Glycosylhydrolases and the control of mannose/galactose ratio in legume-seed galactomannan.

Abstract

This thesis describes the work carried out and results obtained from an investigation into the relationship between the two forms of a-galactosidase found within the maturing and germinating Senna occidentalis endosperms. These two enzymes are responsible for the final mannose/galactose ratio of galactomannan within the maturing senna endosperm and the mobilisation of the galactomannan storage reserve during germination. The methods used to characterise the two a-galactosidase enzymes and the results describing the slight but significant dissimilarities are described. The methods used to isolate RNA from the maturing and germinating endosperms are shown along with a description of the RT-PCR and cloning strategies then employed. The analysis of the relationship between the cDNAs obtained from the maturing and germinating endosperms used southern blotting, 5’RACE-PCR, DNA sequencing reverse-translation and multiple sequence alignments are described. Finally the similarities between the cloned senna a-galactosidases and those obtained from the swiss-prot database are shown and the commercial uses of the agalactosidase are discussed along with the future chances of producing commercially viable transgenic galactomannan yielding crops.