title: Defensin promoters as potential tools for engineering disease resistance in cereal grains.
abstract: Engineering of plant protection in cereals requires well characterized tissue-specific and wounding/pathogen-inducible promoters for targeted expression of pathogen responsive and resistance genes. We describe the isolation of seven wheat and rice defensin genes expressed in early developing grain and during grain germination, two developmental stages that are particularly vulnerable to pathogens and insects. Comparison of three-dimensional (3D) models of these rice and wheat PRPI defensins indicated variations in spatial architectures that could reflect their functional diversities. Wheat and rice were stably transformed with promoter-GUS fusion constructs and the spatial and temporal activities of four promoters were studied using whole-mount and histological assays. PRPI promoters were active before and at anthesis in both transgenic wheat and rice with activity mainly in the ovary. In rice, GUS activity was also observed in vascular tissue of the lemma, palea and anthers. After fertilization, GUS was strongly expressed in the outer cell layers of the pericarp and in the main vascular bundle of the grain. During, and a short time after, seed germination, wheat promoters were active in transgenic rice embryos, roots and/or coleoptiles. All wheat and rice promoters were strongly induced by wounding in leaf, stem and grain of transgenic rice plants. These results suggest that PRPI promoters will be useful for specific targeting and accumulation of proteins conferring resistance to pathogens in vulnerable tissues of developing and germinating grain.
authors: Australian Centre for Plant Functional Genomics, Hartley Grove, Urrbrae, SA, Australia.
authors: Nataliya
authors: N
authors: Kovalchuk
authors: Ming
authors: M
authors: Li
authors: Finni
authors: F
authors: Wittek
authors: Nicolas
authors: N
authors: Reid
authors: Rohan
authors: R
authors: Singh
authors: Neil
authors: N
authors: Shirley
authors: Ainur
authors: A
authors: Ismagul
authors: Serik
authors: S
authors: Eliby
authors: Alex
authors: A
authors: Johnson
authors: Andrew S
authors: AS
authors: Milligan
authors: Maria
authors: M
authors: Hrmova
authors: Peter
authors: P
authors: Langridge
authors: Sergiy
authors: S
authors: Lopato
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D023082:Defensins / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007113:Immunity, Innate; D008958:Models, Molecular; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics*; D056771:Ovule / Q000235:genetics; D010935:Plant Diseases / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified / Q000235:genetics; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D014908:Triticum / Q000235:genetics*
chemical_list: D023082:Defensins; D010940:Plant Proteins