title: Identification of downy mildew resistance gene candidates by positional cloning in maize (Zea mayssubsp.mays; Poaceae).
abstract: OBJECTIVE
  Positional cloning in combination with phenotyping is a general approach to identify disease-resistance gene candidates in plants; however, it requires several time-consuming steps including population or fine mapping. Therefore, in the present study, we suggest a new combined strategy to improve the identification of disease-resistance gene candidates.
  
  
  RESULTS
  Downy mildew (DM)-resistant maize was selected from five cultivars using a spreader row technique. Positional cloning and bioinformatics tools were used to identify the DM-resistance quantitative trait locus marker (bnlg1702) and 47 protein-coding gene annotations. Eventually, five DM-resistance gene candidates, includingbZIP34,Bak1, andPpr, were identified by quantitative reverse-transcription PCR (RT-PCR) without fine mapping of the bnlg1702 locus.
  
  
  CONCLUSIONS
  The combined protocol with the spreader row technique, quantitative trait locus positional cloning, and quantitative RT-PCR was effective for identifying DM-resistance candidate genes. This cloning approach may be applied to other whole-genome-sequenced crops or resistance to other diseases.
authors.affiliation: Department of Plant Resources, College of Industrial Science, Kongju National University, Yesan 32439, Republic of Korea.
authors.forename: Jae Yoon
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Agriculture and Life Science Research Institute, Kangwon National University, Chuncheon 24341, Republic of Korea.
authors.forename: Jun-Cheol
authors.initials: JC
authors.lastname: Moon
authors.affiliation: Department of Life Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea.
authors.forename: Hyo Chul
authors.initials: HC
authors.lastname: Kim
authors.affiliation: Department of Life Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea.
authors.forename: Seungho
authors.initials: S
authors.lastname: Shin
authors.affiliation: Department of Life Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea.
authors.forename: Kitae
authors.initials: K
authors.lastname: Song
authors.affiliation: Department of Life Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea.
authors.forename: Kyung-Hee
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Department of Life Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea.
authors.forename: Byung-Moo
authors.initials: BM
authors.lastname: Lee
keywords: downy mildew; maize; positional cloning; quantitative reverse-transcription PCR (RT-PCR); spreader row technique