X. Huang: Biogenesis of potato starch granules

Producing starches with altered composition, structure and novel physico-chemical properties in planta has huge advantages in starch industry. The starch binding domain (SBD) technology has been extensively explored in our lab for modifying starch in planta and producing so-called “tailored starches”. In this thesis, E. coli glycogen branching enzyme (GlgB) and Neisseria polysaccharea amylosucrase were expressed in potato to modify starch by fusing with an SBD. Expression of these different fusion proteins in potato resulted in starch granule morphology and structure alteration. Furthermore, the transcriptional level analysis of earlier produced MAT/SBD transformants showed that the expression of MAT in potato did not affect the expression of other genes in the starch biosynthesis. A tandem CBM25 domain of amylase from Microbacterium aurum was introduced in potato and the results suggested that it can be used as a novel tool for targeting proteins to granules during starch biosynthesis without causing side-effects.