title: Identification of QTLs and possible candidate genes conferring sheath blight resistance in rice (Oryza sativa L.).
abstract: Sheath blight, caused by the pathogenic fungus Rhizoctonia solani Kühn, is one of the most devastating diseases in rice. Breeders have always faced challenges in acquiring reliable and absolute resistance to this disease in existing rice germplasm. In this context, 40 rice germplasm including eight wild, four landraces, twenty- six cultivated and two advanced breeding lines were screened utilizing the colonized bits of typha. Except Tetep and ARC10531 which expressed moderate level of resistance to the disease, none could be found to be authentically resistant. In order to map the quantitative trait loci (QTLs) governing the sheath blight resistance, two mapping populations (F2 and BC1F2) were developed from the cross BPT-5204/ARC10531. Utilizing composite interval mapping analysis, 9 QTLs mapped to five different chromosomes were identified with phenotypic variance ranging from 8.40 to 21.76%. Two SSR markers namely RM336 and RM205 were found to be closely associated with the major QTLs qshb7.3 and qshb9.2 respectively and were attested as well in BC1F2 population by bulk segregant analysis approach. A hypothetical β 1-3 glucanase with other 31 candidate genes were identified in silico utilizing rice database RAP-DB within the identified QTL region qshb9.2. A detailed insight into these candidate genes will facilitate at molecular level the intricate nature of sheath blight, a step forward towards functional genomics.
authors.affiliation: Institute of Biotechnology, Acharya N G Ranga Agricultural University, Hyderabad, 500030 India.
authors.forename: Shailesh
authors.initials: S
authors.lastname: Yadav
authors.affiliation: Institute of Biotechnology, Acharya N G Ranga Agricultural University, Hyderabad, 500030 India.
authors.forename: Ghanta
authors.initials: G
authors.lastname: Anuradha
authors.affiliation: Department of Molecular Biology and Genetic Engineering, BAU, Sabour, 813210 India.
authors.forename: Ravi Ranjan
authors.initials: RR
authors.lastname: Kumar
authors.affiliation: Institute of Biotechnology, Acharya N G Ranga Agricultural University, Hyderabad, 500030 India.
authors.forename: Lakshminaryana Reddy
authors.initials: LR
authors.lastname: Vemireddy
authors.affiliation: Seed Research and Technology Centre, Rajendranagar, Hyderabad, 500030 India.
authors.forename: Ravuru
authors.initials: R
authors.lastname: Sudhakar
authors.affiliation: Divison of Plant Pathology, Directorate of Rice Research, Rajendranagar, Hyderabad, 500030 India.
authors.forename: Krishnaveni
authors.initials: K
authors.lastname: Donempudi
authors.affiliation: Institute of Biotechnology, Acharya N G Ranga Agricultural University, Hyderabad, 500030 India.
authors.forename: Durgarani
authors.initials: D
authors.lastname: Venkata
authors.affiliation: Institute of Biotechnology, Acharya N G Ranga Agricultural University, Hyderabad, 500030 India.
authors.forename: Farzana
authors.initials: F
authors.lastname: Jabeen
authors.affiliation: Institute of Biotechnology, Acharya N G Ranga Agricultural University, Hyderabad, 500030 India.
authors.forename: Yamini Kalinati
authors.initials: YK
authors.lastname: Narasimhan
authors.affiliation: Institute of Biotechnology, Acharya N G Ranga Agricultural University, Hyderabad, 500030 India ; International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines.
authors.forename: Balram
authors.initials: B
authors.lastname: Marathi
authors.affiliation: Institute of Biotechnology, Acharya N G Ranga Agricultural University, Hyderabad, 500030 India.
authors.forename: Ebrahimali Abubacker
authors.initials: EA
authors.lastname: Siddiq
keywords: Bulk segregant analysis (BSA); Defense response genes; QTL mapping; Rice; Sheath blight