Early embryogenesis is the most fundamental developmental process in biology. Screening of ethyl methanesulfonate （EMS）-mutagenized populations of Arabidopsis thaliana led to the identification of a zygote-lethal mu...Early embryogenesis is the most fundamental developmental process in biology. Screening of ethyl methanesulfonate （EMS）-mutagenized populations of Arabidopsis thaliana led to the identification of a zygote-lethal mutant embryonic factor 19 （fac19） in which embryo development was arrested at the elongated zygote to octant stage. The number of endosperm nuclei decreased significantly in fac19 embryos. Genetic analysis showed fac19 was caused by a single recessive mutation with typical mendelian segregation, suggesting equal maternal and paternal contributions of FAC19 towards zygotic embryogenesis. Positional cloning showed that FAC19 encodes a putative mitochondrial protein with 16 conserved pentatricopeptide repeat （PPR） motifs. The fac19 mutation caused a conversion from hydrophilic serine located in a previously unknown domain to hydrophobic leucine. Crosses between FAC191fac19 and the T-DNA insertion mutants in the same gene failed to complement the fac19 defects, confirming the identity of the gene. This study revealed the critical importance of a PPR protein-mediated mitochondrial function in early embryogenesis.展开更多
基金supported by the National Natural Science Foundation of China (30625018 and 30821007)CAS/SAFEA International Partnership Program for Creative Research Teams (20090491019)CAS 100-Talent Projects of China
文摘Early embryogenesis is the most fundamental developmental process in biology. Screening of ethyl methanesulfonate （EMS）-mutagenized populations of Arabidopsis thaliana led to the identification of a zygote-lethal mutant embryonic factor 19 （fac19） in which embryo development was arrested at the elongated zygote to octant stage. The number of endosperm nuclei decreased significantly in fac19 embryos. Genetic analysis showed fac19 was caused by a single recessive mutation with typical mendelian segregation, suggesting equal maternal and paternal contributions of FAC19 towards zygotic embryogenesis. Positional cloning showed that FAC19 encodes a putative mitochondrial protein with 16 conserved pentatricopeptide repeat （PPR） motifs. The fac19 mutation caused a conversion from hydrophilic serine located in a previously unknown domain to hydrophobic leucine. Crosses between FAC191fac19 and the T-DNA insertion mutants in the same gene failed to complement the fac19 defects, confirming the identity of the gene. This study revealed the critical importance of a PPR protein-mediated mitochondrial function in early embryogenesis.
