Transcriptionally Active Mutator-like Transposable Elements in the Genome of Cassava (Manihot esculenta Crantz)

Randomly sequencing cDNA clones from a library made with mRNA expressed during the Post-harvest Physiological Deterioration (PPD) of cassava root led to the isolation of a clone with high similarity to an Arabidopsis Mutator-like transposable element (MULE) transposase. Southern hybridisation experiment using this cassava MULE transposase cDNA as probe revealed significant differences between the hybridisation pattern of the DNA digested by the isoschizomers, Hpa II and Msp I, suggesting partial methylation of cassava MULE sequences. We detected RNA transcripts of cassava mudrA-related elements under normal growing conditionsby the northern hybridisation protocol. The transcripts expression increased in wounded cassava leaves and during PPD of cassava root. The implication and application of active Mutator-like transposable element in the genome of cassava is discussed.