Xijia Yang1, Wanqi Liang1, Minjiao Chen1, Dabing Zhang1,2,3, Xiangxiang Zhao3, Jianxin Shi4,5. 1. Joint International Research Laboratory of Metabolic and 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. Plant Genomics Center, School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Urrbrae, SA, 5064, Australia. 3. Key Laboratory of Crop Marker-Assisted Breeding of Huaian Municipality, Jiangsu Collaborative Innovation Center of Regional Modern Agriculture and Environmental Protection, Huaian, 223300, China. 4. Joint International Research Laboratory of Metabolic and 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. jianxin.shi@sjtu.edu.cn. 5. Key Laboratory of Crop Marker-Assisted Breeding of Huaian Municipality, Jiangsu Collaborative Innovation Center of Regional Modern Agriculture and Environmental Protection, Huaian, 223300, China. jianxin.shi@sjtu.edu.cn.
Abstract
MAIN CONCLUSION: Loss of function mutation of rice OsACOS12 impairs lipid metabolism-mediated anther cuticle and pollen wall formation, and interferes with tapetum programmed cell death, leading to male sterility. Acyl-CoA Synthetase (ACOS) is one of the enzymes activating fatty acids for various metabolic functions in plants. Here, we show that OsACOS12, an orthologue of Arabidopsis ACOS5 in rice, is crucial for rice fertility. Similar to acos5, osaocs12 mutant had no mature pollen. But unlike acos5, osaocs12 produced defective anthers lacking cutin and Ubisch bodies on the epidermal and inner surfaces, respectively, and delayed programmed cell death (PCD)-induced tapetum degradation. Those phenotypic changes were evident at stage 10, during which OsACOS12 had its maximum expression in tapetal cells and microspores. Chemical analysis revealed that the levels of anther cuticular lipid components (wax and cutin monomers) were significantly reduced in osaocs12, while the expression levels of three known lipid biosynthetic genes were unchanged. Recombinant OsACOS12 enzyme was shown to catalyze the conversion of C18:1 fatty acid to C18:1 CoA in vitro. Phylogenetic analysis indicated that OsACOS12 is an ancient and conserved enzyme associated with the plant's colonization to earth. Collectively, our study suggests that OsACOS12 is an ancient enzyme participating in a conserved metabolic pathway for diversified biochemical functions to secure male reproduction in plants.
MAIN CONCLUSION: Loss of function mutation of rice OsACOS12 impairs lipid metabolism-mediated anther cuticle and pollen wall formation, and interferes with tapetum programmed cell death, leading to male sterility. Acyl-CoA Synthetase (ACOS) is one of the enzymes activating fatty acids for various metabolic functions in plants. Here, we show that OsACOS12, an orthologue of Arabidopsis ACOS5 in rice, is crucial for rice fertility. Similar to acos5, osaocs12 mutant had no mature pollen. But unlike acos5, osaocs12 produced defective anthers lacking cutin and Ubisch bodies on the epidermal and inner surfaces, respectively, and delayed programmed cell death (PCD)-induced tapetum degradation. Those phenotypic changes were evident at stage 10, during which OsACOS12 had its maximum expression in tapetal cells and microspores. Chemical analysis revealed that the levels of anther cuticular lipid components (wax and cutin monomers) were significantly reduced in osaocs12, while the expression levels of three known lipid biosynthetic genes were unchanged. Recombinant OsACOS12 enzyme was shown to catalyze the conversion of C18:1 fatty acid to C18:1 CoA in vitro. Phylogenetic analysis indicated that OsACOS12 is an ancient and conserved enzyme associated with the plant's colonization to earth. Collectively, our study suggests that OsACOS12 is an ancient enzyme participating in a conserved metabolic pathway for diversified biochemical functions to secure male reproduction in plants.
Authors: Clarice de Azevedo Souza; Sung Soo Kim; Stefanie Koch; Lucie Kienow; Katja Schneider; Sarah M McKim; George W Haughn; Erich Kombrink; Carl J Douglas Journal: Plant Cell Date: 2009-02-13 Impact factor: 11.277
Authors: Simon Wallace; Caspar C Chater; Yasuko Kamisugi; Andrew C Cuming; Charles H Wellman; David J Beerling; Andrew J Fleming Journal: New Phytol Date: 2014-09-07 Impact factor: 10.151