Original Article

Planta

, Volume 226, Issue 6, pp 1459-1473

First online:

Cloning and expression analysis of candidate genes involved in wax deposition along the growing barley (Hordeum vulgare) leaf

  • Andrew RichardsonAffiliated withDivision of Biological Sciences, University of PaisleyMillipore
  • , Alexandre BoscariAffiliated withDivision of Biological Sciences, University of PaisleyInteractions Plantes Microorganismes et Santé Végétale, UMR INRA 1064/Université de Nice-Sophia Antipolis/CNRS 6192
  • , Lukas SchreiberAffiliated withDepartment of Ecophysiology, IZMB, University of Bonn
  • , Gerhard KerstiensAffiliated withDepartment of Biological Sciences, Lancaster Environment Centre, Lancaster University
  • , Mike JarvisAffiliated withDepartment of Chemistry, University of Glasgow
  • , Pawel HerzykAffiliated withSir Henry Wellcome Functional Genomics Facility, Institute of Biomedical and Life Sciences, University of Glasgow
  • , Wieland FrickeAffiliated withDivision of Biological Sciences, University of PaisleyUCD School of Biology and Environmental Science, UCD Science Centre West, University College Dublin Email author 

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Abstract

The aim of the present study was to isolate clones of genes which are likely to be involved in wax deposition on barley leaves. Of particular interest were those genes which encode proteins that take part in the synthesis and further modification of very long chain fatty acids (VLCFAs), the precursors of waxes. Previously, it had been shown that wax deposition commences within a spatially well-defined developmental zone along the growing barley leaf (Richardson et al. in Planta 222:472–483, 2005). In the present study, a barley microarray approach was used to screen for candidate contig-sequences (www.barleybase.org) that are expressed particularly in those leaf zones where wax deposition occurs and which are expressed specifically within the epidermis, the site of wax synthesis. Candidate contigs were used to screen an established in-house cDNA library of barley. Six full-length coding sequences clones were isolated. Based on sequence homologies, three clones were related to Arabidopsis CER6/CUT1, and these clones were termed HvCUT1;1, HvCUT1;2 and HvCUT1;3. A fourth clone, which was related to Arabidopsis Fiddlehead (FDH), was termed HvFDH1;1. These clones are likely to be involved in synthesis of VLCFAs. A fifth and sixth clone were related to Arabidopsis CER1, and were termed HvCER1;1 and HvCER1;2. These clones are likely to be involved in the decarbonylation pathway of VLCFAs. Semi-quantitative RT-PCR confirmed microarray expression data. In addition, expression analyses at 10-mm resolution along the blade suggest that HvCUT1;1 (and possibly HvCUT1;2) and HvCER1;1 are involved in commencement of wax deposition during barley leaf epidermal cell development.

Keywords

Cuticle Epidermal cell development Hordeum Leaf growth Microarray Very long chain fatty acid elongation Wax