The fungus, later confirmed as F. pseudograminearum via phenotypic and molecular methods, was re-isolated from the inoculated plant's basal stems. Oat crown rot in Tunisia has been reported to be connected to the presence of F. pseudograminearum, according to Chekali et al. (2019). According to our records, China's oat cultivation experiences the inaugural instance of F. pseudograminearum triggering crown rot. This study's findings provide a crucial foundation for pinpointing oat root rot pathogens and managing disease outbreaks effectively.
Significant strawberry yield losses are caused by the widespread presence of Fusarium wilt in California. Cultivars possessing the FW1 gene, resistant to Fusarium wilt, were shielded from the effects of all Fusarium oxysporum f. sp. strains. Fragariae (Fof) in California displayed the traits of race 1 (meaning they are non-harmful to FW1-resistant cultivars), corroborating findings reported in Henry et al. (2017), Pincot et al. (2018), and Henry et al. (2021). Severe wilt disease plagued an organic strawberry field, sown during the summer of 2022, within the bounds of Oxnard, California. Wilting leaves, along with distorted and intensely chlorotic leaflets and crown discoloration, were frequent indicators of Fusarium wilt. The field's planting featured Portola, a cultivar carrying the FW1 gene, providing resistance to Fof race 1 (Pincot et al., 2018; Henry et al., 2021). Two samples, comprising four plants per sample, were extracted from two different areas of the field. Each sample's crown extract was assessed for the presence of Fof, Macrophomina phaseolina, Verticillium dahliae, and Phytophthora species. Steele et al. (2022) employed recombinase polymerase amplification (RPA), a technique for. For 2 minutes, petioles were treated with a 1% sodium hypochlorite solution for surface sterilization, subsequently being plated on Komada's medium, thereby selecting for the presence of Fusarium species. According to Henry et al. (2021) and Komada (1975),. One RPA sample exhibited a positive response for M. phaseolina, whereas the remaining four samples showed no indication of any of the targeted pathogens. Both samples' petioles manifested a significant proliferation of fluffy, salmon-colored mycelia. The morphology of the colony and its non-septate, ellipsoidal microconidia (ranging in size from 60-13 µm by 28-40 µm) on monophialides displayed a resemblance to F. oxysporum. The single hyphal tip isolation technique was applied to fourteen cultures (P1-P14) to isolate and purify distinct genotypes. The Fof-specific qPCR (Burkhardt et al., 2019) failed to amplify any of the pure cultures, thus corroborating the negative RPA results. click here To amplify the translation elongation factor 1-alpha (EF1α) gene from three isolates, EF1/EF2 primers were utilized, as described by O'Donnell et al. (1998). Through BLAST analysis of sequenced amplicons (GenBank OQ183721), a 100% identical match was found to an isolate of Fusarium oxysporum f. sp. Melongenae is referenced in GenBank as FJ985297. As reported by Henry et al. (2021), at least one nucleotide was different in this sequence compared to all known strains of Fof race 1. Testing for pathogenicity on Fronteras (FW1) and Monterey (fw1), a cultivar vulnerable to race 1, included five isolates (P2, P3, P6, P12, and P13), in addition to a control isolate from Fof race 1, GL1315. Using a technique of dipping roots into either 5 × 10⁶ conidia per milliliter of 0.1% water agar, or sterile 0.1% water agar, five plants per isolate cultivar combination were inoculated and subsequently cultivated in the same manner detailed by Jenner and Henry (2022). Despite six weeks of growth, the control plants that remained uninoculated maintained their vitality, while plants of both inoculated cultivars, subjected to the five isolates, suffered from severe wilting. Identical colonies, mirroring the inoculated isolates in appearance, were produced from the petiole assays. Wilt symptoms were apparent in Monterey, following inoculation with race 1, but absent in the Fronteras group of plants. With P2, P3, P12, and P13, the experiment was carried out again on the San Andreas FW1 cultivar, and the anticipated results manifested once more. In our assessment, this report constitutes the pioneering account of F. oxysporum f. sp. California is home to the fragariae race 2. Sustained losses from Fusarium wilt are foreseen until commercially viable cultivars, demonstrating genetic resilience to this Fof race 2 strain, become widely deployed.
Commercially produced hazelnuts in Montenegro are a small but significantly expanding segment of the agricultural economy. Near Cetinje, in central Montenegro, a 0.3-hectare plantation of six-year-old Hall's Giant hazelnut plants (Corylus avellana) displayed a severe infection in June 2021. The infection affected more than eighty percent of the trees. A profusion of small, irregular, brown, necrotic spots, 2-3 mm in diameter, were apparent on the leaves. These lesions sometimes exhibited a weak chlorotic ring surrounding them. Due to the disease's worsening state, the lesions amalgamated and formed extensive areas of tissue death. Attached to the twigs, necrotic leaves withered and stayed. click here Brown, elongated lesions proliferated along the twigs and branches, ultimately causing the decline of these. Necrosis was evident in the unopened buds, as noted. The orchard's harvest, unfortunately, lacked any fruits. Yellow, convex, mucoid bacterial colonies were isolated from the diseased leaf, bud, and twig bark tissue using yeast extract dextrose CaCO3 medium, and 14 of these isolates were subsequently subcultured. In Pelargonium zonale leaves, the isolates induced hypersensitive responses, identifying them as Gram-negative, catalase-positive, oxidase-negative, and obligate aerobes. These isolates exhibited the ability to hydrolyze starch, gelatin, and esculin; however, they failed to reduce nitrate and did not grow at 37°C or in 5% NaCl. This biochemical profile mirrors that of the reference strain Xanthomonas arboricola pv. The NCPPB 3037 classification applies to the entity corylina (Xac). Employing primer pair XarbQ-F/XarbQ-R (Pothier et al., 2011), a 402 base pair product was amplified from all 14 isolates and the reference strain, unequivocally confirming their species classification as X. arboricola. Furthermore, the isolates underwent PCR analysis utilizing the primer pair XapY17-F/XapY17-R (Pagani 2004; Pothier et al., 2011), yielding a distinctive 943 bp band, confirming the presence of Xac. A set of primers, as described by Hajri et al. (2012), was utilized for the amplification and sequencing of the partial rpoD gene sequence from the two selected isolates, RKFB 1375 and RKFB 1370. DNA sequences obtained from isolates (GenBank Nos. ——) revealed the following genetic information. Comparing rpoD sequences, strains OQ271224 and OQ271225 show a substantial similarity (9947% to 9992%) to Xac strains CP0766191 and HG9923421, sourced from hazelnut crops in France, and HG9923411, originating from hazelnut in the United States. All isolates' pathogenicity was validated by spraying young shoots (20–30 cm in length, possessing 5–7 leaves) onto 2-year-old potted plants of the hazelnut cultivar. click here Using a handheld sprayer, three repetitions of applying a bacterial suspension (108 CFU/mL of sterile tap water) were performed on Hall's Giant. Employing sterile distilled water (SDW) as the negative control and the NCPPB 3037 Xac strain as the positive control was essential. To maintain high humidity, the inoculated shoots were kept under plastic sheeting in a greenhouse that was regulated to 22-26°C for a duration of 72 hours. On inoculated shoots, leaves displayed lesions ringed by a halo, a development observed 5 to 6 weeks after inoculation. Leaves treated with SDW remained symptomless. Using the primer set developed by Pothier et al. (2011), PCR analysis confirmed the identity of the re-isolated pathogen from the necrotic test plant tissue, thereby verifying the validity of Koch's postulates. Analysis of pathogenic, biochemical, and molecular properties revealed that isolates from hazelnut plants in Montenegro were identified as X. arboricola pv. Corylina, an alluring presence, occupied a special place in the scene. This report details the initial incident of Xac's effect on hazelnut production in this nation. Hazelnut production in Montenegro can suffer significant economic harm if the pathogen finds favorable environmental conditions. Thus, phytosanitary measures are indispensable for obstructing the entrance and dispersion of the pathogen to other regions.
The spider flower (Tarenaya (Cleome) hassleriana (Chodat) Iltis, Cleomaceae), a splendid ornamental landscape plant, plays a significant role in horticulture thanks to its lengthy flowering season (Parma et al. 2022). Powdery mildew afflicted spider flower plants situated within the Shenzhen public garden (2235N, 11356E) during the months of May 2020 and April 2021, manifesting as severe symptoms. Roughly 60% of the plant population exhibited infection, with irregular white spots marring the upper leaf surface of affected leaves, appearing on leaves ranging from young to mature stages. A notable finding in severe infections was the simultaneous occurrence of premature defoliation and drying of the infected leaves. Upon microscopic scrutiny of the mycelia, irregularly lobed hyphal appressoria were evident. With a length of 6565-9211 meters, thirty conidiophores were straight, unbranched, and composed of two to three cells. At the tips of conidiophores, individual conidia developed, cylindrical to oblong in shape, and sized between 3215 and 4260 µm by 1488 and 1843 µm (mean 3826 by 1689, n=50), and featuring no discernible fibrosin bodies. The search for chasmothecia produced no positive findings. The 28S rDNA and the internal transcribed spacer (ITS) region were amplified using the primer sets ITS1/ITS5 and NL1/NL4, respectively. The representative ITS and 28S rDNA sequences (GenBank accession numbers are provided). BLASTN analysis of MW879365 (ITS) and MW879435 (28S rDNA) sequences showed a complete 100% identity with Erysiphe cruciferarum sequences within GenBank, referenced by their respective accession numbers.