Plant acclimation and growth under low temperature conditions mediated by REIL proteins

REIL1 and REIL2 proteins in Arabidopsis are homologs of REI1, a yeast ribosome biogenesis factor. REI1 facilitates 60S ribosomal maturation in yeast. Beine-Golovchuk and co-workers have studied the cold acclimation response of the double mutant reil1-1 reil2-1. Previous studies by the same group showed that the double mutant has growth defects below 10°C. In reil1-1 reil1-2, stunted growth was successfully rescued by N-terminal RFP- or GFP-REIL fusion proteins, which allowed the study of REIL1/2  in planta. The FP fusions showed that both REIL1 and REIL2 localized to the cytosol at 20°C and 10°C. One week after the temperature shift to 10°C Col-0 had and increased amount of cytosolic 60S fraction compared to the plastid ribosomal 50s fraction, while rel1-1 reil2-1 had significantly reduced amounts of 60S fraction. Moreover, western blots of the fractions showed that REIL1 associated with the 60s fraction. Further metabolic and gene expression studies showed that in reil1-1 reil2-1, cold genes and metabolites are induced before the temperature shift, highlighting the importance of REILs to suppress the cold response under non stress temperatures. (Summary by Cecilia Vasquez-Robinet) Plant Physiol. 10.1104/pp.17.01448