Seed-Specific Overexpression of SPL12 and IPA1 Improves Seed Dormancy and Grain Size in Rice

Abstract

Pre-harvest sprouting (PHS) often results in reduced grain yield and quality and is a major problem in cereal production. Improved seed dormancy would inhibit PHS. Here we show that seed-specific overexpression of two <i>SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE</i> (<i>SPL</i>) genes <i>SPL12</i> and <i>IPA1</i> enhances seed dormancy and inhibits PHS without noticeable effects on shoot architecture in rice. In addition, seed-specific overexpression of <i>IPA1</i> also increases grain size and thus improves grain productivity. Furthermore, our results suggest that <i>SPL12</i> enhances the seed dormancy through directly regulating many genes in the gibberellin (GA) pathway. This research provides an efficient method to suppress PHS and will facilitate breeding elite crop varieties.