Comparative Phosphoproteomics between Cavendish Banana and Dajiao (Musa spp.) Reveals an Important role of MKK2 Network in Cold Tolerance Mechanisms

ABSTRACT: Cold-sensitive Cavendish Banana and relatively cold-tolerant Dajiao (Musa spp.) comprise an important part of diets for millions of people around the globe. Low temperature is one of the key environment stresses which greatly affect the global banana production. However, little is known about the changes of global protein phosphorylation in Musa spp. and their regulatory roles in response to cold stress. In this study, we employed a TMT6-plex quantitative analysis to conduct a global phosphoproteome profiling between Cavendish Banana and Dajiao subject to the cold stress for 0 hour and 3 hour. A total of 679 phosphopeptides containing 772 distinct phosphorylated sites from 529 phosphoproteins were identified in Cavendish Banana, 180 phosphorylation sites (belonging to 147 phosphoproteins) were differentially changed after 3 h cold stress. While in Dajiao 241 phosphopeptides with 271 individual phosphosites from 207 phosphoproteins were confidently identified, and 83 phosphorylation sites from 63 phosphoproteins were differentially changed under 3 h cold stress. Bioinformatic analysis of protein interaction network indicated that Mitogen-activated protein kinase kinase 2 (MKK2) was located in the center of the MAPK signaling network along with 7 other members whose phosphorylated site abundances were remarkably differentiated between Cavendish Banana and Dajiao in response to cold stress. Western blotting of MKK2 protein and its T31 phosphorylated site showed the increased expression of MKK2 in the time course of cold stress, with no detectable T31 phosphorylation in Cavendish Banana. On the contrary, the decreased MKK2 expression with increased T31 phosphorylation was consistently observed in Dajiao. These results suggest that the MKK2 interaction network in Dajiao, along with other cold-specific phosphoproteins found in this study, appears to play an important role in the molecular mechanisms of Dajiao being high tolerance to cold stress. The results also provide new evidence that cellular MKK2 phosphorylation as a signaling pathway plays an important role in abiotic stress tolerance that serves as a universal plant cold tolerance mechanism. To the best of our knowledge, this is the first report of MKK2 network involved in the regulatory of the Musa spp. response to cold stress.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Musa Abb Group

TISSUE(S): Plant Cell, Leaf

SUBMITTER: Jie Gao  

LAB HEAD: Qiaosong Yang

PROVIDER: PXD004177 | Pride | 2017-01-24

REPOSITORIES: Pride