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, cultivated on wheat bran medium for 10 days by the strain, were washed in sterile deionized water, filtered with three sterile cheesecloth layers, quantified, and their concentration adjusted to 1,000,000 microconidia/mL by 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). In an artificial climate box, inoculated plants experienced a 16-hour photoperiod, regulated at 24 degrees Celsius and 60 percent relative humidity, while undergoing cultivation. 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. 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. The infestation of this pathogen might decrease the yield and caliber of smooth bromegrass production. Hence, the creation and execution of plans for managing and controlling this disease is crucial.
*Podosphaera leucotricha*, the apple powdery mildew disease agent, is a pathogen that is endemic across the globe where apples are produced. Conventional orchards, lacking durable host resistance, depend on single-site fungicides for the most efficient disease management. New York State's climate, becoming progressively more erratic in its precipitation and hotter due to climate change, might be ideal for the growth and dispersion of apple powdery mildew. Under these conditions, the threat posed by apple powdery mildew could overshadow the current focus on diseases like 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. To confirm the effectiveness of key fungicide categories—FRAC 3 (demethylation inhibitors, DMI), FRAC 11 (quinone outside inhibitors, QoI), and FRAC 7 (succinate dehydrogenase inhibitors, SDHI)—a determination of P. leucotricha populations' fungicide resistance was required. 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. medical photography Samples were screened for mutations in the target genes (CYP51, cytb, and sdhB), with a historical association to conferring fungicide resistance in other fungal pathogens to DMI, QoI, and SDHI fungicide classes, respectively. Non-cross-linked biological mesh In all examined samples, no nucleotide sequence alterations leading to detrimental amino acid changes were identified within the target genes. This implies that New York populations of P. leucotricha are still susceptible to DMI, QoI, and SDHI fungicides, assuming no additional resistance mechanisms are active within the population.
American ginseng's yield is directly correlated with the use of seeds. Seeds are critical to the long-distance dissemination of pathogens and contribute to their survival. Effective management of seed-borne diseases hinges on pinpointing the pathogens present within the seeds. This study employed incubation and high-throughput sequencing to examine the fungal communities associated with American ginseng seeds sourced from key Chinese production regions. Selleckchem STX-478 Seed-borne fungi were observed at a rate of 100%, 938%, 752%, and 457% in Liuba, Fusong, Rongcheng, and Wendeng, respectively. From the seeds, sixty-seven fungal species, categorized within twenty-eight genera, were isolated. The seed samples were found to harbor eleven different pathogenic microorganisms. All seed samples contained the Fusarium spp. pathogens. The kernel demonstrated a superior abundance of Fusarium species relative to the shell. A comparison of seed shell and kernel fungal diversity, using the alpha index, revealed significant variation. A non-metric multidimensional scaling analysis demonstrated a clear separation between samples originating from various provinces and between seed shells and kernels. Tebuconazole SC exhibited a fungicide inhibition rate of 7183% against seed-borne fungi in American ginseng, while Azoxystrobin SC showed 4667%, Fludioxonil WP demonstrated 4608%, and Phenamacril SC displayed 1111%. The conventional seed treatment, fludioxonil, displayed a weak inhibitory action against the fungi colonizing American ginseng seeds.
An increase in global agricultural trade has been a contributing factor in the proliferation and re-occurrence of new plant diseases affecting plants. Collectotrichum liriopes, a fungal pathogen, remains a foreign quarantine threat to ornamental Liriope spp. 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. This investigation primarily sought to determine the spatial and host-related distribution of C. liriopes specimens. To accomplish this, genomes, isolates, and sequences from various hosts and geographic locations—China, Colombia, Mexico, and the United States, among others—were analyzed in relation to the ex-type of C. liriopes. 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. Morphological attributes provide compelling support for these results. 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. A comprehensive examination of the data reveals the geographic spread and host expansion of C. liriopes sensu stricto, now including parts of the USA (specifically, Maryland, Mississippi, and Tennessee) and diverse host species in addition to those belonging to 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.
Worldwide, Agaricus bisporus stands tall as one of the most commonly cultivated edible fungi. In December 2021, a mushroom cultivation base in Guangxi, China, witnessed brown blotch disease on the cap of A. bisporus, exhibiting a 2% incidence rate. The cap of A. bisporus initially displayed brown blotches (1-13 cm), which expanded with the ongoing growth of the cap itself. Two days later, the infection had reached the inner tissues of the fruiting bodies, manifesting as dark brown blotches. To isolate causative agents, infected stipe tissue samples (555 mm) were sterilized in 75% ethanol for 30 seconds, rinsed three times with sterile deionized water (SDW), and then mechanically disrupted within sterile 2 mL Eppendorf tubes. Subsequently, 1000 µL of SDW was added, and this suspension was serially diluted to achieve seven concentrations (10⁻¹ to 10⁻⁷). A 24-hour incubation period at 28 degrees Celsius was used for each 120-liter suspension spread on Luria Bertani (LB) medium. Colonies of a whitish-grayish color, smooth and convex, held dominance. The cells were Gram-positive, without flagella or motility, and did not produce pods, endospores, or fluorescent pigments on King's B medium (Solarbio). The 16S rRNA gene (1351 bp; OP740790) amplified from five colonies using primers 27f/1492r (Liu et al., 2022), displayed a 99.26% identity to the sequence of 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. A positive result was obtained for esculin hydrolysis, urea, gelatinase, catalase, sorbitol, gluconate, salicin, and arginine by Woluwensis. No citrate, nitrate reduction, or rhamnose utilization was observed (Funke et al., 1996). The isolates were ascertained 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. bisporus, in its juvenile stage, had a 30-liter bacterial suspension added to its caps and surrounding tissues.