Photosynthetic Regulation Under Salt Stress and Salt-Tolerance Mechanism of Sweet Sorghum

Abstract

Sweet sorghum is a C4 crop with the characteristic of fast-growth and high-yields. It is a good source for food, feed, fiber, and fuel. On saline land, sweet sorghum can not only survive, but increase its sugar content. Therefore, it is regarded as a potential source for identifying salt-related genes. Here, we review the physiological and biochemical responses of sweet sorghum to salt stress, such as photosynthesis, sucrose synthesis, hormonal regulation, and ion homeostasis, as well as their potential salt-resistance mechanisms. The major advantages of salt-tolerant sweet sorghum include: 1) improving the Na + exclusion ability to maintain ion homeostasis in roots under saltstress conditions, which ensures a relatively low Na + concentration in shoots; 2) maintaining a high sugar content in shoots under salt-stress conditions, by protecting the structures of photosystems, enhancing photosynthetic performance and sucrose synthetase activity, as well as inhibiting sucrose degradation. To study the regulatory mechanism of such genes will provide opportunities for increasing the salt tolerance of sweet sorghum by breeding and genetic engineering.

Drought and Salinity Stress Responses and Microbe-Induced Tolerance in Plants

“…For instance, both Sorghum bicolor salt-sensitive and -tolerant genotypes showed a reduction in net CO 2 assimilation rate and PSII efficiency (F v /F m and Φ PSII ), but in the sensitive genotype, these effects were stronger (Sui et al, 2015). In several O. sativa cultivars with different salttolerances, the Φ PSII and net CO 2 assimilation rate were also negatively affected, but the F v /F m was maintained under optimal values (0.75-0.80; Yang et al, 2020).…”

Responses of Membranes and the Photosynthetic Apparatus to Salt Stress in Cyanobacteria

“…Excessive Na + and Cl − flows into the cell disrupted ion homeostasis, leading to accumulation of reactive oxygen species (ROS) (Scarpeci et al, 2008;Feng et al, 2015;Song et al, 2020). High ROS levels are toxic to cells, with the associated destruction of the photosynthetic apparatus and membrane lipid peroxidation (Zhang et al, 2012;Sui and Han, 2014;Yang et al, 2020), adversely affecting photosynthesis. Additionally, high NaCl concentrations inhibit the de novo synthesis of proteins, including many photosystem-related proteins, such as the D1 protein (Allakhverdiev et al, 2002).…”

Profiling Alternative 3′ Untranslated Regions in Sorghum using RNA-seq Data

“…Sorghum cultivars are divided into groups based on their usage: grain sorghum, sweet sorghum, forage sorghum, and energy sorghum. Grain sorghum ranks 5th in global cereal production (Boyles et al, 2019); grain sorghum and forage sorghum serve as significant sources for animal feed; sweet sorghum and energy sorghum are promising bioenergy crops for sugar-and lignocellulosic-based biofuels (Mullet et al, 2014;Mathur et al, 2017;Li et al, 2018;Yang et al, 2020). Sorghum has a relatively small diploid genome with several reference assemblies (Paterson et al, 2009;Deschamps et al, 2018;McCormick et al, 2018;Cooper et al, 2019).…”