scholarly journals Antimicrobial property of chitosan and induction of systemic acquired resistance for the control of rice bacterial blight caused by Xanthomonas oryzae pv. oryzae (Swings et al.)

2009 ◽  
pp. 69-89 ◽  
Author(s):  
Ivy Modina ◽  
Candelario Calibo ◽  
Lucia Borines
Keyword(s):  
Bacterial Blight ◽  
Systemic Acquired Resistance ◽  
Antimicrobial Property ◽  
Acquired Resistance ◽  
Foliar Spray ◽  
Xanthomonas Oryzae ◽  
Rice Plants ◽  
Rice Bacterial Blight ◽  
Commercial Plant

Chitosan has been reported to have antimicrobial property to some pathogen species as well as an elicitor of resistance in plants , particularly Systemic Acquired Resistance (SAR). A bioassay of chitosan against Xanthomonas oryzae pv. oryzae (Xoo) was conducted to determine its antimicrobial property against bacterial blight pathogen and the optimum concentration that is most inhibitory to the pathogen. Chitosan was also tested as foliar spray to rice plants to evaluate its potential to induce SAR against bacterial blight disease. Chitosan treatments (300 ppm, 400 ppm, and 500 ppm) possessed antimicrobial property against Xoo in vitro, producing zones of inhibition which were generally significantly bigger than those of the control (streptomycin, acetic acid, and sterile distilled water) at 2, 4, and 6 days after inoculation. Chitosan-sprayed plants showed significantly shorter bacterial blight lesions which were comparable to the plants sprayed with streptomycin, and Boost, a commercial plant defense activator and a known inducer of SAR. Chitosan is found effective in reducing bacterial blight lesions in rice plants due to its antimicrobial property and also most likely due to the induction of SAR.

scholarly journals Foliar Spray of Validamycin A or Validoxylamine A Controls Tomato Fusarium Wilt

2005 ◽  
Vol 95 (10) ◽  
pp. 1209-1216 ◽  
Author(s):  
Ryo Ishikawa ◽  
Kentaro Shirouzu ◽  
Hideo Nakashita ◽  
Han-Young Lee ◽  
Takayuki Motoyama ◽  
...  
Keyword(s):  
Systemic Acquired Resistance ◽  
Control Method ◽  
Foliar Application ◽  
Acquired Resistance ◽  
Foliar Spray ◽  
Marker Genes ◽  
Pr Genes ◽  
Validamycin A ◽  
Soil Fumigants

Tomato wilt, caused by the soilborne fungus Fusarium oxysporum f. sp. lycopersici, is effectively controlled by a foliar spray of validamycin A (VMA) or validoxylamine A (VAA) (≥10 μg/ml); however, neither VMA nor VAA is antifungal in vitro. In pot tests, the effect of a foliar application of VMA or VAA at 100 μg/ml lasted for 64 days. Plants sprayed with VMA or VAA accumulated salicylic acid and had elevated expression of the systemic acquired resistance (SAR) marker genes P4 (PR-1), Tag (PR-2), and NP24 (PR-5). Foliar spray of VMA also controlled late blight and powdery mildew of tomato. The disease control by VMA and VAA lasted up to 64 days after treatment, was broad spectrum, and induced the expression of PR genes, all essential indicators of SAR, suggesting that VMA and VAA are plant activators. The foliar application of plant activators is a novel control method for soilborne diseases and may provide an economically feasible alternative to soil fumigants such as methyl bromide.

scholarly journals An xa5 Resistance Gene-Breaking Indian Strain of the Rice Bacterial Blight Pathogen Xanthomonas oryzae pv. oryzae Is Nearly Identical to a Thai Strain

2020 ◽  
Vol 11 ◽  
Author(s):  
Sara C. D. Carpenter ◽  
Prashant Mishra ◽  
Chandrika Ghoshal ◽  
Prasanta K. Dash ◽  
Li Wang ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Bacterial Blight ◽  
Xanthomonas Oryzae ◽  
Rice Bacterial Blight ◽  
Indian Strain ◽  
Bacterial Blight Pathogen

scholarly journals Comparison of Methods of Acibenzolar-S-Methyl Application for Post-Infection Fire Blight Suppression in Pear and Apple

Plant Disease ◽  
2016 ◽  
Vol 100 (6) ◽  
pp. 1125-1131 ◽  
Author(s):  
Kenneth B. Johnson ◽  
Todd N. Temple
Keyword(s):  
Fire Blight ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Foliar Spray ◽  
Field Research ◽  
Apple Rootstocks ◽  
Pr Genes ◽  
Treatment Timing ◽  
Guide Field ◽  
Pathogenesis Related

Greenhouse-grown, 1-year-old potted ‘Bosc’ pear and apple rootstock cultivars ‘M.9’ and ‘M.26’ were inoculated with the fire blight pathogen, Erwinia amylovora, and subjected to trunk paint, root drench, or foliar spray treatments with acibenzolar-S-methyl (ASM, 4 to 30 mg a.i./tree) to induce systemic acquired resistance. Each method of ASM treatment suppressed fire blight canker expansion by 22 to 25%. Furthermore, ASM application method and ASM treatment timing (at or ±3 weeks relative to inoculation) interacted significantly (P ≤ 0.02) in each experiment. A root drench was most effective when applied 3 weeks before inoculation (36% suppression) whereas trunk paints and foliar sprays were more effective at inoculation (43 and 34%, suppression, respectively). Sizes of fire blight cankers in potted apple rootstocks M.9 and M.26 (under scions ‘Gala’ or ‘Cameo’) inoculated directly with the pathogen were reduced by 82 and 87% after two pretreatments of ASM applied as a trunk paint or root drench, respectively. Expression of pathogenesis-related (PR) genes PR-1 and -2 in apple leaves sampled after an ASM trunk paint were elevated significantly (P ≤ 0.05) relative to control trees for at least 9 weeks after treatment. Results of this study are being used to guide field research on postinfection therapy with ASM in 1- to 10-year-old pear and apple trees where fire blight has proven difficult to manage with therapeutic pruning only.

scholarly journals Comparative Efficacy of Systemic Acquired Resistance-Inducing Compounds Against Rust Infection in Sunflower Plants

2007 ◽  
Vol 97 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Esther Amzalek ◽  
Yigal Cohen
Keyword(s):  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Foliar Spray ◽  
Racemic Mixture ◽  
In Planta ◽  
Butanoic Acid ◽  
Defense Compounds ◽  
Rust Infection ◽  
Puccinia Helianthi ◽  
Full Protection

Four inducers of systemic acquired resistance (SAR) were examined for their efficacy in controlling rust infection caused by Puccinia helianthi in sunflower plants. Of the four compounds, DL-3-amino-n-butanoic acid (DL-β-aminobutyric acid [BABA]) was the most effective and sodium salicylate (NaSA) was the least effective in protecting against rust. In leaf disk assays, full protection was obtained with BABA at 25 μg/ml, benzodiathiazol-S-methyl ester (BTH) at 100 μg/ml, 2,6-di-chloroisonicotinic acid (INA) at 100 μg/ml, and NaSA at >200 μg/ml. L-2-amino-n-butanoic acid (AABA) was partially effective, whereas N-methyl-BABA and 4-aminobutnoic acid (GABA) were ineffective. The R-enantiomer of BABA, but not the S-enantiomer, was more effective than the racemic mixture. In intact plants, BABA applied as a foliar spray or a root dip, before or after (up to 48 h) inoculation, provided significant protection for 8 days. BTH, INA, and NaSA were less protective and more phytotoxic compared with BABA. BABA did not affect urediospore germination, germ tube growth, appressorial formation, or initial ingress of P. helianthi, but strongly suppressed mycelial colonization in the mesophyll and, consequently, pustule and urediospore formation. No accumulation of defense compounds (phenolics, lignin, or callose) was detected in BABA-treated inoculated or noninoculated plants. This is the first report on the activity of BABA against an obligate Basidomycete pathogen in planta.

Biological control of rice bacterial blight by plant-associated bacteria producing 2,4-diacetylphloroglucinol

2006 ◽  
Vol 52 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Palaniyandi Velusamy ◽  
J Ebenezar Immanuel ◽  
Samuel S Gnanamanickam ◽  
Linda Thomashow
Keyword(s):  
Biological Control ◽  
Pseudomonas Fluorescens ◽  
Bacterial Blight ◽  
Field Experiments ◽  
Screening Method ◽  
Xanthomonas Oryzae ◽  
Rice Bacterial Blight ◽  
Fluorescent Pseudomonas ◽  
Tn5 Mutants ◽  
Bacterial Blight Pathogen

Certain plant-associated strains of fluorescent Pseudomonas spp. are known to produce the antimicrobial antibiotic 2,4-diacetylphloroglucinol (DAPG). It has antibacterial, antifungal, antiviral, and antihelminthic properties and has played a significant role in the biological control of tobacco, wheat, and sugar beet diseases. It has never been reported from India and has not been implicated in the biological suppression of a major disease of the rice crop. Here, we report that a subpopulation of 27 strains of plant-associated Pseudomonas fluorescens screened in a batch of 278 strains of fluorescent pseudomonads produced DAPG. The DAPG production was detected by a PCR-based screening method that used primers Phl2a and Phl2b and amplified a 745-bp fragment characteristic of DAPG. HPLC,1H NMR, and IR analyses provided further evidence for its production. We report also that this compound inhibited the growth of the devastating rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae in laboratory assays and suppressed rice bacterial blight up to 59%–64% in net-house and field experiments. Tn5 mutants defective in DAPG production (Phl–) of P. fluorescens PTB 9 were much less effective in their suppression of rice bacterial blight.Key words: biocontrol, 2,4-diacetylphloroglucinol, Pseudomonas fluorescens, rice, Xanthomonas oryzae pv. oryzae.

scholarly journals Induced systemic resistance against rice grassy stunt virus – a promising field for ecological rice production

2012 ◽  
Vol 2 (1) ◽  
pp. 48-53
Author(s):  
Thanh Toan Le ◽  
Van Dien Luong ◽  
Thuy Nhien Thi Ngo ◽  
Van Kim Pham
Keyword(s):  
Oxalic Acid ◽  
Systemic Acquired Resistance ◽  
Plant Protection ◽  
Acquired Resistance ◽  
Rice Production ◽  
Systemic Resistance ◽  
Diseased Plant ◽  
Defence Reaction ◽  
Rice Plants ◽  
Low Concentrations

Most rice protection methods have currently used toxic chemicals to control pathogens and pests, which leads to environment pollution. Systemic acquired resistance (SAR) taking advantage of natural defence reaction of plants could be proposed as an alternative, ecologically friendly ap-proach for plant protection. Its application into rice production could minimize the chemicals quantity used, and could contribute to the decrease of environmental pollution and the development of sustainable agriculture. The research was conducted to select the best effective chemical and method to improve the health of rice plants infected by grassy stunt disease in net-house of Cantho University. SAR chemicals were used at very low concentrations (in mM). Results showed that the height of rice plants treated with SAR chemicals was higher than that of plants untreated. Besides, the number of diseased plant was reduced and the ratio of firm grain and yield increased when plants were applied by SAR. Among them, oxalic acid was the best systemic acquired resistance. With oxalic acid, seed soaking was better than seed coating in systemic acquired resistance against rice grassy stunt disease. Hầu hết các phương pháp sản xuất lúa hiện nay đều sử dụng các hóa chất độc hại trong việc phòng trừ bệnh và côn trùng gây hại, nên dẫn đến ô nhiễm môi trường. Kích thích tính kháng lưu dẫn giúp kích hoạt cơ chế tự nhiênkháng bệnh của cây có thể là giải pháp bảo vệ thực vật thay thế an toàn với môi trường. Việc ứng dụng tiến bộ này vào trong sản xuất lúa có thể làm giảm lượng hóa chất sử dụng, đóng góp vào việc giảm thiểu ô nhiễmmôi trường và sự phát triển của một nền nông nghiệp bền vững. Nghiên cứu đã được thực hiện tại nhà lưới trường Đại học Cần Thơ để tuyển chọn hóa chất và phương pháp sử dụng hóa chất để tăng cường sức khỏe giúp cây lúa vượt qua bệnh vàng lùn. Hóa chất kích kháng được sử dụng ở một nồng độ rất thấp (đơn vị là mM). Kết quả cho thấy chiều cao cây lúa khi xử lý chất kích kháng tốt hơn so đối chứng không xử lý. Bên cạnh đó, số cây lúa nhiễm bệnh giảm, tỉ lệ hạt chắc và năng suất tăng khi cây lúa được xử lý với chất kích kháng. Trong số các chất kích kháng đã sử dụng, acid oxalic cho hiệu quả vượt trội. Với chất acid oxalic, phương pháp ngâm hạt cho hiệuquả kích kháng tốt hơn phương pháp áo hạt.

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