OsIPMS1 Plays Key Role in Seed Vigor of Rice

Seed vigor is an important trait for the direct seeding of rice. Isopropylmalate synthase (IPMS) is known to catalyze the committed step of leucine (Leu) biosynthesis, but its effect on seed vigor remains unclear. Yongqi He, together with his colleagues, studied the roles of rice OsIPMS1 and OsIPMS2 in seed vigor. Both OsIPMS1 and OsIPMS2 are known to catalyze Leu biosynthesis, and Leu feedback inhibits their IPMS activities.

Disruption of OsIPMS1 resulted in low seed vigor under various conditions, which might be associated with the reduction of amino acids in germinating seeds. Eleven amino acids that associated with stress tolerance, GA biosynthesis, and tricarboxylic acid cycle were also significantly reduced in osipms1 mutants compared with those in wildtypes during seed germination.

Analysis indicated that a total of 1,209 differentially expressed genes were altered in the osipms1 mutant compared with wildtypes at the early germination stage. Most of the genes were involved in glycolysis, protein processing, and mannose metabolism. Further analysis confirmed that the role of OsIPMS1 in seed vigor is involved in starch hydrolysis, glycolytic activity, and energy levels in germinating seeds.

This study provides novel insights into the function of OsIPMS1 on seed vigor.

For more information, read the article in Plant Biotechnology Journal.