Expression of an Eucalyptus grandis Xyloglucan Endoglycosylase Gene in Nicotiana tabacum Confers Tolerance to Abiotic Stress

Comparative analyzes of the xylem transcriptomes from Eucalyptus grandis and E. globulus allowed us to identify a gene sequence putatively encoding an enzyme similar to xyloglucan endotransglucosylase/hydrolase (XTH). XTHs are a family of enzymes involved in plant cell wall modification, impacting cell expansion and growth. Besides cell wall structure remodeling induced by XTHs, the activity of this class of enzymes was also related to plant responses to stress conditions. In this work, we show that in Eucalyptus, EucXTH expression is induced in response to stress conditions such as those promoted by injury, salinity and cold, indicating its involvement in adaptive responses to abiotic stress. Additionally, we demonstrate that Nicotiana tabacum plants overexpressing EucXTH present changes in secondary xylem differentiation, increased mechanical strength and enhanced tolerance to salt stress. These findings demonstrate the potential of the XHT gene to improve plant tolerance to environmental challenges.