A glutamyl-tRNA reductase and its binding protein promote transitory starch biosynthesis and enhance grain quality and yield in rice.

ABSTRACT: Transitory starch in rice leaves is critical for temporary carbon storage, plant growth, and subsequent grain filling, yet the regulatory mechanisms underlying its biosynthesis remain poorly understood. Here, we found that Leaf Starch Deficiency 3 (LSD3), a rice glutamyl-tRNA reductase (GluTR), interacts with GluTR-binding protein (GluTRBP), which in turn associates with granule-bound starch synthase II (GBSSII), the key enzyme responsible for amylose synthesis in leaves. The LSD3-GluTRBP module maintains both the protein stability and enzymatic activity of GBSSII. The lsd3 and glutrbp mutants exhibited markedly reduced GBSSII activity, resulting in significant decreases in leaf starch accumulation. Moreover, these mutants displayed severe defects in carbon-source transport from leaves to

SUBMITTER: Duan Y 

PROVIDER: S-EPMC12785062 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature