Mutations in sorghum SBEIIb and SSIIa affect alkali spreading value, starch composition, thermal properties and flour viscosity

<p>Sorghum is an important food crop for millions of people in Africa and Asia. Whole genome re-sequencing of sorghum EMS mutants exhibiting an alkali spreading value (ASV) phenotype revealed candidate SNPs in <em>Sobic.004G163700</em> and <em>Sobic.010G093400</em>. Comparative genomics identified <em>Sobic.010G093400</em> as a <em>starch synthase IIa</em> and <em>Sobic.004G163700</em> as a <em>starch branching enzyme IIb</em>. Segregation analyses showed that mutations in <em>Sobic.010G093400</em> or <em>Sobic.004G163700</em> co-segregated with the ASV phenotype. Mutants in <em>SSIIa</em> exhibited no change in amylose content but expressed lower final viscosity and lower starch gelatinization temperature (GT) than starches from non-mutant plants. The <em>sbeIIb</em> mutants exhibited significantly higher amylose levels and starch GT and lower viscosity compared to non-mutant starches and <em>ssIIa</em> mutants. Mutations in <em>SBEIIb</em> had a dosage dependent effect on amylose content. Double mutants of <em>sbeIIb</em> and <em>ssIIa</em> resembled their <em>sbeIIb</em> parent in amylose content, starch thermal properties and viscosity profiles. These variants will provide opportunities to produce sorghum varieties with modified starch end-use qualities important for the beer brewing and baking industries and specialty foods for humans with diabetes.</p>

<p>These data files contain whole-genome resequencing data for sorghum genotypes with unique starch properties.</p>

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