Blocking miR396 increases rice yield by shaping inflorescence architecture

Abstract

Strategies to increase rice productivity to meet the global demand have been the main concern of breeders around the world. Although a growing number of functional genes related to crop yield have been characterized, our understanding of its associated regulatory pathways is limited. Using rice as a model, we find that blocking miR396 greatly increases grain yield by modulating development of auxiliary branches and spikelets through direct induction of the growth regulating factor 6 (OsGRF6) gene. The upregulation of OsGRF6 results in the coordinated activation of several immediate downstream biological clades, including auxin (IAA) biosynthesis, auxin response factors, and branch and spikelet development-related transcription factors. This study describes a conserved microRNA (miRNA)-dependent regulatory module that integrates inflorescence development, auxin biosynthesis and signalling pathways, and could potentially be used in engineering high-yield crop plants.