title: Mapping QTLs and candidate genes for rice root traits under different water-supply conditions and comparative analysis across three populations.
abstract: To investigate the genetic factors underlying constitutive and adaptive morphological traits of roots under different water-supply conditions, a recombinant inbred line (RIL) population derived from a cross between the lowland rice variety IR1552 and the upland rice variety Azucena with 249 molecular markers, was used in cylindrical-pot experiments. Eighteen QTLs were detected for seminal root length (SRL), adventitious root number (ARN), and lateral root length (LRL) and lateral root number (LRN) on the seminal root at a soil depth of from 3 to 6 cm under flooding and upland conditions. One identical QTL was detected under both flooding and upland conditions. The relative parameters under the two water-supply conditions were also used for QTL analysis. Five QTLs for upland induced variations in the traits were detected with the positive alleles from Azucena. A comparative analysis was performed for the QTLs detected in this study and those reported from two other populations with Azucena as a parent. Several identical QTLs for root elongation were found across the three populations with positive alleles from Azucena. Candidate genes were screened from ESTs and cDNA-AFLP clones for comparative mapping with the detected QTLs. Two genes for cell expansion, OsEXP2 and endo-1,4-beta-D-glucanase EGase, and four cDNA-AFLP clones from root tissues of Azucena, were mapped on the intervals carrying the QTLs for SRL and LRL under upland conditions, respectively.
authors.affiliation: The State Key laboratory of Plant Physiology and Biochemistry, College of Life Science, Zhejiang University, 310029 Hangzhou, P. R. China.
authors.forename: B S
authors.initials: BS
authors.lastname: Zheng
authors.forename: L
authors.initials: L
authors.lastname: Yang
authors.forename: W P
authors.initials: WP
authors.lastname: Zhang
authors.forename: C Z
authors.initials: CZ
authors.lastname: Mao
authors.forename: Y R
authors.initials: YR
authors.lastname: Wu
authors.forename: K K
authors.initials: KK
authors.lastname: Yi
authors.forename: F Y
authors.initials: FY
authors.lastname: Liu
authors.forename: P
authors.initials: P
authors.lastname: Wu
mesh_terms: D015152:Blotting, Northern; D012275:Oryza / Q000235:genetics* / Q000254:growth & development; D018517:Plant Roots / Q000254:growth & development*; D040641:Quantitative Trait Loci; D014867:Water
chemical_list: D014867:Water