title: Agro-ecological variations of sheath rot disease of rice caused by Sarocladium oryzae and DNA fingerprinting of the pathogen's population structure.
abstract: To examine the impact of regional and seasonal variations on the incidence and severity of sheath rot, a major seed-borne disease of rice caused by Sarocladium oryzae, data on incidence and severity were collected from 27 selected fields in the Gazipur, Rangpur, Bogra, Chittagong, Comilla, Gopalgonj, Jessore, Manikgonj, and Bhola districts of Bangladesh in rain-fed and irrigated conditions. Cultural variability of 29 pathogen isolates obtained from 8 different locations was studied on potato dextrose agar (PDA) and genetic variability was determined by DNA fingerprinting using variable number tandem repeat-polymerase chain reaction markers. Overall, disease incidence and severity were higher in irrigated rice. Disease incidence and severity were highest in the Bhola district in rain-fed rice and lowest in irrigated rice. Mycelial growth of 29 representative isolates was found to vary on PDA and the isolates were divided into 6 groups. The range of the overall size of conidia of the selected isolates was 2.40-7.20 x 1.20-2.40 μm. Analysis of the DNA fingerprint types of the 29 isolates of S. oryzae, obtained from the amplification reactions, revealed 10 fingerprinting types (FPTs) that were 80% similar. FPT-1 was the largest group and included 13 isolates (44.8%), while FPT-2 was the third largest group and included 3 isolates. Each of FPT-3, 4, 5, and 6 included only 1 isolate. We observed no relationship between cultural and genetic groupings.
authors.affiliation: Life and Earth Science Group, National University, Gazipur, Bangladesh.
authors.forename: M
authors.initials: M
authors.lastname: Tajul Islam Chowdhury
authors.affiliation: Plant Pathology Division, Bangladesh Rice Research Institute, Gazipur, Bangladesh.
authors.forename: M
authors.initials: M
authors.lastname: Salim Mian
authors.affiliation: Plant Pathology Division, Bangladesh Rice Research Institute, Gazipur, Bangladesh.
authors.forename: M A
authors.initials: MA
authors.lastname: Taher Mia
authors.affiliation: Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
authors.forename: M Y
authors.initials: MY
authors.lastname: Rafii
authors.affiliation: Plant Pathology Division, Bangladesh Rice Research Institute, Gazipur, Bangladesh.|Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, Selangor, Malaysia.
authors.forename: M A
authors.initials: MA
authors.lastname: Latif
mesh_terms: D016172:DNA Fingerprinting / Q000379:methods; D004463:Ecology; D014644:Genetic Variation; D005828:Genetics, Population; D054884:Host-Pathogen Interactions / Q000235:genetics; D006999:Hypocreales / Q000235:genetics* / Q000472:pathogenicity; D012275:Oryza / Q000235:genetics / Q000382:microbiology*; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D012639:Seeds / Q000235:genetics / Q000382:microbiology