The antifungal mechanism of the biogenic antimicrobial Ningnanmycin on Didymella segeticola involves binding to tryptophanyl-tRNA synthetase, inhibiting translation

Abstract BackgroundTea [Camellia sinensis (L.) Kuntze] has been recently cultivated in Guizhou Province, China, where the cultivated area has reached 350,000 hectares, making it the major tea-growing region in world. Tea leaf spot caused by Didymella segeticola can induce the decreases in quality and quantity of tea leaves, which is an important disease in tea plantations at higher altitude, where cold spells occur in late spring. As a promising biogenic antimicrobial agent against crop diseases, Ningnanmycin (NNM) was produced from Streptomyces noursei var. xichangensisn, represented higher field efficiency against fungal, bacterial and viral phytopathogens, lower toxicity and lower residue. However, the action mechanism of NNM against phytopathogens just stays on the stage of anti-viral mechanism, which limits the application of NNM in the management of plant fungal diseases. Here, we studied the action mechanism of NNM against D. segeticola using many methods of transcriptome, ultrastructure, molecular biology and molecular docking.ResultsNNM strongly inhibited the mycelial growth of D. segeticola with the half-maximal effective concentration of 1287.54 U/mL. Optical, fluorescence, scanning and transmission electron microscopy were applied to observe morphological changes of cellular, organelle for D. segeticola treated by NNM. A great number of morphological changes of D. segeticola indicated that NNM could affect the biosynthesis of the phytopathogen. For further, RNA-Seq results showed that NNM treated D. segeticola induced 1,363 significantly differentially expressed genes (DEGs) comparing with the control (P < 0.05). The DEGs were highly enriched in structural component of ribosome, ribosome and translation by Gene Ontology, as well as in ribosome pathway at Kyoto Encyclopedia of Genes and Genomes. NNM regulated the mRNA levels of RPS7, RPS9, RPS10b, RPL9, RPL11 and TrpRS, and represent the different regulation mode by the comparative analysis with a classical translation extension inhibitor, cycloheximide. The molecular docking indicated that NNM possessed a marked affinity with TrpRS, with the binding free energy is -101.55 kcal/mol.ConclusionsNNM could potentially affect translation by binding to tryptophanyl-tRNA synthetase, thus inhibiting mycelial growth. This study will provide insights for anti-fungal mechanism of NNM and contribute to the control and prevention of tea leaf spot disease.

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Integrated mRNA and small RNA sequencing for analyzing tea leaf spot pathogen Lasiodiplodia theobromae, under in vitro conditions and the course of infection

Phytopathology ◽

10.1094/phyto-07-20-0297-a ◽

2020 ◽

Author(s):

Shilong Jiang ◽

Qiaoxiu Yin ◽

Dongxue Li ◽

Xian Wu ◽

Yong Wang ◽

...

Keyword(s):

Small Rna ◽

Leaf Spot ◽

Guizhou Province ◽

Phytopathogenic Fungus ◽

Future Research ◽

Small Rna Sequencing ◽

Rna Sequences ◽

Lasiodiplodia Theobromae ◽

Tea Leaf

Lasiodiplodia theobromae (Pat.) Griffon & Maubl. is a phytopathogenic fungus, which can cause many different diseases on different crops. The pathogen can cause leaf spot on tea plants (Camellia sinensis), which negatively affects the productivity and quality of tea leaves in tea plantations in Guizhou Province, China. Although the genome sequence of L. theobromae has been published, no data on the transcriptome or small RNA sequences of L. theobromae under in vitro conditions and the course of infection of tea leaf are available. Here, we report the high-quality transcriptome and small RNA sequences of L. theobromae under in vitro conditions and the course of infection of tea leaf using the platform of Illumina HiSeq. This comprehensive expression profiling of the fungal pathogen will provide a valuable resource for future research on trait-specific genes of the pathogen, host-pathogen interactions and on disease resistance in the host.

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Effect of fungicides on the mycelial growth of Alternaria alternata causing leaf spot disease in ashwagandha

INTERNATIONAL JOURNAL OF PLANT PROTECTION ◽

10.15740/has/ijpp/9.1/153-157 ◽

2016 ◽

Vol 9 (1) ◽

pp. 153-157

Author(s):

N. KALIESWARI ◽

I. YESU RAJA ◽

M. DEVI

Keyword(s):

Alternaria Alternata ◽

Leaf Spot ◽

Mycelial Growth ◽

Leaf Spot Disease ◽

Spot Disease

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Integration of Transcriptomic and Proteomic Data Reveals the Possible Action Mechanism of the Antimicrobial Zhongshengmycin against Didymella segeticola, the Causal Agent of Tea Leaf Spot

Phytopathology ◽

10.1094/phyto-02-21-0073-r ◽

2021 ◽

Author(s):

Yafeng Ren ◽

Dongxue Li ◽

Shilong Jiang ◽

Yu Wang ◽

Qin Tang ◽

...

Keyword(s):

Leaf Spot ◽

Mode Of Action ◽

Morphological Changes ◽

Extracellular Polysaccharides ◽

Proteomics Data ◽

Protein Levels ◽

Proteomic Data ◽

Half Maximal Effective Concentration ◽

Tea Leaf

Tea leaf spot, caused by the fungal phytopathogen Didymella segeticola (Q. Chen) Q. Chen, Crous & L. Cai (syn. Phoma segeticola, is an important foliar disease, which can cause a huge loss in terms of the production and quality of tea for no effective management measures to control the disease. This study screened a natural antimicrobial chemical for its activity against D. segeticola and studied its mode of action. Antifungal activity of the Streptomyces-derived antimicrobial Zhongshengmycin (ZSM) against D. segeticola strain GZSQ-4 was assayed in vitro by the mycelial growth rate method. Optical microscopy, scanning and transmission electron microscopy were used to observe the morphological effects on hyphae treated with ZSM, with these studies being complemented by transcriptomics, proteomics, and bioinformatics studies to identify the differentially expressed genes (DEGs) or the differentially expression proteins (DEPs) in hyphae treated with ZSM. Correlation analysis of transcriptomics and proteomics data were used to reveal the mode of action. The results indicated that ZSM could inhibit the growth of hyphae in vitro with a half-maximal effective concentration (EC50) of 5.9 μg mL-1, inducing some morphological changes in organelles, septa, and extracellular polysaccharides, targeting ribosomes to disturb translation, affecting the biosynthesis of some hyphal proteins at the mRNA and protein levels, and revealing correlation between findings from transcriptomes and proteomes.

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First Report of Botryosphaeria dothidea Causing Leaf Spot on Kadsura coccinea in China

Plant Disease ◽

10.1094/pdis-01-21-0150-pdn ◽

2021 ◽

Author(s):

Dan Su ◽

Wenhao Zhang ◽

Rui Sun ◽

Zhuting Zhang ◽

Guozhong Lyu

Keyword(s):

Molecular Characterization ◽

Leaf Spot ◽

Guizhou Province ◽

Leaf Spot Disease ◽

Pathogenicity Test ◽

Botryosphaeria Dothidea ◽

Internal Transcribed Spacer Region ◽

First Report ◽

Kadsura Coccinea ◽

Morphological And Molecular Characterization

Kadsura coccinea (Lem.) A. C. Smith, belonging to Schisandraceae, is an evergreen, woody climbing plant that is distributed widely in southwest China. Additionally, K.coccinea is used as an ethnic medicine and its main chemical components are lignin and terpenoids. The roots of the plant have been effectively used for treatment of cancer and dermatosis and as an anodyne to relieve pain (Song et al. 2010). In June 2019, a leaf spot disease on K. coccinea was first observed in a greenhouse in Qiandongnan Miao and Dong Autonomous Prefecture, Guizhou Province, China. Over 300 plants were surveyed in the three greenhouses, and nearly 70% of the plants were infected. The diseased plants grew poorly and appeared stunted, and severely affected plants died. The symptoms occurred on leaves as small brown spots initially and then developed into suborbicular or irregular-shaped brown necrotic lesions, which often displayed irregular concentric rings. Four diseased leaves from four symptomatic Kadsura coccinea plants were randomly collected for pathogen isolation. Diseased tissues were cut into about 2mm diameter fragments, surface sterilized with 75% ethanol for 15 s and 1% NaClO for 2 min, and then rinsed twice in sterilized distilled water. After being dried on sterilized filter paper, the fragments were placed on potato dextrose agar (PDA) and incubated at 25°C in the dark for 5 days. The same fungus was isolated in 95% of the samples. A representative isolate, F2020003 was used for morphological and molecular characterization. The colonies were initially white, gradually turning gray-green to dark gray after 7 days, with abundant gray aerial mycelium. Conidia were one-celled, hyaline, fusoid to ellipsoid and measured 24.3 ± 1.9 × 4.8 ± 0.7 µm (n = 50). The conidial morphology matched the description of Botryosphaeria dothidea (Slippers et al. 2004). To verify identity, the partial sequences of the internal transcribed spacer region, translation elongation factor 1 alpha genes and beta-tubulin, were amplified from isolate F2020003 with primers ITS1/ITS4 (GenBank accession no. MW111267), EF1-728F/EF1-986R (GenBank accession no. MW196739) and BT-2a/BT-2b (GenBank accession no. MW206378), respectively（Sun et al. 2014）. The isolates were confirmed as B. dothidea based on morphological comparisons and BLAST searches (Zhai et al. 2014). To assess pathogenicity, five healthy leaves on each of the three 6-month-old healthy K. coccinea plants were wound inoculated with a sterilized needle. Mycelium plugs (4 mm in diameter) taken from a 5-day-old culture on PDA were inoculated on surface-sterilized leaves (sprayed with 75% ethanol). PDA plugs with no mycelium were used as a control. Plants with treated leaves were covered with plastic bags and incubated in a greenhouse at 25°C. The pathogenicity test was repeated three times. Within 4 days, all the inoculated points showed lesions similar to those previously observed in the greenhouse, whereas controls were asymptomatic. Fungi re-isolated from inoculated leaves were confirmed as B. dothidea on the basis of morphological and molecular characterization as described above. B. dothidea is a member of Botryosphaeriaceae, it has been reported to cause leaf spot on Celtis sinensis (Wang et al., 2020) and branch canker on Malosma laurina (Aguirre et al., 2018) in China. To our knowledge, this is the first report of B. dothidea causing leaf spot on K. coccinea in China. The identification of this pathogen will be helpful to prevent and control this disease in the future.

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OCCURRENCE OF ALTERNARIA LEAF SPOT DISEASE ON ALOE VERA AND ITS MANAGEMENT

Pakistan Journal of Phytopathology ◽

10.33866/phytopathol.031.01.0396 ◽

2019 ◽

Vol 31 (1) ◽

pp. 75-80

Author(s):

Muhammad M Rasheed ◽

Amer Habib ◽

Mustansar Aslam ◽

Zeeshan Mansha ◽

Abdul Rehman ◽

...

Keyword(s):

Disease Control ◽

Plant Extracts ◽

Leaf Spot ◽

Mycelial Growth ◽

Disease Incidence ◽

Aloe Vera ◽

Leaf Spot Disease ◽

Dry Rot ◽

Alternaria Leaf Spot

Aloe vera is a valuable medicinal crop of the world. It suffers from several diseases but among them alternaria leaf spot and dry rot is most serious fungal disease which effects the commercial production and quality losses to Aloe vera. A survey was conducted to estimate the prevalence of dry rot disease in different nurseries located in urban areas of Faisalabad. During this survey maximum disease incidence was recorded in Horti club nursery (100%) and minimum disease incidence recorded at Faiz baho nursery and Qadir baksh form (13.8%). Among in-vitro tested fungicides Score gives maximum mycelial growth inhibition (89.5%) and maximum disease control (17.7%) as compared to control and other tested chemicals. Among in-vitro tested plant extracts Neem gives maximum mycelial growth inhabitation (41.2%) and in green house gives 14.2% disease control. Out of four tested fungicides and plant extracts Score and Neem gives best results against A. alternata mycelial growth and disease control.

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First report of Alternaria longipes causing leaf spot on tea in China

Plant Disease ◽

10.1094/pdis-07-20-1583-pdn ◽

2021 ◽

Author(s):

Qiaoxiu Yin ◽

Xiaoli An ◽

Xian Wu ◽

Dissanayake Saman Pradeep Dharmasena ◽

Dongxue Li ◽

...

Keyword(s):

Leaf Spot ◽

Disease Incidence ◽

Early Spring ◽

Guizhou Province ◽

Leaf Spot Disease ◽

Control Group ◽

Post Inoculation ◽

First Report ◽

Spot Disease ◽

Light Yellow

Tea [Camellia sinensis (L.) Kuntze)] have been widely planted in Guizhou Province in recent years, and the cultivation area in the region ranks first among all the provinces or cities in China. Leaf spot disease was an important disease of tea in Kaiyang county, Guizhou Province, which mainly damaged young leaves and shoot of tea and led to a huge loss of the production of tea. The spots initially represented brown and round, and then the diameter of the spot was 4-6 mm during later period, with the color of the center in the spot changing white. Tea leaf spot disease always occurs in early spring and the region with 1300 m altitude. From 2016 to 2019, disease incidence of leaves was estimated at 84% to 92%, and the disease severity on a plant basis was determined to be 64% to 76%, depending on the field. To identify the causal agent of the foliar disease, pieces of the lesion margins were surface sterilized with 75% ethanol for 30 s, followed by 0.5% sodium hypochlorite for 5 min, rinsed with sterile water three times, plated on potato dextrose agar (PDA) and incubated in the dark at 25C for 3 to 5 d. The hyphal tips from the margins of the growing colonies were successively picked and transferred to fresh PDA plates to purify the isolates. The result indicated that the isolates on PDA represented initially round form, and white mycelium. The reverse sides of the isolates firstly displayed light yellow on PDA. Conidiophores represent dark brown, geniculate. Brown conidia, narrow ovoid, length: 22.9 ± 4.5 μm, width: 11.1 ± 1.7 μm, with 4 to 8 transverse septa and with conspicuously ornamented walls. The gene of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (Berbee et al. 1999) and the Alternaria allergen 1 (Alt a1) (Hong et al. 2005) of three strains were amplified, sequenced and deposited in Genbank. Maximum parsimony phylogenetic analysis based on concatenated sequences of combined GAPDH (1-583) and Alt a 1 (588-1065) indicated that the strain AXLKY_2019_010 was identical to reference strain Alternaria longipes strain EGS 30-033, and the clade was supported by 96% bootstrap values. According to the Koch’s postulate, the tea leaves were inoculated with PDA plugs with actively growing mycelia using the methods of the puncture, cut and unwound under the laboratory conditions and the natural conditions. Slight yellow spots were gradually formed after 2 d post-inoculation on the inoculated leaves, and the color of the center of the spot changed to be white. With the prolonging of inoculation time, the size of lesion represented to be slightly enlarged. PDA plugs without mycelia were used as a control, and the control group showed no symptoms. The same isolates were consistently reisolated from inoculated leaves. A. longipes can cause leaf blight of carrots in Israel (Vintal et al. 2002), leaf spot of potato in Pakistan (Shoaib et al. 2014) and leaf spot of Atractylodes macrocephala in China (Tan et al. 2012). To our knowledge, this is the first report of A. longipes causing leaf spot on tea in China and our findings will be useful for its management and for further research.

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Whole Genome Sequences of the Tea Leaf Spot Pathogen Didymella segeticola

Phytopathology ◽

10.1094/phyto-02-19-0050-a ◽

2019 ◽

Vol 109 (10) ◽

pp. 1676-1678 ◽

Cited By ~ 1

Author(s):

Yafeng Ren ◽

Dongxue Li ◽

Xiaozhen Zhao ◽

Yong Wang ◽

Xingtao Bao ◽

...

Keyword(s):

Leaf Spot ◽

Guizhou Province ◽

Whole Genome Sequence ◽

Future Research ◽

Whole Genome ◽

Plant Host ◽

Illumina Hiseq ◽

Leaf Production ◽

Clusters Of Orthologous Groups ◽

Tea Leaf

The fungal pathogen Didymella segeticola (basionym Phoma segeticola) causes leaf spot on tea (Camellia sinensis), which leads to a loss in tea leaf production in Guizhou Province, China. D. segeticola isolate GZSQ-4 was sequenced using Illumina HiSeq and Pacific Biosciences (PacBio) RS technologies, and then assembled to approximately 33.4 Mbp with a scaffold N50 value of approximately 2.3 Mbp. In total, 10,893 genes were predicted using the Nonredundant, Gene Ontology, Clusters of Orthologous Groups, Kyoto Encyclopedia of Genes and Genomes, and SWISS-PROT databases. The whole-genome sequence of D. segeticola will provide a resource for future research on host−pathogen interactions, determination of trait-specific genes, pathogen evolution, and plant−host adaptation mechanisms.

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TWO NEW SEVERE LEAF SPOT DISEASE ON FOREST TREES OF JALGAON (MAHARASTRA) INDIA

FLORA AND FAUNA ◽

10.33451/florafauna.v23i2pp288-290 ◽

2017 ◽

Vol 23 (2) ◽

Author(s):

S. A. FIRDOUSI

Keyword(s):

Leaf Spot ◽

Fungal Disease ◽

Leaf Spot Disease ◽

Forest Trees ◽

First Report ◽

Spot Disease ◽

Severe Leaf

During the survey of the forest fungal disease, of Jalgaon district, two severe leaf spot diseases on Lannae coromandelica and ( Ougenia dalbergioides (Papilionaceae) were observed in Jalgaon, forest during July to September 2016-17. The casual organism was identified as Stigmina lanneae and Phomopsis sp. respectively1-4,7. These are first report from Jalgaon and Maharashtra state.

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