Physiological and Transcriptional Analyses Provide Insight into Maintaining Ion Homeostasis of Sweet Sorghum under Salt Stress

Abstract

Sweet sorghum is an important bioenergy grass and valuable forage with a strong adaptability to saline environments. However, little is known about the mechanisms of sweet sorghum coping with ion toxicity under salt stresses. Here, we first evaluated the salt tolerance of a sweet sorghum cultivar “Lvjuren” and determined its ion accumulation traits under NaCl treatments; then, we explored key genes involved in Na+, Cl−, K+ and NO3− transport using transcriptome profiling and the qRT-PCR method. The results showed that growth and photosynthesis of sweet sorghum were unaffected by 50 and 100 mM NaCl treatments, indicative of a strong salt tolerance of this species. Under NaCl treatments, sweet sorghum could efficiently exclude Na+ from shoots and accumulate Cl− in leaf sheaths to avoid their overaccumulation in leaf blades; meanwhile, it possessed a prominent ability to sustain NO3− homeostasis in leaf blades. Transcriptome profiling identified several differentially expressed genes associated with Na+, Cl−, K+ and NO3− transport in roots, leaf sheaths and leaf blades after 200 mM NaCl treatment for 6 and 48 h. Moreover, transcriptome data and qRT-PCR results indicated that HKT1;5, CLCc and NPF7.3-1 should be key genes involved in Na+ retention in roots, Cl− accumulation in leaf sheaths and maintenance of NO3− homeostasis in leaf blades, respectively. Many TFs were also identified after NaCl treatment, which should play important regulatory roles in salt tolerance of sweet sorghum. In addition, GO analysis identified candidate genes involved in maintaining membrane stability and photosynthetic capacity under salt stresses. This work lays a preliminary foundation for clarifying the molecular basis underlying the adaptation of sweet sorghum to adverse environments.

Abiotic Stress Tolerance Boosted by Genetic Diversity in Plants

“…In light of this, rigorous validation of candidate associations is a non-negotiable requirement [55] before one can proceed with more downstream applications. It is as part of this corroboration endeavor that Zhao et al [34], Ma et al [35], and Guo et al [36] envisioned their works, using alfalfa (Medicago sativa), Phoebe bournei (a widely conserved tree in China because of its economic and ecological value), and sorghum (Sorghum bicolor) as study organisms for multiple abiotic stresses, such as salt (all three species), drought (the former two taxa), and heat (the second species). Performing integrated assessment of multiple stresses such as these also enables long-standing questions concerning the scale of molecular pleiotropism beneath concomitant abiotic stresses to be addressed [56], a matter which has already been approached in this Special Issue by Wirojsirasak et al [33] in a multi-environment framework [12], but has yet to be addressed in a multi-trait setup [57].…”

“…In terms of candidate gene functional validation [62], Guo et al [36] also corroborated our knowledge on the genomic architecture for key abiotic stresses by performing transcriptome profiling and qRT-PCR for salt tolerance in sorghum. Ultimately, research investigating how sorghum reacts to salt stress sheds essential light on the plant's extraordinary capacity to adapt to harsh conditions [63].…”

“…Data Availability Statement: For data availability, please see the original articles [31][32][33][34][35][36][37] within the Special Issue "Abiotic Stress Tolerance and Genetic Diversity in Plants" (https://www.mdpi.com/ journal/ijms/special_issues/80P9M9NK87 accessed on 24 March 2023).…”

Revealing the Mechanism of Aroma Production Driven by High Salt Stress in Trichomonascus ciferrii WLW

“…In addition to the ability of T. ciferrii WLW to produce MA while tolerating high salt, the underlying molecular mechanism of the response to salt stress also attracted our attention. A series of studies related to the mechanism of salt tolerance have shown that membrane proteins, ion homeostasis, and transcription factors (TFs) are closely related to the strong salt tolerance of microorganisms under high-salt conditions [ 31 , 32 , 33 ]. Therefore, we used transcriptomic techniques to explore the reason for survival despite high-salt conditions from multiple perspectives, including the expression of key genes in terms of membrane proteins, ionic homeostasis, and salt-stress-related transcription factors.…”

Molecular Mechanism of Exogenous Magnesium in Regulating Cation Homeostasis in Roots of Peanut Seedlings under Salt Stress

“…Globally, soil salinization poses a major threat to plant growth and productivity [1]. Affecting more than 1 billion hectares of land [2], the lack of freshwater resources and unreasonable irrigation methods have aggravated salinization [3] and brought huge economic losses to irrigated areas [4].…”