Manipulation of DET1 expression in tomato results in photomorphogenic phenotypes caused by post-transcriptional gene silencing

• Published in: The Plant journal : for cell and molecular biology Vol. 40; no. 3; pp. 344 - 354
• Main Authors: Davuluri, G.R, Tuinen, A. van, Mustilli, A.C, Manfredonia, A, Newman, R, Burgess, D, Brummell, D.A, King, S.R, Palys, J, Uhlig, J
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.11.2004; Blackwell Science; Blackwell Publishing Ltd
• Subjects: Arabidopsis; Biological and medical sciences; de-etiolated 1 protein; DET1; DNA methylation; epigenetics; Fruit - metabolism; fruit ripening; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Plant; gene silencing; Genotype; Genotype & phenotype; Light; Lycopersicon esculentum; Lycopersicon esculentum - genetics; Lycopersicon esculentum - metabolism; molecular sequence data; nuclear proteins; nucleotide sequences; Phenotype; phenotypic variation; photomorphogenesis; Physical agents; Pigments, Biological - biosynthesis; Plant physiology and development; plant proteins; Plant Proteins - biosynthesis; Plant Proteins - genetics; Plant Proteins - physiology; Plants, Genetically Modified; post-transcriptional gene silencing; Proteins; RNA Interference; signal transduction; siRNA; small interfering RNA; Solanum lycopersicum var. lycopersicum; tomato; Tomatoes; transgenic plants; vegetable crops; Vegetative apparatus, growth and morphogenesis. Senescence; Light effect; DET1; Growth; siRNA; tomato; fruit ripening; Genetic determinism; post-transcriptional gene silencing; Gene silencing; Signal transduction; photomorphogenesis; Vegetable crop; Gene; Dicotyledones; Angiospermae; Lycopersicon esculentum; DNA methylation; Spermatophyta; Solanaceae
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313x.2004.02218.x

The tomato HIGH PIGMENT-2 gene encodes an orthologue of the Arabidopsis nuclear protein DE-ETIOLATED 1 (DET1). From genetic analyses it has been proposed that DET1 is a negative regulator of light signal transduction, and recent results indicate that it may control light-regulated gene expression at the level of chromatin remodelling. To gain further understanding about the function of DET1 during plant development, we generated a range of overexpression constructs and introduced them into tomato. Unexpectedly, we only observed phenotypes characteristic of DET1 inactivation, i.e. hyper-responsiveness to light. Molecular analysis indicated in all cases that these phenotypes were a result of suppression of endogenous DET1 expression, due to post-transcriptional gene silencing. DET1 silencing was often lethal when it occurred at relatively early stages of plant development, whereas light hyper-responsive phenotypes were obtained when silencing occurred later on. The appearance of phenotypes correlated with the generation of siRNAs but not DNA hypermethylation, and was most efficient when using constructs with mutations in the DET1 coding sequence or with constructs containing only the 3'-terminal portion of the gene. These results indicate an important function for DET1 throughout plant development and demonstrate that silencing of DET1 in fruits results in increased carotenoids, which may have biotechnological potential.