Submitted to: Proceedings International Barley Genetics Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 5/23/2004
Publication Date: 6/1/2004
Citation: Skadsen, R.W., Federico, M.L., Abebe, T., Kaeppler, H.F. 2004. Development of tissue-specific gene promoters for targeting anti-fusarium gene expression in barley [abstract]. Proceedings International Barley Genetics Symposium. Paper No. 157.
Technical Abstract: We ientified lemma pericarp epithelium tissues as rapidly infected by Fusarium graminearum. Genes specifically expressed in these tissues were cloned so that their promoters could be used to express antifungal protein genes. These included a lipid transfer protein homologue ("LTP6") highly expressed in the pericarp epithelium but not in vegetative leaves and a jacaline-like gene, Lem2, preferentially expressed in the lemma/palea, compared with the flag leaf. Ltp6 is also expressed in coleoptiles and embryos; mRNA levels increase in response to salt, cold, abscisic acid and salicylic acid in a pattern distinct from other barley Ltps. Transient expression analysis of the promoter showed that 246 bp of upstream sequence confers tissue-specific expression and retains most promoter activity. Substitution of a novel MYC binding site abolishes most of the activity. All 4 Lem2 genes are located in a single BAC and map to chromosome 5(1H). Lem2 is specifically expressed in the lemma/palea and coleoptile. The two LEM2 jacalin-like domains may be involved in pathogen recognition. SA and MeJA induce Lem2 within 2h, suggesting that it is a defensive gene. Particle bombardment with the cloned Lem2 promoter showed strong expression of sgfp in the lemma/palea and very weak expression in leaves.