Cellulose biosynthesis in wood relies on cytosolic invertase activity

In several tree species carbon for cellulose biosynthesis is derived from sucrose. Cellulose is synthesized from UDP-glucose, but the enzyme(s) responsible for the initial sucrose cleavage and the source of UDP-glucose for cellulose biosynthesis in developing wood have not been defined. We investigate the role of CYTOSOLIC INVERTASEs (CINs) during wood formation in hybrid aspen (Populus tremula x tremuloides) and characterize transgenic lines with reduced CIN activity under GT43B wood promoter during secondary cell wall biosynthesis. Total RNAs were extracted from wild type (WT) (Populus tremula x tremuloides) and one CINRNAi transgenic line which had a decrease in total CIN activity compared to WT. WT -1, -2 and -3 are three biological replicates of wild type hybrid aspen and Line2 -1, -2 and -3 are three biological replicates of the CINRNAi transgenic line.