In silico analysis of trehalose biosynthesis genes provides clues to reveal its roles in Avicennia marina adaptation to tidal submergence.

Trehalose has an important function for alleviating various abiotic stress in plants. Nevertheless, the functional and evolutionary characteristics of trehalose biosynthesis genes in mangrove plants is not documented. Here, using typical mangrove Avicennia marina, we found the trehalose content decreased in the roots and leaves and T6P increased significantly in the leaves under tidal submergence. Then, the basic physicochemical properties and gene structure of trehalose biosynthesis genes (AmTPS and AmTPP), and the conserved domain and motifs of AmTPS and AmTPP proteins were analyzed. The collinearity analysis and Ka/Ks values indicated that AmTPS and AmTPP are evolutionarily conserved. Tissue-specific expression profiling showed that most AmTPS and AmTPP genes have tissue specificity. RNA-Seq analysis showed that five AmTPS genes were markedly up-regulated in A. marina treated with tidal submergence. Subcellular localization analysis revealed three genes including AmTPS10B, AmTPS11A and AmTPS11C out of these five up-regulated AmTPS genes work in plasma membrane, cytoplasm and nucleus. Finally, integrative analysis of bioinformatics and RNA-Seq analysis were performed to excavate transcription factors that may regulate AmTPS and AmTPP genes in A. marina response to submergence. Taken together, these findings provide new insights into the response to tidal submergence in A. marina at the aspect of trehalose.