Resistant starch (RS) is the portion of starch that escapes gastrointestinal digestion and acts as a substrate for fermentation of probiotic bacteria in the gut. Aside from enhancing gut health, RS contributes to a lower glycemic index. A genome‐wide association study coupled with targeted gene association studies was conducted utilizing a diverse panel of 281 resequenced Indica rice lines comprising of ~2.2 million single nucleotide polymorphisms. Low‐to‐intermediate RS phenotypic variations were identified in the rice diversity panel, resulting in novel associations of RS to several genes associated with amylopectin biosynthesis and degradation. Selected rice lines encoding superior alleles of SSIIa with medium RS and inferior alleles with low RS groups were subjected to detailed transcriptomic, metabolomic, non‐starch dietary fibre (DF), starch structural and textural attributes. The gene regulatory networks highlighted the importance of a protein phosphatase alongside multiple genes of starch metabolism. Metabolomics analyses resulted in the identification of several metabolite hubs (carboxylic acid, sugars and polyamines) in the medium RS group. Among DF, mannose and galactose from the water‐insoluble fraction were found to be highly associated with low and medium RS lines, respectively. Starch structural analyses revealed that a moderate increase in RS is also linked to an elevation of amylose 1 and amylose 2 fractions. Although rice lines with medium RS content negatively affected textural and viscosity properties in comparison to low RS, the textural property of medium RS lines was in the same acceptable range as IR64, a rice mega variety popular in Asia.

中文翻译：

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平衡增加抗性淀粉含量的双刃剑效应及其对稻米质地的影响：其遗传和分子生​​理机制。

抗性淀粉（RS）是淀粉中不经胃肠道消化的部分，并作为肠道中益生菌发酵的底物。除了增强肠道健康外，RS还有助于降低血糖指数。利用281个重测序的In稻品系（包括约220万个单核苷酸多态性）进行了全基因组关联研究和靶向基因关联研究。在水稻多样性研究小组中发现了中低水平的RS表型变异，从而导致RS与支链淀粉生物合成和降解相关的几个基因形成新型关联。选定的水稻系编码SSIIa的优良等位基因具有中等RS和低RS等位基因的低等位基因需要进行详细的转录组，代谢组学，非淀粉膳食纤维（DF），淀粉的结构和质地属性的分析。基因调控网络突出了蛋白质磷酸酶与淀粉代谢的多个基因一起的重要性。代谢组学分析确定了中等RS组中的几种代谢产物中心（羧酸，糖和多胺）。在DF中，发现水不溶部分中的甘露糖和半乳糖分别与低和中RS系高度相关。淀粉结构分析表明，RS的适度增加也与直链淀粉1和直链淀粉2馏分的升高有关。