Shotgun proteome analysis of Hemerocallis citrina floral and extrafloral nectar

Many angiosperms can secret at least two types of sugar-rich liquids, floral nectar (FN) and extrafloral nectar (EFN), by which plants can make use of the animal partner’s mobility for pollen transportation and attract predatory animals for indirect defense. Both FN and EFN contain considerable amount of proteins which play important roles in nectar biosynthesis process and protection. Hemerocallis citrina (HC) can secrete both FN and EFN on flower during the same developmental stage. Our objective was to compare the HC FN and EFN proteome to understand the difference between their biosynthesis and ecological function. FN was collected from adult HC flowers and concentrated by ultrafiltering. EFN was collected from young HC flower buds and concentrated by ultrafiltering. Proteins were digested with trypsin then analyzed by LC-MS/MS. HSPs are the main protein identified in HC FN but their function in floral nectar is still largely unknown. PR proteins are the main protein identified in HC EFN with antimicrobial activity. Our data provide a good characterization of a monocot nectar proteome. These data, may be useful in understanding the generation process and ecological function of floral and extrafloral nectar.