Rice Glucose 6-Phosphate/Phosphate Translocator 1 is required for tapetum function and pollen development

In plants, non-green plastids in heterotrophic tissues are sites for starch and fatty acids biosynthesis, which are essential for plant development and reproduction. Distinct from chloroplasts, the metabolites for these processes in non-green plastids have to be imported through specific transporters. Glucose 6-Phosphate/Phosphate Translocator 1 is required for the uptake of cytosolic Glucose 6-Phosphate into non-green plastids. In Arabidopsis, GPTI has been demonstrated to play essential roles in male, female gametophyte and embryo development. However, the roles of GPTs in other species are yet largely unknown. Here, we reported that rice OsGPT1 is indispensable for normal tapetal degeneration and pollen exine formation during anther and pollen development. OsGPT1 is localized in the plastid and distributed in the anther wall layers and late-stage pollen grains. Different from the gametic defects caused by mutation in AtGPT1, disruption of OsGPT1 does not affect male and female gamete transmission as well as embryo development. On the contrary, osgpt1 mutant exhibits delayed tapetum degeneration, decreased Ubisch bodies formation and thinner pollen exine, leading to pollen abortion at the mature stage. Furthermore, the expression of several genes involved in tapetal programmed cell death (PCD) and sporopollenin formation is decreased in osgpt1. Our study suggests that OsGPT1 coordinates the development of anther sporophytic tissues and the male gametophyte by integrating carbohydrate and fatty acid metabolism in the plastid. (C) 2021 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

Automated summary

The study found that rice OsGPT1 plays an essential role in anther and pollen development, with its absence leading to abnormal pollen development. OsGPT1 is localized in plastids and is crucial for tapetal degeneration and pollen exine formation.