Efficacy of bacteriocinogenic strains of Xanthomonas oryzae pv. oryzae on the incidence of bacterial blight disease of rice (Oryza sativa L.)

1991 ◽  
Vol 37 (10) ◽  
pp. 764-768 ◽  
Author(s):  
N. Sakthivel ◽  
T. W. Mew
Keyword(s):  
Biological Control ◽  
Bacterial Blight ◽  
Oryza Sativa L ◽  
Disease Incidence ◽  
Bacteriocin Production ◽  
Xanthomonas Oryzae ◽  
Control Treatment ◽  
Bacterial Leaf Streak ◽  
Blight Disease ◽  
Greenhouse Tests

A total of 144 isolates of Xanthomonas oryzae pv. oryzae were screened for bacteriocin production against 30 indicator strains of X. oryzae pv. oryzae. Forty isolates showed broad-spectrum inhibitory activity against 20–27 indicators, presumably because of the production of bacteriocin compounds. The selected isolates were screened for bacteriocin production at 29 °C and tested for virulence on rice differentials. Since all of the isolates were pathogenic, nonpathogenic bacteria were generated through N-methyl-N-nitro-N-nitrosoguanidine mutagenesis and by repeated subculturing. Epiphytic colonization and survival of pathogens and of nonpathogenic bacteriocin producers on rice plants were monitored, using mutants resistant to streptomycin and rifampicin. An improved method of pathogen inoculation was developed and used to evaluate biological control. Treatment with nonpathogenic bacteriocin-producing bacteria resulted in reductions of bacterial blight incidence up to 31–99% in greenhouse tests and 11–73% in the screenhouse. Bacterial leaf streak severity was reduced 4–20% in the greenhouse and disease incidence was reduced 20–39% in the screenhouse. Key words: bacteriocin, biological control, Xanthomonas oryzae pv. oryzae, mutagenesis, rice.

scholarly journals Resistance Genes and their Interactions with Bacterial Blight/Leaf Streak Pathogens (Xanthomonas oryzae) in Rice (Oryza sativa L.)—an Updated Review

Rice ◽  
2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Nan Jiang ◽  
Jun Yan ◽  
Yi Liang ◽  
Yanlong Shi ◽  
Zhizhou He ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Bacterial Blight ◽  
Oryza Sativa L ◽  
Rice Production ◽  
Xanthomonas Oryzae ◽  
Bacterial Leaf Streak ◽  
Viral Pathogens ◽  
Effector Genes ◽  
Broad Spectrum Resistance ◽  
Genomic Studies

AbstractRice (Oryza sativa L.) is a staple food crop, feeding more than 50% of the world’s population. Diseases caused by bacterial, fungal, and viral pathogens constantly threaten the rice production and lead to enormous yield losses. Bacterial blight (BB) and bacterial leaf streak (BLS), caused respectively by gram-negative bacteria Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc), are two important diseases affecting rice production worldwide. Due to the economic importance, extensive genetic and genomic studies have been conducted to elucidate the molecular mechanism of rice response to Xoo and Xoc in the last two decades. A series of resistance (R) genes and their cognate avirulence and virulence effector genes have been characterized. Here, we summarize the recent advances in studies on interactions between rice and the two pathogens through these R genes or their products and effectors. Breeding strategies to develop varieties with durable and broad-spectrum resistance to Xanthomonas oryzae based on the published studies are also discussed.

Efficacy of fungicides in controlling late blight of potato

2015 ◽  
Vol 26 (2) ◽  
pp. 103-108
Author(s):  
MM Anwar ◽  
A Parveen ◽  
MM Hossain ◽  
NU Mahamud ◽  
RK Roy
Keyword(s):  
Late Blight ◽  
Tuber Yield ◽  
Cultural Practices ◽  
Disease Incidence ◽  
Integrated Approach ◽  
Control Treatment ◽  
Commercial Potato ◽  
Late Blight Disease ◽  
Blight Disease ◽  
Late Blight Of Potato

Potato cultivars grown in Bangladesh have low levels of general resistance to late blight. As such, most commercial potato farmers rely on fungicide applications for control of Phytophthora infestans, the causal agent of late blight. Management of late blight of potato requires an integrated approach that includes rotation with non-hosts, resistant cultivars, cultural practices, and fungicides. The study on efficacy of some new fungicides against late blight disease of potato was conducted at ARS, Alamnagar Rangpur during rabi season 2010-2011 to select suitable fungicides against late blight of potato. Thirteen different fungicides were tested and all the tested fungicides showed significantly better performance over control. Considering percentage disease incidence T4,T6 and T12 showed better performance than all other treatment. In case of T4,T6 and T12 treatment disease reduction was more than 80 % over control. Significantly the highest tuber yield 25.5 t ha-1was obtained from T3  which was statistically similar to the yield of T2,T5 , T6, T9, T10, T11and T12  treatment whereas the lowest tuber  yield 14.5 t ha-1 was obtained from control treatment. Field experiment was conducted from 2010 to 2011 to investigate the comparative efficacy of the fungicides. In the field, applications of fungicide that preceded the largest incremental increase in disease incidence provided the best control of disease or increased yield.Progressive Agriculture 26 (2): 103-108, 2015

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 First Report of Xanthomonas oryzae pv. oryzicola Causing Bacterial Leaf Streak of Rice in Uganda

Plant Disease ◽  
2014 ◽  
Vol 98 (11) ◽  
pp. 1579-1579 ◽  
Author(s):  
O. Afolabi ◽  
B. Milan ◽  
L. Poulin ◽  
J. Ongom ◽  
B. Szurek ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Multiplex Pcr ◽  
Dna Sequence ◽  
Disease Incidence ◽  
Xanthomonas Oryzae ◽  
Gyrb Gene ◽  
Sterile Water ◽  
Bacterial Leaf Streak ◽  
Rice Plants ◽  
Multiplex Pcr Assay

In June 2013, symptoms reminiscent of bacterial leaf streak (BLS) caused by Xanthomonas oryzae pv. oryzicola were observed on rice plants at the booting stage in the Doho rice irrigation scheme, Butaleja district, and at the tillering stage in Nambale, Iganga district and Magada, Namutumba district of Uganda. In areas surveyed, disease incidence was about 80, 40, and 30% in Doho, Nambale, and Magada, respectively. Outside the irrigation schemes, it was lower but widespread. Affected leaves showed typical BLS symptoms, such as water-soaked lesions, translucent stripes, and yellow-brown to black streaks, sometimes with visible exudates at the leaf surfaces. To check for the presence of the bacteria, symptomatic leaves were ground in sterile water and the suspension obtained was subjected to a multiplex PCR assay for X. oryzae pathovars, leading to the three diagnostic DNA fragments for X. oryzae pv. oryzicola (3). In parallel, bacterial strains were isolated from surface-sterilized symptomatic leaves. To this end, rice leaves were ground in sterile distilled water and serial dilutions of the cell suspensions were plated on semi-selective PSA medium (4). Each of the three samples yielded yellow, mucoid Xanthomonas-like colonies that resembled the positive control strain MAI10 (1). These isolates were named Ug_1, Ug_10, and Ug_14, which originated from Doho, Magada, and Nambale, respectively. Multiplex PCR on the pure cultures strongly supported that these isolates corresponded to X. oryzae pv. oryzicola. Two isolates, Ug_1 and Ug_14, were further subjected to partial DNA sequence analysis of the gyrB gene upon PCR amplification using the primers XgyrB1F and XgyrB1R (5). The 467-bp DNA sequence was identical to the gyrB sequences from the X. oryzae pv. oryzicola strains BLS256 (Philippines), ICMP 12013 (China), and MAI3 (Mali) (2). The partial nucleotide sequence of the gyrB gene of strain Ug_1 was submitted to GenBank (KJ921786). Pathogenicity tests were performed on greenhouse-grown 4-week-old rice plants of the cultivars Nipponbare, Azucena, IRBB 1, IRBB 2, IRBB 3, FKR 14, PNA64F4-56, TCS 10, Gigante, and Adny 11. For this purpose, bacterial cultures were grown overnight in PSA medium and re-suspended in sterile water at a concentration of 1 × 108 CFU/ml. Bacterial suspensions were sprayed on leaves of rice seedlings. Four seedlings per accession and isolate were inoculated. Fifteen days after incubation in a BSL-3 containment facility (27 ± 1°C with a 12-h photoperiod), inoculated leaves exhibited typical water-soaked lesions with yellow exudates that were similar to the symptoms seen in the fields. Re-isolation of the bacteria from the diseased leaves yielded colonies with the typical morphology of Xanthomonas. Multiplex PCR and sequence analysis of portions of the gyrB gene confirmed that these isolates are X. oryzae pv. oryzicola, thus fulfilling Koch's postulates. One of the three isolates, Ug_1, has been deposited in the Collection Française de Bactéries Phytopathogènes (CFBP) as strain CFBP 8171 ( http://www.angers-nantes.inra.fr/cfbp/ ). Further surveys and strain collections in East and Central Africa will help assess the geographic distribution and importance of BLS. References: (1) C. Gonzalez et al. Mol. Plant Microbe Interact. 20:534, 2007. (2) A. Hajri et al. Mol. Plant Pathol. 13:288, 2012. (3) J. M. Lang et al. Plant Dis. 94:311, 2010. (4) L. Poulin et al. Plant Dis. 98:1423, 2014. (5) J. M. Young et al. Syst. Appl. Microbiol. 31:366, 2008.

scholarly journals Cloning of the rice Xo1 resistance gene and interaction of the Xo1 protein with the defense-suppressing Xanthomonas effector Tal2h

2020 ◽  
Author(s):  
Andrew C. Read ◽  
Mathilde Hutin ◽  
Matthew J. Moscou ◽  
Fabio C. Rinaldi ◽  
Adam J. Bogdanove
Keyword(s):  
Resistance Gene ◽  
Resistance Genes ◽  
Bacterial Blight ◽  
Rice Variety ◽  
Susceptible Variety ◽  
Xanthomonas Oryzae ◽  
Physical Interaction ◽  
Bacterial Leaf Streak ◽  
Transcription Activator ◽  
Rice Leaves

AbstractThe Xo1 locus in the heirloom rice variety Carolina Gold Select confers resistance to bacterial leaf streak and bacterial blight, caused by Xanthomonas oryzae pvs. oryzicola and oryzae, respectively. Resistance is triggered by pathogen-delivered transcription activator-like effectors (TALEs) independent of their ability to activate transcription, and is suppressed by variants called truncTALEs common among Asian strains. By transformation of the susceptible variety Nipponbare, we show that one of 14 nucleotide-binding, leucine-rich repeat (NLR) protein genes at the locus, with a zfBED domain, is the Xo1 gene. Analyses of published transcriptomes revealed that the Xo1-mediated response is similar to those of NLR resistance genes Pia and Rxo1 and distinct from that associated with induction of the executor resistance gene Xa23, and that a truncTALE dampens or abolishes activation of defense-associated genes by Xo1. In Nicotiana benthamiana leaves, fluorescently-tagged Xo1 protein, like TALEs and truncTALEs, localized to the nucleus. And, endogenous Xo1 specifically co-immunoprecipitated from rice leaves with a pathogen-delivered, epitope-tagged truncTALE. These observations suggest that suppression of Xo1-function by truncTALEs occurs through direct or indirect physical interaction. They further suggest that effector co-immunoprecipitation may be effective for identifying or characterizing other resistance genes.

scholarly journals Occurrence of a Subpopulation of Xanthomonas oryzae pv. oryzae with Virulence to Rice Cv. IRBB21 (Xa21) in Southern India

Plant Disease ◽  
1999 ◽  
Vol 83 (8) ◽  
pp. 781-781 ◽  
Author(s):  
V. Brindha Priyadarisini ◽  
S. S. Gnanamanickam
Keyword(s):  
Bacterial Blight ◽  
Agricultural Research ◽  
Oryza Sativa L ◽  
Xanthomonas Oryzae ◽  
Southern India ◽  
Lesion Length ◽  
Research Station ◽  
Cornell University ◽  
Bacterial Blight Pathogen ◽  
Kerala State

About 200 isolates of the bacterial blight pathogen Xanthomonas oryzae pv. oryzae were obtained from infected rice (Oryza sativa L.) leaf samples from the Palghat District of Kerala State in southern India during January and February, 1998, when there was a severe epidemic of bacterial blight in the farmers' fields. One hundred and forty of these isolates were assayed for pathogenicity on rice cv. IR24 (no R gene), IRBB21 (Xa21), and NH56 (Xa4+xa5+xa13+Xa21) at their maximum tillering stage by the standard clip-inoculation technique (1) at the Regional Agricultural Research Station (Kerala Agricultural University), Pattambi. In two separate experiments, all the isolates were found to be pathogenic to IR24, producing lesions greater than 10 cm in length. None of the isolates induced susceptible symptoms on cv. NH56 and the average lesion length was less than 2 cm. Twenty of the 140 isolates, however, showed virulence to IRBB21 (seeds supplied by S. R. McCouch, Cornell University, and by P. Ronald, University of California-Davis) and induced lesions of 10.0 to 18.0 cm. We report here the presence of Indian races of X. oryzae pv. oryzae that are virulent to IRBB21 (Xa21), contradicting an earlier report of avirulence (2). These results suggest that the deployment of Xa21 alone will not be a sound strategy for the management of bacterial blight in southern India. References: (1) S. S. Gnanamanickam et al. Plant Dis. 78:173, 1994. (2) G.-L.Wang et al. Mol. Plant-Microbe Interact. 9:850, 1996.

scholarly journals Impact of chemicals, plant extracts and their combination on bacterial blight of cotton

2017 ◽  
Author(s):  
Muhammad Sajid ◽  
Shahabaz Talib Sahi ◽  
Muhammad Atiq ◽  
Muhammad Abid ◽  
Rashida Perveen ◽  
...  
Keyword(s):  
Plant Extracts ◽  
Bacterial Blight ◽  
Field Experiments ◽  
Disease Incidence ◽  
Inhibition Zone ◽  
Bacterial Disease ◽  
Green House ◽  
Maximum Inhibition ◽  
Blight Disease ◽  
The Impact

Five chemicals, incuding Flare, Plant Protector, Mancozeb, Agrimycine, and Copper oxychloride, and five plant extracts including N. tabacum, A. indica, M. oleifera, D. alba and C. longa were evaluated against bacterial blight of cotton caused by Xanthomonas citri pv. malvacearum (a bacterium). The impact of chemicals and plant extracts on bacterial development was tested in laboratory while on disease reduction was tested in green house and field experiments. Laboratory experiments showed that maximum inhibition zone of bacterial growth was expressed by Flare (1.693cm) at all concentrations followed by Plant Protector (1.473 cm), Mancozeb (1.290 cm), Agrimycine (1.150 cm) and copper oxy-chloride (0.953) cm respectively while in case of plant extracts maximum inhibition was expressed by N. tabacum (0.650 cm) followed by A. indica (0.486), M. oleifera (0.350), D. alba (0.256 cm) and C. longa (0.168 cm). Green house experiment revealed that the best result was produced by the combination of Flare and N. tabacum by indicating lowest disease incidence (32.27%) at all the tested concentration. Same results were obtained in field experiment, where the lowest disease incidence (40.41%) was recorded when the ,Flare and N. tabacum were applied in combination although it was higher then green house. This study concludes that N. tabacum and Flare are better option against bacterial disease development and even their combination is more significant lowering the bacterial blight disease incidence on cotton. Selection of suitable formulation and method of application could be the future aspects of plant product especially N. tabacum related research.

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