THE EFFECT OF OVER-EXPRESSION OF CELLULOSE SYNTHASE-LIKE GENES (HvCSLF) ON (l,3;l,4)-p-D-GLUCAN LEVELS IN TRANSGENIC BARLEY PLANTS

摘要

A large component of dietary fibre is found in the cell walls of plants, including cereals. In this case, the wall polysaccharides are resistant to digestion in the human small intestine, but are completely or partially fermented in the large intestine (Topping, 2007). The (l,3;l,4)-p-D-glucans (P-glucans) are the major cell wall polysaccharide in the starchy endosperm of barley and oats (Fincher and Stone, 2004). They have been implicated in numerous health benefits, including the lowering of plasmacholesterol, a reduction in the risk of cardiovascular disease and a reduction in the risk of colorectal cancer (Topping, 2007). The cellulose synthase like (Csl) gene family has been implicated in the biosynthesis of P-glucan in plants, in particular the CslF and CslH genes (Burton et al., 2006; Doblin et al., 2009). Transcript levels of the HvCslF6 gene are the highest of the HvCslF family in the developing barley endosperm (Burton et al., 2008) and HvCslF4 is one of the genes present in a cluster ofHvCslF genes on chromosome 2H that co-locates with a major QTL influencing barley grain P-glucan (Han et al., 1995; Burton et al., 2006). For these reasons these two genes were chosen as possible candidates to manipulate P-glucan synthesis in the developing barley endosperm. In this paper the generation and analysis of transgenic plants over-expressing the HvCslF4 and HvCslF6 genes are described.