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.
Ren
Guodong
G
State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200433, China.
Zhou
Qian
Q
Wu
Shouxin
S
Zhang
Yufan
Y
Zhang
Lingang
L
Huang
Jirong
J
Sun
Zhenfei
Z
Kuai
Benke
B
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