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%. The microconidia of the strain, grown on wheat bran medium for 10 days, were purified by washing with sterile deionized water, then filtered through three sterile layers of cheesecloth. The concentration was quantified, and adjusted to 1 million microconidia per milliliter using 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). In a controlled environment, provided by an artificial climate box, inoculated plants were cultured under a 16-hour photoperiod, with temperatures maintained at 24 degrees Celsius and a 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. Re-isolation of the same E. nigum strain from inoculated plants was confirmed using the previously described morphological and molecular identification techniques. We believe this is the initial instance of smooth bromegrass leaf spot disease induced by E. nigrum, found within the borders of China, and on a worldwide scale. Smooth bromegrass's agricultural output and quality might be affected by infection with this pathogen. Hence, the creation and execution of plans for managing and controlling this disease is crucial.
In apple-growing areas around the world, the fungus *Podosphaera leucotricha* is endemic, acting as the causal agent of apple powdery mildew. Conventional orchards, lacking durable host resistance, depend on single-site fungicides for the most efficient disease management. Climate change's impact on New York State, particularly in terms of increasingly unpredictable precipitation and warming temperatures, may create a region with improved conditions for apple powdery mildew proliferation. This presented case study could lead to apple powdery mildew outbreaks becoming the dominant disease management concern, surpassing the current focus on 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. A crucial step was to evaluate the fungicide resistance level within P. leucotricha populations to ensure the effectiveness of key classes of single-site fungicides, including FRAC 3 (demethylation inhibitors, DMI), FRAC 11 (quinone outside inhibitors, QoI), and FRAC 7 (succinate dehydrogenase inhibitors, SDHI). A two-year study (2021-2022) yielded 160 specimens of P. leucotricha, originating from 43 orchards spanning New York's major production areas, categorized as conventional, organic, low-input, and unmanaged. https://www.selleckchem.com/products/3-3-cgamp.html 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. Genomics Tools The analysis of all samples demonstrated no nucleotide sequence mutations within the target genes that resulted in problematic amino acid substitutions. Consequently, New York P. leucotricha populations remain susceptible to DMI, QoI, and SDHI fungicides, contingent upon no other resistance mechanisms being operational.
American ginseng's yield is directly correlated with the use of seeds. Long-distance dissemination of pathogens, and their survival, heavily rely on seeds as a critical medium. To effectively manage seed-borne diseases, the pathogens carried by the seeds must be understood. This study employed incubation and high-throughput sequencing to examine the fungal communities associated with American ginseng seeds sourced from key Chinese production regions. Immune enhancement Seed-borne fungi were observed at a rate of 100%, 938%, 752%, and 457% in Liuba, Fusong, Rongcheng, and Wendeng, respectively. Sixty-seven fungal species, stemming from twenty-eight genera, were isolated from the seeds. Seed samples yielded the identification of eleven distinct pathogens. The Fusarium spp. pathogens were ubiquitous in the seed samples tested. The concentration of Fusarium species was greater within the kernel than within the shell. A comparison of seed shell and kernel fungal diversity, using the alpha index, revealed significant variation. The results of the non-metric multidimensional scaling analysis clearly distinguished samples from various provinces, along with a marked separation between the samples of seed shells and seed kernels. 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. Seed-borne fungi associated with American ginseng were shown to be only slightly inhibited by fludioxonil, a traditional seed treatment agent.
A more prevalent aspect of global agricultural trade is the acceleration of newly emerging and recurring plant pathogens. The fungal pathogen Colletotrichum liriopes, a foreign quarantine concern for ornamental plants, particularly Liriope spp., continues to be a problem in the United States. Even though reports of this species exist on various asparagaceous hosts in East Asia, its only documented occurrence in the USA was in 2018. That study, however, solely depended on ITS nrDNA for identification, and no cultured or vouchered specimens were retained. The present study's central objective was to identify the geographic and host range of samples classified as C. liriopes. 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. Employing multilocus phylogenetic analyses (ITS, Tub2, GAPDH, CHS-1, HIS3), phylogenomic insights, and splits tree constructions, the studied isolates/sequences displayed a well-supported clade with insignificant intraspecific variation. Morphological analyses provide confirmation of these results. Multilocus and genomic data, along with a Minimum Spanning Network analysis, reveal a recent spread of East Asian genotypes, showing low nucleotide diversity and negative Tajima's D, from countries of ornamental plant production (e.g. South America), eventually reaching import destinations such as the USA. The study's detailed analysis reveals a substantial broadening of the geographic and host spectrum of C. liriopes sensu stricto, now extending to the USA (with confirmed presence in Maryland, Mississippi, and Tennessee) and encompassing a variety of hosts beyond those within the Asparagaceae and Orchidaceae families. 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. A mushroom cultivation base in Guangxi, China, experienced a 2% incidence of brown blotch disease on the cap of A. bisporus, detected in December 2021. 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. Within forty-eight hours, the infection had spread to the interior tissues of the fruiting bodies, marked by the emergence of dark brown discoloration. The isolation of causative agents required processing 555 mm internal tissue samples from infected stipes. These were first sterilized in 75% ethanol for 30 seconds and then thoroughly rinsed three times using sterile deionized water (SDW). After this, the samples were homogenized in sterile 2 mL Eppendorf tubes, and 1000 µL of SDW was added. Finally, the suspension was serially diluted to achieve seven concentrations (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. The single, dominant colonies were smooth, convex, and a whitish-grayish hue. Gram-positive, non-flagellated, nonmotile cells displayed no formation of pods or endospores, and no fluorescent pigments were produced on King's B medium (Solarbio). The 16S rRNA sequence (1351 bp; OP740790), amplified from five colonies using universal primers 27f/1492r (Liu et al., 2022), demonstrated a 99.26% sequence identity with 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. Three isolates (n=3) underwent biochemical testing, using bacterial micro-biochemical reaction tubes provided by Hangzhou Microbial Reagent Co., LTD, resulting in the same biochemical characteristics observed in the Ar strain. Woluwensis bacteria display positive results in tests for esculin hydrolysis, urea decomposition, gelatin hydrolysis, catalase reaction, sorbitol fermentation, gluconate breakdown, salicin fermentation, and arginine metabolism. According to Funke et al. (1996), the organism exhibited no citrate production, nitrate reduction, or rhamnose fermentation. The isolates, upon identification, proved to be Ar. Phylogenetic analyses, coupled with morphological characteristics and biochemical tests, definitively establish the identity of woluwensis. Pathogenicity assessments were conducted on bacterial suspensions, grown in LB Broth at 28°C with 160 rpm agitation for 36 hours, at a concentration of 1 x 10^9 CFU/ml. A 30-liter bacterial suspension was applied to the caps and tissues of the young A. bisporus mushrooms.