Journal of Microbiology

Research Support, Non-U.S. Gov'ts

Molecular Detection and Genotyping of Fusarium oxysporum f. sp. psidii Isolates from Different Agro-Ecological Regions of India: Rupesh Kumar Mishra , Brajesh Kumar Pandey , Vijai Singh , Amita John Mathew , Neelam Pathak , Mohammad Zeeshan; J. Microbiol. 2013;51(4):405-412. Published online August 30, 2013; DOI: https://doi.org/10.1007/s12275-013-2638-3

Abstract: Twenty one isolates of Fusarium oxysporum f. sp. psidii (Fop), causing a vascular wilt in guava (Psidium guajava L.), were collected from different agro-ecological regions of India. The pathogenicity test was performed in guava seedlings, where the Fop isolates were found to be highly pathogenic. All 21 isolates were confirmed as F. oxysporum f. sp. psidii by a newly developed, species-specific primer against the conserved regions of 28S rDNA and the intergenic spacer region. RAPD and PCR-RFLP were used for genotyping the isolates to determine their genetic relationships. Fifteen RAPD primers were tested, of which five primers produced prominent, polymorphic, and reproducible bands. RAPD yielded an average of 6.5 polymorphic bands per primer, with the amplified DNA fragments ranging from 200–2,000 bp in size. A dendrogram constructed from these data indicated a 22–74% level of homology. In RFLP analysis, two major bands (350 and 220 bp) were commonly present in all isolates of F. oxysporum. These findings provide new insight for rapid, specific, and sensitive disease diagnosis. However, genotyping could be useful in strain-level discrimination of isolates from different agro-ecological regions of India.

A Method for Comparing Multiple Bacterial Community Structures from 16S rDNA Clone Library Sequences: Inae Hur , Jongsik Chun; J. Microbiol. 2004;42(1):9-13.; DOI: https://doi.org/2008 [pii]

Abstract: Culture-independent approaches, based on 16S rDNA sequences, are extensively used in modern microbial ecology. Sequencing of the clone library generated from environmental DNA has advantages over fingerprint-based methods, such as denaturing gradient gel electrophoresis, as it provides precise identification and quantification of the phylotypes present in samples. However, to date, no method exists for comparing multiple bacterial community structures using clone library sequences. In this study, an automated method to achieve this has been developed, by applying pair wise alignment, hierarchical clustering and principle component analysis. The method has been demonstrated to be successful in comparing samples from various environments. The program, named CommCluster, was written in JAVA, and is now freely available, at http://chunlab.snu.ac.kr/commcluster/.

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