The COP9 Signalosome regulates seed germination by facilitating protein degradation of RGL2 and ABI5
Fig 5
csn1-10 and csn5a-1 show different genetic interactions with rgl2-13, and different responses to PAC.
(A and B) rgl2-13 rescued the germination deficiency of csn1-10 but not csn5a-1. (A) The csn1-10 rgl2-13 double mutants displayed normal germination rate as wild type Col and rgl2-13, in contrast to low germination of csn1-10. Double mutants db26 and db35 are two different lines of the csn1-10 rgl2-13. (B) Germination rate of csn5a-1 rgl2-13 double mutants displayed low germination rate similar to csn5a-1 single mutant, compared to wild type Col and rgl2-13. Double mutants db19 and db20 are two different lines of the csn5a-1 rgl2-13. (C) csn5a-1 was hypersensitive to PAC. Cold stratified seeds were germinated on regular GM plate, GM plate containing PAC (1 μM), or PAC (1 μM) plus GA3 (50 μM). Seed germination rates were shown in graphs. (D) rgl2-13 conferred resistance to PAC (1 μM) in germination of rgl2-13 and double mutant csn1-10 rgl2-13, but not double mutant csn5a-1 rgl2-13. (E) The csn5a-1 rgl2-13 double mutant showed abnormally prolonged accumulation of ABI5, similar to csn5a-1 single mutant. Samples were taken at indicated times after imbibition of the seeds, and proteins were probed with antibodies as indicated on the left. (A-D) Error bars represent standard deviation from 4 repeats (n = 4). See also S4 Fig.