Knockdown of p -Coumaroyl Shikimate/Quinate 3'-Hydroxylase Delays the Occurrence of Post-Harvest Physiological Deterioration in Cassava Storage Roots.

Cassava storage roots are an important source of food, feed, and material for starch-based industries in many countries. After harvest, rapid post-harvest physiological deterioration (PPD) reduces their palatability and marketability. During the PPD process, vascular streaking occurs through over-accumulation of coumarins, the biosynthesis of which involves the key enzyme p -coumaroyl shikimate/quinate 3'-hydroxylase (C3'H). Repression of MeC3'H expression by RNA interference in transgenic cassava plants caused a significant delay in PPD by decreasing scopoletin and scopolin accumulation in field-harvested storage roots. This study demonstrates that MeC3'H is the key enzyme participating in coumarin biosynthesis during PPD and shows that MeC3'H is a useful target gene for editing to prolong the shelf life of cassava storage roots.