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Transient expression of members of the germin‐like gene family in epidermal cells of wheat confers disease resistance
Author(s) -
Schweizer Patrick,
Christoffel Andreas,
Dudler Robert
Publication year - 1999
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1999.00624.x
Subject(s) - gene , biology , gene family , blumeria graminis , transgene , gene expression , powdery mildew , biochemistry , chemistry , microbiology and biotechnology , plant disease resistance , botany
Summary The wheat genome encodes a family of germin‐like proteins that differ with respect to regulation and tissue specificity of expression of the corresponding genes. While germin exhibits oxalate oxidase (E.C. 1.2.3.4.) activity, the germin‐like proteins (GLPs) have no known enzymatic activity. A role of oxalate oxidase in plant defence has been proposed, based on the capacity of the enzyme to produce H 2 O 2 , a reactive oxygen species. The role in defence of germin and other members of the germin ‐like gene family was functionally assessed in a transient assay system based on particle bombardment of wheat leaves. Transient expression of the pathogen‐induced germin gf‐2.8 gene, but not of the constitutively expressed HvGLP1 gene, reduced the penetration efficiency of Blumeria (syn. Erysiphe ) graminis f.sp. tritici , the causal agent of wheat powdery mildew, on transformed cells. Two engineered germin‐gf‐2.8 genes and the TaGLP2a gene, which all encoded proteins without oxalate oxidase activity, also reduced the penetration efficiency of the fungus, demonstrating that oxalate oxidase activity is not required for conferring enhanced resistance. Instead, activity tagging experi‐ments showed that in cells transiently expressing the germin gf‐2.8 gene, the transgene product became insolubilised at sites of attempted fungal penetration where localised production of H 2 O 2 was observed. Thus, germin and GLPs may play a structural role in cell‐wall re‐enforcement during pathogen attack.