Waxy gene deficiency shapes the multi-level wheat starch structure and noodle quality

The role of Wx alleles in amylose biosynthesis is well-established; however, how Wx deficiency triggers hierarchical changes in starch structure and consequently affects noodle quality is still poorly understood. Here, analysis of near-isogenic lines (NILs) revealed that Wx deficiency preferentially increases the proportion of short amylopectin chains (DP 6–24) and shifts granule size distribution toward smaller B-type granules. Although complete Wx deletion (BBB genotype) enhanced starch crystallinity and enthalpy, it concomitantly led to an undesirable decrease in paste viscosity. In contrast, partial deletion (e.g., ABA) yielded noodles with a superior soft-yet-springy texture, marked by significantly improved springiness and chewiness without excessive hardness. This optimal texture is attributed to a higher proportion of short amylopectin chains (DP 6–24) coupled with a lower proportion of long amylose chains (DP > 500). This work demonstrates targeted manipulation of Wx alleles can engineer starch multi-level structure for specific end-use quality, moving beyond conventional amylose-centric breeding strategies.