosa (Jiang et al. 2023). As far as we know, leaf necrosis caused by A. tenuissima has been found on P. cyrtonema (Li et al. 2020). To our knowledge, this is the first report of A. alternata causing leaf spot disease in P. cyrtonema. These findings form the basis for the management of this leaf spot disease.

Epimedium sagittatum (Sieb.et Zucc.) Maxim, belonging to the family Berberidaceae and the genus Epimedium, is effective in dispersing wind and cold, tonifying the kidneys and bones, and strengthening muscles and bones (Song et al. 2024). In June 2023, a new leaf disease appeared on 33.35 hm² of E. sagittatum cultivation in Xinning County, Shaoyang City, Hunan Province, China (111°43'00″N, 27°26'40″E), with symptoms appearing on about 50% of the cultivation area. Initially lesions appear on the leaf tips, then the spots gradually widen and become yellowish-white and dry, with a dark yellow halo around the periphery. We collected ten infected leaves from different growing areas and rinsed them with running sterile water. To isolate the pathogen, small infected parts cut from the leaves were surface disinfected with 3% hydrogen peroxide for 30 s and then treated with 75% alcohol for 45 s. Finally, the diseased parts were rinsed five times with sterile water and incubated on water agar (WA) plates at 28°C for 3-5 days. After mycelial growth was observed, the hyphae were transferred to potato dextrose agar (PDA) plates and incubated for 3-5 days at 28°C in the dark. Finally, eight isolates were obtained, and six of them belonged to Colletotrichum genus based on their morphological characterisation on PDA plates (isolation frequency 75%). Three representative strains (YYH5, YYH6 and YYH7) were selected for further study. The colonies were initially round with white aerial and later grey-black to white on the back. Under the microscope the conidia were short and cylindrical. They had rounded ends and measured 12.936 to 15.894 × 6.119 to 8.137μm (n = 100). To further confirm the identity of the isolates, five gene regions of the isolates, including internal transcribed spacer (ITS), actin (ACT), chitin synthase (CHS), calmodulin (CAL) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were amplified and sequenced using the universal primers ITS4/ITS5, ACT-512F/ACT-783R, CHS-79F/CHS-345R, CL1C/CL2C and GDF/GDR respectively (Weir et al. 2012). Sequences were submitted to GenBank (ITS: PP898147, PP898149, PP898150; ACT: PP925578, PP925579, PP925585; CHS: PP925576, PP925577, PP925584; CAL: PP925580, PP925581, PP925586; GAPDH: PP925582, PP925583, PP925587). Analysis of the constructed five-gene joint phylogenetic tree showed that these three isolates were significantly clustered with Colletotrichum karstii. Pathogenicity was tested using three representative strains. The epidermis of young E. sagittatum leaves was punctured with a sterile needle and 6 × 6 mm mycelial blocks cultured on PDA for 7 days were placed on the wound. Controls were treated in the same way except that sterile PDA blocks were used. There were three replicates for each treatment. All plants used in the experiment were kept in a constant climate chamber at 28°C. The photoperiod was 12 hours and the relative humidity of the chamber was maintained at 80%. Three days later, lesions appeared at the inoculation sites on the plants. Symptoms worsened after five days. All strains re-isolated from diseased spots had the same colony characteristics as the representative strain and were confirmed as C. karstii by DNA sequencing. Therefore, Koch's postulates is fulfilled. C. karstii has been shown to cause anthracnose on Fragaria x ananassa Duch (Soares et al. 2021), Piper nigrum L. (Lin et al. 2022) and Glycine max (Luo et al. 2024). To our knowledge, this is the first report of C. karstii causing anthracnose on E. sagittatum. This research will lay the foundations for future control of the disease.

Lily (Lilium brownii var. Viridulum Baker) is a well-known edible plant with large, white and sweet bulb scales that has important medicinal value (Zhou et al. 2021) and is grown mainly in the Hebe...