J Integr Plant Biol. ›› 2017, Vol. 59 ›› Issue (9): 612-628.DOI: 10.1111/jipb.12574

• Research Articles • Previous Articles     Next Articles

The polyketide synthase OsPKS2 is essential for pollen exine and Ubisch body patterning in rice

Xiaolei Zhu1*, Jing Yu1†, Jianxin Shi1, Takayuki Tohge2, Alisdair R. Fernie2, Sagit Meir3, Asaph Aharoni3, Dawei Xu1, Dabing Zhang1,4 and Wanqi Liang1*   

  1. 1Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University–University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
    2Central Metabolism Group, Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
    3Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
    4School of Agriculture, Food and Wine, University of Adelaide, SA 5005, Australia
  • Received:2017-06-28 Accepted:2017-08-03 Published:2017-08-07
  • About author:These authors contributed equally to this work
    *Correspondences: E-mail: Wanqi Liang (wqliang@sjtu.edu.cn)


Lipid and phenolic metabolism are important for pollen exine formation. In Arabidopsis, polyketide synthases (PKSs) are essential for both sporopollenin biosynthesis and exine formation. Here, we characterized the role of a polyketide synthase (OsPKS2) in male reproduction of rice (Oryza sativa). Recombinant OsPKS2 catalyzed the condensation of fatty acyl-CoA with malonyl-CoA to generate triketide and tetraketide α-pyrones, the main components of pollen exine. Indeed, the ospks2 mutant had defective exine patterning and was male sterile. However, the mutant showed no significant reduction in sporopollenin accumulation. Compared with the WT (wild type), ospks2 displayed unconfined and amorphous tectum and nexine layers in the exine, and less organized Ubisch bodies. Like the pksb/lap5 mutant of the Arabidopsis ortholog, ospks2 showed broad alterations in the profiles of anther-related phenolic compounds. However, unlike pksb/lap5, in which most detected phenolics were substantially decreased, ospks2 accumulated higher levels of phenolics. Based on these results and our observation that OsPKS2 is unable to fully restore the exine defects in the pksb/lap5, we propose that PKS proteins have functionally diversified during evolution. Collectively, our results suggest that PKSs represent a conserved and diversified biochemical pathway for anther and pollen development in higher plants.

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