Distribution, abundance and properties of restriction enzymes On genomic dna of granule-bound starch synthase i and ii in Cassava (<i>Manihot Esculenta</i> Crantz)

Abstract

There is high demand for modified starch globally for both food and industrial uses because of its ability to

withstand processing conditions such as extreme temperature, diverse pH, high shear stress and freeze-thaw

variations. The study described the distribution, abundance and properties of restriction enzymes on genomic

DNA of granule-bound starch synthase (GBSS) I and II with a view to manipulate the genes for production of

modified starch in cassava. Thirty-one sites of 16 restriction enzymes were evenly distributed on 721 base-pair granule-bound starch synthase I (GBSS I) genomic DNA. About 63% of the restriction enzymes on GBSS I produced overhang DNA end, 88% were methylation sensitive and 69% utilized lambda DNA as substrate.  Most of the enzymes (94%) have optimum incubation temperature of 37⁰C while 95% of the enzymes recognized palindromic sequences. Similarly, 1690 base-pair long genomic DNA of GBSS II had 20 restriction sites cut by 16 restriction enzymes. About 67% of the restriction enzymes on GBSS II produced overhang DNA end, 88% were methylated sensitive, 93% use lambda substrate as substrate and all the enzymes has optimum  incubation temperature of 37⁰C. About 88% of the enzymes recognized palindromic sequences. Restriction enzymes were evenly distributed on GBSS I and II and EcoRI is the cheapest enzyme on both DNAs. The study concluded that cassava GBSS I and GBSS II genomic DNAs contain sites for suitable and abundant restriction enzymes with desirable properties for manipulation of the genes for production of modified starch.

Key words: Amylose synthesis, Cassava, Endonuclease, Genomic DNA.