Proteomic Analysis of Shoot Tips from Two Alfalfa Cultivars with Different Florescence

Flowering is an indispensable biological process for the complete life cycle of angiosperms, crucial to the regeneration of plants and the continuation of species. In this work, a proteomic approach was applied to investigate differences in protein expression in two alfalfa cultivars with different flowering periods. Shoot tips (containing bud) were collected simultaneously at the bud stage from early flowering (FF) and late flowering (MF) cultivar alfalfa. In total, 442 differentially accumulated proteins were identified, including 230 down-regulated and 212 upregulated proteins. The identified proteins were mainly involved in metabolism, biosynthetic processes, the immune system, and responses to stimulus and translation and programmed cell death (PCD). The expression profiles demonstrated that the ubiquitin protease pathway and inositol phospholipid signaling pathway are involved in flower development regulation. Furthermore, the transcript-expression patterns of the coding proteins were consistent with the proteomic results of the increased synthesis of amino acids associated with floral organ development and involvement of Sec14p-like phosphatidylinositol transfer family protein and RAB GTPase-like protein A5D, in accordance with early pollen development. The current study is devoted to exploration of protein expression profiles during alfalfa flower development, which would be conducive to illuminate the underlying molecular mechanisms during the alfalfa flowering process. These results may provide further insights into the potential strategies for artificially controlling flowering time in alfalfa.