FT-IR profiling reveals differential response of roots and leaves to salt stress in a halophyte Sesuvium portulacastrum (L.) L.

In a halophyte, Sesuvium portulacastrum (L.) L., we have applied Fourier Transform InfraRed (FT-IR) spectroscopy to detect the corresponding changes associated with salt-induced physiological changes under long- term treatment with 0, 100 and 500 mM NaCl. FT-IR profiles showed changes in chemical composition and functional groups of proteins, lipids and carbohydrates due to salt treatments, evident as differential FT-IR profiles in both roots and leaves specific to these metabolites. Further, the Principle Component Analysis (PCA) was applied to identify the main sources of variation in FT-IR data due to differential treatment. In PCA, the PC1 showed 85.55% and PC2 showed 18.18% variability in data and confirmed differential response of root and leaves to salt treatment in Sesuvium. The results suggest that FT-IR spectrometry can be used to study stress-induced metabolic changes in plants in relation to their salt tolerance.

Looking at Halophytic Adaptation to High Salinity Through Genomics Landscape.

Soil salinity is an important stress factor that limits plant growth and productivity. For a given plant species, it is critical to sense and respond to salt stimuli followed by activation of multitude of mechanisms for plants to survive. Halophytes, the wonders of saline soils, have demonstrated ability to withstand and reproduce in at least 200 mM NaCl concentration, which makes them an ideal system to study mechanism of salt adaptation for imparting salt tolerance in glycophytes. Halophytes and salt sensitive glycophytes adapt different defense strategies towards salinity stress. These responses in halophytes are modulated by a well orchestrated network of signaling pathways, including calcium signaling, reactive oxygen species and phytohormones. Moreover, constitutive expression of salt stress response related genes, which is only salt inducible in glycophytes, maintains salt tolerance traits in halophytes. The focus of this review is on the adaptive considerations of halophytes through the genomics approaches from the point of view of sensing and signaling components involved in mediating plant responses to salinity.

Salt responsive physiological, photosynthetic and biochemical attributes at early seedling stage for screening soybean genotypes.

Salt stress affects all the stages of plant growth however seed germination and early seedling growth phases are more sensitive and can be used for screening of crop germplasm. In this study, we aimed to find the most effective indicators of salt tolerance for screening ten genotypes of soybean (SL-295, Gujosoya-2, PS-1042, PK-1029, ADT-1, RKS-18, KDS-344, MAUS-47, Bragg and PK-416). The principal component analysis (PCA) resulted in the formation of three different clusters, salt sensitive (SL-295, Gujosoya-2, PS-1042 and ADT-1), salt tolerant (MAUS-47, Bragg and PK-416) and moderately tolerant/sensitive (RKS-18, PK-1029 and KDS-344) suggesting that there was considerable genetic variability for salt tolerance in the soybean genotypes. Subsequently, genotypes contrasting in salt tolerance were analyzed for their physiological traits, photosynthetic efficiency and mitochondrial respiration at seedling and early germination stages under different salt (NaCl) treatments. It was found that salt mediated increase in AOX-respiration, root and shoot K+/Na+ ratio, improved leaf area and water use efficiency were the key determinants of salinity tolerance, which could modulate the net photosynthesis (carbon assimilation) and growth parameters (carbon allocation). The results suggest that these biomarkers could be can be useful for screening soybean genotypes for salt tolerance.