title: Molecular detection and genotyping of Fusarium oxysporum f. sp. psidii isolates from different agro-ecological regions of India.
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.
authors.affiliation: Molecular Plant Pathology Laboratory, Central Institute for Subtropical Horticulture, Lucknow 227107, India. rupeshkmishra@rediffmail.com
authors.forename: Rupesh Kumar
authors.initials: RK
authors.lastname: Mishra
authors.forename: Brajesh Kumar
authors.initials: BK
authors.lastname: Pandey
authors.forename: Vijai
authors.initials: V
authors.lastname: Singh
authors.forename: Amita John
authors.initials: AJ
authors.lastname: Mathew
authors.forename: Neelam
authors.initials: N
authors.lastname: Pathak
authors.forename: Mohammad
authors.initials: M
authors.lastname: Zeeshan
mesh_terms: D021903:DNA, Ribosomal Spacer; D004783:Environmental Microbiology; D005670:Fusarium / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D010641:Phenotype; D010802:Phylogeny; D011110:Polymorphism, Genetic
chemical_list: D021903:DNA, Ribosomal Spacer