SQUAMOSA promoter binding protein-like transcription factors: targets for improving cereal grain yield

Grain size and shape are prime targets for crop breeders, as they affect both yield and quality of rice. In addition, breeders target plant vegetative and reproductive shoot architecture, because these traits influence grain number, and thus yield potential. Accordingly, genetic control of grain size and shape as well as shoot architecture has been extensively investigated in recent years. In a recent study, Bin Han and colleagues have used genome-wide association analysis of grain size in a diverse collection of rice varieties of worldwide origin and identified a major quantitative trait locus GLW7, which encodes a SQUAMOSA promoter binding protein-like 13 (OsSPL13), a member of the plant-specific SBP domain family of transcription factors (Si et al., 2016). GLW7 positively regulates the size of rice grain cells, thus increasing grain length. GLW7 also regulates rice reproductive shoot (panicle) architecture, and the combined effects of GLW7 on panicle and grain structure increase yield (Si et al., 2016).