ecofriendly management of sheath rot of rice caused by sarocladium oryzae

Abstract

newline Rice plants showing the typical sheath rot disease symptoms were collected newlinefrom the fifteen various rice growing areas of southern districts of Tamil Nadu. The newlinevarious isolates of sheath rot pathogen showed their difference in their virulence, newlinemorphological, cultural and physiological characters. These isolates were subjected to newlinecharacterization and the isolate SOMDU4 was identified as virulent. On the basis of newlinenucleotide sequencing data the virulent isolate was identified as S. oryzae. To support newlinethe morphological identification of the several pathogenic isolates of Sarocladium, newlineDNA were exposed to PCR amplification using universal primers of ITS1 and ITS4. newlineThe amplified genomic product was partially sequenced for the virulent isolate newlineSOMDU4 and performed rDNA homology searches by using BLAST and NCBI newline(USA). The isolate SOMDU4 (MT111120.1) was 99 per cent homologus with the newlineS. oryzae. newlineAmong the twenty isolates of Pseudomonas spp., PTN5 recorded the newlinemaximum (82.22 %) inhibition followed by PTN1 which recorded 77.78 per cent newlineinhibition on the mycelial growth and among the twenty Bacillus spp., BTK1 isolate newlinesignificantly recorded the highest (75.56) per cent reduction of mycelial growth of newlineS. oryzae. newlineVariability among the fifteen isolates of S. oryzae and twenty isolates of newlinePseudomonas spp. and Bacillus spp. was analysed and confirmed by RAPD-PCR newlinetechnique. PCR was performed to identify the Pseudomonas spp. a fragment of newlineapproximately 1490 bp corresponding to the region of the 16S-23S rDNA. Partial newlinesequencing of the effective isolates PTN1 and PTN5 were sequenced. Comparison of newlinethe nucleotide sequences with the database available in the NCBI Genbank disclosed newlinethat the isolates PTN1 and PTN5 were identified as Pseudomonas aeruginosa newline(MW404517.1) and Pseudomonas aeruginosa (MW404529.1) respectively. Genomic newlineDNA of Bacillus spp. isolates was approximately amplified at 549 bp of 16S-23S newlinerDNA. Partial sequencing of the effective isolate BTK1 was done and comparison of newlinethe nucleotide