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

作　　者：Xiaolei Zhu Jing Yu Jianxin Shi Takayuki Tohge Alisdair R.Fernie Sagit Meir Asaph Aharoni Dawei Xu Dabing Zhang Wanqi Liang 

机构地区：[1]Joint 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 [2]Central Metabolism Group,Max Planck Institute of Molecular Plant Physiology,14476 Potsdam-Golm,Germany [3]Department of Plant Sciences,Weizmann Institute of Science,PO Box 26,Rehovot 76100,Israel [4]School of Agriculture,Food and Wine,University of Adelaide,Waite Campus,SA 5005,Australia

出　　处：《Journal of Integrative Plant Biology》2017年第9期612-628,共17页植物学报（英文版）

基　　金：supported by funds from the National Key Research and Development Program of China(No.2016YFD0101107);the National Key Basic Research Developments Program of the Ministry of Science and Technology of China(No.2013CB126902);the National Natural Science Foundation of China(No.31322040,31670309);the Innovative Research Team of the Ministry of Education and the 111 Project(No.B14016)

摘　　要：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/laps, in which most detected phenolics were substantially decreased, ospks2 accumu- lated higher levels of phenolics. Based on these results and our observation that OsPKS2 is unable to fully restore the exine defects in the pksb/laps, 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.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/laps, in which most detected phenolics were substantially decreased, ospks2 accumu- lated higher levels of phenolics. Based on these results and our observation that OsPKS2 is unable to fully restore the exine defects in the pksb/laps, 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.

关 键 词：PKS The polyketide synthase OsPKS2 is essential for pollen exine and Ubisch body patterning in rice Figure 

分 类 号：Q944.4[生物学—植物学]