For the pathogenicity study, smooth bromegrass seeds were steeped in water for four days, and then planted into six pots (10 cm diameter, 15 cm height). These pots were kept in a greenhouse with a 16-hour light cycle, a temperature range of 20-25°C, and a relative humidity of 60%. Microconidia, harvested from the strain's culture on wheat bran medium after 10 days of growth, were washed in sterile deionized water, filtered through three layers of sterile cheesecloth, enumerated, and the concentration adjusted to 1,000,000 microconidia per milliliter using a hemocytometer. Once the plants had attained a height of approximately 20 centimeters, the leaves of three pots were sprayed with a spore suspension, at 10 milliliters per pot, and the remaining three pots served as control pots, receiving sterile water (LeBoldus and Jared 2010). The artificial climate box provided the regulated conditions necessary for the cultured inoculated plants, a 16-hour photoperiod with a temperature of 24 degrees Celsius and a 60 percent relative humidity. After five days, the treated plants' leaves exhibited noticeable brown spots, contrasting with the unblemished leaves of the control group. From the inoculated plants, the same E. nigum strain was re-isolated, its identity confirmed via the morphological and molecular techniques outlined above. This report, to our knowledge, is the first to describe leaf spot disease in smooth bromegrass, specifically linked to E. nigrum, in China, and internationally. Smooth bromegrass's agricultural output and quality might be affected by infection with this pathogen. For that reason, the creation and execution of methods for the handling and dominion over this affliction are warranted.
*Podosphaera leucotricha*, the fungus responsible for apple powdery mildew, is an endemic pathogen globally where apples are produced. Single-site fungicides are the predominant method of managing the disease in conventional orchards, absent sustained host resistance. Climate change-induced fluctuations in precipitation and temperature trends in New York State could potentially lead to a rise in apple powdery mildew. Apple powdery mildew's prevalence in this situation could potentially displace the established management strategies for apple scab and fire blight. Currently, there are no reports from producers about fungicides failing to control apple powdery mildew, but the authors have both observed and recorded an increase in the incidence of the disease. It was necessary to evaluate the resistance status of P. leucotricha populations to fungicides, particularly the key classes of single-site fungicides (FRAC 3, demethylation inhibitors, DMI; FRAC 11, quinone outside inhibitors, QoI; FRAC 7, succinate dehydrogenase inhibitors, SDHI), to maintain their efficacy. From 43 orchards across New York's leading agricultural regions, we collected 160 samples of P. leucotricha over two years (2021-2022). These orchards represented conventional, organic, low-input, and unmanaged agricultural practices. Paramedian approach Historically known to confer fungicide resistance in other fungal pathogens to the DMI, QoI, and SDHI fungicide classes, respectively, samples were screened for mutations in the target genes (CYP51, cytb, and sdhB). vaccines and immunization A comprehensive evaluation of all samples exhibited no nucleotide sequence mutations in the target genes translating into problematic amino acid substitutions. This points to a probable sensitivity of New York populations of P. leucotricha to DMI, QoI, and SDHI fungicides, assuming no other resistance mechanisms exist.
Seeds are essential to the successful creation of American ginseng. The significant role seeds play in the far-reaching spread and the crucial survival of pathogens is undeniable. To effectively manage seed-borne diseases, the pathogens carried by the seeds must be understood. This paper investigated the fungi carried by American ginseng seeds from major Chinese production zones, using incubation and high-throughput sequencing as the primary methods. Cy7 DiC18 supplier Fungal counts on seeds from Liuba, Fusong, Rongcheng, and Wendeng demonstrated seed-borne rates of 100%, 938%, 752%, and 457%, respectively. From the seeds, sixty-seven fungal species, categorized within twenty-eight genera, were isolated. Eleven pathogenic species were ascertained to be present in the seed samples. Fusarium spp. pathogens were present in every seed sample examined. Fusarium spp. were more plentiful within the kernel than within the shell. According to the alpha index, fungal diversity varied considerably between the seed shell and kernel. A non-metric multidimensional scaling analysis clearly separated the seed samples from different provinces and those collected from either the seed shell or kernel part of the seed 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%. 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. Within the United States, the quarantine status of the fungal pathogen Colletotrichum liriopes persists for ornamental plants, specifically Liriope spp. Whilst this species has been sighted on numerous asparagaceous plants throughout East Asia, its single report in the USA took place in 2018. In contrast to the other studies, that particular study relied only on ITS nrDNA for species identification, without any preserved cultures or vouchers. We sought to determine the geographic and host-based distribution of identified C. liriopes specimens in this study. New and existing isolates, sequences, and genomes, originating from diverse host species and geographic locations, including China, Colombia, Mexico, and the United States, were compared to the ex-type of C. liriopes to accomplish this goal. 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. The study of morphology validates the presented findings. 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. Analysis of the study demonstrates that the geographic range and host diversity of C. liriopes sensu stricto have extended to encompass the United States (specifically, Maryland, Mississippi, and Tennessee), and now include various hosts beyond Asparagaceae and Orchidaceae. This study provides fundamental insights that can be employed to curtail losses and costs from agricultural trade, and to expand our comprehension of the dissemination of pathogens.
Edible fungus Agaricus bisporus is a widely cultivated and popular choice across the world. 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. Beginning with the emergence of brown blotches (1-13 centimeters in size) on the cap, these blemishes gradually expanded as the cap of the A. bisporus grew. Two days later, the infection had reached the inner tissues of the fruiting bodies, manifesting as dark brown blotches. Causative agent isolation commenced with the sterilization of 555 mm internal tissue samples from infected stipes in 75% ethanol for 30 seconds. The samples were rinsed thrice in sterile deionized water (SDW) and then homogenized in sterile 2 mL Eppendorf tubes, to which 1000 µL SDW was added. Serial dilutions of this suspension yielded seven concentrations ranging from 10⁻¹ to 10⁻⁷. Morphological examination of the isolates, as described by Liu et al. (2022), was conducted on samples of each 120-liter suspension following a 24-hour incubation period at 28 degrees Celsius in Luria Bertani (LB) medium. Colonies of a whitish-grayish color, smooth and convex, held dominance. No pods, endospores, or fluorescent pigments were produced by the Gram-positive, non-flagellated, nonmotile cells cultured on King's B medium (Solarbio). The amplified 16S rRNA gene (1351 base pairs; OP740790) from five colonies, employing universal primers 27f/1492r (Liu et al., 2022), exhibited a 99.26% sequence identity to Arthrobacter (Ar.) woluwensis. Using the method of Liu et al. (2018), amplification of the partial sequences for the ATP synthase subunit beta (atpD) gene (677 bp; OQ262957), RNA polymerase subunit beta (rpoB) gene (848 bp; OQ262958), preprotein translocase subunit SecY (secY) gene (859 bp; OQ262959), and elongation factor Tu (tuf) gene (831 bp; OQ262960) from colonies exhibited a similarity greater than 99% to Ar. woluwensis. Using bacterial micro-biochemical reaction tubes (Hangzhou Microbial Reagent Co., LTD), the biochemical characteristics of three isolates (n=3) were examined, exhibiting the same traits as seen in the Ar strain. Esculin hydrolysis, urea, gelatinase, catalase, sorbitol, gluconate, salicin, and arginine tests are all positive for the Woluwensis species. The tests for citrate, nitrate reduction, and rhamnose were all negative, as reported by Funke et al. (1996). The isolates were ascertained to be Ar. The scientific categorization of woluwensis rests upon a comprehensive approach that includes morphological observations, biochemical analyses, and phylogenetic reconstruction. Bacterial suspensions, at a density of 1 x 10^9 CFU/ml, were grown in LB Broth at 28°C with 160 rpm agitation for 36 hours prior to pathogenicity testing. The cap and tissue of young A. bisporus were treated with a 30-liter volume of bacterial suspension.