Relative Level of Bacteriophage Multiplication in vitro or in Phyllosphere May Not Predict in planta Efficacy for Controlling Bacterial Leaf Spot on Tomato Caused by Xanthomonas perforans

White leaf spot pathogen: Neopseudocercosporella capsellae causes significant damage to many economically important Brassicaceae crops, including oilseed rape through foliar, stem, and pod lesions under cool and wet conditions. A lack of information on critical aspects of the pathogen’s life cycle limits the development of effective control measures. The presence of single-celled spores along with multi-celled conidia on cotyledons inoculated with multi-celled conidia suggested that the multi-celled conidia were able to form single-celled spores on the host surface. This study was designed to demonstrate N. capsellae morphological plasticity, which allows the shift between a yeast-like single-celled phase and the multi-celled hyphal phase. Separate experiments were designed to illustrate the pathogen’s morphological transformation to single-celled yeast phase from multi-celled hyphae or multi-celled macroconidia in-vitro and in-planta. Results confirmed the ability of N. capsellae to switch between two morphologies (septate hyphae and single-celled yeast phase) on a range of artificial culture media (in-vitro) or in-planta on the host surface before infection occurs. The hyphae-to-yeast transformation occurred through the production of two morphologically distinguishable blastospore (blastoconidia) types (meso-blastospores and micro-blastospores), and arthrospores (arthroconidia).

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Stability of bacterial leaf spot resistance in peach regenerants under in vitro, greenhouse and field conditions

Euphytica ◽

10.1007/bf00024026 ◽

1994 ◽

Vol 76 (1-2) ◽

pp. 101-106 ◽

Cited By ~ 4

Author(s):

F. A. Hammerschlag ◽

D. J. Werner ◽

D. F. Ritchie

Keyword(s):

Leaf Spot ◽

Field Conditions ◽

Bacterial Leaf Spot

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Synthesis and Characterization of Novel Copper Nanoparticles for the Control of Leaf Spot and Anthracnose Diseases of Olive

Nanomaterials ◽

10.3390/nano11071667 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1667

Author(s):

Panagiota Ntasiou ◽

Alexandra Kaldeli Kerou ◽

Theodora Karamanidou ◽

Afrodite Vlachou ◽

George T. Tziros ◽

...

Keyword(s):

Leaf Spot ◽

Mycelial Growth ◽

Crop Protection ◽

Attenuated Total Reflection ◽

Colletotrichum Acutatum ◽

In Planta ◽

Colletotrichum Spp ◽

Type 3

Olive crop is frequently treated with copper fungicides to combat foliar and fruit diseases such as olive leaf spot caused by Fusicladium oleagineum and anthracnose caused by Colletotrichum spp. The replacement of copper-based products with more eco-friendly alternatives is a priority. Metal nanoparticles synthesized in several ways have recently revolutionized crop protection with applications against important crop pathogens. In this study, we present the development of four copper-based nanoparticles (CuNP Type 1 to 4) synthesized with a wet chemistry approach. The CuNPs were characterized using Transmission Electron Microscopy, Dynamic Light Scattering, Laser Doppler Electrophoresis, and Attenuated Total Reflection measurements. In addition, the activity of the four CuNP types was tested in vitro and in planta against F. oleagineum and Colletotrichum spp. In vitro sensitivity measurements showed that for both pathogens, mycelial growth was the most susceptible developmental stage to the tested compounds. Against both pathogens, CuNP Type 1 and Type 2 were found to be more active in reducing mycelial growth compared to the reference commercial compounds of copper oxide and copper hydroxide. In planta experiments showed that CuNP Type 3 and CuNP Type 4 exhibited a strong protectant activity against both F. oleagineum and Colletotrichum acutatum with control efficacy values significantly higher than those achieved by the applications of either reference product.

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In-vitro Evaluation of Chemotoxicants Inhibiting the Bacterial Leaf Spot Pathogen of Betelvine (Pseudomonas betle)

International Journal of Current Microbiology and Applied Sciences ◽

10.20546/ijcmas.2018.708.303 ◽

2018 ◽

Vol 7 (08) ◽

pp. 2872-2876

Author(s):

S. Hembram ◽

S. Baskey ◽

D.C. Khatua

Keyword(s):

Leaf Spot ◽

Bacterial Leaf Spot ◽

In Vitro Evaluation

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Bacterial Leaf Spot of Tomato (Solanum lycopersicum) in Louisiana is Caused by Xanthomonas perforans, Tomato Race 4

Plant Disease ◽

10.1094/pdis-12-15-1451-pdn ◽

2016 ◽

Vol 100 (6) ◽

pp. 1233-1233 ◽

Cited By ~ 3

Author(s):

M. L. Lewis Ivey ◽

A. Strayer ◽

J. K. Sidhu ◽

G. V. Minsavage

Keyword(s):

Solanum Lycopersicum ◽

Leaf Spot ◽

Bacterial Leaf Spot ◽

Xanthomonas Perforans ◽

Race 4

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In vitro Efficacy Bioagents against Bacterial Leaf Spot of Chilli caused by Xanthomonas axonopodis pv. vesicatoria

International Journal of Current Microbiology and Applied Sciences ◽

10.20546/ijcmas.2020.912.014 ◽

2020 ◽

Vol 9 (12) ◽

pp. 106-111

Author(s):

S. M. Chapke ◽

D. S. Bharti ◽

P. L. Sontakke ◽

M. G. Patil ◽

D. N. Dhutraj

Keyword(s):

Leaf Spot ◽

Bacterial Leaf Spot ◽

Xanthomonas Axonopodis

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Bacterial Leaf Spot of Leafy Crucifers in Oklahoma Caused by Pseudomonas syringae pv. maculicola

Plant Disease ◽

10.1094/pdis.2000.84.9.1015 ◽

2000 ◽

Vol 84 (9) ◽

pp. 1015-1020 ◽

Cited By ~ 37

Author(s):

Youfu Zhao ◽

John P. Damicone ◽

David H. Demezas ◽

Vidhya Rangaswamy ◽

Carol L. Bender

Keyword(s):

Carbon Source ◽

Pseudomonas Syringae ◽

Leaf Spot ◽

Xanthomonas Campestris ◽

Bacterial Disease ◽

Bacterial Leaf Spot ◽

Local Strains ◽

Fluorescent Pseudomonas ◽

Reference Strains

During 1995 and 1996, bacterial leaf spots severely damaged fields of kale, spinach mustard, and turnip in Oklahoma. Symptoms were small, brown, necrotic spots with irregular edges surrounded by chlorotic halos. Lesion margins were often water-soaked on the abaxial surface. The spots enlarged and coalesced, causing extensive leaf yellowing and necrosis. Nineteen strains of a fluorescent Pseudomonas spp. were isolated from symptomatic plants. LOPAT tests and carbon source oxidation using Biolog GN MicroPlates were used to classify the strains as P. syringae. Cluster analysis of carbon source oxidation profiles for the local strains and selected reference strains of P. syringae pv. maculicola and pv. tomato produced one group with 79.5% similarity. In spray inoculations, all local strains caused chlorotic or water-soaked lesions on collards, kale, cauliflower, and tomato. A few local strains caused necrotic lesions on mustard. Most local strains caused one of the three lesion types on turnip and spinach mustard. Reference strains of P. syringae pv. maculicola caused similar symptoms. All but three of the local strains produced coronatine in vitro. The local strains were thus classified as P. syringae pv. maculicola, the cause of bacterial leaf spot of crucifers. Two distinct groups of P. syringaepv. maculicola were identified by repetitive sequence-based polymerase chain reaction (rep-PCR) with both REP and BOXA1R primers. Three subgroups within each group were further identified using the BOXA1R primer. Except for two strains of P. syringae pv. tomato which were pathogenic on crucifers, the pathovars maculicola and tomato had different genetic fingerprints. The pathogen was recovered from seven of ten fields sampled during 1994 to 1996. In five of the fields with P. syringae pv. maculicola, pathovars of Xanthomonas campestris were also isolated from lesions forming a bacterial disease complex. This is the first report of bacterial leaf spot caused by P. syringaepv. maculicola on leafy crucifers in Oklahoma.

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Sugar maple autumn-shed leaf extract: a potential antibacterial agent for the management of lettuce bacterial leaf spot (Xanthomonas campestris pv. vitians) and varnish spot (Pseudomonas cichorii)

Canadian Journal of Plant Science ◽

10.1139/cjps-2019-0040 ◽

2020 ◽

Vol 100 (1) ◽

pp. 78-85 ◽

Cited By ~ 2

Author(s):

M. Delisle-Houde ◽

R.J. Tweddell

Keyword(s):

Leaf Spot ◽

Xanthomonas Campestris ◽

Sugar Maple ◽

Foliar Application ◽

Antibacterial Activities ◽

Northern Red Oak ◽

Bacterial Leaf Spot ◽

Pseudomonas Cichorii ◽

Bacterial Diseases

Different extracts prepared from wastes (barks, branches, needles, or leaves) of different trees (grey alder, balsam fir, American larch, red maple, sugar maple, white spruce, black spruce, jack pine, white pine, quaking aspen, sweet cherry, and northern red oak) were investigated for their potential use as antibacterial agents for the management of lettuce varnish spot and bacterial leaf spot caused by Pseudomonas cichorii (Swingle) Stapp and Xanthomonas campestris pv. vitians (Brown) Dye, respectively. Extracts were first screened for their antibacterial activities against P. cichorii and X. campestris pv. vitians using the in vitro disk diffusion assay. Based on the diameter of the inhibition zone, ethanol (95%) extract prepared from sugar maple autumn-shed leaves (SMASL) and aqueous ethanol (50%, v/v) extracts prepared from SMASL and from sugar maple green leaves showed the strongest antibacterial activities. Ethanol (95%) SMASL extract was further investigated for its efficacy to manage bacterial diseases when applied on lettuce plants grown in the greenhouse. Foliar application of ethanol (95%) SMASL extract at a concentration of 3.2 g L−1 was shown to significantly (P ≤ 0.05) reduce bacterial leaf spot severity compared with the control without causing phytotoxicity symptoms that could prevent the commercial marketing of the lettuce. Ethanol (95%) SMASL extract (1.6 and 3.2 g L−1) was also shown to significantly reduce varnish spot severity in one experiment out of two. This study identifies for the first time the possibility of exploiting SMASL to manage bacterial diseases affecting horticultural crops.

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