Purine permease (PUP) family gene PUP11 positively regulates the rice seed setting rate by influencing seed development

Abstract

Abstract The distribution of cytokinins in plant tissues determines plant growth and development and is regulated by several cytokinin transporters. Purine permease (PUP) is a cytokinin transporter found in plants. Although 13 PUP genes have been identified in the rice genome, however, most of their functions remain unknown. We found that pup11mutants showed extremely low seed setting rates and a unique filled seed distribution. Our research revealed that pup11 mutants showed seed formation arrest because the accumulated starch disappeared 10 days after flowering. PUP11 has two major transcripts with different expression patterns and subcellular locations, and further studies revealed that they have redundant positive roles in regulating the seed setting rate. We also found that type-A RR genes were upregulated in the developing grains of the pup11 mutant compared with the wild type. The results also showed that PUP11 altered the expression of several sucrose transporters and significantly upregulated certain starch biosynthesis genes. In summary, our results indicate that PUP11 influences the rice seed setting rate by regulating sucrose transport and starch accumulation during grain filling. This research provides new insights into the relationship between cytokinins and seed development, which may help improve cereal yield.