Breeding for Improved Plant–Symbiont Thermotolerance and Symbiotic Performance by Regulating Heat Shock Proteins, RNA Binding Proteins, and Chaperones

Abstract

As metaorganisms, plants are in close multi-symbiotic relationships with fungal and bacterial symbionts. In all organisms, protein processing and homeostasis control all aspects of life. Activity of heat-shock proteins (HSPs), RNA-binding proteins (RBPs) and molecular chaperones differentially regulate stress responses by protecting protein structures and functions, regulating gene expression and, thereby, cellular processes under both normal and stress conditions. Recent studies highlight the importance of the regulation of molecular chaperones in order to promote plant-symbiont growth, performance, and tolerance to multiple stresses, particularly salinity, drought, and extreme temperatures, which are the major constraints in agriculture. Compared to genetic manipulation, regulation of protein homeostasis and activation of stress responsive genes and symbiotic genes indirectly through symbiosis or biotech symbionts have received a great attention as a promising and more environment-friendly strategies in breeding programs. Among different stresses, extreme temperatures can cause devastating effects on symbiosis. Thus, this review discusses the molecular repertoire of HSPs, RBPs, and molecular chaperones as biotechnological tools in order to improve plant-symbiont growth, development, yield, symbiotic performance, and tolerance to different stresses with particular emphasis to extreme temperatures.