SNOWY COTYLEDON 2 Promotes Chloroplast Development and Has a Role in Leaf Variegation in Both Lotus japonicus and Arabidopsis thaliana  

作　　者：Nicola Zagari Omar Sandoval-lbanez Niels Sandal Junyi Su Manuel Rodriguez-Concepcion Jens Stougaard Mathias Pribil Dario Leister Pablo Pulido 

机构地区：[1]Plant Molecular Biology, Department of Biology I, Ludwig-Maximilians-Universitat Munchen, 82152 Planegg-Martinsried, Germany [2]Copenhagen Plant Science Center, University of Copenhagen, 1871 Frederiksberg C, Denmark [3]Research and Innovation Center, Fondazione Edmund Mach, via E. Mach 1, 38010 San Michele all'Adige, Italy [4]Centre for Carbohydrate Recognition and Signalling, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10, 8000 Aarhus C, Denmark [5]Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain

出　　处：《Molecular Plant》2017年第5期721-734,共14页分子植物（英文版）

摘　　要：Plants contain various factors that transiently interact with subunits or intermediates of the thylakoid multiprotein complexes, promoting their stable association and integration. Hence, assembly factors are essential for chloroplast development and the transition from heterotrophic to phototrophic growth. Snowy cotyledon 2 （SCO2） is a DNAJ-like protein involved in thylakoid membrane biogenesis and interacts with the light-harvesting chlorophyll-binding protein LHCBI. In Arabidopsis thaliana, SCO2 function was previ- ously reported to be restricted to cotyledons. Here we show that disruption of SC02 in Lotus japonicus results not only in paler cotyledons but also in variegated true leaves. Furthermore, smaller and pale- green true leaves can also be observed in A. thaliana sco2 （atsco2） mutants under short-day conditions. In both species, SCO2 is required for proper accumulation of PSlI-LHCll complexes. In contrast to other variegated mutants, inhibition of chloroplastic translation strongly affects L. japonicus sco2 mutant devel- opment and fails to suppress their variegated phenotype. Moreover, inactivation of the suppressor of variegation AtClpR1 in the atsco2 background results in an additive double-mutant phenotype with variegated true leaves. Taken together, our results indicate that SCO2 plays a distinct role in PSll assembly or repair and constitutes a novel factor involved in leaf variegation.Plants contain various factors that transiently interact with subunits or intermediates of the thylakoid multiprotein complexes, promoting their stable association and integration. Hence, assembly factors are essential for chloroplast development and the transition from heterotrophic to phototrophic growth. Snowy cotyledon 2 （SCO2） is a DNAJ-like protein involved in thylakoid membrane biogenesis and interacts with the light-harvesting chlorophyll-binding protein LHCBI. In Arabidopsis thaliana, SCO2 function was previ- ously reported to be restricted to cotyledons. Here we show that disruption of SC02 in Lotus japonicus results not only in paler cotyledons but also in variegated true leaves. Furthermore, smaller and pale- green true leaves can also be observed in A. thaliana sco2 （atsco2） mutants under short-day conditions. In both species, SCO2 is required for proper accumulation of PSlI-LHCll complexes. In contrast to other variegated mutants, inhibition of chloroplastic translation strongly affects L. japonicus sco2 mutant devel- opment and fails to suppress their variegated phenotype. Moreover, inactivation of the suppressor of variegation AtClpR1 in the atsco2 background results in an additive double-mutant phenotype with variegated true leaves. Taken together, our results indicate that SCO2 plays a distinct role in PSll assembly or repair and constitutes a novel factor involved in leaf variegation.

关 键 词：SCO2 DNAJ-like PHOTOSYNTHESIS assembly factor VARIEGATION chloroplast development 

分 类 号：Q94[生物学—植物学]