title: Molecular characterization and functional analysis of barley semi-dwarf mutant Riso no. 9265.
abstract: BACKGROUND
  sdw1/denso is one of the most important and useful semi-dwarf genes in barley breeding. At least four sdw1/denso alleles have been reported and HvGA20ox 2 is considered as the candidate gene. Up to date, results of studies have not univocally proven the genetic relationship between sdw1/denso and HvGA20ox 2 .
  
  
  RESULTS
  In the present study, a complete deletion of Morex_contig_40861 including both HvGA20ox 2 and Mloc_56463 genes was identified at the sdw1 locus from a semi-dwarf mutant Riso no. 9265. Expression of the genes encoding gibberellin biosynthesis (HvGA20ox 1 and HvGA3ox 2 ) were increased in the mutant compared to the wild type Bomi, while the expression of GA catabolic gene HvGA2ox 3 was decreased. Over-expression of HvGA20ox 2 could rescue the semi-dwarf phenotype and increase GAs concentration.
  
  
  CONCLUSIONS
  We confirmed that a GA biosynthetic enzyme HvGA20ox2, acted as GA 20-oxidase, is the functional gene for the sdw1/denso semi-dwarfism. Lose of HvGA20ox 2 is partially compensated by HvGA20ox 1 and further feedback is regulated by gibberellin. We also deduced that the sdw1/denso allele itself affects later heading owing to its reduced endogenous GAs concentration.
authors.affiliation: Institute of Crop Science, Zhejiang University, Hangzhou, 310058, China.|Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
authors.forename: Qiaojun
authors.initials: Q
authors.lastname: Jia
authors.affiliation: Western Barley Genetics Alliance, Murdoch University, Murdoch, WA6150, Australia.
authors.forename: Chengdao
authors.initials: C
authors.lastname: Li
authors.affiliation: Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Shang
authors.affiliation: Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
authors.forename: Jinghuan
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Hua
authors.affiliation: Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
authors.forename: Junmei
authors.initials: J
authors.lastname: Wang
authors.affiliation: Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China. jmyang@163.com.
authors.forename: Jianming
authors.initials: J
authors.lastname: Yang
authors.affiliation: Institute of Crop Science, Zhejiang University, Hangzhou, 310058, China. zhanggp@zju.edu.cn.
authors.forename: Guoping
authors.initials: G
authors.lastname: Zhang
mesh_terms: D017353:Gene Deletion; D017343:Genes, Plant; D001467:Hordeum / Q000033:anatomy & histology / Q000235:genetics*; D009154:Mutation