title: A novel dominant glossy mutation causes suppression of wax biosynthesis pathway and deficiency of cuticular wax in Brassica napus.
abstract: BACKGROUND
  The aerial parts of land plants are covered with cuticular waxes that limit non-stomatal water loss and gaseous exchange, and protect plants from ultraviolet radiation and pathogen attack. This is the first report on the characterization and genetic mapping of a novel dominant glossy mutant (BnaA.GL) in Brassica napus.
  
  
  RESULTS
  Transmission electron microscopy revealed that the cuticle ultrastructure of GL mutant leaf and stem were altered dramatically compared with that of wide type (WT). Scanning electron microscopy corroborated the reduction of wax on the leaf and stem surface. A cuticular wax analysis of the GL mutant leaves further confirmed the drastic decrease in the total wax content, and a wax compositional analysis revealed an increase in aldehydes but a severe decrease in alkanes, ketones and secondary alcohols. These results suggested a likely blockage of the decarbonylation step in the wax biosynthesis pathway. Genetic mapping narrowed the location of the BnaA.GL gene to the end of A9 chromosome. A single-nucleotide polymorphism (SNP) chip assay in combination with bulk segregant analysis (BSA) also located SNPs in the same region. Two SNPs, two single sequence repeat (SSR) markers and one IP marker were located on the flanking region of the BnaA.GL gene at a distance of 0.6 cM. A gene homologous to ECERIFERUM1 (CER1) was located in the mapped region. A cDNA microarray chip assay revealed coordinated down regulation of genes encoding enzymes of the cuticular wax biosynthetic pathway in the glossy mutant, with BnCER1 being one of the most severely suppressed genes.
  
  
  CONCLUSIONS
  Our results indicated that surface wax biosynthesis is broadly affected in the glossy mutant due to the suppression of the BnCER1 and other wax-related genes. These findings offer novel clues for elucidating the molecular basis of the glossy phenotype.
authors: Yuanyuan
authors: Y
authors: Pu
authors: Jie
authors: J
authors: Gao
authors: Yanli
authors: Y
authors: Guo
authors: Tingting
authors: T
authors: Liu
authors: Lixia
authors: L
authors: Zhu
authors: Ping
authors: P
authors: Xu
authors: Bin
authors: B
authors: Yi
authors: Jing
authors: J
authors: Wen
authors: Jinxing
authors: J
authors: Tu
authors: Chaozhi
authors: C
authors: Ma
authors: Tingdong
authors: T
authors: Fu
authors: Jitao
authors: J
authors: Zou
authors: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China. jxshen@mail.hzau.edu.cn.
authors: Jinxiong
authors: J
authors: Shen
mesh_terms: D053898:Biosynthetic Pathways / Q000235:genetics*; D029688:Brassica napus / Q000166:cytology / Q000235:genetics* / Q000648:ultrastructure; D002463:Cell Membrane Permeability; D002855:Chromatography, Thin Layer; D020090:Chromosome Segregation; D032461:Chromosomes, Plant / Q000235:genetics; D003433:Crosses, Genetic; D015536:Down-Regulation / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D005799:Genes, Dominant; D017343:Genes, Plant / Q000235:genetics; D007438:Introns / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D020161:Physical Chromosome Mapping; D019441:Plant Epidermis / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D017422:Sequence Analysis, DNA; D014867:Water; D014885:Waxes / Q000378:metabolism*
chemical_list: D014885:Waxes; D014867:Water