Comparative Proteomic Analysis of Wheat Response to Powdery Mildew Infection in Wheat Pm30 Near-Isogenic Lines

Wheat powdery mildew, caused by Blumeria graminis f.sp. tritici (Bgt), is an important disease worldwide, causing significant yield losses annually. However, little is known about the proteomic response to powdery mildew infection in wheat. To analyse the leaf proteome changes of wheat in susceptible and resistant cultivars in response to Bgt, we compared the leaf proteins of susceptible cultivar Jingdong 8 (JD8) and its powdery mildew resistance near-isogenic line (NIL) with a single Pm resistance gene Pm30 (JD8-Pm30) at 0, 24 and 48 hours postinoculation (hpi) using a combination of two-dimensional electrophoresis (2-DE) and MALDI-TOF MS. In total, 449 and 452 protein spots were reproducibly detected in leaves of JD8 and JD8-Pm30, respectively, among which 53 (11.8%) and 44 (9.7%) were found to be polymorphic among 0, 24 and 48 hpi with the fold change of more than 1.5 and significant difference (P < 0.05). Both quantitative and qualitative differences were observed between extracts of different inoculation time, which can be clustered into seven possible patterns. Remarkably, most of the spot changes were unique in each genotype, and only one (spot 195) was shared in two genotypes, indicating that their response to Bgt infection at translational level is different for the near-isogenic lines. Moreover, 26 of the 97 differentially expressed proteins were identified, which included such functional categories as transcription and translation, energy and metabolism, signal transduction, disease and defence, as well as unclassified proteins. Results are discussed in terms of the functional implications of the proteins identified, with special emphasis on their putative roles in defence.