Trehalose metabolism contributed to abiotic stress tolerance of Larix gmelinii seedlings

Trehalose is widely involved in growth, development, metabolic regulation, as well as stress resistance of many angiosperms. Whether it plays roles in stress tolerance of gymnospermae had not been evaluated. Larix gmelinii, which is a native afforestation conifer in north China, shows strong drought-tolerance in Pinaceae family. Here, the role of trehalose in abiotic stress tolerance of Larix gmelinii were analyzed. Results showed that trehalose pretreatment at 30 mM achieved the best protection on L. gmelinii seedlings, with an obviously increase in antioxidant enzymes activity and chlorophyll content, and a decrease in MDA content. Trehalose pretreatment lowered the transcript level of genes related to starch and sucrose metabolism, but elevated the content of sucrose, starch and trehalose in L. gmelinii seedlings. Altogether 8 LgTPS and 2 LgTPP genes were selected from the transcriptome. Most LgTPSs and LgTPPs were induced by drought, cold, or salt stress. Overexpression of both LgTPS1.1 and LgTPPI in A. thaliana enhanced tolerance of the transgenic lines to salt stress. Overall, our results showed that the trehalose metabolism pathway was also one of the key pathways to combat abiotic stress in L. gmelinii, and this work will shed light on further related study in other conifers.