I was aware that light levels can influence orientation of chloroplasts within plant cells, but the fact that their location can also be affected by temperature was new to me. Anyway, Yuka Ogasawara et al. report cold-induced organelle relocation in the liverwort Marchantia polymorpha, not only of chloroplasts, but nuclei and peroxisomes, too. Recognising that these organelle movements take place naturally in winter, the team propose that it might somehow facilitate cold tolerance in the plants. Intriguingly, mitochondria, however, did not ‘cold-relocate’. Given that chloroplasts, peroxisomes and mitochondria are intimately connected via the process of photorespiration, I wonder what effect increased spatial separation of the latter organelle from the other two might have on this important metabolic process…? Nevertheless, further study of cold-induced organelle relocation in what is now probably the model species for this phenomenon is likely to be of relevance to other plants. Brrr-illiant!
[Whilst such intracellular, small-scale chloroplast movements are fascinating, the ultimate large-scale, ‘chloroplasts-on-the-move’ story must be those integrated into the bodies of sacoglossan sea-slugs, and which remain functional within their animal host. For more on this fascinating phenomenon of trans-Kingdom organelle relocation, see Sónia Cruz et al.’s review article – Ed.]