Issue Information

Lysine is the main limiting essential amino acid in rice, a major energy and nutrition source for humans and livestock. In higher plants, the rate‐limiting steps in lysine biosynthesis pathway are catalyzedby two key enzymes, aspartate kinase (AK) and dihydrodipicolinate synthase (DHDPS), both extremely sensitive to feedback inhibition by lysine. Yang et al have constructed lysine‐insensitive rice AK andDHDPS mutants, each carrying a single amino acid substitution, AK2 (S 449 → L) and DHDPS1 (S 124 → N). Simultaneously expressing these modified enzymes and inhibiting the lysine catabolic enzymes LKR/SDH (lysine ketoglutaric acid reductase/saccharopine dehydropine dehydrogenase) through LKR ‐RNAi, led to significant elevation of free lysine level in rice seeds, while the growth, development and seed appearance remined normal in the transgenic lines. Cover illustration refers to the article in this issue (Yang et al ., 490–501).