Amorphophallus konjac Transcriptome or Gene expression

A Roche 454 cDNA deep sequencing experiment was performed of a developing corm of Amorphophallus konjac – also known as Voodoo Lily. The corm of this plant consists of up to 60% (% dry weight) of the storage polysaccharide glucomannan, a hemicellulose also known to exist in the cell walls of higher plants. The 454 sequencing of a cDNA library created from the tissue of the developing A.konjac corm lead to 246 Mbp sequencing data from which 4,513 distinct contigs were assembled. Within the Voodoo Lily EST database genes from the entire pathway of glucomannan biosynthesis were identified, starting from the sucrose metabolism via nucleotide sugar conversion pathways for the formation of GDP-mannose to a putative glucomannan synthase. Based on the EST analysis hitherto unknown pathways for the synthesis of GDP-glucose, a necessary precursor for glucomannan biosynthesis, could be proposed. Most importantly, the results highlight transcriptional bottlenecks for the synthesis of this hemicellulose.