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植物病害防治Plant disease control

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For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Sensitivity and resistance risk analysis of Didymella bryoniae populations to fluopyram Zhiwen Wu, Xiaowei Cai, Xuewei Mao, Mingguo Zhou, Yiping Hou 2024, 23 (7): 2306-2317.   DOI: 10.1016/j.jia.2023.11.044 Abstract （119）      PDF in ScienceDirect       Fluopyram is an succinate dehydrogenase inhibitors (SDHI) fungicide that has been registered in China to control gummy stem blight (GSB) in watermelons for many years.  However, whether the field pathogens of GSB are still sensitive to fluopyram or not is unknown.  Therefore, we collected 69 Didymella bryoniae isolates from the fields that usually use fluopyram to control GSB to determine the sensitivity change.  The EC50 (50% inhibition effect) values of fluopyram against D. bryoniae ranged from 0.0691 to 0.3503 μg mL–1 and the variation factor was 5.07.  The mean EC50 value was (0.1579±0.0669) μg mL–1 and the curve of sensitivity was unimodal.  No resistant strains were found in the isolates, which means that the pathogens were still sensitive to fluopyram.  The minimal inhibition concentration (MIC) of fluopyram against D. bryoniae was 3 μg mL–1.  Four low-resistant mutants and two medium-resistant mutants were obtained using fungicide taming and the resistance of mutants could be inherited stably.  The growth rate of mutants decreased significantly compared with that of wild-type strains while the biomass of most mutants was similar to that of wild-type strains.  The sensitivity of most resistant mutants to various stresses was increased compared with that of wild-type strains.  The virulence of mutants receded except for low-resistant mutant XN51FR-1, which had the same lesion area as XN51 on the watermelon leaves.  The results indicated that the fitness of resistant mutants was decreased compared with that of wild-type strains.  The cross-resistance assay indicated that fluopyram-resistant mutants were positive cross-resistant to all six SDHI fungicides in this test but were still sensitive to fluazinam and tebuconazole.  So the resistance risk of D. bryoniae to fluopyram was moderate.  In addition, we found that the SdhB gene of low-resistant mutant XN30FR-1 had three new point mutations at positions K258N, A259P, and H277N.  Medium-resistant mutant XN52FR-1 showed a mutation at position H277N and other mutants did not have any point mutation.  Reference | Related Articles | Metrics Select Establishment of a system for screening and identification of novel bactericide targets in the plant pathogenic bacterium Xanthomonas oryzae pv. oryzae using Tn-seq and SPR Chaoyue Pang, Ling Jin, Haoyu Zang, Damalk Saint-Claire S. Koklannou, Jiazhi Sun, Jiawei Yang, Yongxing Wang, Liang Xu, Chunyan Gu, Yang Sun, Xing Chen, Yu Chen 2024, 23 (5): 1580-1592.   DOI: 10.1016/j.jia.2023.04.043 Abstract （388）      PDF in ScienceDirect       Xanthomonas spp. cause severe bacterial diseases.  However, effective strategies for prevention and management of these diseases are scarce.  Thus, it is necessary to improve the efficiency of control of diseases caused by Xanthomonas.  In this study, Xanthomonas oryzae pv. oryzae (Xoo), which causes rice bacterial leaf blight, has been studied as a representative.  A transposon insertion library of Xoo, comprising approximately 200,000 individual insertion mutants, was generated.  Transposon sequencing data indicated that the mariner C9 transposase mapped at 35.7–36.4% of all potential insertion sites, revealing 491 essential genes required for the growth of Xoo in rich media.  The results show that, compared to the functions of essential genes of other bacteria, the functions of some essential genes of Xoo are unknown, 25 genes might be dangerous for the Xanthomonas group, and 3 are specific to Xanthomonas.  High-priority candidates for developing broad-spectrum, Xanthomonas-specific, and environment-friendly bactericides were identified in this study.  In addition, this study revealed the possible targets of dioctyldiethylenetriamine using surface plasmon resonance (SPR) in combination with high performance liquid chromatography–mass spectrometry (HPLC–MS).  The study also provided references for the research of some certain bactericides with unknown anti-bacterial mode of action.  In conclusion, this study urged a better understanding of Xanthomonas, provided meaningful data for the management of bacterial leaf blight, and disclosed selected targets of a novel bactericide. Reference | Related Articles | Metrics Select Discovery and structure-activity relationship studies of novel tetrahydro-β-carboline derivatives as apoptosis initiators for treating bacterial infections Shanshan Su, Hongwu Liu, Junrong Zhang, Puying Qi, Yue Ding, Ling Zhang, Linli Yang, Liwei Liu, Xiang Zhou, Song Yang 2024, 23 (4): 1259-1273.   DOI: 10.1016/j.jia.2023.05.031 Abstract （161）      PDF in ScienceDirect       Developing and excavating new agrochemicals with highly active and safe is an important tactic for protecting crop health and food safety.  In this paper, to discover the new bactericide candidates, we designed, prepared a new type of 1,2,3,4-tetrahydro-β-carboline (THC) derivatives and evaluated the in vitro and in vivo bioactivities against the Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas axonopodis pv. citri (Xac), and Pseudomonas syringae pv. actinidiae (Psa).  The in vitro bioassay results exhibited that most title molecules possessed good activity toward the three plant pathogenic bacteria, the compound A17 showed the most active against Xoo and Xac with EC50 values of 7.27 and 4.89 mg mL–1 respectively, and compound A8 exhibited the best inhibitory activity against Psa with EC50 value of 4.87 mg mL–1.  Pot experiments showed that compound A17 exhibited excellent in vivo antibacterial activities to manage rice bacterial leaf blight and citrus bacterial canker, with protective efficiencies of 52.67 and 79.79% at 200 mg mL–1, respectively.  Meanwhile, compound A8 showed good control efficiency (84.31%) against kiwifruit bacterial canker at 200 mg mL–1.  Antibacterial mechanism suggested that these compounds could interfere with the balance of the redox system, damage the cell membrane, and induce the apoptosis of Xoo cells.  Taken together, our study revealed that tetrahydro-β-carboline derivatives could be a promising candidate model for novel broad-spectrum bactericides. Reference | Related Articles | Metrics Select Identification, pathogenicity, and fungicide sensitivity of Eutiarosporella dactylidis associated with leaf blight on maize in China Cheng Guo, Xiaojie Zhang, Baobao Wang, Zhihuan Yang, Jiping Li, Shengjun Xu, Chunming Wang, Zhijie Guo, Tianwang Zhou, Liu Hong, Xiaoming Wang, Canxing Duan 2024, 23 (3): 888-900.   DOI: 10.1016/j.jia.2023.09.032 Abstract （428）      PDF in ScienceDirect       Maize (Zea mays L.) is an economically vital grain crop that is cultivated worldwide.  In 2011, a maize foliar disease was detected in Lingtai and Lintao counties in Gansu Province, China.  The characteristic signs and symptoms of this disease include irregular chlorotic lesions on the tips and edges of infected leaves and black punctate fruiting bodies in dead leaf tissues.  Given favourable environmental conditions, this disease spread to areas surrounding Gansu.  In this study, infected leaves were collected from Gansu and Ningxia Hui Autonomous Region between 2018 and 2020 to identify the disease-causing pathogen.  Based on morphological features, pathogenicity tests, and multi-locus phylogenetic analysis involving internal transcribed spacer (ITS), 18S small subunit rDNA (SSU), 28S large subunit rDNA (LSU), translation elongation factor 1-alpha (TEF), and β-tubulin (TUB) sequences, Eutiarosporella dactylidis was identified as the causative pathogen of this newly discovered leaf blight.  Furthermore, an in vitro bioassay was conducted on representative strains using six fungicides, and both fludioxonil and carbendazim were found to significantly inhibit the mycelial growth of E. dactylidis.  The results of this study provide a reference for the detection and management of Eutiarosporella leaf blight. Reference | Related Articles | Metrics Select Resistance risk and molecular mechanism associated with resistance to picoxystrobin in Colletotrichum truncatum and Colletotrichum gloeosporioides SHI Niu-niu, LIAN Jin-pan, QIU De-zhu, CHEN Fu-ru, DU Yi-xin 2023, 22 (12): 3681-3693.   DOI: 10.1016/j.jia.2023.07.037 Abstract （217）      PDF in ScienceDirect       Anthracnose, caused by Colletotrichum truncatum and C. gloeosporioides, is amongst the most serious diseases of soybean in China.  Picoxystrobin, a quinone outside inhibitor fungicide, is commonly used for the control of anthracnose.  Its resistance risk and mechanism in C. truncatum and C. gloeosporioides are unclear.  In this study, the sensitivities of 128 C. truncatum and 121 C. gloeosporioides isolates to picoxystrobin were investigated, and unimodal distributions were observed with average EC50 values of 0.7740 and 1.1561 μg mL–1, respectively.  Eleven picoxystrobin-resistant mutants of C. truncatum and six mutants of C. gloeosporioides were acquired, with EC50 values varying from 5.40–152.96 and 13.53–28.30 μg mL–1, respectively.  Compared to the parental isolates, mutants showed similar or higher relative fitness in conidial production and germination, and pathogenicity.  Collectively, the resistance risk of C. truncatum and C. gloeosporioides to picoxystrobin is moderate to high.  There was positive cross-resistance between picoxystrobin and pyraclostrobin, but not between picoxystrobin and fluazinam, difenoconazole, or propiconazole.  The G143S mutation in Cyt b protein was detected in seven high-resistant mutants of C. truncatum (RF>100), and G137R occurred in four moderate-resistant mutants (RF<50).  Contrastingly, there were no point mutations in Cyt b of any C. gloeosporioides mutants.  Molecular docking confirmed that two mutations conferred different resistance levels to picoxystrobin.  Under greenhouse trials, picoxystrobin did not control mutants with the G143S mutation, those bearing G137R or no point mutation were somewhat controlled, but at a lower level compared to wild-type isolates.  These results showed that integrated management strategies should be implemented to preserve fungicide effectiveness. Reference | Related Articles | Metrics Select Exploring the nano-fungicidal efficacy of green synthesized magnesium oxide nanoparticles (MgO NPs) on the development, physiology, and infection of carrot (Daucus carota L.) with Alternaria leaf blight (ALB): Molecular docking Lukman AHAMAD, Azmat ALI KHAN, Masudulla KHAN, Orudzhev FARID, Mahboob ALAM 2023, 22 (10): 3069-3080.   DOI: 10.1016/j.jia.2023.02.034 Abstract （404）      PDF in ScienceDirect       In this research, green synthesized magnesium oxide nanoparticles (MgO NPs) from lemon fruit extracts and their fungicidal potential was evaluated against Alternaria dauci infection on carrot (Daucus carota L.) under greenhouse conditions.  The scanning and transmission electron microscopy (SEM and TEM) and ultra-violet (UV) visible spectroscopy were used to validate and characterize MgO NPs.  The crystalline nature of MgONPs was determined using selected area electron diffraction (SAED).  MgO NPs triggered substantial antifungal activity against A. dauci when exposed to 50 and 100 mg L–1 concentrations but the higher antifungal potential was noticed in 100 mg L–1 under in-vitro conditions.  In fungal inoculated plants, a marked decrease in growth, photosynthetic pigments, and an increase in phenol, proline contents, and defense-related enzymes of carrot were seen over control (distilled water).  However, foliar application of MgO NPs at 50 and 100 mg L–1 resulted in significant improvement of plant growth, photosynthetic pigments, phenol and proline contents, and defense enzymes activity of carrots with and without A. dauci infection.  Spraying of MgO NPs at 100 mg L–1 had more plant length (17.11%), shoot dry weight (34.38%), plant fresh weight (20.46%), and root dry weight (49.09%) in carrots when challenged with A. dauci over inoculated control.  The leaf blight indices and percent disease severity were also reduced in A. dauci inoculated plants when sprayed with MgO NPs.  The non-bonding interactions of Alternaria genus protein with nanoparticles were studied using molecular docking. Reference | Related Articles | Metrics Select Novel 18β-glycyrrhetinic acid amide derivatives show dual-acting capabilities for controlling plant bacterial diseases through ROS-mediated antibacterial efficiency and activating plant defense responses SONG Ying-lian, LIU Hong-wu, YANG Yi-hong, HE Jing-jing, YANG Bin-xin, YANG Lin-li, ZHOU Xiang, LIU Li-wei, WANG Pei-yi, YANG Song 2023, 22 (9): 2759-2771.   DOI: 10.1016/j.jia.2022.10.009 Abstract （235）      PDF in ScienceDirect       Natural products have long been a crucial source of, or provided inspiration for new agrochemical discovery.  Naturally occurring 18β-glycyrrhetinic acid shows broad-spectrum bioactivities and is a potential skeleton for novel drug discovery.  To extend the utility of 18β-glycyrrhetinic acid for agricultural uses, a series of novel 18β-glycyrrhetinic acid amide derivatives were prepared and evaluated for their antibacterial potency.  Notably, compound 5k showed good antibacterial activity in vitro against Xanthomonas oryzae pv. oryzae (Xoo, EC50=3.64 mg L–1), and excellent protective activity (54.68%) against Xoo in vivo.  Compound 5k induced excessive production and accumulation of reactive oxygen species in the tested pathogens, resulting in damaging the bacterial cell envelope.  More interestingly, compound 5k could increase the activities of plant defense enzymes including catalase, superoxide dismutase, peroxidase, and phenylalanine ammonia lyase.  Taken together, these enjoyable results suggested that designed compounds derived from 18β-glycyrrhetinic acid showed potential for controlling intractable plant bacterial diseases by disturbing the balance of the phytopathogen’s redox system and activating the plant defense system Reference | Related Articles | Metrics Select Degradation effects on dichlorvos by a biocontrol strain, Trichoderma atroviride T23 SUN Jia-nan, SI Gao-yue, LIU Hong-yi, LI Ya-qian, WANG Xin-hua, CHEN Jie 2023, 22 (9): 2746-2758.   DOI: 10.1016/j.jia.2023.01.009 Abstract （206）      PDF in ScienceDirect       Excessive use of organophosphate pesticides (OP), such as dichlorvos, in farming system poses a threat to human health through potential contamination of environment.  To date, biodegradation has been prospected most promising approach to eliminate environmental OP residues.  Trichoderma species as a biological control microorganism is often exposed to the chemical pesticides applied in environments, so it is necessary to understand the mechanism of degradation of dichlorvos by Trichoderma.  In this study, dichlorvos significantly inhibited the growth, sporulation and pigmentation of T. atroviride T23, and the dichlorvos degradation activity of T23 required the initial induction effect of dichlorvos and the culture conditions, including the nutrient and pH values of the medium.  Various changed primary and secondary metabolites released from T23 in the presence of dichlorvos were speculated as the energy and antioxidants for the strain itself to tolerate dichlorvos stress.  The results showed that T23 could produce a series of enzymes, especially the intracellular enzymes, to degrade dichlorvos.  The activities of the intracellular enzyme generated by T23 were differentially changed along time course and especially relied on initial dichlorvos concentration, ammonium sulfate and phosphate added in the medium.  In conclusion, some dichlorvos-induced chemical degradation related enzymes of T23 were proved to be involved in the degradation of dichlorvos. Reference | Related Articles | Metrics Select Mitochondrial dynamics caused by QoIs and SDHIs fungicides depended on FgDnm1 in Fusarium graminearum KANG Jin-bo, ZHANG Jie, LIU Yin-kai, SONG Ji-chang, OU Jian-lin, TAO Xian, ZHOU Ming-guo, DUAN Ya-bing 2023, 22 (2): 481-494.   DOI: 10.1016/j.jia.2022.08.118 Abstract （482）      PDF in ScienceDirect       Fusarium head blight (FHB) caused by Fusarium graminearum is a devastating fungal disease on small grain cereal crops, because it reduces yield and quality and causes the mycotoxin contamination to the grain.  Dynamins and dynamin-related proteins (DRPs) are large GTPase superfamily members, which are typically involved in the budding and division of vesicles in eukaryotic cells, but their roles in Fusarium spp. remain unexplored.  Here, we found that FgDnm1, a DRP and homolog to Dnm1 in Saccharomyces cerevisiae, contributes to the normal fungal growth, sexual reproduction and sensitivity to fungicides.  In addition, we found FgDnm1 co-localizes with mitochondria and is involved in toxisome formation and deoxynivalenol (DON) production.  Several quinone outside inhibitors (QoIs) and succinate dehydrogenase inhibitors (SDHIs) cause fragmentated morphology of mitochondria.  Importantly, the deletion of FgDnm1 displays filamentous mitochondria and blocks the mitochondrial fragmentation induced by QoIs and SDHIs.  Taken together, our studies uncover the effect of mitochondrial dynamics in fungal normal growth and how such events link to fungicides sensitivity and toxisome formation.  Thus, we concluded that altered mitochondrial morphology induced by QoIs and SDHIs depends on FgDnm1. 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