title: Genes associated with agronomic traits in non-heading Chinese cabbage identified by expression profiling.
abstract: BACKGROUND
  The genomes of non-heading Chinese cabbage (Brassica rapa ssp. chinensis), heading Chinese cabbage (Brassica rapa ssp. pekinensis) and their close relative Arabidopsis thaliana have provided important resources for studying the evolution and genetic improvement of cruciferous plants. Natural growing conditions present these plants with a variety of physiological challenges for which they have a repertoire of genes that ensure adaptability and normal growth. We investigated the differential expressions of genes that control adaptability and development in plants growing in the natural environment to study underlying mechanisms of their expression.
  
  
  RESULTS
  Using digital gene expression tag profiling, we constructed an expression profile to identify genes related to important agronomic traits under natural growing conditions. Among three non-heading Chinese cabbage cultivars, we found thousands of genes that exhibited significant differences in expression levels at five developmental stages. Through comparative analysis and previous reports, we identified several candidate genes associated with late flowering, cold tolerance, self-incompatibility, and leaf color. Two genes related to cold tolerance were verified using quantitative real-time PCR.
  
  
  CONCLUSIONS
  We identified a large number of genes associated with important agronomic traits of non-heading Chinese cabbage. This analysis will provide a wealth of resources for molecular-assisted breeding of cabbage. The raw data and detailed results of this analysis are available at the website http://nhccdata.njau.edu.cn.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Song
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Tongkun
authors.initials: T
authors.lastname: Liu
authors.forename: Weike
authors.initials: W
authors.lastname: Duan
authors.forename: Zhinan
authors.initials: Z
authors.lastname: Huang
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Huawei
authors.initials: H
authors.lastname: Tan
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement/Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China. hxl@njau.edu.cn.
authors.forename: Xilin
authors.initials: X
authors.lastname: Hou
mesh_terms: D001937:Brassica / Q000235:genetics* / Q000502:physiology; D020869:Gene Expression Profiling / Q000379:methods*; D018506:Gene Expression Regulation, Plant