For the pathogenicity test, smooth bromegrass seeds were steeped in water for four days, subsequently planted in six pots (diameter 10 cm, height 15 cm). These pots were maintained in a greenhouse environment, subject to a 16-hour photoperiod, with temperatures controlled between 20 and 25°C and a relative humidity of 60%. After ten days of incubation on wheat bran, microconidia of the strain were harvested, washed with sterile deionized water, filtered through three layers of sterile cheesecloth, enumerated, and the suspension adjusted to 1×10^6 microconidia/mL using a hemocytometer. Three pots of plants, upon reaching a height of about 20 centimeters, experienced foliar spraying with a spore suspension of 10 milliliters per pot, while the remaining three pots were treated with sterile water, functioning as a control (LeBoldus and Jared 2010). Under controlled conditions provided by an artificial climate box, inoculated plants were cultured, experiencing a 16-hour photoperiod with a temperature of 24 degrees Celsius and a relative humidity of 60 percent. The leaves of the treated plants showed brown discoloration after five days, in contrast to the healthy leaves of the untreated controls. Using the previously described morphological and molecular methods, the identical E. nigum strain was re-isolated from the inoculated plants. To the best of our knowledge, this is the initial report detailing leaf spot disease caused by E. nigrum in smooth bromegrass, in China, as well as on a worldwide scale. Smooth bromegrass yields and quality may suffer as a result of infection by this organism. Therefore, the development and execution of strategies for managing and controlling this condition are essential.
The worldwide presence of *Podosphaera leucotricha*, the agent of apple powdery mildew, demonstrates its endemic status in apple-producing regions. Single-site fungicides prove most effective for disease management in conventional orchards where durable host resistance is absent. In New York State, the evolving climate, specifically the increase in erratic precipitation and warmer temperatures due to climate change, could encourage the emergence and propagation of apple powdery mildew. This scenario suggests a potential shift in disease management priorities, where outbreaks of apple powdery mildew could take precedence over apple scab and fire blight. No reports of fungicide failure in controlling apple powdery mildew have been received from producers, although the authors have observed and documented a rise in disease prevalence. Therefore, to maintain the potency of the single-site fungicide classes (FRAC 3 demethylation inhibitors, DMI; FRAC 11 quinone outside inhibitors, QoI; FRAC 7 succinate dehydrogenase inhibitors, SDHI), action was essential to evaluate the fungicide resistance status of P. leucotricha populations. Across a two-year period (2021 and 2022), 160 samples of P. leucotricha were gathered from 43 orchards in New York's key agricultural regions, encompassing conventional, organic, low-input, and unmanaged orchard systems. biocidal effect The screening of samples for mutations in the target genes (CYP51, cytb, and sdhB) – historically linked to conferring fungicide resistance in other fungal pathogens to the DMI, QoI, and SDHI fungicide classes, respectively – was undertaken. selleck Analysis of all samples revealed no mutations in the target genes that resulted in problematic amino acid substitutions. This indicates that New York populations of P. leucotricha are likely sensitive to DMI, QoI, and SDHI fungicides, contingent upon the absence of alternative resistance mechanisms.
Seeds are critical to the output of American ginseng. Pathogens utilize seeds as a significant vehicle for long-distance dissemination and survival strategies. Determining the pathogens that seeds carry is essential for managing seed-borne diseases successfully. Our study investigated fungal species on American ginseng seeds sourced from key Chinese production regions, leveraging both incubation and high-throughput sequencing methodologies. immune related adverse event The fungal loads on seeds in Liuba, Fusong, Rongcheng, and Wendeng measured 100%, 938%, 752%, and 457%, respectively. The isolation from the seeds yielded sixty-seven fungal species, categorized into twenty-eight genera. Eleven pathogens were discovered in the examined seed samples. All seed samples showed the presence of pathogens identified as Fusarium spp. The kernel harbored a greater concentration of Fusarium species than the shell. According to the alpha index, fungal diversity varied considerably between the seed shell and kernel. Non-metric multidimensional scaling analysis definitively separated samples collected from various provinces and those derived from either the seed shell or kernel. Fungicide efficacy against seed-carried fungi infecting American ginseng revealed differing inhibition percentages. Tebuconazole SC yielded a 7183% rate, contrasted by 4667% for Azoxystrobin SC, 4608% for Fludioxonil WP, and 1111% for Phenamacril SC. Conventional seed treatment agent fludioxonil demonstrated a limited ability to inhibit fungi found on seeds of American ginseng.
Global agricultural trade acts as a catalyst for the appearance and reappearance of fresh plant pathogens. The United States maintains foreign quarantine status for the fungal pathogen Colletotrichum liriopes, which poses a threat to ornamental Liriope species. Despite its presence on various asparagaceous plants in East Asia, the species's initial and solitary report in the USA dates back to 2018. Nevertheless, the identification in that study relied solely on ITS nrDNA sequences, without any accompanying cultured samples or preserved specimens. The present study sought to map the distribution of C. liriopes specimens across various geographic regions and host organisms. To attain this, a comparative analysis was performed on the ex-type of C. liriopes with isolates, sequences, and genomes obtained from diverse hosts and geographical regions, specifically including, but not limited to, China, Colombia, Mexico, and the United States. The isolates/sequences under investigation, subjected to multilocus phylogenetic analysis (utilizing ITS, Tub2, GAPDH, CHS-1, HIS3), phylogenomic studies, and splits tree analyses, displayed a robustly supported clade with minimal intraspecific variability. Examination of the morphology reinforces these conclusions. A recent migration of East Asian genotypes, as suggested by the low nucleotide diversity, negative Tajima's D observed in multilocus and genomic data, and the Minimum Spanning Network topology, is inferred to have occurred first to countries of ornamental plant cultivation (such as South America), and then later to import destinations 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.
Among the most prevalent edible fungi cultivated globally is Agaricus bisporus. December 2021 marked the observation of brown blotch disease on the cap of A. bisporus, with a 2% incidence rate, in a mushroom cultivation base within 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. Two days later, the infection had reached the inner tissues of the fruiting bodies, manifesting as dark brown blotches. Internal tissue samples (555 mm) from infected stipes were prepared for causative agent isolation by sterilization in 75% ethanol for 30 seconds, followed by three rinses in sterile deionized water (SDW). Next, these samples were homogenized in sterile 2 mL Eppendorf tubes, where 1000 µL of SDW was added. The resulting suspension was then serially diluted into seven concentration levels (10⁻¹ to 10⁻⁷). Luria Bertani (LB) medium was used to distribute each 120-liter suspension, which was then incubated for 24 hours at 28 degrees Celsius. A whitish-grayish color, smooth texture, and convex shape defined the dominant single colonies. 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). Universal primers 27f/1492r (Liu et al., 2022) were used to amplify the 16S rRNA gene (1351 bp; OP740790) from five colonies, which exhibited a 99.26% identity match with Arthrobacter (Ar.) woluwensis. Using the Liu et al. (2018) procedure, partial sequences of the genes encoding the ATP synthase subunit beta (atpD), RNA polymerase subunit beta (rpoB), preprotein translocase subunit SecY (secY), and elongation factor Tu (tuf), were amplified from the colonies. These sequences (677 bp; OQ262957, 848 bp; OQ262958, 859 bp; OQ262959, and 831 bp; OQ262960, respectively) displayed a remarkable similarity exceeding 99% with Ar. woluwensis. Via bacterial micro-biochemical reaction tubes (Hangzhou Microbial Reagent Co., LTD), biochemical tests were performed on three isolates (n=3), yielding results consistent with the biochemical characteristics of Ar. The Woluwensis strain demonstrates positive reactions across the following tests: esculin hydrolysis, urea hydrolysis, gelatinase activity, catalase production, sorbitol fermentation, gluconate utilization, salicin metabolism, and arginine utilization. Results from the citrate, nitrate reduction, and rhamnose tests were all negative, consistent with Funke et al.'s findings (1996). The isolates were identified as being Ar. Phylogenetic analysis, morphological characteristics, and biochemical assays converge to define the characteristics of woluwensis. 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. A 30-liter bacterial suspension was applied to the caps and tissues of the young A. bisporus mushrooms.