A protective role for the embryo surrounding region of the maize endosperm, as evidenced by the characterisation of ZmESR-6, a defensin gene specifically expressed in this region

Plant Mol Biol. 2005 May;58(2):269-82. doi: 10.1007/s11103-005-3479-1.


A Zea mays cDNA clone, ZmESR-6, was isolated as a gene specifically expressed at the basal region of immature kernels. ZmESR-6 cDNA encoded for a small (11.1 kDa) protein homologous to plant defensins. As for other defensins, the protein contained an N-terminal signal peptide signature and a C-terminal acidic peptide, the mature peptide has a molecular mass of 5.5 kDa. ZmESR-6 was highly expressed in developing kernels but the transcript could not be detected in any other maize tissue. The recombinant ZmESR-6 protein, purified from E. coli, showed strong in vitro inhibitory activity against bacterial and fungal plant pathogens, suggesting a role for ZmESR-6 in plant defence. The distribution of the transcripts was restricted to the embryo surrounding region (ESR) of the kernel. Immunolocalisation experiments revealed, however, that at the grain filling phase ZmESR-6 was accumulated in the placentochalaza-cells, rather than in the ESR cells that produce it. Our results suggest that the ESR has a role in protecting the embryo at the very early stages of seed development, whilst contributes to the general defence mechanism of the kernel at later developmental stages.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Anti-Infective Agents / pharmacology
  • Bacteria / drug effects
  • Bacteria / growth & development
  • Base Sequence
  • Blotting, Northern
  • Blotting, Western
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics
  • DNA, Complementary / isolation & purification
  • Defensins / genetics*
  • Defensins / metabolism
  • Defensins / pharmacology
  • Fungi / drug effects
  • Fungi / growth & development
  • Gene Expression Regulation, Developmental
  • Gene Expression Regulation, Plant
  • Immunohistochemistry
  • In Situ Hybridization
  • Inhibitory Concentration 50
  • Molecular Sequence Data
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Plant Proteins / pharmacology
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Recombinant Proteins / metabolism
  • Recombinant Proteins / pharmacology
  • Seeds / genetics*
  • Seeds / growth & development
  • Seeds / metabolism
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Zea mays / genetics*
  • Zea mays / growth & development
  • Zea mays / metabolism


  • Anti-Infective Agents
  • DNA, Complementary
  • Defensins
  • Plant Proteins
  • RNA, Messenger
  • Recombinant Proteins