Comparative proteomics analyses of flowers at different development stages in Thermopsis turcica, endemic to Turkey

Flower development is a complex physiological phenomenon which is affected by many environmental stimuli and endogenous signals. To date, several molecular approaches have provided a comprehensive view of the physiological processes associated to flower development, but little is known about proteome changes. Therefore, we investigated the proteome alterations during flower development in endemic Thermopsis turcica Kit Tan, Vural & Küçüködük, an unusual legume species with 3-4 free carpels in a single flower. Proteins were extracted from the flower buds and fully opened flowers, and separated by two-dimensional gel electrophoresis (2-DE). Image analysis revealed that 66 protein spots were differentially expressed throughout flower development. Among them, 32 protein spots were successfully identified using MALDI-TOF/TOF (matrix-assisted laser-desorption ionization-time of flight/time of flight) mass spectrometry (MS) and database search. Functional annotation of these flower proteins revealed their involvement in transcription and protein metabolism, energy and carbohydrate metabolism, plant defense, photosynthesis, cell wall, secondary metabolism, and amino acid metabolism. Moreover, most of these proteins were down-regulated at the latter stage of flower development. Regulation of many proteins related to protein metabolism, sugar metabolism and stress defense suggest their possible roles in a developmental manner. These results have given new insights to the proteome alterations during flower development.