Short tandem target mimic rice lines uncover functions of miRNAs in regulating important agronomic traits

Significance Plant microRNAs (miRNAs) control intricate gene regulatory networks and have been implicated in important developmental switches and stress responses. Plant miRNAs have recently emerged as promising targets for crop improvement because they can control complex agronomic traits; however, functional studies using reverse genetics have been hampered by practical difficulties. We have silenced 35 miRNA families in rice to generate a resource for discovering new functions of miRNAs and targets of agronomic improvements. As a proof of concept, we show that manipulation of a promising miRNA, miRNA398, leads to important yield improvements. Our findings also reveal important agronomic roles for several miRNAs.