Mechanism underlying barnacle larval adhesion to material surface: transcriptome and proteome

Barnacle is an important marine biofouling organism and its attachment to the surface of marine engineering equipment has a strong impact on the use of the equipment and causes huge economic losses. The development of environmentally friendly antifouling technology against barnacle is inseparable from fundamental studies of the molecular regulatory mechanism underlying the larval attachment and metamorphosis process which has not been fully studied. The attachment of barnacle larvae involves many complex processes, such as the growth and development of the larvae, the exploration of the substrate for permanent attachment, the metamorphosis process and the secretion of barnacle glue. These processes are difficult to be analyzed in detail by the traditional methods of cell biology and molecular biology. In recent years, transcriptomics and proteomics based on high-throughput sequencing technology have played an important role in studying the attachment process of marine biofouling organisms, and have accumulated a large amount of data in revealing the attachment mechanism of barnacle larvae. In the present paper, recent studies on the barnacle adhesion mechanism at home and abroad were reviewed. We mainly focused on omics studies on the attachment and metamorphosis of the barnacle larvae, composition and curing of the barnacle glue. The collective archives have revealed an increasing application of omics tools in the biofouling field since the pioneering work of Anthony Clare’s group. Transcriptome and proteome data provide insights into the signaling pathways in barnacle larval adhesion. It was found that receptor tyrosine kinases and mannose receptors may be involved in signal perception. In addition, many receptors related to vision, auditory and mechanical senses were identified and supposed to be involved in cyprid searching and attachment. Some studies focused on the water-soluble pheromone which are crucial for the aggregation of barnacles. As for the identification of the cement proteins, proteome analyses were commonly applied, which yielded characterization of biomineralization-related and adhesion-related proteins, as well as some proteins involved in other cellular processes. These findings inferred that the attachment of the cyprids and adult barnacles was a complex biochemical reaction coupling several physiological responses. At last, we briefly discussed the future perspectives of antifouling technology. Much attention has been paid to developing antifouling coatings with prevalent and long-term effects. However, the tests were usually conducted in the lab, while the real scenarios are extremely complex where multi-factors are coupled. And we suggest that individualized antifouling design according to the local marine environment, work site and other factors, rather than a cure-all, may improve efficiency and reduce the cost in the future.