Comparative shotgun proteomic profiles for identification of differentially expressed proteins in response to topping in Nicotiana tabacum leaves

摘要

The aim of this study was to explore the differences of protein expression in tobacco leaves in response to topping. Comparative shotgun proteomic approach combined with mass spectrometry was used to screen the differentially expressed proteins between leaves before topping and leaves after topping. Additionally, quantitative real-time PCR was applied to validate the differentially expressed proteins. A total of 198 and 193 differentially expressed proteins were identified in leaves before and after topping, respectively. Among them, 64 and 59 proteins were uniquely identified in leaves before and after topping, respectively. In leaves before topping, uniquely expressed proteins were mainly involved in photosynthesis and ATPase energy. In leaves after topping, uniquely expressed proteins (such as glucan endo-1,3-betaglucosidase acidic isoform, GI9 and pathogenesis-related protein IB) were mainly involved in resistance/defense. Moreover, uniquely expressed proteins (such as cytosolic acetoacetyl-coenzyme A thiolase and plastid transketolase) were related to secondary metabolism. The outcomes demonstrated that topping may weaken the expressions of proteins related to energy and synthesis metabolism, as well as trigger the expressions of proteins involved in defense and secondary metabolism.