Reverse genetic identification of CRN1 and its distinctive role in chlorophyll degradation in Arabidopsis.
Recent identification of NYE1/SGR1 brought up a new era for the exploration of the regulatory mechanism of Chlorophyll (Chl) degradation. Cluster analysis of senescence associated genes with putative chloroplast targeting sequences revealed several genes sharing a similar expression pattern with NYE1. Further characterization of available T-DNA insertion lines led to the discovery of a novel stay-green gene CRN1 (Co-regulated with NYE1). Chl breakdown was significantly restrained in crn1-1 under diversified senescence scenarios, which is comparable with that in acd1-20, but much more severe than that in nye1-1. Notably, various Chl binding proteins, especially trimeric LHCP II, were markedly retained in crn1-1 four days after dark-treatment, possibly due to a lesion in disassociation of protein-pigment complex. Nevertheless, the photochemical efficiency of PSII in crn1-1 declined, even more rapidly, two days after dark-treatment, compared to those in Col-0 and nye1-1. Our results suggest that CRN1 plays a crucial role in Chl degradation, and that loss of its function produces various side-effects, including those on the breakdown of Ch-protein complex and the maintenance of the residual photosynthetic capability during leaf senescence.
State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, China.
Guodong
G
Ren
Qian
Q
Zhou
Shouxin
S
Wu
Yufan
Y
Zhang
Lingang
L
Zhang
Jirong
J
Huang
Zhenfei
Z
Sun
Benke
B
Kuai
D017360:Arabidopsis / Q000166:cytology / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D016922:Cellular Senescence; D002734:Chlorophyll / Q000378:metabolism*; D016000:Cluster Analysis; D003624:Darkness; D018506:Gene Expression Regulation, Plant; D005820:Genetic Testing / Q000379:methods*; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010788:Photosynthesis; D010858:Pigmentation / Q000235:genetics; D055550:Protein Stability
D029681:Arabidopsis Proteins; D002734:Chlorophyll