This study demonstrates a dose-dependent response of Trichoderma harzianum Th-56 in improving drought tolerance in rice by modulating proline, SOD, lipid peroxidation product and DHN / AQU transcript level, and the growth attributes. In the present study, the effect of colonization of different doses of T. harzianum Th-56 strain in rice genotypes were evaluated under drought stress. The rice genotypes treated with increasing dose of T. harzianum strain Th-56 showed better drought tolerance as compared with untreated control plant. There was significant change in malondialdehyde, proline, higher superoxide dismutase level, plant height, total dry matter, relative chlorophyll content, leaf rolling, leaf tip burn, and the number of scorched/senesced leaves in T. harzianum Th-56 treated rice genotypes under drought stress. This was corroborated with altered expression of aquaporin and dehydrin genes in T. harzianum Th-56 treated rice genotypes. The present findings suggest that a dose of 30 g/L was the most effective in improving drought tolerance in rice, and its potential exploitation will contribute to the advancement of rice genotypes to sustain crop productivity under drought stress. Interaction studies of T. harzianum with three aromatic rice genotypes suggested that PSD-17 was highly benefitted from T. harzianum colonization under drought stress.

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Plant cells and tissues remain always on risk under abiotic and biotic stresses due to increased production of reactive oxygen species (ROS). Plants protect themselves against ROS induced oxidative damage by the upregulation of antioxidant machinery. Out of many components of antioxidant machinery, glutathione reductase (GR, EC 1.6.4.2) and glutathione (GSH, γ-Glu-Cys-Gly) play important role in the protection of cell against oxidative damage. In stress condition, the GR helps in maintaining the reduced glutathione pool for strengthening the antioxidative processes in plants. Present study investigates genome wide analysis of GR from rice and Arabidopsis. We were able to identify 3 rice GR genes (LOC_Os02 g56850, LOC_Os03 g06740, LOC_Os10 g28000) and 2 Arabidopsis GR genes (AT3G54660, AT3G24170) from their respective genomes on the basis of their annotation as well as the presence of pyridine nucleotide-disulphide oxidoreductases class-I active site. The evolutionary relationship of the GR genes from rice and Arabidopsis genomes was analyzed using the multiple sequence alignment and phylogenetic tree. This revealed evolutionary conserved pyridine nucleotide-disulphide oxidoreductases class-I active site among the GR protein in rice and Arabidopsis. This study should make an important contribution to our better understanding of the GR under normal and stress condition in plants.

The present investigation was aimed to understand the physiological and biochemical basis of water-deficit stress tolerance in pearl millet [Pennisetum glaucum (L.) R. Br.] hybrid ICMH 356 and its parents ICMR 356 (♂) and ICMB 88004 (♀) in response to and recovery from drought stress and also to comprehend crop adaptation under dryland conditions. A field experiment was conducted in a split plot design with moisture levels as the main plot and genotypes as the sub plots. A comparative analysis of hybrid and parents under well-watered and water-deficit stress conditions revealed that the hybrid was superior over the parents in terms of leaf water relations, excised leaf water retention capacity, accumulation of compatible solutes, photosynthesis, membrane stability index and antioxidative enzyme viz., superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX) and guaiacol peroxidase (GPOX) activities. ANOVA for these parameters was also found to be significant for genotypes, treatments and their interactions at 0.01% level. Maintenance of superiority in terms of these physiological and biochemical parameters coupled with better recovery ability upon stress relief are crucial physiological mechanisms contributing to water deficit stress tolerance in pearl millet. Simple correlation coefficient analysis revealed significant positive association of yield at 0.01% level with relative water content, leaf water potential, stomatal conductance, photosynthesis, proline, total soluble sugars, free amino acids, membrane stability index, leaf area index and total biomass, while a significant negative association with solute potential and malondialdehyde content, under water-deficit stress clearly indicated that such relationships can be positively attributed to drought tolerance