AtSRP1, SMALL RUBBER PARTICLE PROTEIN HOMOLOG, functions in pollen growth and development in Arabidopsis

• AtSRP1 is localized to lipid droplets and ER in plant cells.
• atsrp1 mutants exhibit reduced fertility and abnormal seed shape.
• AtSRP1 functions in pollen growth and development.

To identify novel roles of SMALL RUBBER PARTICLE PROTEIN Homolog in the non-rubber-producing plant Arabidopsis (AtSRP1), we isolated a T-DNA-insertion knock-out mutant (FLAG_543A05) and investigated its functional characteristics. AtSRP1 is predominantly expressed in reproductive organs and is localized to lipid droplets and ER. Compared to wild-type (WT) Arabidopsis, atsrp1 plants contain small siliques with a reduced number of heterogeneously shaped seeds. The size of anther and pollen grains in atsrp1 is highly irregular, with a lower grain number than WT. Therefore, AtSRP1 plays a novel role related to pollen growth and development in a non-rubber-producing plant.