Abstract
BackgroundResistant Starch (RS) is a functional starch that has functions of regulating diabetes, hypertension and obesity. The effects of most starch synthesis-related genes (SSRGs) on RS content and their relationships are largely unknown. ResultsIn current study, ninety-nine lines from a recombinant inbred line were selected to investigate the effects of SSRGs on the RS content in different process status. Results revealed that RS content decreased dramatically after cooking, but it did not increase significantly after cooling for 7 days. And RS was closely related to many indexes of physicochemical properties, but was not correlated with granule size. Waxy (Wx) played an important role in controlling RS content and Wxa could elevate RS content in raw milled rice, cooked rice and retrograded rice. Soluble starch synthase IIa (SSIIa) had an impact on RS2, and RS2 content of indica SSIIa were significantly higher than that of japonica SSIIa (SSIIaj). Moreover, interaction of Wx and SSIIa was responsible for variations of RS content in three sample types, RS2 and volume proportion of different size starch granules. ConclusionsWx and SSIIa together significantly regulate different types content of RS in rice, but SSIIa only affects RS2. Wxa-SSIIaj is favorable to forming large-diameter starch granules.