Comparative Analysis Between Hemolymph Proteome Of Western (Apis Mellifera Ligustica) And Eastern (Apis Cerana Cerana) Honeybee Workers During The Larval And Pupal Development Stages

Apis cerana and Apis mellifera are the two important eastern and western honeybee species that are widely distributed, reared and studied as model honeybees. The hemolymph of honeybee (the fluid analogous to the blood of the vertebrates) circulates in open circulatory systems and mainly transports nutrients, ions and hormones. It also involves in the humoral responses and acts as an important barrier to pathogen infection. The components of this fluid vary depending on developmental stages. However, knowledge on time-resolved studies of honeybee hemolymph protein changes throughout the laval and pupal development are still very limited. Therefore, comparative analysis of hemolymph proteome change were carried out during the larval to pupal development stages of worker bees(Apis melifera ligustica), and between two species of western and eastern honeybees (Apis mellifera ligustica (Aml) and Apis cerana cerana (Ace)) larvae day1to pupae day5by two-dimensional electrophoresis based proteomics. There were significant protein expression differences (p<0.05) qualitatively and quantitatively during the larval to pupal development stages of Aml as well as between the two species of bees (Aml vs. Acc). Interestingly, of the80differentially expressed protein spots,59.2%were upregulated in the larvae compared to the40.8%in the pupae of Aml. Proteins involved in carbohydrate metabolism and energy production, folding activities, development, cytoskeleton and antioxidant system had higher abundance in the larval hemolymph suggesting the roles in enhancing their development and immunity build up. Whereas proteins related to food (energy) storage, metabolism of fatty acids and amino acids were abundantly expressed from the late larval to pupal development stage indicating their main function to support pupal metamorphoses. The data reveals that the honeybee life transition goes with the essential functional adjustment of hemolymph that serves as nutrition carrier and humoral immune system.Regarding the comparison between the two species, from the total of32,43,54,35,39, and19differentially expressed protein spots,78.0,53.5,55.5,74.0,72.0, and47.0%were abundantly expressed in the Aml against22.0,46.5,44.5,26,28.0and53.0%in the Acc honeybee worker larvae and pupae on day1,3and5, respectively. Higher expressions of proteins involved in MRJPs, food storage, energy metabolism, development, protein folding and cytoskeleton were observed in the Aml compared to the Acc bees. These suggest that they are the key role players that shape the significant biological variations and development process between the Aml and the Acc bees. To better adaptation of essential biological divergences, the two bees have employed evolutionary strategy of changes in their hemolymph proteome in a manner of an age-dependent up/down regulation of proteins during the larval and pupal stages. Hence, this regulates the development, immune system and transition of larva-pupa of worker honeybees of Aml and Acc.