Transgenic tobacco plants expressing grass AstEXPA1 gene show improved performance to several stresses

Expansins are cell wall-loosening proteins and now widely accepted to associate with the plant resistance against various abiotic stresses. In this study, we cloned an expansin gene of AstEXPA1 from Agrostis stolonifera, a heat-resistant creeping bentgrass cultivar, and transformed it into tobacco plants. Physiological index test showed that the transgenic lines were resistant to various abiotic stresses of drought, heat, cold, and salt in comparison to non-transgenic plants. Comprehensive analysis of four physiological response indices showed that the transgenic plants performed much better resistance to drought, following to heat, cold and salt stress, respectively. Meanwhile soluble sugar content displayed more weight to plant resistance by over-expressing AstEXPA1 gene, followed as proline content, REL, and MDA content. The results here would expand our understanding of the expansin roles and drive better insights into plant molecular breeding against stress.