Smooth bromegrass seeds, pre-soaked in water for four days, were then planted in six pots (10 cm in diameter, 15 cm in height). These pots were housed within a greenhouse, where a 16-hour photoperiod, a temperature range of 20-25 degrees Celsius, and a 60% relative humidity were maintained. Microconidia produced on wheat bran medium after ten days, from the strain, were washed with sterile deionized water, filtered through three layers of sterile cheesecloth, quantified, and adjusted to a concentration of 1 x 10^6 microconidia per milliliter using a hemocytometer. At a height of approximately 20 centimeters, three pots of plants were sprayed with a spore suspension, 10 milliliters per pot, while the remaining three pots served as control groups, being treated with sterile water (LeBoldus and Jared 2010). Under a 16-hour photoperiod, and within an artificial climate box, inoculated plants were grown, keeping a consistent temperature of 24 degrees Celsius and a 60 percent relative humidity. The leaves of the treated plants showed brown discoloration after five days, in contrast to the healthy leaves of the untreated controls. Re-isolates from the inoculated plants were identified as the same E. nigum strain, employing the aforementioned morphological and molecular techniques. Based on our current knowledge, this is the pioneering report of smooth bromegrass leaf spot disease caused by E. nigrum, observed not only in China, but globally. Exposure to this pathogen could potentially reduce the profitability and quality of smooth bromegrass harvests. Accordingly, strategies for the oversight and command of this malady should be designed and deployed.
Regions worldwide where apples are grown harbor the endemic pathogen *Podosphaera leucotricha*, the cause of apple powdery mildew. Single-site fungicides are the predominant method of managing the disease in conventional orchards, absent sustained host resistance. New York State's climate, increasingly characterized by inconsistent precipitation and higher temperatures due to climate change, could render the region more prone to the establishment and expansion 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. Consequently, assessing the fungicide resistance of P. leucotricha populations was necessary to guarantee the continued efficacy of crucial single-site fungicide classes (FRAC 3, demethylation inhibitors, DMI; FRAC 11, quinone outside inhibitors, QoI; FRAC 7, succinate dehydrogenase inhibitors, SDHI). Across 2021 and 2022, we collected 160 samples of P. leucotricha from a diverse group of 43 orchards. These New York orchards were categorized as conventional, organic, low-input, and unmanaged, representing the range of orchard management styles found in the major production regions. Whole Genome Sequencing Screening samples for mutations in the target genes (CYP51, cytb, and sdhB), historically recognized for conferring fungicide resistance in other fungal pathogens to the DMI, QoI, and SDHI fungicide classes respectively, was performed. Immune enhancement 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.
Seeds are a primary component in the manufacturing of American ginseng. The long-distance dissemination of pathogens and their survival is fundamentally linked to seeds. Pinpointing the pathogens associated with seeds is paramount to the effective management of seed-borne diseases. Using incubation and high-throughput sequencing techniques, this research investigated the fungal species present on the seeds of American ginseng cultivated in major Chinese production areas. Ozanimod Seed-borne fungi were observed at a rate of 100%, 938%, 752%, and 457% in Liuba, Fusong, Rongcheng, and Wendeng, respectively. Seeds yielded sixty-seven fungal species, representing twenty-eight genera. The seed samples were found to harbor eleven different pathogenic microorganisms. The Fusarium spp. pathogens were ubiquitous in the seed samples tested. The kernel's population of Fusarium species exceeded the shell's. According to the alpha index, fungal diversity varied considerably between the seed shell and kernel. Multidimensional scaling analysis, employing a non-metric approach, indicated a significant distinction between samples sourced from disparate provinces and those stemming from either the seed shell or the kernel. The effectiveness of four fungicides against seed-carried fungi in American ginseng varied significantly. Tebuconazole SC exhibited a 7183% inhibition rate, followed by Azoxystrobin SC (4667%), Fludioxonil WP (4608%), and Phenamacril SC (1111%). There was a noticeably low inhibitory outcome against the fungi residing on American ginseng seeds when using fludioxonil, a conventional seed treatment agent.
New plant pathogens, both old and new, have been accelerated by the intensification of global agricultural trade. In the U.S., the ornamental plant species Liriope spp. are still subject to quarantine regulations due to the fungal pathogen Colletotrichum liriopes. 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 investigation, however, employed only the ITS nrDNA gene for species determination, lacking any preserved cultures or specimens. A key aim of this current investigation was to pinpoint the geographical and host-species prevalence of C. liriopes specimens. In order to achieve this objective, a comparative analysis was conducted on newly acquired and previously documented isolates, genetic sequences, and complete genomes derived from a range of host species and geographical regions (including, but not limited to, China, Colombia, Mexico, and the United States), juxtaposed against the ex-type specimen of C. liriopes. Multilocus phylogenetic analyses (including ITS, Tub2, GAPDH, CHS-1, and HIS3), phylogenomic studies, and splits tree analyses underscored the formation of a robust clade by all the examined isolates/sequences, displaying a negligible degree of intraspecific variance. Examination of the morphology reinforces these conclusions. Recent introduction and spread of East Asian genotypes to countries where ornamental plants are produced, exemplified by the low nucleotide diversity, negative Tajima's D in multilocus and genomic datasets, and the Minimum Spanning Network, is suspected to have happened initially to South America, and subsequently into importing countries like the USA. The research concludes that the geographic and host distribution of C. liriopes sensu stricto has been expanded to incorporate the USA (particularly, Maryland, Mississippi, and Tennessee), encompassing numerous host types in addition to those already known within Asparagaceae and Orchidaceae. The current investigation generates essential knowledge applicable to mitigating economic losses and costs associated with agricultural trade, as well as enhancing our understanding of the propagation of pathogens.
Agaricus bisporus, an edible fungus, is among the most commonly cultivated varieties worldwide. The cap of A. bisporus, cultivated in a mushroom farming base in Guangxi, China, displayed brown blotch disease with a 2% incidence rate in December 2021. Early on, the cap of A. bisporus showcased the appearance of brown blotches, spanning in size from 1 to 13 centimeters, which subsequently grew and spread as the cap developed further. After forty-eight hours, the infection advanced into the inner tissues of the fruiting bodies, leaving behind noticeable 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. Luria Bertani (LB) medium was used to distribute each 120-liter suspension, which was then incubated for 24 hours at 28 degrees Celsius. Colonies of a whitish-grayish color, smooth and convex, held dominance. 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). Amplification of the 16S rRNA gene (1351 base pairs; OP740790) from five colonies, using the universal primers 27f/1492r (Liu et al., 2022), resulted in a 99.26% similarity to Arthrobacter (Ar.) woluwensis. 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. 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. 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. According to Funke et al. (1996), the organism exhibited no citrate production, nitrate reduction, or rhamnose fermentation. Subsequent examination of the isolates concluded they are Ar. Biochemical examinations, alongside morphological characterizations and phylogenetic studies, collectively support the identification of woluwensis. Pathogenicity tests were conducted on bacterial suspensions (1 x 10^9 colony-forming units per milliliter) cultivated in LB Broth at 28 degrees Celsius, with 160 revolutions per minute, for 36 hours. Immature Agaricus bisporus specimens had 30 liters of bacterial suspension added to their caps and tissues.