Leptosphaerulina americana causing holing disease on tobacco in China.

Tobacco (Nicotiana tabacum) is one of the most important industrial crops in the world. Its leaves are the main raw material for cigarettes, but they are often threatened by fungal pathogens in the production process (Wang et al. 2022). From May to June 2022, a disease of tobacco (cv K326) (15% of plants) in a 0.3-ha field in Jingxi of Guangxi Province showed symptoms of local necrosis and perforation of middle and basal leaves (Fig S1). Pieces of leaf tissue (3 × 3 mm) were excised from the edge of the necrotic lesion of each plant, treated with 75% ethanol for 10 s, soaked in 2% NaClO solution for 1-2 min, rinsed with sterile water for three times, and then plated on potato dextrose agar（PDA）medium and incubated at 28°C. Isolate TJYA13 was used for subsequent studies. After 8 days, the colony margin was yellowish brown and irregular, the center was black and plicated. The isolate TJYA13 was incubated on oatmeal agar medium at 28°C for 4 days, and many pseudothecia were observed embedded on the surface of the medium. Pseudothecium was globose or subglobose, dark brown, and size was 184.7-304.7 µm × 187.5-340.5 µm (n=20). Ascospores were usually wrapped by the saccate ascus in pseudothecium, cylindrical or ellipsoidal, with 5-6 transverse septa, and size was 12.2-18.5 µm × 35.6-51.8 µm (n=80). The morphological characteristics of ascospores were consistent with a Leptosphaerulina species (Hou et al. 2020). For accurate identification, the genomic DNA of isolate TJYA13 was extracted with Ezup Column Fungi Genomic DNA Purification Kit (Sangon, Shanghai, China). The ITS region, 28s ribosomal RNA (LSU), ß-tubulin (TUB), and RNA polymerase II second largest subunit (RPB2) were amplified with primers ITS1/ITS4 (Gardes and Bruns 1993; White et al. 1990), LROR/LR7 (Rehner and Samuels 1994), Btub2Fd/Btub4Rd (Woudenberg et al. 2009), and RPB2-5F2/fRPB2-7cR (Liu et al. 1999), respectively and sequenced at Sangon Biotech (Sichuan, China). The sequences were deposited in GenBank (accession nos. OP926927, OP926933, OP939419, OP939422). The phylogenetic analysis grouped the isolate TJYA13 within the L. americana clade (Fig S2) (Hou et al. 2020). Pathogenicity of the isolate TJYA13 was verified on four healthy tobacco plants (cv K326). The mycelial plugs were inoculated on leaves sterilized with 75% ethanol, and control plants were inoculated with sterile PDA plugs. Plants were incubated at 28 ℃ and 78% humidity. After 10 days, the leaves inoculated with mycelial plugs had symptoms similar to those in the field, but there were no symptoms on the control leaves. L. americana were reisolated from the leaves inoculated with the mycelial plugs. To the best of our knowledge, this is the first report of L. americana causing holing disease on tobacco in China. This disease may reduce yields and lower quality of flue-cured tobacco leaf. Therefore, the emergence of tobacco holing disease should be noted to prevent potential damage to tobacco production in Guangxi. Reference 1. Hou L. W., et al. 2020. Stud. Mycol. 96: 309-396 2. Liu, Y. J., et al. 1999. Mol. Biol. Evol. 16:1799. 3. Rehner, S. A., and Samuels, G. J. 1994. Mycol. Res. 98:625. 4. Wang H. et al. 2022. Microorganisms. 10: 1890. 5. White, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA. 6. Woudenberg, J. H. C., et al. 2009. Persoonia 22:56. The author(s) declare no conflict of interest. Funding: Funding was provided by Guangxi Zhuang Autonomous Region Tobacco Monopoly Bureau (grant no. 202,145,000,024,006). Tobacco (Nicotiana tabacum) is one of the most important industrial crops in the world. Its leaves are the main raw material for cigarettes, but they are often threatened by fungal pathogens in the production process (Wang et al. 2022). From May to June 2022, a disease of tobacco (cv K326) (15% of plants) in a 0.3-ha field in Jingxi of Guangxi Province showed symptoms of local necrosis and perforation of middle and basal leaves (Fig S1). Pieces of leaf tissue (3 × 3 mm) were excised from the edge of the necrotic lesion of each plant, treated with 75% ethanol for 10 s, soaked in 2% NaClO solution for 1-2 min, rinsed with sterile water for three times, and then plated on potato dextrose agar（PDA）medium and incubated at 28°C. Isolate TJYA13 was used for subsequent studies. After 8 days, the colony margin was yellowish brown and irregular, the center was black and plicated. The isolate TJYA13 was incubated on oatmeal agar medium at 28°C for 4 days, and many pseudothecia were observed embedded on the surface of the medium. Pseudothecium was globose or subglobose, dark brown, and size was 184.7-304.7 µm × 187.5-340.5 µm (n=20). Ascospores were usually wrapped by the saccate ascus in pseudothecium, cylindrical or ellipsoidal, with 5-6 transverse septa, and size was 12.2-18.5 µm × 35.6-51.8 µm (n=80). The morphological characteristics of ascospores were consistent with a Leptosphaerulina species (Hou et al. 2020). For accurate identification, the genomic DNA of isolate TJYA13 was extracted with Ezup Column Fungi Genomic DNA Purification Kit (Sangon, Shanghai, China). The ITS region, 28s ribosomal RNA (LSU), ß-tubulin (TUB), and RNA polymerase II second largest subunit (RPB2) were amplified with primers ITS1/ITS4 (Gardes and Bruns 1993; White et al. 1990), LROR/LR7 (Rehner and Samuels 1994), Btub2Fd/Btub4Rd (Woudenberg et al. 2009), and RPB2-5F2/fRPB2-7cR (Liu et al. 1999), respectively and sequenced at Sangon Biotech (Sichuan, China). The sequences were deposited in GenBank (accession nos. OP926927, OP926933, OP939419, OP939422). The phylogenetic analysis grouped the isolate TJYA13 within the L. americana clade (Fig S2) (Hou et al. 2020). Pathogenicity of the isolate TJYA13 was verified on four healthy tobacco plants (cv K326). The mycelial plugs were inoculated on leaves sterilized with 75% ethanol, and control plants were inoculated with sterile PDA plugs. Plants were incubated at 28 ℃ and 78% humidity. After 10 days, the leaves inoculated with mycelial plugs had symptoms similar to those in the field, but there were no symptoms on the control leaves. L. americana were reisolated from the leaves inoculated with the mycelial plugs. To the best of our knowledge, this is the first report of L. americana causing holing disease on tobacco in China. This disease may reduce yields and lower quality of flue-cured tobacco leaf. Therefore, the emergence of tobacco holing disease should be noted to prevent potential damage to tobacco production in Guangxi.

First Report of Colletotrichum truncatum Causing Anthracnose in Tobacco in China.

In July 2022, large spots were observed on the leaves of tobacco in Guangxi province, China, whose shape was round and elliptical or irregular. The margins of spots were brown or dark brown with a pale yellow centre and several small black fruiting bodies. The pathogen was isolated by tissue isolation. Diseased leaves collected were cut into small pieces, sterilized with 75% ethanol for 30s and 2% sodium hypochlorite (NaCIO) for 60s, and rinsed with sterile deionized water for three times. Each air-dried tissue segment was cultured on potato dextrose agar (PDA) and incubated at 28℃ for 5 to 7 days in the dark (Wang et al. 2022). A total of six isolates were isolated, with differences in colony shape, edge type and colony colour, and aerial mycelium morphology, with the colony shape round or subrounded, and the edge rounded crenate, dentate or sinuate. The color of the colony was initially light yellow, then gradually changed to yellow and dark yellow. After 3-4 days, white aerial mycelia gradually grew up, which was peony-like or covered the whole colony, thus the color of the colony appeared white, and then gradually changed to orange, gray or nearly black, and all six isolates rarely produced conidia, which was consistent with the description of previous reports(Mayonjo and Kapooria 2003, Feng et al. 2021, Xiao et al. 2018). Conidia were hyaline, aseptate, and falcate, with the size of 7.8 to 12.9 × 2.2 to 3.5 µm. For molecular identification, the colony PCR method was used to amplify the internal transcribed spacer(ITS), actin(ACT), chitin synthase(CHS), and beta-tubulin(TUB2) loci of the six isolates using primer pairs ITS1/ITS4, ACT-512F/ACT-783R, CHS-79F/CHS-354R, and T1/Bt2b, respectively(Cheng et al. 2014). Partial sequences were amplified, sequenced, and uploaded to GenBank (GenBank accession Nos. OP484886，OP518265，OP518266，OP756065，OP756066, and OP756067 for ITS, OP620430 to OP620435 for ACT, OP620436 to OP620441 for CHS, and OP603924 to OP603929 for TUB2). These sequences had 99 to 100% similarity with C. truncatum isolates C-118(ITS), TM19(ACT), OCC69(CHS), and CBS 120709(TUB2) in GenBank. Homology matching was performed using BLAST and a phylogenetic tree was constructed using the Neighbor-Joining (NJ) method using MEGA (7.0) software based on ITS, ACT, CHS, and TUB2 sequences, which showed that all six isolates clustered in the same score as the C. truncatum. A pathogenicity test was performed with healthy tobacco infected with mycelial plugs (about 5 mm in diameter) of six isolates of C. truncatum from a 5-day-old culture, while negative controls on the other leaves were inoculated with sterile PDA plugs. All plants were placed in a greenhouse at 25℃ to 30℃ with 90% relative humidity. The experiment was conducted three times. Five days later, all inoculated leaves had diseased spots, whereas no symptoms appeared on negative controls. The same pathogen, C. truncatum, was identified from the inoculated leaves on the basis of morphological and molecular charchseristics as described above, fulfilling Koch's postulates. In this study, it is the first time to report that the anthracnose on tobacco was caused by C. truncatum. Thus, this work provides a foundation for controlling tobacco anthracnose in the future.

Ethiodized poppyseed oil-based contrast medium is superior to water-based contrast medium during hysterosalpingography regarding image quality improvement and fertility enhancement: A multicentric, randomized and controlled trial.

Background: The efficacy of ethiodized poppyseed oil in hysterosalpingography (HSG) image quality and fertility enhancement has been revealed, but whether this HSG modality has similar effects in the Chinese population is still unclear. Methods: Between July 18, 2017, and December 29, 2019, this multicentric, randomized, two-arm, clinical trial was performed involving 15 medical centers. Infertile women meeting HSG indications were randomly assigned to an oil group and a water group. The coprimary outcome included HSG image quality during HSG and fertility-enhancing effects of HSG. This study was registered on ClinicalTrials.gov (NCT03370575). Findings: A total of 1026 subjects were randomly assigned to an oil group (N = 508) and a water group (N = 518). HSG image quality revealed that the oil group had outstanding visualization (all P < 0.001); total image quality scores for uterus opacification or uterine outline (2.9 ± 0.4 vs. 2.7 ± 0.5), fallopian tube outline (2.3 ± 0.8 vs. 1.7 ± 0.7), fimbrial rugae (1.7 ± 1.0 vs. 1.3 ± 0.8), fallopian tube spillage (2.1 ± 0.9 vs. 1.6 ± 0.8), peritoneal distribution (2.6 ± 0.9 vs. 2.1 ± 1.0) and diagnostic quality (11.6 ± 3.4 vs. 9.5 ± 3.1) (all P < 0.001) were higher in the oil group than in the water group. Regarding fertility-enhancing evaluation, the oil group showed an increased cumulative on-going pregnancy rate, on-going pregnancy within 6 months (29.1% vs. 20.1%), clinical pregnancy (39.5% vs. 29.1%) and live birth ≥ 24 weeks of gestation (36.1% vs. 27.7%) but a shorter time to pregnancy than the water group (all P < 0.01). Concerning adverse events, the oil group showed a lower occurrence rate of abdominal pain and vaginal bleeding after HSG (both P < 0.01). Interpretation: Ethiodized poppyseed oil-based contrast is superior to water-based contrast during HSG in terms of image quality improvement and fertility enhancement. This study indicates the priority of the application of ethiodized poppyseed oil-based contrast during the HSG procedure in infertile patients. Funding: No funding was received.