For the pathogenicity analysis, smooth bromegrass seeds were soaked in water for four days, subsequently distributed into six pots (10 centimeters in diameter and 15 centimeters in height), and maintained within a greenhouse. These plants were exposed to a 16-hour photoperiod, with temperatures ranging from 20 to 25 degrees Celsius and a relative humidity of 60%. After 10 days of growth on wheat bran, the microconidia of the strain were washed with sterile deionized water, passed through three layers of sterile cheesecloth, counted, and the concentration brought to 1,000,000 per milliliter with the aid of a hemocytometer. When the plants had reached a height of about 20 centimeters, spore suspension was applied to the leaves of three pots, at 10 milliliters per pot, whereas the remaining three pots were given sterile water as controls (LeBoldus and Jared 2010). Cultivation of inoculated plants took place in an artificial climate box, with a 16-hour photoperiod, a temperature of 24 degrees Celsius and 60 percent relative humidity. Following five days of treatment, the leaves of the treated plants displayed brown spots, in marked contrast to the healthy state of the control leaves. From the inoculated plants, the same E. nigum strain was re-isolated, its identity confirmed via the morphological and molecular techniques outlined above. According to our information, this report marks the first occasion of leaf spot disease from E. nigrum on smooth bromegrass, within China's agricultural sector, as well as on a global scale. This pathogen's invasion can have a detrimental effect on the yield and quality of smooth bromegrass. Therefore, the development and execution of strategies for managing and controlling this condition are essential.
Apple powdery mildew, caused by *Podosphaera leucotricha*, is an internationally widespread pathogen in apple-producing regions. In the case of a lack of durable host resistance, single-site fungicides offer the most effective disease management strategy within conventional orchards. The combination of more erratic precipitation patterns and higher temperatures, both indicators of climate change in New York State, could make the region more susceptible to the development and propagation of apple powdery mildew. This particular circumstance may see apple powdery mildew outbreaks replace apple scab and fire blight as the key diseases requiring management attention. Although no reports of fungicide control issues for apple powdery mildew have come from producers, the authors have observed and documented a growing prevalence of this fungal disease. A crucial action item was to assess the fungicide resistance profile of P. leucotricha populations to maintain the efficacy of critical single-site fungicides: FRAC 3 (demethylation inhibitors, DMI), FRAC 11 (quinone outside inhibitors, QoI), and FRAC 7 (succinate dehydrogenase inhibitors, SDHI). The 2021-2022 survey focused on 43 orchards in New York's main agricultural regions. From these locations, 160 samples of P. leucotricha were gathered, representing a variety of orchard management approaches, including conventional, organic, low-input, and unmanaged operations. sports medicine Mutations in the target genes (CYP51, cytb, and sdhB), previously known to confer fungicide resistance in other fungal pathogens to the DMI, QoI, and SDHI fungicide classes respectively, were screened for in the samples. read more No problematic mutations in the target genes' nucleotide sequences, leading to harmful amino acid changes, were observed in any of the samples. This suggests that the New York populations of P. leucotricha remain sensitive to DMI, QoI, and SDHI fungicides, except for the possibility of other resistance mechanisms.
In the production of American ginseng, seeds hold a pivotal role. Not only do seeds facilitate long-range dissemination, but they are also essential for the persistence of pathogens. Identifying the pathogens present in seeds forms the foundation for effective strategies to control seed-borne diseases. To determine the fungi present on American ginseng seeds from key Chinese production regions, we implemented incubation and high-throughput sequencing techniques in this study. Banana trunk biomass A 100%, 938%, 752%, and 457% seed-borne fungal presence was observed in Liuba, Fusong, Rongcheng, and Wendeng, respectively. Twenty-eight genera, each containing at least one of sixty-seven isolated fungal species, were found in the seeds. Eleven pathogenic species were ascertained to be present in the seed samples. Every seed sample contained a presence of Fusarium spp. pathogens. Fusarium spp. were more plentiful within the kernel than within the shell. The alpha index highlighted a substantial disparity in fungal diversity between the seed's shell and its kernel. A non-metric multidimensional scaling procedure isolated samples from different provinces and those originating from either seed shells or kernels, indicating a clear separation. Among four fungicides tested on seed-carried fungi of American ginseng, Tebuconazole SC exhibited the highest inhibition rate of 7183%, followed by Azoxystrobin SC at 4667%, Fludioxonil WP at 4608%, and Phenamacril SC at 1111%. The seed treatment agent, fludioxonil, a common practice, displayed a comparatively low inhibitory effect on the fungi associated with American ginseng seeds.
The spread of global agricultural trade has contributed to the emergence and resurgence of various plant pathogens. The United States maintains foreign quarantine status for the fungal pathogen Colletotrichum liriopes, which poses a threat to ornamental Liriope species. Although this species has been documented in various asparagaceous hosts across East Asia, its inaugural and sole sighting within the United States occurred in 2018. That investigation, however, employed only the ITS nrDNA gene for species determination, lacking any preserved cultures or specimens. The present study sought to map the distribution of C. liriopes specimens across various geographic regions and host organisms. The ex-type of C. liriopes served as a benchmark against which isolates, sequences, and genomes from various hosts and geographic locations (China, Colombia, Mexico, and the United States, for example) were scrutinized and compared, thereby achieving the desired outcome. Multilocus phylogenetic analyses (incorporating ITS, Tub2, GAPDH, CHS-1, and HIS3) in conjunction with phylogenomic and splits tree analyses indicated the presence of a well-supported clade encompassing all studied isolates/sequences, with minimal intraspecific variation. The observed morphological characteristics corroborate these findings. Indications of a recent colonization event, exemplified by low nucleotide diversity, negative Tajima's D values in both multilocus and genomic datasets, and a Minimum Spanning Network analysis, point to an initial spread of East Asian genotypes to countries producing ornamental plants (e.g., South America), followed by importation to countries like the USA. The study findings suggest an increased geographic and host distribution of C. liriopes sensu stricto, now extending into the USA (including locations such as Maryland, Mississippi, and Tennessee) and involving a wider range of hosts than previously known, beyond Asparagaceae and Orchidaceae. This investigation provides essential knowledge to reduce costs and losses from agricultural commerce, and to broaden our comprehension of the movement of pathogens.
In the realm of globally cultivated edible fungi, Agaricus bisporus stands out as one of the most prevalent. In December 2021, a 2% occurrence of brown blotch disease was noted on the cap of A. bisporus, within a mushroom cultivation base in Guangxi, China. On the cap of A. bisporus, brown blotches of 1-13 cm in size first appeared, and then gradually increased in extent along with the growth of the cap. A two-day incubation period allowed the infection to reach the inner tissues of the fruiting bodies, accompanied by dark brown blotches. Internal tissue samples (555 mm) from infected stipes underwent sterilization in 75% ethanol for 30 seconds, followed by triple rinsing with sterile deionized water (SDW). These samples were then macerated in sterile 2 mL Eppendorf tubes, to which 1000 µL of SDW was added, resulting in a suspension subsequently diluted into seven concentrations (10⁻¹ to 10⁻⁷) for causative agent isolation. Suspensions (120 liters each) were spread across Luria Bertani (LB) medium, followed by a 24-hour incubation at 28 degrees Celsius. Convex, smooth, whitish-grayish colonies were the prevailing single ones. No fluorescent pigments were produced, and no pods or endospores were formed by the Gram-positive, non-flagellated, and nonmotile cells growing on King's B medium (Solarbio). The 16S rRNA gene sequence (1351 bp; OP740790), amplified from five colonies via universal primers 27f/1492r (Liu et al., 2022), showed 99.26% identity with the Arthrobacter (Ar.) woluwensis sequence. The amplified partial sequences of the ATP synthase subunit beta gene (atpD), RNA polymerase subunit beta gene (rpoB), preprotein translocase subunit SecY gene (secY), and elongation factor Tu gene (tuf), all originating from the colonies and having lengths of 677 bp (OQ262957), 848 bp (OQ262958), 859 bp (OQ262959), and 831 bp (OQ262960) respectively, showed similarity exceeding 99% to Ar. woluwensis using the Liu et al. (2018) method. The three isolates (n=3) were subjected to biochemical testing using micro-biochemical reaction tubes from Hangzhou Microbial Reagent Co., LTD, and the results displayed the same biochemical attributes as found in Ar. Woluwensis strains exhibit a positive response in esculin hydrolysis, urea utilization, gelatin degradation, catalase activity, sorbitol metabolism, gluconate assimilation, salicin fermentation, and arginine utilization. No citrate, nitrate reduction, or rhamnose utilization was observed (Funke et al., 1996). Analysis of the isolates indicated they are Ar. Morphological features, biochemical assays, and phylogenetic studies jointly establish the woluwensis species based on scientific criteria. After 36 hours of incubation in LB Broth at 28°C with 160 rpm agitation, bacterial suspensions (1×10^9 CFU/ml) were subjected to pathogenicity tests. Immature Agaricus bisporus specimens had 30 liters of bacterial suspension added to their caps and tissues.