Abstract
Land plants respond to cold through complicated physiological, morphological, and metabolic processes, including abnormalities and changes in organelles, while plant mitochondrial gene expressions are regulated through several unique post-transcriptional events, such as cis-/trans-intron splicing and RNA editing. The author tries to clarify the relationship between these post-transcriptional events at low temperatures. Some intron-containing transcripts before splicing increase in rice and wheat after several days under cold conditions, while certain RNA editing events in IBS (Intron Binding Sites: which is present in exons and make complementary base pairing with Exon Binding Sites located in introns) have tight associations with splicing, some of which are sensitive to cold in intron-containing transcripts. However no correlation is observed between post-transcriptional events and the organization of introns: the primary sequence of introns, splicing manner (cis or trans), intron length, and splice-site sequence. These findings suggest that nucleus-encoded factors regulate mitochondrial gene expressions, some of which are cold-sensitive. In wheat, a cold acclimatable plant, accumulation of some intron-spliced transcripts also increase at low temperatures, as well as intron-containing transcripts, which may be one of the phenomena related to cold acclimation. The study about plant mitochondrial gene expression at low temperatures has the potential to become an alternative system to see how mitochondrial genes are regulated, which, in turn, has the potential to enhance plant breeding for cold tolerance.
