Discovery and Characterization of a Novel Tomato Mutant from an EMS Mutagenized Micro-Tom Population.

In tomato (), there are at least three () genes acting as susceptibility genes for the powdery mildew disease caused by , namely , and . Of the three homologs, the gene plays a major role since a natural mutant allele called can almost completely prevent fungal penetration by formation of papillae. The allele contains a 19-bp deletion in the coding sequence of the gene, resulting in a premature stop codon within the second cytoplasmic loop of the predicted protein.

Silencing of DND1 in potato and tomato impedes conidial germination, attachment and hyphal growth of Botrytis cinerea.

Background: Botrytis cinerea, a necrotrophic pathogenic fungus, attacks many crops including potato and tomato. Major genes for complete resistance to B. cinerea are not known in plants, but a few quantitative trait loci have been described in tomato.

A receptor-like kinase mediates the response of Arabidopsis cells to the inhibition of cellulose synthesis.

Background: A major challenge is to understand how the walls of expanding plant cells are correctly assembled and remodeled, often in the presence of wall-degrading micro-organisms. Plant cells, like yeast, react to cell-wall perturbations as shown by changes in gene expression, accumulation of ectopic lignin, and growth arrest caused by the inhibition of cellulose synthesis.

Results: We have identified a plasma-membrane-bound receptor-like kinase (THESEUS1), which is present in elongating cells.

Fruit-specific RNAi-mediated suppression of DET1 enhances carotenoid and flavonoid content in tomatoes.

Tomatoes are a principal dietary source of carotenoids and flavonoids, both of which are highly beneficial for human health. Overexpression of genes encoding biosynthetic enzymes or transcription factors have resulted in tomatoes with improved carotenoid or flavonoid content, but never with both. We attempted to increase tomato fruit nutritional value by suppressing an endogenous photomorphogenesis regulatory gene, DET1, using fruit-specific promoters combined with RNA interference (RNAi) technology.

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

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.

Manipulation of light signal transduction as a means of modifying fruit nutritional quality in tomato.

Fruit constitutes a major component of human diets, providing fiber, vitamins, and phytonutrients. Carotenoids are a major class of compounds found in many fruits, providing nutritional benefits as precursors to essential vitamins and as antioxidants. Although recent gene isolation efforts and metabolic engineering have primarily targeted genes involved in carotenoid biosynthesis, factors that regulate flux through the carotenoid pathway remain largely unknown.