To validate the experiment's design, SDW was assigned as a negative control. All treatments were maintained at a constant temperature of 20 degrees Celsius and 80 to 85 percent humidity. Employing five caps and five tissues of young A. bisporus per repetition, the experiment was performed three times. Upon examination 24 hours after inoculation, brown blotches were seen on every part of the inoculated caps and tissues. At the 48-hour mark, a change in the inoculated caps manifested as a darkening to dark brown, and the infected tissues progressed from brown to black, eventually encompassing the entire block, leading to a profoundly decayed look and a strong, foul odor. The indicators of this disease displayed similarities with those of the original specimens. No lesions characterized the control group members. The pathogenicity test yielded results that allowed for the re-isolation of the pathogen from the infected caps and tissues. This re-isolation was confirmed by morphological analysis, 16S rRNA sequence comparisons, and biochemical assays, thereby satisfying the stipulations of Koch's postulates. Bacteria belonging to the Arthrobacter genus. These entities are commonly observed across varied environmental settings (Kim et al., 2008). Two studies, up to the present time, have validated Arthrobacter species as the agents responsible for the ailment of edible fungi (Bessette, 1984; Wang et al., 2019). In a novel observation, this report details Ar. woluwensis as the causative agent of brown blotch disease affecting A. bisporus, representing a significant advancement in the field. This research has implications for developing effective treatments and controls against this ailment.
The study by Chen, J., et al. (2021) highlights Polygonatum cyrtonema Hua, a cultivated variety of Polygonatum sibiricum Redoute, as an important cash crop in China. Between 2021 and 2022, P. cyrtonema leaves in Wanzhou District, Chongqing (30°38′1″N, 108°42′27″E), displayed symptoms akin to gray mold, with a disease incidence ranging from 30% to 45%. Symptoms initially appeared between April and June, while a more than 39% leaf infection rate developed from July through September. The affliction began as irregular brown spots, and worsened by spreading to the leaf edges, the tips, and even the stems. genetic connectivity When dryness prevailed, the infected tissue presented a dried, thin profile, a light brownish tint, and, in the later phases of the disease, became arid and cracked. High relative humidity fostered the development of water-soaked decay on infected leaves, marked by a brown streak bordering the affected area, and the subsequent appearance of a gray fungal layer. Eight representative diseased leaves were collected to pinpoint the causal agent. Leaf tissue, divided into 35 mm pieces, underwent a surface sterilization procedure involving a one-minute dip in 70% ethanol and a five-minute soak in 3% sodium hypochlorite, then rinsed thrice in sterile water. The samples were then spread on potato dextrose agar (PDA) supplemented with streptomycin sulfate (50 g/ml), and incubated at 25°C in darkness for 3 days. Six colonies possessing a similar morphology and size (3.5 to 4 centimeters in diameter) were subsequently moved to new, sterile agar plates. At the outset of isolate cultivation, the hyphal colonies were characterized by a dense, white, clustered growth pattern, radiating outwards. On the medium's bottom, embedded sclerotia, ranging in size from 23 to 58 mm in diameter, exhibited a color change from brown to black after a 21-day period. After evaluation, the six colonies exhibited the characteristics of Botrytis sp. By this JSON schema, a list of sentences is returned. Branching conidiophores held clusters of conidia, which were arranged in grape-like structures. The conidiophores' morphology was straight and their length was between 150 and 500 micrometers. The conidia, single-celled and elongated in an ellipsoidal or oval shape, were aseptate and had dimensions of 75 to 20 or 35 to 14 micrometers (n=50). To determine the molecular identity, DNA was extracted from representative strains 4-2 and 1-5. Using primers ITS1/ITS4, RPB2for/RPB2rev, and HSP60for/HSP60rev, the amplification of the internal transcribed spacer (ITS) region, the RNA polymerase II second largest subunit (RPB2) sequences, and the heat-shock protein 60 (HSP60) genes was achieved, respectively, following the protocols described in White T.J., et al. (1990) and Staats, M., et al. (2005). Within GenBank, the sequences identified by accession numbers 4-2 and 1-5, comprising ITS, RPB2 (OM655229/OQ160236), HSP60 (OM960678/OQ164790), and HSP60 (OM960679/OQ164791), were deposited. Nedometinib Strains 4-2 and 1-5 displayed a complete identity in their sequences compared to the B. deweyae CBS 134649/ MK-2013 ex-type (ITS; HG7995381, RPB2; HG7995181, HSP60; HG7995191). Multi-locus sequence alignment and phylogenetic analysis substantiated the classification of strains 4-2 and 1-5 as B. deweyae. As detailed by Gradmann, C. (2014), Koch's postulates were applied to Isolate 4-2 to assess whether B. deweyae could produce gray mold on P. cyrtonema. The leaves of P. cyrtonema, grown in pots, were washed with sterile water and subsequently treated with 10 mL of hyphal tissue immersed in 55% glycerin. Utilizing 10 mL of 55% glycerin, a control group of leaves from a different plant was treated, and the experiments based on Kochs' postulates were carried out three times. In a chamber with a meticulously regulated relative humidity of 80% and a temperature maintained at 20 degrees Celsius, inoculated plants were housed. Following the inoculation period of seven days, leaf symptoms evocative of those encountered in the field were observed in the treated plants, contrasting with the asymptomatic state of the control specimens. Following inoculation, the fungus was re-isolated and confirmed as B. deweyae through a multi-locus phylogenetic analysis. B. deweyae, as far as we know, is most often found on Hemerocallis, and it's probable that this organism contributes substantially to the emergence of 'spring sickness' symptoms (Grant-Downton, R.T., et al. 2014), signifying this as the initial report of B. deweyae causing gray mold on P. cyrtonema within China. Despite B. deweyae's restricted host range, its potential to threaten P. cyrtonema cannot be dismissed. This research effort will establish a basis for future disease prevention and therapeutic interventions.
The pear tree (Pyrus L.) in China holds a prominent position in the global fruit industry due to its massive cultivation area and yield, as confirmed by Jia et al. (2021). June 2022 marked the onset of brown spot symptoms on 'Huanghua' pear trees, a Pyrus pyrifolia Nakai cultivar. The germplasm garden of Anhui Agricultural University (High Tech Agricultural Garden), in Hefei, Anhui, China, houses the Huanghua leaves. The diseased leaf percentage, approximately 40%, was calculated from 300 leaves (50 per plant across 6 plants). Small, brown, round to oval lesions, gray at the core and encircled by brown to black margins, appeared first on the leaves. These rapidly expanding spots ultimately led to an abnormal shedding of leaves. In order to isolate the brown spot pathogen, symptomatic leaves were gathered, washed in sterile water, disinfected with 75% ethanol for 20 seconds, and then rinsed with sterile water multiple times, 3 to 4 rinses. Leaf fragments were deposited onto PDA medium, which was incubated at 25°C for seven days to obtain the desired isolates. The incubation of the colonies for seven days led to the emergence of aerial mycelium with a coloration ranging from white to pale gray, culminating in a diameter of 62 mm. The conidiogenous cells, identifiable as phialides, displayed shapes that ranged morphologically from doliform to ampulliform. A wide array of shapes and sizes were observed in the conidia, encompassing forms from subglobose to oval or obtuse, characterized by thin walls, aseptate hyphae, and a smooth surface. The diameter was determined to be between 42 and 79 meters, and between 31 and 55 meters. Similar morphologies to Nothophoma quercina, as noted in prior studies (Bai et al., 2016; Kazerooni et al., 2021), were observed. Primers ITS1/ITS4 for internal transcribed spacers (ITS), Bt2a/Bt2b for beta-tubulin (TUB2), and ACT-512F/ACT-783R for actin (ACT) regions, were used respectively for the amplification of these regions in the molecular analysis. Accession numbers OP554217, OP595395, and OP595396 were assigned to the ITS, TUB2, and ACT sequences, respectively, which were submitted to GenBank. Medial extrusion Analysis by nucleotide BLAST revealed a strong homology between the examined sequences and those of N. quercina, exemplified by MH635156 (ITS 541/541, 100%), MW6720361 (TUB2 343/346, 99%), and FJ4269141 (ACT 242/262, 92%). Using MEGA-X software's neighbor-joining method, a phylogenetic tree was constructed from ITS, TUB2, and ACT sequences, revealing the highest similarity to N. quercina. To validate pathogenicity, three healthy plant leaves were treated with a spore suspension (10^6 conidia per milliliter), while control leaves received sterile water. Plastic sheeting enveloped the inoculated plants, which were cultivated in a controlled environment chamber (90% relative humidity) at 25°C. Seven to ten days after inoculation, the typical disease symptoms manifested on the treated leaves, while the control leaves remained symptom-free. Re-isolation of the same pathogen from the afflicted leaves confirmed Koch's postulates. Following morphological and phylogenetic tree analyses, we validated *N. quercina* fungus as the causative organism of brown spot disease, reiterating the earlier conclusions made by Chen et al. (2015) and Jiao et al. (2017). To the best of our understanding, this marks the first instance of brown spot disease stemming from N. quercina on 'Huanghua' pear leaves observed in China.
Cherry tomatoes (Lycopersicon esculentum var.), with their enticing sweetness and miniature size, are a popular choice for snacking and cooking. In Hainan Province, China, the cerasiforme tomato variety stands out for its nutritional value and sweet flavour, a quality praised by Zheng et al. (2020). The period from October 2020 to February 2021 witnessed the occurrence of a leaf spot disease on cherry tomatoes (cultivar Qianxi) in Chengmai, Hainan Province.