Control Of Bacterial Leaf Blight Research Articles

Marker-assisted gene introgression for resistance to Xanthomonas oryzae pv. oryzae in rice for the control of bacterial leaf blight

Marker-assisted gene introgression for resistance to Xanthomonas oryzae pv. oryzae in rice for the control of bacterial leaf blight

Application and Mechanism of Cryptolepine and Neocryptolepine Derivatives as T3SS Inhibitors for Control of Bacterial Leaf Blight on Rice.

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv oryzae (Xoo) is extremely harmful to rice production. The traditional control approach is to use bactericides that target key bacterial growth factors, but the selection pressure on the pathogen makes resistant strains the dominant bacterial strains, leading to a decline in bactericidal efficacy. Type III secretion system (T3SS) is a conserved and critical virulence factor in most Gram-negative bacteria, and its expression or absence does not affect bacterial growth, rendering it an ideal target for creating drugs against Gram-negative pathogens. In this work, we synthesized a range of derivatives from cryptolepine and neocryptolepine. We found that compound Z-8 could inhibit the expression of Xoo T3SS-related genes without affecting the growth of bacteria. an in vivo bioassay showed that compound Z-8 could effectively reduce the hypersensitive response (HR) induced by Xoo in tobacco and reduce the pathogenicity of Xoo in rice. Furthermore, it exhibited synergy in control of bacterial leaf blight when combined with the quorum quenching bacterial F20.

Derivative of cinnamic acid inhibits T3SS of Xanthomonas oryzae pv. oryzae through the HrpG-HrpX regulatory cascade

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) has a significant impact on rice yield and quality worldwide. Traditionally, bactericide application has been commonly used to control this devastating disease. However, the overuse of fungicides has led to a number of problems such as the development of resistance and environmental pollution. Therefore, the development of new methods and approaches for disease control are still urgent. In this paper, a series of cinnamic acid derivatives were designed and synthesized, and three novel T3SS inhibitors A10, A12 and A20 were discovered. Novel T3SS inhibitors A10, A12 and A20 significantly inhibited the hpa1 promoter activity without affecting Xoo growth. Further studies revealed that the title compounds A10, A12 and A20 significantly impaired hypersensitivity in non-host plant tobacco leaves, while applications on rice significantly reduced symptoms of bacterial leaf blight. RT-PCR showed that compound A20 inhibited the expression of T3SS-related genes. In summary, this work exemplifies the potential of the title compound as an inhibitor of T3SS and its efficacy in the control of bacterial leaf blight.

Control of bacterial leaf blight and rice blast with antagonist microbial in the agroecosystem of irrigated rice

Bacterial leaf blight (Xanthomonas oryzae) and rice blast (Pyricularia oryzae) cause yield losses in rice production. Antagonist microbial application through seed treatment and foliar spray during rice growing stage is suggested to prevent the disease which is more reliable to reduce the disease incidence than curing it. This research aimed to determine the severity of bacterial leaf blight and rice blast among varieties that treated with antagonist microbial complex in the agro ecosystem of irrigated rice. Research was conducted in Kalibawang sub district, Kulon Progo, Yogyakarta, October 2018 to January 2019. The experimental design was randomized block design with 7 treatments and 4 replications. The treatments were the application of antagonist microbial complex formula A (Azotobacter vinelandii, Azospirillum sp., Bacillus cereus, Bradyzhizobium sp., and Methylobacterium sp. >107 CFU/g) and formula B (Azotobacter chroococum, Azotobacter vinelandii, Azospirillum sp., Pseudomonas cepacia, Penicillium sp., and Acinetobacter sp. >107 CFU/g) to several rice varieties (Inpari 9, Inpari 33, and Ciherang). Results shows that formula B had the lowest severity of bacterial leaf blight (14.44%) and leaf blast (6.94%) at Ciherang while formula A had the lowest panicle blast (6.55%). The highest yield (10.62 t/ha) was obtained from Ciherang treated with formula B.

Application of biological control Paenibacillus polymyxa toward bacterial leaf blight disease in rice plant

Diseases that often attack rice plants are bacterial leaf blight, this disease can reduce rice production by up to 60%. Control of bacterial leaf blight in addition to using chemicals can also use biological agents, one of which is Paenibacillus polymyxa. Testing of biological control applications begins with inoculation of Xanthomonas oryzae bacteria on ciherang rice seeds 9 days after planting (DAP). Planting rice using Randomized Block Design using biological control Paenibacillus polymyxa consists of four treatments, Control (P0), 2,5 ml l-1 (P1), 5 ml l-1 (P2), and 7,5 ml l-1 (P3). The biological control application is carried out on seeds, 10 DAP, 2 week after planting (WAP), and 4 WAP. Observations were made once a week to observe the rice growth and intensity of the disease. Observations were made in the vegetative phase. The results of the Paenibacillus polymyxa biological control test can reduce the level of bacterial leaf blight attack even though the difference in each treatment is not significantly different. The recommended concentration of Paenibacillus polymyxa biological control is 7,5 ml l-1. This concentration can reduce the level of bacterial leaf blight attack in the vegetative phase.

Endophytic Bacterial Consortia as Biological Control of Bacterial Leaf Blight and Plant Growth Promoter of Rice (Oryza sativa L.)

The consortia of endophytic bacteria with various mechanisms (competition, antibiotics, induction of resistance, and others), simultaneously, are more effective in controlling pathogens and increasing plant growth. The purpose of this study was to obtain endophytic bacterial consortia capable of suppressing of bacterial leaf blight and promoting the growth of rice plants. The study consisted of three experimental stages. The first stage was the test on the antibiosis ability of the endophytic bacterial consortia to suppress of pathogenic bacteria Xanthomonas oryzae pv. oryzae (Xoo) using the Kirby Bauer method. The second stage was the test on the ability of endophytic bacterial consortia to promote the growth of rice seedlings. The experiment was arranged in a Completely Randomized Design (CRD) which consisted of six combinations of endophytic bacterial consortia and 15 replications within each combination. The endophytic bacterial consortia were introduced by soaking the seeds, and the observations were made on the plant height, number of leaves, root length, fresh weight, and dry weight of rice seedlings. Meanwhile, the third stage was the test on the ability of endophytic bacterial consortia to suppress of bacterial leaf blight (BLB) diseases and to promote the rice plant growth. The experiment was arranged in a Completely Randomized Design (CRD) with six combinations of endophytic bacterial consortia and five replications within each combination. The endophytic bacterial consortia were introduced by soaking the roots of the seedlings. The observations were made on the incidence of disease, disease severity, number of leaves, plant height, and number of tillers. The results showed that all endophytic bacterial consortia had antibiosis abilities. The best endophytic bacterial consortia for controlling bacterial leaf blight and promoting the growth of rice seedlings and plants were the C (Bacillus sp SJI; Bacillus sp HI) and D (Bacillus sp SJI; S.marcescens isolate JB1E3) consortia.

Isolation and characterization of a novel phage Xoo-sp2 that infects Xanthomonas oryzae pv. oryzae.

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a serious bacterial disease in rice-growing regions worldwide. Phage therapy has been proposed as a potential measure to treat bacterial infections. In this study, a novel phage, Xoo-sp2, which infects Xoo was isolated from soil. The characteristics of Xoo-sp2, including the morphology, one-step growth curve and host range, were analysed. The genome of phage Xoo-sp2 was sequenced and annotated. The results demonstrated that Xoo-sp2 is a siphovirus and has a broad lytic spectrum, infecting 9 out of 10 representative Xoo strains. Genome analysis showed that the Xoo-sp2 genome consists of a linear double-stranded DNA molecule of length 60 370 bp. Annotation of the whole genome indicated that Xoo-sp2 encodes 79 putative open reading frames (ORFs). Comparative genomics analysis of Xoo-sp2 showed that it shares significant similarity only with Pseudomonas and Stenotrophomonas phages (with maximum identity reaching 80 % along 69 % of the genome), and thus represents a novel Xanthomonas phage. Xoo-sp2 significantly inhibited Xoo growth in liquid culture. An experiment with potted plants indicated that Xoo-sp2 could efficiently control BLB in living rice. In summary, our work characterized a novel Xanthomonas phage and demonstrated its potential as a prophylactic agent in the control of BLB in rice.

Potency of Some Plant Extracts and Pesticides on Bacterial Leaf Blight Diseases of Cocoyam (Colocasia Esculenta) in Umudike, South Eastern Nigeria

A pot trial was conducted in 2010 and 2011 cropping seasons at the screen house of Michael Okpara University of Agriculture, Umudike to determine the potency of some plant extracts and pesticides for the control of bacterial leaf blight of cocoyam (Colocasia esculenta L.) Scholt. The materials employed include: lemon grass (Cymbopogon citrates). Black pepper seed (Piper guineense), orange peel (Citrus sinesis), streptomycin sulphate (antibiotic), copper oxychloride (fungicide) and sterile water (control). The experiment was laid in complete randomized design (CRD) and replicated six times. The plant materials used were first made into aqueous extracts using cold water extraction and diluted to 10% concentration. Application on leaves was by use of a hand sprayer for two weekly intervals. Data were collected on disease severity and incidence including growth parameters and on yield of corms. The results obtained showed that all the plant extracts were able to reduce disease and increase yield better than the untreated control.

台風直後に散布した銅剤,抗生物質,倒伏防止剤の稲白葉枯病に対する効果

台風直後に散布した銅剤,抗生物質,倒伏防止剤の稲白葉枯病に対する効果

Biological control of rice bacterial blight by Lysobacter antibioticus strain 13-1

Bacterial leaf blight (BB) is a worldwide destructive rice disease caused by pathogen Xanthomonas oryzae pv. oryzae ( Xoo). A novel strain of Lysobacter antibioticus, which was isolated from the rhizosphere of rice in Yunnan Province of China, can significantly inhibit the growth of various phytopathogenic bacteria and fungi, especially BB pathogen Xoo. In greenhouse experiments, whole bacterial broth culture (WBC) of strain 13-1 was more effective in reducing BB than other components of the culture, with disease suppression efficiency up to 69.7%. However, bacterial cells re-suspended in water, cell-free culture extracts, and heated cultures also significantly reduced BB severity. Suppression efficiencies ranged from 79.0% to 61.8% for undiluted to 100-fold dilution treatments and from 57.6% to 31.7% when the WBC of strain 13-1 (10 8 CFU/mL) was applied at 3 days and 7 days prior to pathogen inoculation, respectively. In three field trials, strain 13-1 reduced BB incidence by 73.5%, 78.3%, and 59.1%, respectively. Disease suppression by strain 13-1 varied significantly among different rice cultivars, although efficacy was not directly related to the susceptibility level of the cultivars. Efficacy of biocontrol was also affected by different pathogen isolates, with some isolates of Xoo being more sensitive to 13-1 suppression than others. These results suggest that antibiotics and density of colonization on leaves may be involved for biological control of rice BB by strain 13-1. To our knowledge, this is the first report of L. antibioticus being a potential biocontrol agent for rice bacterial blight.

Biology and Control of Bacterial Leaf Blight of Cornus mas

Cornelian cherry (Cornus mas L.) has been free of disease and pest problems until recently when a bacterial leaf blight caused by Pseudomonas syringae was reported. Since its first observation in middle Tennessee in 1999, the disease has become endemic in the nursery where it was first discovered. The objective of this study was to assess the disease, evaluate factors that favor disease development, and develop disease management strategies. Cool temperatures of 20 to 24 °C (day) and 10 to 15 °C (night) were most favorable to the disease and young leaves were highly susceptible while mature leaves were resistant to infection. Leaf wounding increased the susceptibility of leaves and mature leaves developed infection at 28 °C, temperature at which nonwounded leaves were completely resistant to infection. Results from this study also showed that plant propagation from seemingly healthy branches of infected plants may have perpetuated the disease at the nursery. Six chemicals—Phyton-27 (copper sulfate), Camelot (copper salt of fatty acids), Agri-Mycin 17 (streptomycin), Kocide 101 (copper hydroxide), Basicop (elemental copper 53%), and, Bordeaux mixture (cupric sulfate + lime) were evaluated for disease control. Phyton-27, and Agri-Mycin—were most effective and reduced disease severity to 10% of foliage showing disease symptoms. Information from this study will be useful in designing effective disease management strategies.

Chemical Control of Bacterial Leaf Blight of Rice

Abstract Antibiotics, Agrimycin 100, Agrimycin 500, Agric. Terramycin 17, A.S. 50 and Streptocycline, and fungicides, Brestanol, Fytolan and Vitavax, were evaluated under field conditions for control of bacterial leaf blight of rice caused by Xanthomonas oryzae. Agric. Terramycin 17, Brestanol, Agrimycin 500 and a combination of Agrimycin 100 + Fytolan gave effective control of the blight phase of the disease. The combination of Agrimycin 100 + Fytolan spraying gave good control of the disease and an economic return on susceptible varieties like Sona.

Control of Bacterial Leaf Blight of Rice Assay of Chemicals

An invitro study was conducted to findout the suitable and effective fungicides and antibiotics to control the leaf blight of rice caused by Xanthomonas oryzae. Twelve fungicides and nineteen antibiotics with 50, 100, 200, 400. 500 and 1000 concentrations were sprayed three times at 15 day interval, in the rice variety Karuna. The seedlings were sprayed 24 hours of chemical spray with heavy suspension of bacteria. Among the fungi- cides mercuric chloride was, superior in its inhibion of bacterial growth followed by duter, kocide and wet ceresan. Similarly the antibiotic tetracycline-Het was found to record highest inhibition zone followed by terramycin. ledermycin erythromycin and chlor- amphenic. The porculture experiments with similar treatments have shown that ery thromycin was highly effective followed chloramphenicol, terramycin tetracycline-Hcl. edermycin celdion (T.F. 130) and duter. Regarding fungicides, all the chemical used were effective in reducing the leafblight disease intensity and increase the yield.

Epidemiology and Control of Bacterial Leaf Blight of Corn

Epidemiology and Control of Bacterial Leaf Blight of Corn

Activity of Thiosemicarbazides for the Control of Bacterial Leaf Blight of Rice

Activity of Thiosemicarbazides for the Control of Bacterial Leaf Blight of Rice

イネ白葉枯病に対するTF-128の水面施薬効果ならびにその使用法に関する2, 3の試験

イネ白葉枯病に対するTF-128の水面施薬効果ならびにその使用法に関する2, 3の試験

Epidemiology and Control of Bacterial Leaf Blight of Rice

INTRODucnoN The bacterial leaf blight disease of rice was first observed in the latter part of the last century in various localities of southern Japan. Severe dam­ age has been caused annually since then. Scant information is available on the occurrence of this disease in other countries. It has been reported in Korea (105), Taiwan (21), the Philippines (15-17, 19, 77), Indonesia (15, 16), Thailand (19), India (5,84,86-88 ), and China (8 ,9 ,107). According to investigations carried out in recent years (59, 66, 119), the disease has become of economic importance in many other countries of Asia, namely Ceylon, Cambodia, and Malaysia. It occasionally causes severe damage to rice yields and is recognized as one of the most important diseases of rice growing areas in Asian countries. No reports of the presence of the disease in America, Australia, Africa, and European countries growing rice have been received. Possibly the disease is nonexistent in these countries or is not of any great importance. Early investiga tions during 190 8 to 1910 indicated that bacterial blight occurred in almost all southwestern prefectures of Japan (73, 79, 104). It gradually spread to northern Japan and in 1962 was observed in Hokkaido. At present, the disease is widespread in all prefectures of Japan, although its severity and damage is limited in the north. The acreage infected by leaf blight disease was 50,000 to 60,000 hectares in 1940, exceeded 100,000 hec­ tares durin g the Second World War, and is now 300,000 to 500,000 hect ares. This corresponds approximately to 10 per cent of the total rice area in Japan.

Effect of dihydrostreptomycin spray upon the grain development and carbohydrate content of rice

Spraying with dihydrostreptomycin (Dsm) has been reported to be effective for control of bacterial leaf blight of rice, incited by Xanthomonas oryzae, but occasionally causes reduction of the grain yield. The present experiment showed that, two or three times applications of Dsm to rice plant, including spray at the stage of flowering, caused reduction in the percentage of grains of standard weight, but not in the number of panicles per plant nor number of spikelets per panicle. It was also indicated that Dsmspray at the flowering stage did not effect fertilization, but caused reduction in average grain weight, suggesting a retarding effect on the ripening process of rice grains. Quantitative analysis was made for sugar and starch in the selected organs of rice plant, sprayed with Dsm (1000ppm) at the flowering stage. It was revealed that contents of total sugar, reducing sugar, and starch in the flag leaf of rice plant sprayed, were equal to those of check. Sugar and starch contents in the sheath and culm of plant subjected to spray with Dsm were greater than those of check. In the grains, however, sugar content of the sprayed plant was much greater, and starch was considerably less, than that of check. Accordingly, the difference in sugar content between flag leaf and grain of Dsm-sprayed plant was considerably small as compared with that of checkplant. It is suggested that Dsm-spray may give an inhibitory effect to translocation of sugar from flag leaf to grain and starch accumulation in grain of rice plant.