Starch content and activities of starch biosynthetic enzymes in wheat, rice and millets

The aim of the study was to correlate the accumulation of amylose and total starch with activities of starch biosynthetic enzymes (AGPase, SSS and GBSS) in cereals like rice (PB-2, PD-19), wheat (UP-262, PBW-343) and millets (Barnyard millet, Finger millet and Foxtail millet) at different stages of endosperm development. ADP-glucose pyrophosphorylase (AGPase) activity was found higher in all varieties during developmental stage followed by granule bound starch synthase (GBSS) and soluble starch synthase (SSS). Accumulation of amylose was positively influenced by activity of AGPase and GBSS. Total starch accumulation was positively correlated with activity of AGPase and SSS. In all these varieties rate of enzymes activity was found higher at S3 stage. Higher ratio of AGPase and GBSS contributes lesser resistant starch, amylose content and am/ap ratio. Ratio of AGPase and GBSS can be used as an index for amylose content when it was studied in large sample size of similar varieties.