Lipid metabolism and MAPK-ICE1 cascade play crucial roles in cold tolerance of banana

Low temperature is a major environmental factor that limits the growth, yield, and geographical distribution of Cavendish and Dajiao bananas ( Musa spp.). Dajiao bananas exhibit a significantly higher cold tolerance than the Cavendish cultivar. However, the underlying mechanisms involved in cold tolerance regulation in Dajiao plants have not been determined. In this study, we investigated the mechanisms underlying the differences in cold tolerance at the cellular level between the cold-sensitive Cavendish and cold-tolerant Dajiao banana types through comparative metabolomics and transcriptomics analyses in calli exposed to cold treatment under dark conditions. A higher accumulation of lipids was observed in Dajiao calli cells compared to Cavendish cells under cold stress. After cold treatment, 4,626 and 5,516 differentially expressed genes (DEGs) were identified in Cavendish and Dajiao banana cells, respectively. By integrating the transcriptomic and metabolomic datasets, we discovered that the linoleic acid and α-linoleic acid metabolism and the Abscisic acid (ABA)-independent Mitogen-activated protein kinase (MAPK) cascade-Inducer of CBF expression 1 (ICE1) signal transduction pathway (including Mitogen-activated protein kinase kinase kinase 1 [ MEKK1 ], MAPK5 , ICE1 , and Cold-regulated 47 [ COR47 ]) played crucial roles in the cold tolerance of Dajiao bananas. Our study provides new insights into cold response regulation and novel cold tolerance mechanisms, providing valuable leads and targets for the genetic improvement of cold tolerance in bananas.