title: ZmGA3ox2, a candidate gene for a major QTL, qPH3.1, for plant height in maize.
abstract: Maize plant height is closely associated with biomass, lodging resistance and grain yield. Determining the genetic basis of plant height by characterizing and cloning plant height genes will guide the genetic improvement of crops. In this study, a quantitative trait locus (QTL) for plant height, qPH3.1, was identified on chromosome 3 using populations derived from a cross between Zong3 and its chromosome segment substitution line, SL15. The plant height of the two lines was obviously different, and application of exogenous gibberellin A(3)  removed this difference. QTL mapping placed qPH3.1 within a 4.0 cM interval, explaining 32.3% of the phenotypic variance. Furthermore, eight homozygous segmental isolines (SILs) developed from two larger F(2)  populations further narrowed down qPH3.1 to within a 12.6 kb interval. ZmGA3ox2, an ortholog of OsGA3ox2, which encodes a GA3 β-hydroxylase, was positionally cloned. Association mapping identified two polymorphisms in ZmGA3ox2 that were significantly associated with plant height across two experiments. Quantitative RT-PCR showed that SL15 had higher ZmGA3ox2 expression relative to Zong3. The resultant higher GA(1)  accumulation led to longer internodes in SL15 because of increased cell lengths. Moreover, a large deletion in the coding region of ZmGA3ox2 is responsible for the dwarf mutant d1-6016. The successfully isolated qPH3.1 enriches our knowledge on the genetic basis of plant height in maize, and provides an opportunity for improvement of plant architecture in maize breeding.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Teng
authors.forename: Lihong
authors.initials: L
authors.lastname: Zhai
authors.forename: Ruixiang
authors.initials: R
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Bai
authors.forename: Liqiu
authors.initials: L
authors.lastname: Wang
authors.forename: Dongao
authors.initials: D
authors.lastname: Huo
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Tao
authors.forename: Yonglian
authors.initials: Y
authors.lastname: Zheng
authors.forename: Zuxin
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D018533:Biomass; D032461:Chromosomes, Plant; D017343:Genes, Plant; D005875:Gibberellins / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000378:metabolism; D009154:Mutation; D011110:Polymorphism, Genetic; D040641:Quantitative Trait Loci; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development
chemical_list: D005875:Gibberellins; D006899:Mixed Function Oxygenases; C108186:gibberellin 3beta-hydroxylase