Lycium barbarum L. is an important economic crop in Qinghai province, China. However, root rot seriously reduces the economic results of L. barbarum. Here, we collected the diseased L. barbarum roots from Nuomuhong Farm of Haixi Mongolian and Tibetan Autonomous Prefecture, Qinghai Province, China, to clarify the diversity, pathogenicity, and biological characteristics of its root rot pathogens. A total of 125 isolates were collected, and based on morphological characteristics and rDNA ITS, TEF-1α, and RPB2 genes sequence analysis, they were identified as Fusarium equiseti, F. avenaceum, F. solani, F. citri, F. acuminatum, F. culmorum, F. sambucinum, F. incarnatum, F. oxysporum, F. tricinctum, Microdochium bolleyi, and Clonostachys rosea. These fungi were used to inoculate the roots of 1-year-old L. barbarum seedlings using scratching and root-irrigation inoculation methods, and all isolates caused root rot. This is the first report that M. bolleyi, F. avenaceum, and F. citri caused root rot in L. barbarum. And the best media, the lethal temperatures, and the optimum carbon sources and nitrogen sources of the 12 pathogen species were determined in this study. Moreover, our findings provide a theoretical foundation for root rot management in the future.

The source region of the Yellow River, as the main flow-producing area, contributes more than 35% of the total flow of the Yellow River. Here, we surveyed the spatial distribution of the bacterial and fungal communities in the 17 sedimental sites of Longyangxia Valley and Donggi Conag Lake within the source region of the Yellow River. The results revealed that bacterial richness and diversity were higher at the lower elevation of Longyangxia Valley (2588 m) than at higher elevation of Donggi Conag Lake (4096 m), while no obvious differences in fungal richness and diversity were observed. The abundance of the bacterial phylum Actinobacteriota increased in Donggi Conag Lake (30.8%) compared to Longyangxia Valley (15.9%) as the elevation increased. Meanwhile, the abundance of the fungal phylum Rozellomycota decreased (17.6-3.0%) as the elevation increased. The redundancy analysis suggested that the structures of the bacterial and fungal communities were influenced by environmental factors including elevation, organic matter content, hydrolyzed nitrogen, total phosphorus, total potassium, and pH. The results highlighted that rather than the fungal community, the bacterial community in sediments exhibited more significant spatial variation in lake wetlands driving by the influence of elevation and physicochemical variables.

Root rot in Lycium barbarum, an economically vital crop, is a critical barrier to its sustainable development in China. To elucidate the underlying micro-ecological mechanisms, this study aimed to characterize and compare the rhizosphere microbial communities of healthy and diseased plants from the Qaidam Basin. We employed PacBio full-length amplicon sequencing to analyze bacterial and fungal populations, complemented by network analysis and in vitro antagonistic assays. The results indicated that while microbial species richness was similar, the community structures of healthy and diseased soils were fundamentally different, suggesting that the disease is primarily driven by microbial dysbiosis rather than species loss. Healthy soil was enriched with beneficial Trichoderma, whereas diseased soil was dominated by the pathogen Fusarium, with an abundance 6.7 times higher than that in healthy soil. Network analysis revealed the healthy fungal community was significantly more stable (modularity index: 0.818) than the diseased network (0.4131), where Fusarium occupied a core hub position. Crucially, Trichoderma strains isolated from healthy soil exhibited strong antagonistic activity against Fusarium, with an average inhibition rate exceeding 75%. This study identifies Fusarium as the key pathogen of Goji root rot and native Trichoderma as a potent biocontrol agent, providing a scientific basis for a sustainable, micro-ecological control strategy.

Astragalus membranaceus var. mongholicus (Mongolian milkvetch) is one of the most important traditional Chinese medicinal plants. In July 2021, root rot of A. membranaceus var. mongholicus was found in a field in Tongren City, Huangnan Tibetan Autonomous Prefecture, Qinghai Province, China. The aboveground part of the plants exhibited yellowing, wilting and defoliation in severe cases. Seven fungal isolates were obtained, and their pathogenicity, morphology and phylogeny were analysed. A pathogenicity test was performed using the scratch and root irrigation methods, and the results showed that all seven isolates caused root rot on inoculated plants. Based on morphological characteristics and phylogenetic analysis of multi-locus sequences (ITS, translation elongation factor [TEF-1 alpha], and RNA polymerase II beta subunit [RPB2] genes), two isolates were identified as Fusarium avenaceum, and five isolates were identified as F. flocciferum. To the best of our knowledge, this is the first report of F. avenaceum and F. flocciferum causing root rot of A. membranaceus var. mongholicus in China.

Taraxacum mongolicum is a perennial herbaceous plant in the family Asteraceae, with a high edible and medicinal value and is widely planted in China. In August 2022, leaf spots were found on T. mongolicum in Tianjiazhai Town, Xining City, Qinghai Province, China (36°27'17.65″N, 101°47'19.65E, elevation: 2,408 m). The plants exhibited round or irregular brown spots, and the centers of some of the spots were gray (Fig. S1A). An investigation was performed over a hectare area, and the incidence of leaf spot reached 15%-30%, seriously affecting the quality and yield of T. mongolicum. Eleven T. mongolicum leaf spot samples were collected. To isolate the pathogenic fungus, approximately 0.5 cm×0.5 cm pieces of tissues were obtained using sterile scissors from the junction of infected and healthy tissues. The symptomatic leaves were surface-disinfected with 3% NaClO for 1.5 min and washed three times with sterile water. The disinfected pieces were dried and placed on water agar plates in an incubator for 2 days at 25°C. Subsequently, the leaf surface exhibited conidiophores and conidia. Eleven isolates were obtained by single spore isolation. The sparse aerial mycelia were dark grey to black brown in color on potato dextrose agar (PDA) (Fig. S2A), and produced dark, multi-septate conidia with 7-11 transverse septa and 1-2 longitudinal septa (Fig. S2C). Conidia with one or two beaks were long-ovoid, with an average length and width of 103.4 × 21.2 μm, and 80.7 × 3.9 μm of the beaks. One hundred and ten conidia were measured. The identification of 11 isolates was confirmed by multilocus sequence analyses of the internal transcribed spacer of ribosomal DNA (rDNA ITS) (White et al. 1990), and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (Xu et al. 2022), actin (ACT) (Yang et al. 2020), histone 3 (HIS3) (Zheng et al. 2015), translation elongation factor 1-α (TEF1-α) (Carbone. 1999), and the second largest subunit of RNA polymerase II (RPB2) (Liu et al. 1999) genes. The sequences of all the isolates were deposited in Genbank (NCBI Accession Nos. ITS: OR105029-OR105039, ACT: OR135220-OR135230, GAPDH: OR135231-OR135241, HIS3: OR122992-OR123002, TEF1-α: PP055972-PP055982, and RPB2: PP055983-PP055993), and the sequence similarity of ITS, ACT, GAPDH, HIS3，TEF1-α and RPB2 were 100%, 98%, 100%, 99%, 100%, and 99% to the sequences of Alternaria solani, respectively. Combined sequences of ITS, GAPDH, TEF1-α, and RPB2 genes were concatenated and a maximum parsimony tree was constructed with PAUP* v. 4.0 alpha. The results indicated that 11 isolates were clustered together with A. solani (Fig. S2D). Therefore, 11 isolates were identified as A. solani based on their morphological and molecular characteristics. Eleven isolates were inoculated on their host to perform Koch's postulates. The isolates were grown on PDA for six days. Healthy one month old T. mongolicum seedlings were planted in 10 cm flowerpots (Fig. S1B) or the seedlings were moved to Petri dish (Fig. S1C), and their leaves were inoculated with 5 mL of hyphae suspension by smearing method. In addition, seedlings of the same age were treated with sterile water to serve as the control. The inoculated seedlings were moved into an artificial climatic box at 25℃, relative humidity was 70%, with 12 h light/12 h dark condition. Totally 80 seedlings were inoculated with isolates and 15 were used as the control. After 7 days, similar symptoms were observed on the plants inoculated with isolates, while control plants did not produce symptoms. The assays were conducted three times. Furthermore, isolates were re-isolated from the symptomatic leaves, and the colonial morphology was the same as the original isolates (Fig S2 A and B). The recovered isolates were identified as A. solani by amplifying and sequencing a portion of the HIS3 gene. Alternaria solani has been previously reported to cause early blight of potato and other Solanum crops (van der Waals et al. 2004; Zheng et al. 2015). To our knowledge, this is the first report of A. solani causing leaf spot of T. mongolicum in China. This disease must be considered in management practices, and our finding provided a basis for disease prevention and management.

Qinghai Province is one of China's five major pastoral areas located in the northeastern part of the Qinghai-Tibet Plateau, and animal husbandry plays a great part in the local economy. One of the most important crops in Qinghai Province is maize for silage, which sustains ecological animal husbandry. However, the leaf spot disease of maize has seriously impeded the healthy development of the maize industry. We found that from 2019 to 2020 leaf spot of silage maize caused by Cladosporium was a common disease in Qinghai Province. This leaf spot disease formed water-soaked round or irregular spots at the early stage and gradually expanded to black at the later stage, and the incidence of the leaf spot in the fields reached 15%-45%. In this study, 125 isolates were isolated from seven locations in Qinghai Province, with 123 isolated from leaves and two isolated from bracts of maize for silage. Their phylogeny, morphology, and pathogenicity were analysed to identify pathogens and investigate the differences among them. Based on phylogenetic analysis of multi-locus (ITS, actin, and translation elongation factor (1-alpha)) sequences and morphology characteristics, the 125 isolates were identified to belong to eight species of Cladosporium: C. allicinum, C. cladosporioides, C. xylophilum, C. herbarum, C. macrocarpum, C. asperulatum, C. subinflatum, and C. floccosum. Pathogenicity tests by artificial inoculation demonstrated that 125 isolates were pathogenic on eight maize cultivars for silage, and pathogenicity differentiation was not observed. Taken together, our results demonstrated that these eight species of Cladosporium caused leaf spot disease of maize in Qinghai Province. This is the first analysis report on Cladosporium species from maize in China, and our findings provide a theoretical foundation for the management of this disease in the future.

以环青海湖地区的退化人工草地为研究对象,探究施有机肥对土壤微生物群落中不同物种之间的相互作用以及物种功能特征的影响.结果表明:施有机肥显著改变了退化人工草地植被盖度及土壤理化性质(P＜0.05).同时,也改变了草地土壤微生物群落物种组成和结构,对细菌群落而言,施有机肥降低了绿弯菌门(Chloroflexi)、巴纽尔斯菌门(Balaeo-laeota)、螺旋体门(Spirochiaetes)和Candidatus Saccharibacteria的相对丰度(P＜0.05),增加了 Gp7和不动杆菌属(Acineto-bacter)的相对丰度(P＜0.05),而对真菌群落相对丰度的改变不显著.单边网络结构在施用有机肥后表现出更为复杂和紧密的关系,且改变了人工草地微生物网络结构中的核心物种.本研究结果表明施用有机肥会对退化人工草地土壤微生物群落结构以及物种相互作用产生更大的影响、提供了建立恢复草地微生物动态变化的重要见解.

"农业植物病理学"是植物保护专业的一门核心课程.新农科建设研讨会从宏观层面提出了面向新农业、新乡村、新农民、新生态发展新农科的"四个面向"新理念,因此,新时期对农科类大学生的综合素质要求越来越高.通过探讨新形势下"农业植物病理学"课程教学的机遇和挑战,从优化教学内容、改进教学方法、调整考核方式等方面,对新形势下"农业植物病理学"课程的教学进行改革,保障教学质量,以期建设更加符合当前社会发展需求和满足学生就业需要的核心课程,培养高素质的植物保护专业人才.

为理清青贮玉米蠕形菌生物学特性及筛选出防治该类病害的有效药剂,本研究测定不同氮、碳源和pH值对青贮玉米6种蠕形菌菌丝生长的影响及8种杀菌剂对蠕形菌的抑菌作用.结果表明,供试氮源中的酵母提取物、蛋白胨、酶水解酪蛋白和酸水解酪蛋白对6种蠕形菌的生长具有明显的促进作用,供试碳源中甘露醇、蔗糖、淀粉、葡萄糖、麦芽糖和乳糖对6种蠕形菌的生长具有最明显的促进作用.6株菌株在pH值为4～11都可生长,pH值为4、5、9时MH-41(穗状弯孢菌)、CJZ-8(大斑突脐孢菌)、DT-68(新月弯孢菌)和GDX-65(麦根腐平脐蠕孢菌)菌丝生长速率最快.药剂试验表明,50％咯菌腈可湿性粉剂、50％苯醚甲环唑悬浮剂、25％硅唑·咪鲜胺水乳剂和25％吡唑醚菌酯悬浮剂对6种蠕形菌的抑制效果较好.

Elymus nutans is a perennial grass of the Gramineae family. Due to its cold-resistance and nutrition deficiency tolerance, it has been applied to the ecological restoration of degraded alpine grassland on the Qinghai-Tibet Plateau. As an important symbiotic microorganism, arbuscular mycorrhizal fungi (AMF) have been proven to have great potential in promoting the growth and stress resistance of Gramineae grasses. However, the response mechanism of the AMF needs to be clarified. Therefore, in this study, Rhizophagus irregularis was used to explore the mechanism regulating cold resistance of E. nutans. Based on pot experiments and metabolomics, the effects of R. irregularis were investigated on the activities of antioxidant enzyme and metabolites in the roots of E. nutans under cold stress (15/10°C, 16/8 h, day/night). The results showed that lipids and lipid molecules are the highest proportion of metabolites, accounting for 14.26% of the total metabolites. The inoculation with R. irregularis had no significant effects on the activities of antioxidant enzyme in the roots of E. nutans at room temperature. However, it can significantly change the levels of some lipids and other metabolites in the roots. Under cold stress, the antioxidant enzyme activities and the levels of some metabolites in the roots of E. nutans were significantly changed. Meanwhile, most of these metabolites were enriched in the pathways related to plant metabolism. According to the correlation analysis, the activities of antioxidant enzyme were closely related to the levels of some metabolites, such as flavonoids and lipids. In conclusion, AMF may regulate the cold-resistance of Gramineae grasses by affecting plant metabolism, antioxidant enzyme activities and antioxidant-related metabolites like flavonoids and lipids. These results can provide some basis for studying the molecular mechanism of AMF regulating stress resistance of Gramineae grasses.

为筛选防治三种药用植物根腐病的高效生防药剂,本研究测定了 7种生物药剂对7种来源于当归、黄芪和藏红花根腐病菌的抑制作用;结果表明,1.8％阿维菌素对7种病原菌具有很强的抑制作用,对藏红花根腐病菌尖孢镰刀菌ZHH-1的抑制作用最好,EC50 为0.004 mg/L;拮抗菌类抑菌剂中,解淀粉芽孢杆菌的抑制作用最好,多粘类芽孢杆菌和哈茨木霉菌的抑制作用次之;通过当归根腐病大田防治试验发现,解淀粉芽孢杆菌对当归根腐病的防治效果较好,防治效果为66.97％.试验结果为青海省当归、黄芪和藏红花根腐病的综合防治提供参考.

为了解青贮玉米链格孢叶斑病菌的生物学特性并筛选出防治该病害的有效杀菌剂,本研究测定了9种碳源和7种氮源对交链格孢、芸薹链格孢、致密链格孢、极细链格孢和茄链格孢5种病原菌菌丝生长的影响,以及7种杀菌剂对病原菌的抑菌作用.结果表明,供试碳源中淀粉、麦芽糖和葡聚糖对5种链格孢生长的促进作用最为明显;供试氮源中蛋白胨、酵母提取物和牛肉膏对5种链格孢生长的促进作用最为明显.室内防治药剂试验中,45％咪鲜胺水乳剂和40％氟硅唑乳油对5种病原菌表现出很强的抑制作用,EC50在0.527～5.092 mg/L之间.

To investigate the pathogen species of silage maize leaf spot in Minhe County, the diseased leaves with typical symptoms were collected from the corn planting area. The diseased leaves were classified according to the symptoms. The strains of pathogen were obtained by tissue isolation method, and the isolates were identified by molecular biology method. The results showed that there were three types of leaf spots observed in Minhe County. The first type of spot was irregular, large lesions, in brownish yellow color. The second type of spot was long strip, yellow brown in the center, or purple brown or dark brown in the edge, sometimes with 2～3 concentric rings, and the vein could be infected. The third kind of lesions were oval, slightly larger, yellow, scattered on the leaves. Fourteen isolates were isolated and identified by rDNA-ITS sequence analysis as Alternaria alternat, A. burnsii, A. tenuissima, Fusarium proliferatum, F. tricinctum and F. longifundum. The pathogens caused corn leaf spot in Minhe County belonged to 2 genera, 6 species, respectively. The main pathogens are Alternaria.

HomePlant DiseaseVol. 106, No. 6First Report Disease of Clonostachys rosea Causing Root Rot on Astragalus membranaceus in China PreviousNext DISEASE NOTE OPENOpen Access licenseFirst Report Disease of Clonostachys rosea Causing Root Rot on Astragalus membranaceus in ChinaHexing Qi, Xiaoming Duan, Wenhua Xu, Yuantao Zhou, Haixia Ma, Weili Ma, and Guihua MaHexing Qi†Corresponding author: H. Qi; E-mail Address: [email protected]https://orcid.org/0000-0001-5092-2837College of Agriculture and Animal Husbandry, Qinghai University, Xining, Qinghai, 810016, China, Xiaoming DuanCollege of Agriculture and Animal Husbandry, Qinghai University, Xining, Qinghai, 810016, China, Wenhua XuNorthwest Institute of Plateau Biology, the Chinese Academy of Science, Xining, Qinghai, 810016, China, Yuantao ZhouCollege of Agriculture and Animal Husbandry, Qinghai University, Xining, Qinghai, 810016, China, Haixia MaCollege of Agriculture and Animal Husbandry, Qinghai University, Xining, Qinghai, 810016, China, Weili MaCollege of Agriculture and Animal Husbandry, Qinghai University, Xining, Qinghai, 810016, China, and Guihua MaCollege of Agriculture and Animal Husbandry, Qinghai University, Xining, Qinghai, 810016, ChinaAffiliationsAuthors and Affiliations Hexing Qi1 † Xiaoming Duan1 Wenhua Xu2 Yuantao Zhou1 Haixia Ma1 Weili Ma1 Guihua Ma1 1College of Agriculture and Animal Husbandry, Qinghai University, Xining, Qinghai, 810016, China 2Northwest Institute of Plateau Biology, the Chinese Academy of Science, Xining, Qinghai, 810016, China Published Online:14 Apr 2022https://doi.org/10.1094/PDIS-07-21-1511-PDNAboutSectionsView articlePDFSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat View articleAstragalus membranaceus, a perennial plant in the family Leguminosae, is one of the most important traditional Chinese medicines. Root rot is a serious constraint to commercial production of this plant in northeastern, northern, and northwestern China. In June 2020, A. membranaceus plants in a field in Sada, Minhe County, Haidong City, Qinghai Province (36°19′8.58″N, 102°51′30.8″E, 2,437 m.a.s.l.), showed symptoms of many brown longitudinal cracks or turtle cracks in the root, weak aboveground growth, and yellowing and falling off of leaves in severe cases. Root rot seriously affects the quality and yield of A. membranaceus. An investigation was performed in a 3,996-m2 field with a root rot incidence of 10%. Five root rot samples were collected. To isolate the fungus, rotted root pieces (∼0.5 cm) were cut with sterile scissors at the junction of infected and healthy tissues. Symptomatic roots were surface disinfected with 3% NaClO for 1.5 min and washed three times with sterile water. The disinfected pieces were dried and placed on a water agar plate in an incubator for 2 days at 25°C. After the root surface was moldy, abundant conidiophores and conidia formed. Conidia were put into sterile water with a pipette to prepare a spore suspension. Then, 200 μl of spore suspension was spread on the surface of a water agar plate and put in an incubator for 12 h at 25°C. Single spores were picked under a stereomicroscope and single spore isolates were cultured on potato dextrose agar (PDA). Ten isolates were obtained. Mycelia were white or light yellow on PDA. Primary conidiophores were Verticillium-like with two to three levels. Stipe length was 41.91 to 97.62 μm. Secondary conidiophores were penicillate with two or three whorls of phialides. Stipe length was 36.67 to 65.98 μm. Conidiogenous cells were slender cylindrical. Conidia were colorless, round or oval, and aseptate, with an average of 6.5 to 8.5 × 2.5 to 3.5 μm. Chlamydospores were round or oval, with an average of 9.91 to 16.21 × 8.07 to 13.64 μm. The identity of 10 isolates was confirmed by sequencing the internal transcribed spacer (ITS) locus using the primers ITS1F/ITS4 (sequence length was 526 bp), the translation elongation factor 1-alpha (EF-1α) gene using the primers EF-1H/EF-2T (sequence length was 567 bp) (Cao et al. 2020), and sequences including ITS1, 5.8S ribosomal RNA gene, ITS2, and large ribosomal RNA gene using the primers F1/F2 (sequence length 1010 bp) (Cao et al. 2020). BLAST analysis of all three sequences of isolates HQ-1, HQ-1-1, HQ-2-1, HQ-3-1, HQ-4, HQ-6, HQ-6-1, HQ-7-1, HQ-9-1, and HQ-10-1 in the GenBank database resulted in matches of 99.2% or more for Clonostachys rosea (NCBI accession Nos. MZ433169 to MZ433178 [ITS], MZ451390 to MZ451399 [TEF1-α], and MZ433195 to MZ433204 [ITS 1, 5.8 S rRNA, ITS 2, and LSU]. Ten isolates were inoculated on their host for pathogenicity test. The isolates were grown on PDA for 6 days for sporulation. Healthy seedling stage roots were inoculated with 10 ml of conidia suspension (1 × 105 conidial/ml). A control group of 10 seedlings of the same age was treated with sterile water. Inoculated roots were put in an artificial climate box at 25°C, 70% relative humidity, and 12 h light/12 h dark. Typical symptoms first appeared as tiny brown spots at ∼3 days, extended and cracked for 5 to 7 days, and mycelia were observed on the surfaces of the lesions. Uninoculated plants remained healthy. Isolates were reisolated from the symptomatic root, and the colonial morphology was the same as the original isolate. The assays were conducted three times. These results showed that these isolates maintained their pathogenicity to their own hosts. To our knowledge, this is the first report of C. rosea causing root rot of A. membranaceus in China. C. rosea has been previously reported to cause root rot of soybeans in the United States (Bienapfl et al. 2012). The disease must be considered in management practices, and our findings provide a foundation for preventing or curing this disease.The author(s) declare no conflict of interest.References:Bienapfl, J. C., et al. 2012. Plant Dis. 96:1700. https://doi.org/10.1094/PDIS-06-12-0550-PDN Link, ISI, Google ScholarCao, Z. Y., et al. 2020. J. Plant Prot. 47:178. Google ScholarFunding: Funding was provided by Scientific Research Foundation of Qinghai University (4139040111).The author(s) declare no conflict of interest.DetailsFiguresLiterature CitedRelated Vol. 106, No. 6 June 2022SubscribeISSN:0191-2917e-ISSN:1943-7692 Download Metrics Article History Issue Date: 2 Jun 2022 Published: 14 Apr 2022 First Look: 24 Jan 2022 Accepted: 5 Jan 2022 Page: 1752 Information© 2022 The American Phytopathological SocietyFundingQinghai UniversityGrant/Award Number: 4139040111KeywordsAstragalus membranaceusClonostachys rosearoot rotThe author(s) declare no conflict of interest.PDF downloadCited byFirst Report of Colletotrichum spinaciae Causing Leaf Anthracnose on Quinoa in ChinaLin Wei, Wei Li, Rong Hu, Shuo Shen, and Jian Wang17 November 2023 | Plant Disease, Vol. 107, No. 12Isolation of Main Pathogens Causing Postharvest Disease in Fresh Codonopsis pilosula during Different Storage Stages and Ozone Control against Disease and Mycotoxin Accumulation21 January 2023 | Journal of Fungi, Vol. 9, No. 2

为鉴定青海省民和地区蒙古黄芪(Astragalus membranaceus var.mongholicus)根腐病病原菌及筛选防治该病害的有效杀菌剂,本研究基于形态学特征、rDNA-ITS,TEF-1α和RPB2序列分析对蒙古黄芪根腐病病原进行鉴定,并利用菌丝生长速率法测定8种杀菌剂对病原菌的抑制作用.结果发现,引起黄芪根腐病的病原菌为腐皮镰刀菌(Fusarium soani)、逗号镰刀菌(F.virguliforme)、木贼镰刀菌(F.equiseti)和锐顶镰刀菌(F.acuminatum).室内药剂试验表明硅唑·咪鲜胺对4种镰刀菌的抑制作用最好,EC50在0.195～0.588 mg·L-1之间;多菌灵对腐皮镰刀菌、木贼镰刀菌和锐顶镰刀菌的抑制作用较强,EC50在0.113～0.869 mg·L1之间;咯菌腈对逗号镰刀菌、木贼镰刀菌和锐顶镰刀菌的抑制作用较强,EC50在0.153～0.390 mg·L-1之间;甲基硫菌灵、噁霉灵、溴菌腈和石硫合剂对4种镰刀菌的抑制作用较差,EC50在1.018～4.360 mg·L-1之间.试验结果为生产上合理选用杀菌剂防治黄芪根腐病提供了科学依据.

稻梨孢除了能侵染水稻,引起稻瘟病造成严重产量损失外,还能侵染多种禾本科作物和杂草.为了探究水稻来源稻梨孢与狗尾草来源稻梨孢之间是否具有交互侵染作用,本研究以水稻和狗尾草叶片病斑上分离得到的101株稻梨孢作为研究对象.经形态学鉴定,101株菌株都为稻梨孢.对15株代表菌株进行肌动蛋白、β微管蛋白和钙调蛋白基因扩增,构建系统发育树,发现基于钙调蛋白和3个基因联合构建的系统发育树中水稻来源菌株聚为1个分支,狗尾草来源菌株聚为1个分支,表明稻梨孢存在种群分化现象.52株水稻来源稻梨孢可以侵染狗尾草,49株狗尾草来源稻梨孢不能侵染水稻.因此,种植水稻时应及时清除稻田周围杂草,以减少稻梨孢野生寄主数量.

Angelica sinensis is a perennial plant in the Apiaceae and a source of one of the most important traditional medicines in China. This medicinal herb has been mainly cultivated in Gansu, Sichuan, Yunnan, Shanxi, Hubei, and Qinghai Provinces. In June 2020, angelica plants in a field in the village of Sada, Minhe County, Haidong city, in Qinghai Province (102°83'00.00″E, 36°31'93.00″N, elevation:2437 m), displayed symptoms of yellowing, stunting, root rot, and wilting（Fig. S1）. Severe brown discoloration of vascular tissue in the stems of infected plants was observed. Root rot seriously affected the quality and yield of A. sinensis. The incidence of root rot in the fields reached 15% in 2020 and 18% in 2021. Fungi were isolated from diseased roots using a single spore method. The identity of isolates was confirmed by sequencing the nuclear ribosomal internal transcribed spacer (ITS) using the primers ITS1/ITS4 (White et al, 1990) and the translation elongation factor 1-alpha (TEF1-α) gene using the primers EF-1/EF-2 (O'Donnell et al. 1998). BLAST analysis of the ITS and TEF1-α sequences of isolates DG-1, DG-1-1, DG-1-2, DG-2, DG-2-1, DG-5, and DG-5-1 in the NCBI database showed 99% to 100 % nucleotide identity to those of Clonostachys rosea (NCBI accession Nos. MZ424803-MZ424809 (ITS), and MZ451383-MZ451389 (TEF1-α)). BLAST analysis of the ITS and TEF1-α sequences of isolates, DG-3, DG-3-1, and DG-4 in the NCBI database produced matches of 99.1% or better to Fusarium acuminatum (NCBI accession Nos. MZ424810-MZ424812 (ITS), and MZ441148-MZ441150 (TEF1-α)). Conidia of C. rosea were hyaline, round or oval, aseptate, with an average length and width of 6.5-8.5×2.5-3.5 μm. Chlamydospores were round or oval, with an average length and width of 9.9-16.2×8.1-13.6 μm. Conidiophores of C. rosea were hyaline, septate, Verticillium-like, conidiogenous cells were slender and cylindrical. Macroconidia of F. acuminatum were hyaline, falciform, 0-5 septate, with an average length and width of 22.5-39.5 × 2.5-4.5 μm. Microconidia were rare. Chlamydospores were oval, with an average length and width of 9.5-14.3×8.1-11.8 μm. Conidiophores of F. acuminatum were hyaline, septate, branched (Fig. S2). A pathogenicity test was performed by inoculating a conidial suspension of 1×105 per ml in 0.025% Tween 20 onto roots of A. sinensis. Inoculated roots were incubated in a humid and dark chamber at 26°C for 24 h, and then with 12 h light/12 h dark for six days. The pathogenicity assay was repeated three times for each isolate. Root rot was observed seven days after inoculation and mycelia were observed on the surface of the lesions (Fig. S1). Two isolates were recovered from the lesions and named DG-2-D and DG-3-1-D. The colonial morphology of these two isolates and the original isolates DG-2 and DG-3-1 was identical after six days of inoculation on PDA (potato dextrose agar) (Fig. S2). The two isolates recovered were identified as C. rosea and F. acuminatum, respectively, by amplifying and sequencing a portion of the TEF1-α gene. To our knowledge, this is the first report of C. rosea causing root rot of A. sinensis in China. Fusarium acuminatum was reported to cause root rot of A. sinensis in Gansu province, China in 2021 (Niu et al. 2021). Clonostachys rosea has been previously reported to cause root rot of soybean in the United States (Bienapfl et al. 2012). The disease must be considered in existing management practices, and our findings provide a foundation for management this disease.

Polyphylla gracilicornis is one of the important underground pest species that damage agricultural and forestry plants and often requires chemical control during outbreak. Here, we determined the complete mitochondrial genome sequence of P. gracilicornis (GenBank accession no. MW143080) using Illumina NovaSe Sequencing System with a read length of 150 bp. The complete mitogenome consists of a 16,793 bp circular DNA molecule and the overall base composition was 36.97% A, 31.95% T, 10.41% G and 20.67% C. The full mitochondrial genome contains 38 sequence elements: 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and a putative control region (CR). All protein-coding genes of P. gracilicornis have the typical ATN (Met) start codons and typical TAN stop codons. Phylogenetic analysis revealed that P. gracilicornis clustered into a clade with homologous species with high bootstrap support.

青贮玉米是青海省玉米发展的优势产业,但是链格孢叶枯病的发生对青贮玉米的品质和产量造成了影响.为了对青贮玉米链格孢叶枯病病原菌进行鉴定及对其致病力进行分析,本研究从青海省不同海拔高度青贮玉米种植区采集病叶,从中分离得到177株病原菌,根据菌落和孢子等的形态特征和rDNA-ITS序列分析对病原菌进行鉴定;根据对金皇828、铁研53号和中单2号青贮玉米的接种结果计算病情指数,对155株菌株致病力进行分析.结果表明交链格孢(Alternaria alternata)、极细链格孢(A.tenuissima)、致密链格孢(A.compacta)和Alternaria sp,分别占病原菌总数的28.2％、17.5％、15.2％和21.5％,为优势病原菌.155株病原菌都能侵染3种青贮玉米,接种铁研53号后强致病力菌株、中等致病力菌株和弱致病力菌株分别有68、56和31株;接种金皇828后强、中等和弱致病力菌株分别有69、60和26株;接种中单2号后强、中等和弱致病力菌株分别有64、58和33株.本研究结果表明青贮玉米链格孢叶枯病是由多种链格孢属真菌共同侵染造成的,且病原菌存在致病力分化.

球茎腐烂病是严重影响藏红花球茎品质和柱头产量的病害.为鉴定引起藏红花球茎腐烂病的病原菌及筛选防治该病害的有效杀菌剂,本研究基于形态学特征、rDNA-ITS和TEF-1α序列分析,对青海省藏红花球茎腐烂病的病原菌进行了鉴定,并利用菌丝生长速率法测定了10种杀菌剂对病原菌的抑菌作用.结果 发现,引起藏红花球茎腐烂病的病原菌为尖孢镰刀菌Fusarium oxysporum和木贼镰刀菌F.equiseti,其中尖孢镰刀菌为优势病原菌.室内药剂试验表明70％甲基硫菌灵WP、50％咯菌腈WP、50％苯醚甲环唑SC和25％硅唑·咪鲜胺EW对两种镰刀菌均具有较好的抑制作用,EC50在0.5740～1.8086 mg/L之间,64％噁霜·锰锌WP、30％噁霉灵AS和45％石硫合剂WP对2种镰刀菌的抑菌作用较差,EC50在2.1344～7.9153 mg/L之间.试验结果为生产上合理选用杀菌剂防治藏红花球茎腐烂病提供了科学依据.