LAUSR

The widespread agricultural problem of pre-harvest sprouting (PHS) could potentially be overcome by improving seed dormancy. Here, we report that miR156, an important grain yield regulator, also controls seed dormancy in rice. We found that mutations in one MIR156 subfamily enhance seed dormancy and suppress PHS with negligible effects on shoot architecture and grain size, whereas mutations in another MIR156 subfamily modify shoot architecture and increase grain size but have minimal effects on seed dormancy. Mechanistically, mir156 mutations enhance seed dormancy by suppressing the gibberellin (GA) pathway through de-represssion of the miR156 target gene Ideal Plant Architecture 1 (IPA1), which directly regulates multiple genes in the GA pathway. These results provide an effective method to suppress PHS without compromising productivity, and will facilitate breeding elite crop varieties with ideal plant architectures. Pre-harvest sprouting reduces the yield of agriculturally important crops such as rice. Here, the authors show that mutating specific members of the MIR156 gene family can suppress pre-harvest sprouting in rice without negative effects on plant architecture, suggesting a practical route to elite crop varieties.