In October 2010, soybean (Glycine max) plants growing in commercial soybean fields in Zengcheng City, Guangdong Province developed symptoms consisting of stem and root rot, yellowing, and defoliation of leaves. Reddish, spherical fruiting bodies appeared in lesions that developed on stems. Plants with symptoms were sampled from fields. Fruiting bodies were excised from diseased tissues. Microscopic examination revealed that they were perithecia, globose to pyriform, and measured 197 to 260 μm in diameter and 226 to 358 μm long. When squeezed gently, cylindrical to clavate asci, 7.2 to 9.6 μm in diameter and 75.4 to 92.0 μm long, containing eight ascospores were exuded from the perithecia. Ascospores were ellipsoid to obovate, two celled, slightly constricted at the septum, had longitudinal striations, and measured 4.9 to 6.0 μm in diameter and 10.6 to 15.0 μm long. The fungus was isolated from the basal stem tissues of diseased soybean plants and cultured on potato dextrose agar (PDA) medium amended with streptomycin sulfate. On PDA, the culture developed into blue-pigmented colonies with whitish mycelium that produced oval to cylindrical microconidia. Microconidia had 0 to 1 septum, ranged from 2.5 to 5.2 × 7.6 to 29.4 μm, and were produced on monophialides. Macroconidia were cylindrical to falcate, thick walled, 2 to 5 septa, and 3.5 to 6.0 × 25.4 to 66.8 μm. Chlamydospores were present and ranged from 6.8 to 13.6 × 5.5 to 9.5 μm. Orange-to-reddish perithecia were readily formed in old culture. These morphological characteristics were consistent with descriptions of Nectria haematococca (anamorph Fusarium solani) (1). The rDNA internal transcribed spacer (ITS) region and the fragment of translation elongation factor 1-alpha (EF1-α) genes of the fungus were amplified, respectively, with universal primers ITS1/ITS4 and ef1/ef2 primers and sequenced. BLAST searches showed that the ITS sequences of three isolates (GenBank Accession Nos. JN015069, JN190942, and JN190943) had 99% similarity with those of N. haematococca(GenBank Accession Nos. DQ535186, DQ535185, and DQ535183) and the EF1-α sequences of three isolates (GenBank Accession Nos. JN874641, JN874642, and JN874643) had 100% similarity with those of F. solani (GenBank Accession Nos. DQ247265 and DQ247327). Completion of Koch's postulates confirmed the pathogenicity of the isolates in a replicated experiment. Thirty-day-old soybean seedlings of cultivar Huaxia No. 3 were inoculated by soaking their root systems in a conidial suspension (10 6 conidia per ml) for 30 min and then transplanted in plastic pots (20 cm in diameter) and incubated at 25 ± 2°C in a greenhouse. Control plants were treated with sterile water in the same way. There were four plants per pot and there were six replicates for each treatment. Within 3 weeks, more than 70% of the inoculated plants exhibited symptoms of leaf yellowing, stem rot, and root rots while control plants were symptomless. N. haematococca was reisolated from the diseased plants. To our knowledge, this is the first report of N. haematococca causing stem rot of soybean in China and the first description of sexual reproduction of F. solani causing soybean stem rot in nature. This pathogen may pose a serious threat to soybean production in China where soybean is a main crop. Reference: (1) C. Booth. The Genus Fusarium. CAB International, Wallingford, UK, 1971.
The two-spotted spider mite, Tetranychus urticae, is an important pest of horticultural crops worldwide and has developed resistance against multiple kinds of pesticides. To date, information on the resistance to pesticides is inadequate for T. urticae populations in Hainan, south China. In the current study, we determined the resistance to seven pesticides in five field populations of T. urticae that were collected on cucurbit crops in Hainan in 2021. The results showed that T. urticae populations developed high to extremely high resistance to abamectin and bifenthrin and medium to high resistance to pyridaben, profenofos, and cyflumetofen. However, four of the five populations were either susceptible to or had only low resistance to bifenazate and B-azolemiteacrylic. We also determined the frequencies of mutations previously associated with T. urticae resistance to abamectin, pyrethroids, organophosphates, bifenazate, or pyridaben; mutation frequencies as high as 100% were detected for some of the mutations in some of the populations. The results should facilitate the development of rational strategies for the chemical control of T. urticae populations in Hainan, China.
Biocontrol agents (BCAs) could be used for the control of postharvest decay of fruit. In this study, biocontrol bacteria were isolated from litchi soil, leaves and fruit tissues, and their efficacy on the control of postharvest litchi downy blight, caused by Peronophythora litchii, were determined. After evaluating the ability of 188 bacterial isolates to produce certain enzymes and metabolites, and their antagonistic activity in vitro against P. litchii, as well as preliminary identification of 82 representative isolates based on 16 S rDNA sequencing, five isolates including Bacillus amyloliquefaciens PP19 and LI24, Exiguobacterium acetylicum SI17, B. pumilus PI26, and B. licheniformis HS10 were selected for further assessments in several trials in 2016 and 2017. In comparison with control treatment, isolates PP19, SI17 and PI26 could delay the disease development of postharvest litchi downy blight. Furthermore, isolates PP19 and SI17 were able to colonize fruit pericarp without affecting fruit quality. Additionally, the colonization of PP19 changed the microbial community composition on litchi pericarp as demonstrated by pericarp microbiome sequencing. This is the first report of an E. acetylicum acted as a BCA against a phytopathogenic oomycete P. litchii. We conclude that PP19 and SI17 can be used as effective BCAs against postharvest litchi downy blight, especially applied during preharvest stage.
Abstract Leaf spot, caused by Neofusicoccum parvum , is an important disease limiting the growth of Chinese cinnamon ( Cinnamomum cassia ) in the field. This disease was first observed in Deqing (Guangdong Province, China) in 2018, manifesting as circular or irregularly shaped necrotic lesions along the leaf margins and tips, enlarging to irregular lesions with numerous black dots. Representative isolates were isolated from affected leaves and identified based on morphological characteristics and phylogenetic analyses of the internal transcribed spacer (ITS) region, the translation elongation factor 1‐α ( EF1‐α ) gene and a portion of the β‐tubulin gene ( TUB2 ). Colonies were initially white on PDA, turning grey–black after 7 days. The conidia were fusiform to oval, hyaline, thin‐walled with rounded apices and truncate bases. The pathogen was placed in the same clade as Neofusicoccum parvum in phylogenetic trees constructed using concatenated sequences of ITS, EF1‐α and TUB2 genes. Based on morphological and phylogenetic data, the pathogen was identified as N . parvum . On infected leaves, Koch's postulates were fulfilled, and the same pathogen re‐isolated. To our knowledge, this is the first report of N. parvum causing disease on Chinese cinnamon worldwide.
Abstract Background: Organic mulching is an important management practice in agricultural production to improve soil quality, control crop pests and diseases and increase the biodiversity of soil microecosystem. However, the information about soil microbial diversity and composition in litchi plantation response to organic mulching and its attribution to litchi downy blight severity was limited. This study aimed to investigate the effect of organic mulching on litchi downy blight, and evaluate the biodiversity and antimicrobial potential of soil microbial community of litchi plantation soils under organic mulching. Results: Organic mulching could decrease the disease incidence in the litchi plantation. As a result of high-throughput 16S rRNA and ITS rDNA gene illumine sequencing, higher bacterial and fungal community diversity indexes were found in organic mulching soils, the relative abundance of norank f norank o Vicinamibacterales, norank f Vicinamibacteraceae, norank f Xanthobacteraceae, Unclassified c sordariomycetes, Aspergillus and Thermomyces were significant more than that in control soils. Isolation and analysis of antagonistic microorganism showed that 29 antagonistic bacteria strains and 37 antagonistic fungi strains were unique for mulching soils. Conclusions: Thus, we believe that organic mulching has a positive regulatory effect on the litchi downy blight and the soil microbial communities, and so, is more suitable for litchi plantation.
Abstract Organic mulching is an important management practice in agricultural production to improve soil quality, control crop pests and diseases and increase the biodiversity of soil microecosystem. However, the information about soil microbial diversity and composition in litchi plantation response to organic mulching and its attribution to litchi downy blight severity was limited. This study aimed to investigate the effect of organic mulching on litchi downy blight, and evaluate the biodiversity and antimicrobial potential of soil microbial community of litchi plantation soils under organic mulching. Our results showed that organic mulching could decrease the disease incidence in the litchi plantation. As a result of high-throughput 16S rRNA and ITS rDNA gene illumine sequencing, higher bacterial and fungal community diversity indexes were found in organic mulching soils, the relative abundance of norank f norank o Vicinamibacterales, norank f Vicinamibacteraceae, norank f Xanthobacteraceae, Unclassified c sordariomycetes, Aspergillus and Thermomyces were significant more than that in control soils. Isolation and analysis of antagonistic microorganism showed that 29 antagonistic bacteria strains and 37 antagonistic fungi strains were unique for mulching soils. Thus, we believe that organic mulching has a positive regulatory effect on the litchi downy blight and the soil microbial communities, and so, is more suitable for litchi plantation.
Abstract This study investigates the role of USP47, a deubiquitinating enzyme, in the tumor microenvironment and its impact on antitumor immune responses. Analysis of TCGA database revealed distinct expression patterns of USP47 in various tumor tissues and normal tissues. Prostate adenocarcinoma showed significant downregulation of USP47 compared to normal tissue. Correlation analysis demonstrated a positive association between USP47 expression levels and infiltrating CD8 + T cells, neutrophils, and macrophages, while showing a negative correlation with NKT cells. Furthermore, using Usp47 knockout mice, we observed a slower tumor growth rate and reduced tumor burden. The absence of USP47 led to increased infiltration of immune cells, including neutrophils, macrophages, NK cells, NKT cells, and T cells. Additionally, USP47 deficiency resulted in enhanced activation of cytotoxic T lymphocytes (CTLs) and altered T cell subsets within the tumor microenvironment. These findings suggest that USP47 plays a critical role in modulating the tumor microenvironment and promoting antitumor immune responses, highlighting its potential as a therapeutic target in prostate cancer.
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