Abstract: The present invention relates to a method for identifying at least one metabolic conversion step, the modulation of which increases the amount of a metabolite of interest in a plant cell, plant or plant part, said method comprising establishing a stoichiometric network model for the metabolism of the plant cell, plant or plant part including the synthesis pathway for the metabolite of interest, identifying at least one candidate metabolic conversion step by applying at least one algorithm of Growth-coupled Design, and validating the at least one candidate metabolic conversion step by a constraint-based modeling approach in the stoichiometric network model, wherein an increase in the metabolite of interest occurring in said constraint-based modeling approach is indicative for a metabolic conversion step, the modulation of which increases the amount of the metabolite of interest in the plant cell, plant or plant part.

Abstract: The present invention relates to optimized ketolase coding sequences, corresponding coding sequences and genetic constructs alone or in combination with beta-cyclase coding sequences, their use for the expression in plants, in particular in plants of the genus Tagetes, to such genetically modified plants, to a process for the preparation of carotenoid products by culturing the genetically modified plants. The present invention further relates to the expression of optimized ketolase coding sequences alone or in combination with beta-cyclase coding sequences under control of an Antirrhinum majus ANTHIRRHINUM FIDDLEHEAD (AFI) promoter, In addition the invention relates to the use of an AFI promoter for heterologous gene expression, preferably for flower-specific expression of genes in plants of the genus Tagetes, to the genetically modified plants of the genus Tagetes, and to a process for producing biosynthetic products by cultivating the genetically modified plants.

Abstract: New ketolases for the production of ketocarotenoids in Tagetes Abstract A ketolase having a polypeptide sequence SEQ ID NO:6, a sequence derived from SEQ ID NO:6 by substitution, insertion or deletion of aminoacids, which has an identity of at least 60% with the respective sequence SEQ. ID. NO: 6 or a functionally equivalent fragment of the sequences mentioned above and processes for production of ketocarotenoids in Tagetes.

Abstract: The invention relates to improved recombination systems and methods for eliminating maker sequences from the genome of plants. Particularly the invention is based on use of an expression cassette comprising the parsley ubiquitin promoter, and operably linked thereto a nucleic acid sequence coding for a sequence specific DNA-endonuclease.