title: Functional characterization of Brassica napus DNA topoisomerase Iα-1 and its effect on flowering time when expressed in Arabidopsis thaliana.
abstract: Previous studies have shown that DNA topoisomerase Iα (AtTOP1α) has specific developmental functions during growth and development in Arabidopsis thaliana. However, little is known about the roles of DNA topoisomerases in the closely related and commercially important plant, rapeseed (Brassica napus). Here, the full-length BnTOP1α-1 coding sequence was cloned from the A2 subgenome of the Brassica napus inbred line L111. We determine that all BnTOP1α paralogs showed differing patterns of expression in different organs of L111, and that when expressed in tobacco leaves as a fusion protein with green fluorescent protein, BnTOP1α-1 localized to the nucleus. We further showed that ectopic expression of BnTOP1α-1 in the A. thaliana top1α-7 mutant fully complemented the early flowering phenotype of the mutant. Moreover, altered expression levels in top1α-7 seedlings of several key genes controlling flowering time were restored to wild type levels by ectopic expression of BnTOP1α-1. These results provide valuable insights into the roles of rapeseed DNA topoisomerases in flowering time, and provide a promising target for genetic manipulation of this commercially significant process in rapeseed.
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Chenhao
authors.initials: C
authors.lastname: Gao
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Shuanghui
authors.initials: S
authors.lastname: Qi
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Kaige
authors.initials: K
authors.lastname: Liu
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Li
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Changyu
authors.initials: C
authors.lastname: Jin
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Shaowei
authors.initials: S
authors.lastname: Duan
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Zhang
authors.affiliation: College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China. Electronic address: cmx786@nwafu.edu.cn.
authors.forename: Mingxun
authors.initials: M
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D029688:Brassica napus / Q000201:enzymology / Q000235:genetics*; D002467:Cell Nucleus / Q000201:enzymology / Q000235:genetics; D026942:DNA Topoisomerases / Q000235:genetics* / Q000378:metabolism; D035264:Flowers / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D009154:Mutation; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics
chemical_list: D010940:Plant Proteins; D049452:Green Fluorescent Proteins; D026942:DNA Topoisomerases
keywords: Arabidopsis; BnTOP1α-1; DNA topoisomerase; Flowering time; Rapeseed