The grain yield modulator miR156 regulates seed dormancy through the gibberellin pathway in rice

Chunbo Miao,Juanjuan Yao,Huazhong Shi,Kai Hua,Xue Liu,Jian-Kang Zhu,Zhen Wang,Lin Zhang

doi:10.1038/s41467-019-11830-5

Abstract

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.

Highlights

The widespread agricultural problem of pre-harvest sprouting (PHS) could potentially be overcome by improving seed dormancy
Our research reveals in vivo associations of Ideal Plant Architecture 1 (IPA1) with the promoters of many GA biosynthetic, signaling, and deactivating genes, suggesting that IPA1 mediates the effects of mir[156] mutations by directly regulating multiple genes in the GA pathway
We used an Agrobacterium-mediated method to transform the vectors into Nipponbare, a japonica variety widely used in laboratories, and Xiushui 134 (XS134), an elite japonica cultivar widely cultivated by farmers in southeast China

Summary

Introduction

The widespread agricultural problem of pre-harvest sprouting (PHS) could potentially be overcome by improving seed dormancy. Mir[156] 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. Our research reveals in vivo associations of IPA1 with the promoters of many GA biosynthetic, signaling, and deactivating genes, suggesting that IPA1 mediates the effects of mir[156] mutations by directly regulating multiple genes in the GA pathway

Methods

Results

Conclusion