Overexpression of OsMed16 inhibits rice growth and causes spontaneous cell death

Abstract Background The Mediator complex transduces information from the DNA-bound transcription factors to the RNA polymerase II transcriptional machinery. Research on plant Mediator subunits was mainly performed in Arabidopsis, while very few of them have been functionally characterized in rice. Results Here the rice Mediator subunit 16, OsMed16, was studied. OsMed16 encoded a putative protein of 1301 amino acids, which is longer than the reported version. It was expressed in various rice organs, and localized in nucleus. Knockout of OsMed16 caused rice seedling lethality. Its overexpression led to rice growth retardation, low yield, and spontaneous cell death in leaf blade and leaf sheath. RNA sequencing suggested that overexpression of OsMed16 altered the expression of a large number of genes. Among them, the up-regulation of some defense-related genes was verified. Conclusions Our results demonstrated that OsMed16 can regulate the expression of a wealth of genes, and alterations in its expression have profound impact on plant growth, development and defense response in rice.