Proteome profile of salt gland-rich epidermis extracted from a salt-tolerant tree species

Preparation of proteins from salt-gland-rich tissues of mangrove plant is necessary for a systematic study of proteins involved in the plant's unique desalination mechanism. Extraction of high-quality proteins from the leaves of mangrove tree species, however, is difficult due to the presence of high levels of endogenous phenolic compounds. In our study, preparation of proteins from only a part of the leaf tissues (i.e. salt gland-rich epidermal layers) was required, rendering extraction even more challenging. By comparing several extraction methods, we developed a reliable procedure for obtaining proteins from salt gland-rich tissues of the mangrove species Avicennia officinalis. Protein extraction was markedly improved using a phenol-based extraction method. Greater resolution 1D protein gel profiles could be obtained. More promising proteome profiles could be obtained through 1D-LC-MS/MS. The number of proteins detected was twice as much as compared to TUTS extraction method. Focusing on proteins that were solely present in each extraction method, phenol-based extracts contained nearly ten times more proteins than those in the extracts without using phenol. The approach could thus be applied for downstream high-throughput proteomic analyses involving LC-MS/MS or equivalent. The proteomics data presented herein are available via ProteomeXchange with identifier PXD001691.