PagTPS1 and PagTPS10, the trehalose-6-phosphate synthase genes, increase trehalose content and enhance drought tolerance

Trehalose-6-phosphate synthase (TPS) genes play an active role in the trehalose metabolism pathway that regulates the responses of plants to diverse stresses. However, the functional identification, comparison, and conservatism of TPS genes in the responses of woody plants, especially poplars, to drought stress remain unclear. Here, the trehalose content of 84K (Populus alba × P. glandulosa) poplars was down-regulated and PagTPS and PagTPP genes had diverse response patterns under drought stress. Physicochemical properties, expression patterns, and functions of PagTPS1 and PagTPS10, two class I members of TPS gene family, were identified and compared. Transgenic 84K poplars overexpressing PagTPS1 and PagTPS10 had significantly higher trehalose content with approximately 138% and 123%, respectively, and stronger drought tolerance compared to WT. PagTPS1 and PagTPS10 promoted the expression of TPPA genes and drought-responsive genes. Accordingly, poplars inhibiting PagTPS1 and PagTPS10 expression via RNA interference had lower trehalose content and drought tolerance. Simultaneously, overexpressing PagTPS1 and PagTPS10 improved the trehalose content and drought tolerance of Arabidopsis. Overall, we proposed a model of the effects of PagTPS1 and PagTPS10 as conservative regulators on the responses of plants to drought, which would provide new insights into the functional explorations of TPS genes in plants.