Most ReadTo screen microbial resources for the control of tomato late blight caused by pathogen Phytophthora infestans, strains with strong antagonistic activity were isolated from soil using the plate confrontation method. Their taxonomic status was determined using integrating morphological, physiological, and biochemical characteristics, combined with the 16S rDNA gene sequence analysis. The antifungal activity, action mechanisms, and control effect of the antagonistic strains were investigated via the mycelial growth inhibition method, spore germination assay, and pot experiment. The results showed that a total of 11 strains exhibited antagonistic activities against P. infestans. Among these antagonistic strains, strain C-21 exhibited the highest mycelial growth inhibition rate of 84.41%, and it was identified as Streptomyces flavogriseus. This strain could produce extracellular enzymes including cellulase, protease and amylase. Its fermentation broth could disrupt the mycelial morphology and cell membrane integrity of P. infestans, and significantly inhibited spore germination and zoospore release, with inhibition rates of 69.31% and 57.94%, respectively. The preventive and curative control effects of strain C-21 against tomato late blight were 43.57% and 59.28%, respectively. These findings indicated that strain C-21 had an excellent control effect on tomato late blight, and exhibited promising biocontrol potential for further development and application.
Blueberries (Vaccinium spp.) are widely cultivated worldwide for their high economic and nutritional value. However, fungal diseases constitute a major biotic constraint limiting the development of the blueberry industry. To date, more than 20 fungal diseases have been reported on blueberry, causing substantial economic losses. This review systematically summarizes the pathogen species, geographic distribution, typical symptoms, and damage severity of major fungal diseases affecting blueberry production. The principal diseases discussed include stem blight, canker, root rot, leaf spot, anthracnose, powdery mildew, gray mould, and fruit rot. Previous studies have shown that severe outbreaks of these diseases may result in yield losses ranging from 20% to 85%. Pathogenic fungi associated with blueberry exhibit high diversity, encompassing over 150 species from more than 20 genera, including Diaporthe, Fusarium, Neofusicoccum, Pestalotiopsis, Phytophthora, Colletotrichum, and Alternaria. In addition, the main transmission routes of these pathogens are summarized. Based on current knowledge, integrated disease management strategies are proposed, including cultural practices, chemical control, and biological control. Furthermore, the current shortcomings in research on blueberry fungal diseases are clarified, particularly in aspects of etiology, disease epidemiology, and resistance breeding. Future work should focus on strengthening studies on pathogen biology, epidemic dynamics, breeding of high-yield, high-quality, and disease-resistant cultivars, and promoting green control technologies centered on agricultural and biological measures. Overall, this review provides both strong theoretical support and targeted practical guidance for the healthy development of the blueberry industry in China.
To identify the pathogens causing grapevine root rot in Ningxia Hui Autonomous Region (hereinafter referred to as Ningxia) and to explore indigenous antagonistic microorganisms for developing biocontrol agents, grapevine samples with root rot symptoms were collected from representative winery vineyards in five cities and counties of Ningxia. The pathogens were identified through isolation, identification and pathogenicity tests. Using the more virulent pathogens as indicator strains and the wine grape cultivar Cabernet Sauvignon as the experimental material, the biocontrol efficacy of bacteria isolated from the rhizosphere soil of healthy grapevines was evaluated through plate confrontation assays, mycelial growth inhibition tests and pot experiments. The results showed that the pathogens causing grapevine root rot in Ningxia were Fusarium acuminatum, Fusarium solani, Rhizoctonia solani, Neofusicoccum parvum and Lasiodiplodia theobromae, among which R. solani, N. parvum and L. theobromae are new records as pathogens of grapevine root rot. Fusarium acuminatum, R. solani, N. parvum and L. theobromae exhibited stronger pathogenicity. A total of 62 bacterial and actinomycete strains with distinct colony morphologies were isolated from the rhizosphere soil of healthy grapevines, and four strains exhibiting over 60% inhibitory activity against all four highly pathogenic fungi were selected, namely Bacillus velezensis, Streptomyces alfalfae, Amycolatopsis orientalis and Streptomyces griseus. Among these, the 10.0% sterile culture filtrate of B. velezensis exhibited the strongest inhibitory effect against the four pathogens tested, with inhibition rates ranging from 80.56% to 84.65%, and its volatile compounds exhibited the strongest inhibitory effect against L. theobromae, with an inhibition rate of 73.67%. The three antagonistic actinomycetes showed differential inhibitory effects against different pathogens. Inoculation with the four antagonistic strains via wounded root irrigation inhibited grapevine root rot to varying degrees and promoted an increase in root branch number, indicating that these four antagonistic strains exhibit significant growth-promoting and disease-suppressing effects and possess potential for development as biocontrol agents against grape root rot.
To identify effective fungicides for the control of gray mold in quinoa Chenopodium quinoa, the inhibitory effects and in vitro toxicity of 12 fungicides against pathogen Botrytis cinerea were determined. Two fungicides with different modes of action were selected for combination, and the optimal volume ratio and formulation of the combined fungicides were determined. The efficacy of the combined fungicides against gray mold in quinoa was comprehensively evaluated through in vitro leaf tests, in vitro pot experiments and field trials. The results showed that pydiflumetofen, azoxystrobin, tebuconazole and pyraclostrobin had significant in vitro toxicity against B.cinerea, with EC50 values of 0.49, 0.39, 0.09 and 0.03 μg/mL, respectively. When the volume ratio of pydiflumetofen to tebuconazole was 4∶6 and 5∶5, it showed a synergistic effect, with toxicity ratios of 1.49 and 1.37, respectively. When the mass ratio of pydiflumetofen and tebuconazole was 9∶2, the synergistic effect was optimal, and the synergistic coefficient was 2.85. After treatment with high and medium concentrations of the combined fungicides, the protective and treatment effect on in vitro leaves were 94.97%-97.18%, and the protective and treatment effect of indoor pot experiments were 71.45%-82.01%. The field control effects of the high and medium concentrations of the compound fungicides were 87.77% and 79.91%, respectively, which were higher than other treatments, and could significantly increase the yield of quinoa. It was indicated that the field recommended concentration of 200 g/L pydiflumetofen suspension concentrate (SC) and 430 g/L tebuconazole SC at a mass ratio of 9∶2 (200 μg/mL pydiflumetofen + 44.4 μg/mL tebuconazole and 160 μg/mL pydiflumetofen + 35.6 μg/mL tebuconazole) could not only effectively control gray mold in quinoa, but also significantly increase quinoa yield.
To clarify the sensitivity of different physiological races of Puccinia triticina (Pt) in Hebei Province to triadimefon, samples of wheat infected with Pt were collected from nine regions in Hebei Province from 2023 to 2024. Single-spore isolation was employed to isolate Pt strains, test hosts were used to identify the physiological races, and the spore germination inhibition method was adopted to determine the sensitivity of physiological races to triadimefon. The resistance differences of physiological races to triadimefon across different regions in Hebei Province were compared, their sensitivity to this fungicide was monitored, and the cross-resistance of different triazole fungicides was investigated, followed by field validation. The results showed that a total of 193 Pt strains were isolated, and 12 physiological races were identified, with THTT and PHTT being the prevalent races. The EC50 of triadimefon against the tested strains ranged from 5.09 to 51.04 μg/mL, and the sensitivity baseline was established as 8.07 μg/mL. Sensitive strains accounted for 97.41% of the total, with only five resistant strains detected, primarily from Handan City and Shijiazhuang City, which should be designated as key areas for fungicide resistance monitoring. No significant cross-resistance was observed between triadimefon and other fungicides sharing the same mechanism of action, including tebuconazole and hexaconazole. Field efficacy trials were conducted to test six commonly used fungicides, demonstrating that 25% pyraclostrobin suspension concentrate exhibited the best control effect with a long duration, making it the preferred fungicide for control. In contrast, 44% triadimefon suspension concentrate exhibited the poorest control efficacy and is recommended for cautious use.
To identify the pathogen causing a natural epizootic of white muscardine in Tricentrus sp. in a tea plantation and to evaluate its potential for controlling tea green leafhopper Empoasca onukii, cadaver samples collected from the tea plantation were subjected to isolation, purification, and culture. The taxonomic status of the pathogen was determined based on morphological characteristics and phylogenetic analysis using combined sequences of Bloc, RPB1, RPB2, and TEF genes. Population genetic diversity of isolates from different hosts was analyzed using 12 SSR primer pairs. Six strains derived from hosts in Membracidea and Cicadellidae were selected to evaluate their virulence against the 3rd instar nymphs of E. onukii. The results showed that the pathogen causing the natural epizootic of white muscardine in Tricentrus sp. in the tea plantation was B. bassiana. The B. bassiana populations exhibited a high level of genetic diversity, with 100.00% polymorphic loci, a Shannon’s information index of 0.73, and a Nei’s gene diversity index of 0.39. Among the four B. bassiana populations from different hosts, the genetic differentiation coefficient was 0.38 and the gene flow was 0.54, indicating limited genetic exchange among populations. A total of 89 isolates were divided into 31 genotypes and clustered into three groups at a similarity coefficient of 0.68, with group III accounting for 76.40% of the isolates and representing the dominant group. Strain JCPX121 exhibited the highest virulence. After treatment with a conidial suspension at a concentration of 1.0×108 conidia/mL for eight days, the corrected mortality rate of 3rd instar nymphs of E. onukii reached 80.66% and the median lethal time (LT50) was 5.90 d. In summary, strain JCPX121 has the potential to be developed as a biocontrol agent.
To investigate the population structure and phylogenetic relationships among different geographic populations of Asiatic rice borer Chilo suppressalis in Ningbo City, China,whole-genome resequencing was performed on 37 individuals from eight populations (six from Ningbo, one from Beijing, and one from Hangzhou). Genomic variations were identified, and population genetic analyses including population structure, selective sweeps, genetic diversity, and historical effective population size were conducted. The results showed that a total of 42 149 215 single nucleotide polymorphisms and 11 912 812 insertions/deletions were identified across the 37 genomes, with most variations located in intergenic and intronic regions. Among the six Ningbo populations, Yinzhou, Yuyao and Haishu populations were closely related, whereas the Xiangshan population showed the greatest genetic distance from the other Ningbo populations and exhibited moderate genetic differentiation. Genes within the selective sweep regions of the Xiangshan population was significantly enriched in seven signaling pathways, including melanogenesis and circadian entrainment. Among the Ningbo populations, nucleotide diversity was relatively higher in the Haishu and Yinzhou populations, but lower in the Xiangshan and Fenghua populations. The Ningbo populations experienced a rapid contraction approximately 3 000—1 000 years ago, followed by a rapid population expansion.
To systematically investigate the differences in predation capacity and control efficiency of predatory ladybirds against aphids under different conditions, laboratory experiments were conducted to evaluate predation at different aphid densities, environmental temperatures, and predator density gradients. The data were fitted with Holling’s disc equation and models of interference and competition. The results showed that the functional responses of Harmonia axyridis to Aphis gossypii, Aphis glycines, Aphis sophoricola, and Chaitophorus populeti all conformed to Holling type II functional response. Among the tested aphid species, H. axyridis exhibited the strongest predation capacity and control efficiency against C. populeti, with a theoretical maximum daily predation of 500.00 individuals, whereas its control efficiency against A. sophoricola was the weakest, with a theoretical maximum daily predation of only 90.91 individuals. The predation capacity of H. axyridis against A. glycines increased with temperature within the range of 21-33 ℃ and reached a maximum at 33 ℃, after which it declined at higher temperatures. Moreover, the fourth-instar larvae of H. axyridis exhibited higher control efficiency against A. glycines than adult females. Increasing predator density intensified intraspecific competition in H. axyridis populations; although total predation increased, the mean predation per individual decreased significantly with increasing predator density, indicating that predation efficiency was constrained by density-dependent interference. Compared with H. axyridis, Adonia variegata showed stronger predation capacity against A. sophoricola. With increasing aphid density, the searching efficiency of both species declined. These results indicate that predatory ladybirds have strong predation potential against aphids, and their functional responses and predation efficiencies are influenced by aphid species, temperature, and the intensity of intraspecific competition, with notable differences among ladybird species.
To elucidate the control effect of the rice metabolite betaine on rice blast and its resistance-inducing mechanism, exogenous betaine sprays at different concentrations and time points were applied to assess the resistance of rice cultivars against rice blast. The optimal concentration and timing for exogenous betaine application were screened. Furthermore, transcriptome sequencing was performed on rice treated with betaine under the optimal application conditions to analyze its resistance induction mechanism. The results showed that exogenous application of betaine effectively reduced the severity of rice blast in the susceptible rice varieties Huangkenuo and Lijiangxintuanheigu. The optimal relative control effect (40.06%) was achieved with a pretreatment of 20 mmol/L betaine applied 24 hours before inoculation with Magnaporthe oryzae. Transcriptome analysis of rice leaves pretreated with betaine indicated that differentially expressed genes were significantly enriched in the phenylpropanoid biosynthesis pathway at 0, 24, and 48 hours. This treatment also induced the expression of lignin synthesis-related genes, including OsCCR17, OsCCR14, OsPAL3, OsCOMT15, OsCAD2, and the peroxidase gene OsPOX1. Additionally, lignin content and the activities of peroxidase and superoxide dismutase were significantly increased. These findings suggest that betaine induces the expression of genes involved in lignin synthesis and antioxidant enzymes, promotes lignin accumulation, and enhances antioxidant enzyme activity, thereby improving systemic resistance in rice against rice blast.
To clarify the detoxification metabolism and environmental adaptation mechanisms of Puccinia striiformis f. sp. tritici (Pst) physiological race CYR34, members of the glutathione S-transferase (GST) gene family were identified based on the their nucleotide sequence and GFF3 annotation files of CYR34. Bioinformatics analyses were conducted on the physicochemical properties of the encoded proteins, chromosomal localization, phylogenetic relationships, and cis-acting elements in the promoter regions. In addition, the temporal expression patterns of GST family genes during urediniospore germination and host infection were analyzed by quantitative real-time PCR. The results showed that six GST genes (GST1-GST6) were identified in CYR34. The encoded proteins ranged from 187 to 207 amino acids in length, all containing conserved GST domains and being distributed on three chromosomes. A total of 26 types of cis-acting elements were detected in the promoter regions. During urediniospore germination, GST1, GST3, GST4, GST5, and GST6 all reached relatively high expression levels at 24 hours post inoculation (hpi), among which GST5 showed the greatest up-regulation, reaching 9.04-fold that of the control group. During wheat infection by CYR34, GST4 and GST6 generally exhibited an upward expression trend, with GST4 reaching its highest expression level at 48 hpi, 3.14-fold that of the control group. These results indicate that the GST genes in CYR34 may participate in the regulation of environmental adaptation and detoxification metabolism during urediniospore germination and infection.