Proteomic Analysis of the Inflorescence Stem Mechanical Strength Difference in Herbaceous Peonies (Paeonia lactiflora Pall.)

[Image: see text] The herbaceous peony (Paeonia lactiflora Pall.) is a traditional rare flower in China, and production of its cut flowers has developed gradually in many places of the world. However, the inflorescence stems of some P. lactiflora cultivars have such low mechanical strength that the cut flower production was severely restricted. To better understand the causes of this problem from a protein expression level, two P. lactiflora cultivars with different inflorescence stem mechanical strengths were analyzed by two-dimensional electrophoresis and MALDI-TOF/MS. More than 1700 clear protein spots were detected, 53 of which varied significantly. Moreover, 23 of the differentially expressed proteins were identified and confirmed and are involved in various biological processes such as metabolism, protein biosynthesis and transport, signal transduction, and defensive response. Especially, cinnamyl alcohol dehydrogenase (CAD) and xyloglucan endotransglucosylase/hydrolase (XTH) were strongly connected to the inflorescence stem mechanical strength in P. lactiflora.