Engineering trehalose biosynthesis pathway improves yield potential in rice under drought, saline and sodic conditions

Abstract

Edaphic factors such as salinity, sodicity, and drought alone, or in combination, adversely affect crop productivity. Despite the burgeoning soil sodicity problem being reported worldwide, limited efforts have been made to address this issue. In the present study, we have targeted the generation of sodicity tolerant rice in conjunction with tolerance to salinity and drought. Using a fusion gene from E. coli coding for trehalose-6-phosphate synthase/phosphatase (TPSP) under the control of ABA-inducible promoter, we report here generation of marker-free transgenic high yielding rice (IR64) which can tolerate high pH (~9.9), high EC (~10.0 dS/m) and severe drought (30-35% soil moisture content). These plants retain higher relative water content, chlorophyll content, K+/Na+ ratio, stomatal conductance and photosynthetic efficiency than wild type under above-mentioned stresses. A positive correlation between trehalose overproduction and high yield parameters has been observed under drought, saline and sodic conditions. Metabo-profiling using GC-MS reflects that overproduction of trehalose in leaves differently modulates other metabolic switches leading to significant changes in the levels of sugars, amino acids, and organic acids in transgenic plants under control and stress conditions. Our findings reveal a novel technological solution to tackle multiple stresses under changing climatic conditions.