Luca Tadini1, Roberto Ferrari1, Marie-Kristin Lehniger2, Chiara Mizzotti1, Fabio Moratti3, Francesca Resentini4, Monica Colombo5, Alex Costa1, Simona Masiero6, Paolo Pesaresi7. 1. Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy. 2. Molecular Genetics, Institute of Biology, Humboldt University of Berlin, Berlin, Germany. 3. Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany. 4. Instituto de Biologıa Molecular y Celular de Plantas (CSIC-Universidad Politécnica de Valencia), Valencia, Spain. 5. Centro Ricerca e Innovazione, Fondazione Edmund Mach, San Michele all'Adige, Italy. 6. Dipartimento di Bioscienze, Università degli Studi di Milano, Milan, Italy. simona.masiero@unimi.it. 7. Dipartimento di Scienze Agrarie e Ambientali - Produzione, Territorio, Agroenergia, Università degli studi di Milano, Milan, Italy. paolo.pesaresi@unimi.it.
Abstract
MAIN CONCLUSION: AtPPR4-mediated trans-splicing of plastid rps12 transcripts is essential for key embryo morphogenetic events such as development of cotyledons, determination of provascular tissue, and organization of the shoot apical meristem (SAM), but not for the formation of the protodermal layer. Members of the pentatricopeptide repeat (PPR) containing protein family have emerged as key regulators of the organelle post-transcriptional processing and to be essential for proper plant embryo development. In this study, we report the functional characterization of the AtPPR4 (At5g04810) gene encoding a plastid nucleoid PPR protein. In-situ hybridization analysis reveals the presence of AtPPR4 transcripts already at the transition stage of embryo development. As a consequence, embryos lacking the AtPPR4 protein arrest their development at the transition/early-heart stages and show defects in the determination of the provascular tissue and organization of SAM. This complex phenotype is due to the specific role of AtPPR4 in the trans-splicing of the plastid rps12 transcripts, as shown by northern and slot-blot hybridizations, and the consequent defect in 70S ribosome accumulation and plastid protein synthesis, in agreement with the role proposed for the maize orthologue, ZmPPR4.
MAIN CONCLUSION: AtPPR4-mediated trans-splicing of plastid rps12 transcripts is essential for key embryo morphogenetic events such as development of cotyledons, determination of provascular tissue, and organization of the shoot apical meristem (SAM), but not for the formation of the protodermal layer. Members of the pentatricopeptide repeat (PPR) containing protein family have emerged as key regulators of the organelle post-transcriptional processing and to be essential for proper plant embryo development. In this study, we report the functional characterization of the AtPPR4 (At5g04810) gene encoding a plastid nucleoid PPR protein. In-situ hybridization analysis reveals the presence of AtPPR4 transcripts already at the transition stage of embryo development. As a consequence, embryos lacking the AtPPR4 protein arrest their development at the transition/early-heart stages and show defects in the determination of the provascular tissue and organization of SAM. This complex phenotype is due to the specific role of AtPPR4 in the trans-splicing of the plastid rps12 transcripts, as shown by northern and slot-blot hybridizations, and the consequent defect in 70S ribosome accumulation and plastid protein synthesis, in agreement with the role proposed for the maize orthologue, ZmPPR4.
Authors: Shifeng Cheng; Bernard Gutmann; Xiao Zhong; Yongtao Ye; Mark F Fisher; Fengqi Bai; Ian Castleden; Yue Song; Bo Song; Jiaying Huang; Xin Liu; Xun Xu; Boon L Lim; Charles S Bond; Siu-Ming Yiu; Ian Small Journal: Plant J Date: 2016-02 Impact factor: 6.417
Authors: José M Alonso; Anna N Stepanova; Thomas J Leisse; Christopher J Kim; Huaming Chen; Paul Shinn; Denise K Stevenson; Justin Zimmerman; Pascual Barajas; Rosa Cheuk; Carmelita Gadrinab; Collen Heller; Albert Jeske; Eric Koesema; Cristina C Meyers; Holly Parker; Lance Prednis; Yasser Ansari; Nathan Choy; Hashim Deen; Michael Geralt; Nisha Hazari; Emily Hom; Meagan Karnes; Celene Mulholland; Ral Ndubaku; Ian Schmidt; Plinio Guzman; Laura Aguilar-Henonin; Markus Schmid; Detlef Weigel; David E Carter; Trudy Marchand; Eddy Risseeuw; Debra Brogden; Albana Zeko; William L Crosby; Charles C Berry; Joseph R Ecker Journal: Science Date: 2003-08-01 Impact factor: 47.728