Gene expression and bioactivity estimation of Piriformospora Indica co-cultivated red amaranth (Amaranthus tricolor) plants under temperature stress conditions

Abstract

Amaranthus tricolor is one of the major leafy vegetables. Red amaranth is most vulnerable to climatic changes, especially a rise in temperature. Piriformospora indica symbiosis with red amaranth reduces the negative effects of temperature stress. . This study was aimed to gene expression and bioactivity estimation of P. indica co-cultivated red amaranth plants under temperature stress conditions. One week old red amaranth seedlings were is transferred to a suitable medium containing soil with P. indica for co-culture. P. indica co-cultured red amaranth was maintained in a growth chamber with various temperature treatments for a period of three hours at 25οC, 30C, 35C and 40C. Uninoculated plants maintained at 25οC, 30C, 35C, and 40C was be served as control. The changes in plant phenotypes and biochemical parameters were measured. To identify temperature stress tolerant genes conferred by P. indica, colonized and uncolonized plants were analyzed after 3 hours of temperature stress induction. Results obtained showed that colonization of red amaranth roots by P. indica revealed significant variation in leaf number, leaf length, leaf area and plant height of P. indica plants compared to untreated plants for a period of 2 months at 15 days intervals. In addition, chlorophyll a, b, a + b, carotenoid and anthocyanin contents were increased in the leaves of the P. indica colonized plants under temperature stress conditions. Mineral estimation revealed that plants treated with P. indica increased the accumulation of Ca and Mg elements and slightly decreased the oxalate content. Furthermore, the expression of the various genes catalase, ascorbate peroxidase, superoxide dismutase, dihydroflavonol 4- reductase, sHSP 17.8 and 17.9 genes were significantly up- regulated in P. indica treated plants in comparison with untreated plants. At 25°C the expression of CAT, APX, SOD, DFR, sHSP 17.8 and sHSP 17.9 were up-regulated by 1.5, 2, 2.5, 2, 2.9, and 1.4 folds. At 30°C the expression of CAT, APX, SOD, DFR, sHSP 17.8 and sHSP 17.9 were up regulated by 2.5, 2.45, 2.8, 2.5, 3.1 and 1.9 folds. At 35°C the expression of CAT, APX, SOD, DFR, sHSP 17.8 and sHSP 17.9 were up-regulated by 3.35, 2.8, 3.5, 3.56, 3.35 and 112 2.6 folds. At 40°C the expression of CAT, APX, SOD, DFR, sHSP 17.8 and sHSP 17.9 were up-regulated by 3.5, 3, 3.7, 3, 3.68 and 3.2. In conclusion, P. indica has the potential to enhance the growth of red amaranth under temperature stress and increased phenotypic and physiological parameters of the plant which would help them to grow in higher temperature zones