OsPKS1 is required for sexine layer formation, which shows functional conservation between rice and Arabidopsis.

•The plant polyketide synthase is required for the sporopollenin precursor biosynthesis.•Knockout of the rice OsPKS1 leads to abnormal bacula deposition and ubisch body structures for sexine formation.•This protein was preferentially localized to the ER in tapetal cells during microspore development.•The function of polyketide synthase in sporopollenin synthesis pathway are conserved in rice and Arabidopsis.