Novel strategies to deal with salinity in Sorghum bicolor seedlings

Abstract

Sorghum is a crop that has become more relevant in recent years due to its uses and properties (biofuel, gluten-free flours) as well as its versatility to grow in unfavorable environmental conditions. Salinity is one of the main abiotic stresses affecting crop production and yield worldwide. The aim of this work was to study the response of sorghum seedlings to soil salinity in two genotypes with known performance to cope with water stress. Physiological parameters related to plant water status as well as the sodium content in the plant were analyzed. We studied the possible role of pricklet and microhairs in the response to salt conditions. Our results showed a differential response to salinity, probably denoting different mechanisms that involve internal water redistribution (in 200 mM NaCl) and a specific replacement of silicon by sodium (when the NaCl reaches 300 mM). The main result was that sodium was absent in all analyzed hairs and leaf surface. Surprisingly, we detected the presence of silicon inside the pricklet at 300 mM NaCl after 24 hours, but not in the microhair. NIPs aquaporins could be involucrate in silicon transport. Our novel results provide further evidence regarding the role of silicon in the response to salt stress. HighlightGrain sorghum has a different strategy to deal with salinity stress depending on the salt concentration, that involves the leaves pricklets and the migration of silicon.