scholarly journals Antagonistic activity of rice rhizosphere isolates against Xanthomonas oryzae pv. oryzae bacterial blight pathogen

2021 ◽  
pp. 211-215
Author(s):  
Yamini sousheel N. ◽  
Bharati Narayan Bhat ◽  
Gouri Shankar Laha ◽  
S. Triveni
Keyword(s):  
Bacterial Blight ◽  
Antagonistic Activity ◽  
Xanthomonas Oryzae ◽  
Lesion Length ◽  
Pseudomonas Spp ◽  
Fluorescent Pseudomonas ◽  
Rice Rhizosphere ◽  
Bacillus Spp ◽  
Bacterial Blight Pathogen

Attempts were made to isolate beneficial bio agents from rice rhizosphere which resulted in isolation of  46 Bacillus spp and 15 fluorescent Pseudomonas spp which were further investigated for their potential aginst BB of rice diseaseAmong twenty six isolates of Bacillus, two isolates were most antagonistic and showed highest inhibition percentage (57.09) The potential isolates of Pseudomonas (P-4, P-5, P-6, P-7 and P-8), Bacillus (ARI 1-2, ARI 2-4, ARI 1-3, D1-1-2 and D2-1-1) were tested in vivo under glass house conditions for antagonism against Xoo which revealed that P-7 was effective in reduction of lesion length (18.5cm) when compared to control (20.37cm). The potential isolates of Pseudomonas (P-4, P-5, P-6, P-7 and P-8), Bacillus (ARI 1-2, ARI 2-4, ARI 1-3, D1-1-2 and D2-1-1) were tested in vivo under glass house conditions for antagonism against Xoo which revealed that P-7 was effective in reduction of lesion length (18.5cm) when compared to control (20.37cm). The present study indicated that PGPR isolates P-4, P-6, P-7 and P-8 can be used as biofertilizers, which will add up for enhanced growth of rice.   

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 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 Antagonistic activity of selected bacteria of the soil environment of carrot

2017 ◽  
Vol 63 (No. 6) ◽  
pp. 277-281
Author(s):  
Patkowska Elżbieta ◽  
Błażewicz-Woźniak Marzena ◽  
Wach Dariusz
Keyword(s):  
Cover Crops ◽  
Avena Sativa ◽  
Growth And Development ◽  
Laboratory Tests ◽  
Experimental Treatment ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
Soil Environment ◽  
Pseudomonas Spp ◽  
Bacillus Spp

The purpose of the present studies was to determine the antagonistic effect of bacteria Bacillus spp. and Pseudomonas spp. towards selected fungi from the soil environment of carrot. Oats (Avena sativa L.), tansy phacelia (Phacelia tanacetifolia Bentham) and vetch (Vicia satica L.) were used as cover crops in the cultivation of this plant. In the traditional cultivation of carrot the population of bacteria was the smallest, while after the application of oats it was the largest. Laboratory tests showed that cover crops promoted the development of antagonistic Bacillus spp. and Pseudomonas spp. Irrespective of the experimental treatment, those bacteria were the most effective in limiting the growth and development of Fusarium oxysporum and Thanatephorus cucumeris (syn. Rhizoctonia solani), while being less effective towards Altenaria dauci and Alternaria radicina, and the least towards Sclerotinia sclerotiorum. The best total antagonistic effect of Pseudomonas spp. and Bacillus spp. towards the tested fungi was found after using oats and vetch, while the worst – in the traditional cultivation of carrot.

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