Incorporation of two trehalose biosynthetic genes in banana increases trehalose levels and protects the photosynthetic apparatus from salt-stress damage

SummaryThere are no reports on the possible protective role of trehalose in tropical monocot plants such as banana, when exposed to salt stress. In the present work, banana plants (Musa acuminata ‘Grand Nain’) were transformed with a fusion of two genes from Saccharomyces cerevisiae involved in the biosynthetic pathway of trehalose [trehalose-6-phosphate synthase (tps); and trehalose-6-phosphate phosphatase (tpp)] under the control of the Arabidopsis rd29A drought-stress inducible promoter. Transformed (rd29A::tps-tpp; TF) and wild-type (WT) plants were subjected to three different concentrations of NaCl (100, 200, or 300 mM) for 9 d. The trehalose concentration in the leaves of WT plants was approx. 3.5 µg g−1 fresh weight (FW) when not exposed to salinity, and increased only slightly (to 4.0 µg g−1 FW) when exposed to 100 or 200 mM NaCl. In TF plants, however, the trehalose concentration was approx. 4.0 µg g−1 FW when not exposed to salinity, but increased with salinity, reaching values of ≥ 8.0 µg g−1 ...