Journal of Phytopathology最新文献

Tobacco black shank (TBS) and tobacco root black rot (TRBR) are two of the most devastating tobacco soil-borne diseases that threaten sustainable tobacco planting. This study investigated the effects of Trichoderma sp. and a resistance inducer (RI) extracted from traditional Chinese medicine, individually or in combination, on the control of TBS and TRBR. The results showed that the application of Trichoderma sp. and RI, individually or in combination, significantly controlled the two soil-borne diseases by significantly affecting the bacterial, but not fungal, Shannon and Simpson diversity indexes. The disease indexes of TBS and TRBR in integrated application management were the lowest, resulting in the highest potassium contents in the tobacco leaves. The control efficacies of TBS and TRBR in the integrated application treatment were 71.52 ± 1.43% and 68.33 ± 0.69%, respectively. The integrated treatment altered the composition of the rhizosphere soil microbial community. The bacterial community, but not the fungal community, of the control treatment was separated from those of other treatments. The relative abundance of bacteria involved in chemoheterotrophy and fermentation in the control treatment increased, whereas that of bacteria involved in nitrification and aerobic ammonia oxidation decreased compared with the other treatments. Importantly, the application of Trichoderma sp. and RI, individually or in combination, clearly increased the relative abundance of saprotrophic fungi in contrast to the control treatment, while decreasing that of pathotrophic fungi. Our study suggests that a suitable integrated application of bioagents and RI has synergistic effects on the suppression of two tobacco soil-borne diseases by altering the rhizosphere microbiome composition in the field.

There is a paucity of information on the relationship between anthers and Type II expression of Fusarium Head Blight resistance (measured by point inoculation of a spikelet and observing disease spread over the wheat spike). Twenty-nine UK commercial wheat varieties were evaluated for the expression of Type II resistance. Anther extrusion was measured by counting the number of spikelets with anthers trapped between the lemma and palea (anthers trapped). In five spikelets where trapped anthers were not observed, the number of spikelets with anthers contained within the spikelet was counted (anthers retained). There was variation in expression in the expression of Type II resistance (p < .001), anthers trapped (p < .001) and anthers retained (p < .001). Anthers trapped and anthers retained were not correlated with each other, indicating both should be considered independently. Later maturity correlated with great resistance in the AHDB Type I resistance ratings but to greater susceptibility to point inoculations (Type II). Consistent with previous literature higher numbers of anthers trapped to increase susceptibility to FHB Type I. However, the relationships were reversed for the expression of resistance measured by point inoculation within the spikelet, where anthers trapped between the lemma and palea reduced susceptibility to Type II point inoculation (p < .01). This suggests a benefit of releasing some pollen from within the spikelet for this inoculation method. Similarly, anthers retained contributed to increased Type II susceptibility (p < .05), potentially providing substrates within the spikelet inoculation site aiding fungal growth, but correlated to greater Type I resistance (p < .05) indicating the anthers are hidden from initial infection on the outside of the spikelet, particularly under low infection pressure. While preliminary, this work suggests that variation in anthers trapped, anthers retained and maturity date may increase Type II expression of resistance and could relate to increased Type I FHB susceptibility.

The effects of the seed gall nematode ‘Anguina tritici’ (Steinbuch, 1799) on the agronomic characteristics of some bread wheat cultivars were investigated at the Trakya Agricultural Research Institute, Türkiye. An experiment was carried out in two different locations in Edirne in the 2019–2020 growing season. A total of 19 winter bread wheat cultivars were evaluated to assess infected grain number, healthy grain number, infected grain rate and yield. According to the results of the combined variance analysis, a statistically significant difference (p ≤ .01) was found in terms of yield from the application of inoculum. Compared to the control in wheat cultivars, there was a 52.15% decrease in the yield of infected parcels due to the damage of wheat seed gall nematode. The highest yield loss in infected parcels occurred in cv. Damla with 64.22% loss, while the least yield loss occurred in cv. Yüksel cultivar with 19%. Pathological symptoms, curling and twisting of the leaves, were not observed on green plants of cv. Yüksel cultivated in the field.

Apple rot disease, caused by Alternaria alternata, is causing significant losses in apple production, especially in post-harvest periods. Alternaria alternata, was isolated from rotten apple fruit of cv Amasya. Identification of the strain isolated from rotten apple fruit was made by ITS sequence and morphological analysis. In the present study, 58 different endophytic bacteria strains were isolated from apple fruit for use in apple rot disease control. Among the isolated strains, 26 endophyte strains were determined to inhibit the radial growth of mycelia of A. alternata in binary culture in PDA media. Based on 16S rRNA sequencing analysis, these antagonistic endophytic bacteria strains were identified as Bacillus ssp. Bacillus methylotrophicus (ib17) showed the highest significant inhibitory effect on the mycelial growth of A. alternata at a rate of 79.5% in PDA medium. The results of in vivo experiments showed that Bacillus licheniformis (ib20) achieved 100% biocontrol when endophyte bacterial strains were inoculated 24 h before the inoculation of A. alternata. When the three bacteria species and A. alternata were inoculated simultaneously, Bacillus myloliquefaciens (ib1), Bacillus licheniformis (ib21) and the Endophytic bacterium (ib16) showed the highest biocontrol efficacy against A. alternata at 81.8%. Furthermore, when the bacterial strains were inoculated at 24 h after inoculation of A. alternata, B. licheniformis (ib21) showed the highest biocontrol efficacy of 83.3% against the fungal pathogen compared to the controls. The endophytic bacterial strains produced fungal cell wall hydrolysing enzymes such as chitinase, cellulase, amylase and protease. According to the results of this study, apple endophytic bacteria are potential candidates to control apple decay caused by A. alternata through cell wall hydrolysing enzymes and reduce disease severity. However, the efficacy of the biological control was dependent on the applied time of epiphytic bacterial strains. Further research is needed on the biochemical mechanisms underlying the activity of these bacteria against A. alternata.

Tomato (Solanum lycopersicum) is a crucial vegetable globally, pivotal in securing the world's food supply. However, viral diseases pose a significant threat to tomato cultivation, resulting in considerable yield losses. Employing sensitive, rapid, and cost-effective detection methods is imperative for mitigating such losses in agricultural production. In response, we developed a Taqman® probe-based real-time multiplex PCR method capable of concurrently detecting three major plant viruses: Tomato brown rugose fruit virus (ToBRFV), tomato spotted wilt orthotospovirus (TSWV), and pepino mosaic virus (PepMV), all of which are prominent viral pathogens affecting tomato production. Utilizing envelope protein encoding sequences of these pathogens, we designed primers and probes, assigning the FAM reporter for ToBRFV, the HEX reporter for TSWV, and the Cy5 reporter for PepMV detection. The multiplex RT-qPCR experiment yielded successful results, with Ct values of 29.34, 25.93, and 27.47 for ToBRFV (at 10⁻⁶ dilution), TSWV (at 10⁻² dilution), and PepMV (at 10⁻³ dilution), respectively. Developed primers facilitate the early detection of destructive pathogens ToBRFV, TSWV, and PepMV using both RT-PCR and RT-qPCR, offering a user-friendly and cost-effective approach.

Nectria dematiosa exhibiting orange red colour perithecia on stems and branches of young and old apple trees were reported under field conditions during 2020 and 2021. Reddish discoloration followed by papery appearance of stem and branches were the characteristic symptoms observed. Ascomata were non-papillate, surface irregular comprising numerous cylindrical to narrowly clavate asci. Ascospores were ellipsoidal to fusiform, straight or slightly curved, hyaline with 0 to 1-septa. Richard and Royal Delicious variety of apple were more susceptible with moderate to high severity of the European canker. Based on nucleotide homology and phylogenetic analysis, the pathogen was confirmed as N. dematiosa (accession no. OQ152022). To the best of our knowledge, this is the first report of N. dematiosa causing European canker of apple in India.

Macadamia cultivation plays significant role in the economy of South Africa. Despite its importance, the industry grapples with disease-related challenges, notably flower blight, which threatens substantial economic losses by affecting yield and nut quality. In 2022, diagnostic services at the Agricultural Research Council and the Forestry and Agricultural Biotechnology Institute received macadamia flowers displaying blight symptoms. Employing two methods for fungal isolation, 25 isolates were obtained which were classified into one group based on morphological characteristics. DNA analysis identified the isolates as Botrytis cinerea. The pathogenicity testing was conducted on macadamia flowers to confirm Koch's postulates. This is the first report of B. cinerea affecting Macadamia integrifolia Maiden & Betche in South Africa, underlining its potential threat to the industry.

Productivity in agriculture plays a major role in economic expansion. Because plant disease is a widespread occurrence, plant disease detection is an important problem in the world of agriculture. Plants do suffer a significant consequence if the required care is not taken at the beginning, which affects the amount, quality or productivity of the relevant products. Because it can detect disease symptoms at the earliest stage and reduces the labour required for large crop farm tracking, the automated plant disease detection system is more advantageous. In order to detect plant diseases, this paper proposes a novel, four-step methodology that consists of improved deep joint image segmentation, feature extraction (which includes LGXP, MBP, colour feature and hierarchy of skeleton feature extraction) and detection via hybrid DL classifier, specifically improved RNN with the transfer learning process and GoogleNet. By averaging the classifiers' results scores, the final detection result is calculated. In terms of several performance metrics, the suggested work's effectiveness is verified in comparison to the traditional models. In contrast to the SVM (79.5597), KNN (59.2767), LSTM (78.1446), GoogleNet (79.4025), CNN (77.6729), and CAE + CNN (80.1886), the F-measure of the IRNN-TL is 91.1949.

Türkiye is a prominent contributor to pear and diverse pome fruit production. Pear fruit with unusual brown to black spots and rot symptoms observed in public marketplaces in Mardin province have raised concerns regarding postharvest fruit health. The consistent isolation of a fungus from these fruits revealed morphological features indicative of Neoscytalidium dimidiatum. Phylogenetic confirmation of its identity ensued through BLASTn searches targeting, the internal transcribed spacer (ITS) of ribosomal DNA, the partial translation elongation factor 1-alpha gene (tef1), and the partial β-tubulin gene (tub2). Pathogenicity evaluations were conducted on common pome fruits, namely pears, apples, and quinces, unveiling the susceptibility of all examined fruits to postharvest infection by this emergent pathogen. Furthermore, an investigation was carried out to discern the pathogen's response to varying temperature ranges on pear fruits, revealing that the most pronounced lesions occurred at 30°C, followed by 25°C, 35°C, and 20°C. Conversely, no lesion development was observed at 10°C, 15°C, or 40°C. To the best of our knowledge, this study represents the first report of N. dimidiatum as the etiological agent responsible for postharvest rot in pear fruit. The implications of these findings highlight the potential threat posed by this pathogen to pome fruits postharvest, especially in regions where cold storage facilities are not widely utilized, warranting increased vigilance and preventive measures.

Stalk rot disease is becoming an important disease in sweet corn crops because it causes significant yield losses of the crop. In July 2022, typical symptoms of stem rot were observed in fields of Mae Hia Agricultural Research, Demonstration and Training Center in Chiang Mai province of Thailand. The symptoms exhibited by affected crop included circular water-soaked lesions, rot and necrotic tissue at the base of the stalk. Koch's postulates were fulfilled with reisolation of the inoculated strain from the inoculated tissues, and confirmation was obtained by phenotypic characters and 16S rRNA sequences. The isolated colony on nutrient agar was cream-coloured, circular, with a convex elevation, entire margin and smooth surface; the optical character was translucent and exuded a yellowish pigment that diffused in the nutrient agar, gram-negative, lacked arginine dihydrolase, occurrence of the oxidase and catalase reaction. The strains were able to utilize d-galactose and glucose but were unable to utilize d-maltose, d-cellobiose, d-fructose, d-mannose, mannitol, lactose and sucrose. The strains showed positive results for gelatine liquefaction test, citrate utilization and casein hydrolysis, but starch hydrolysis and indole production were negative result. These characteristics are the same as those described previously for Burkholderia gladioli. Disease severity in sweet corn was 43.8%, with infections showing spots with dark margins and soft rot on mature leaves and flag leaves. Disease severity in waxy corn and maize were 21.9% and 15.6%, respectively, showing a few light or dark brown spots at the infection sites. Therefore, this represents the first report of leaf stripe and stalk rot disease in sweet corn in Thailand.