Exogenous Selenium Endows Salt-Tolerant and Salt-Sensitive Soybeans with Salt Tolerance through Plant-Microbial Coactions

Abstract

Soil salinization is a common abiotic stress that seriously affects soybean growth and yield, underscoring the need to enhance plant salt tolerance for sustainable agriculture development. Selenium is a beneficial element that has been shown to promote plant growth, development and stress resistance. This study employed pot experiments to investigate the effects of different salt levels (0, 50, 100 and 150 mM NaCl) on salt-tolerant (Zhonghuang 13) and salt-sensitive soybean (Dongnong 63) varieties. Additionally, the critical salt concentration (100 mM NaCl) was selected to explore the effects of exogenous selenium (0, 0.5, 1 and 3 mg·kg−1) on improving salt tolerance in salt-tolerant and salt-sensitive soybeans under salt stress. Results showed that as salt concentration increased, plant height, shoot and root fresh weight, SPAD value and enzyme activity of both salt-tolerant and salt-sensitive soybeans significantly decreased. The increasing concentration of exogenous selenium significantly decreased the proline content of salt-sensitive and salt-tolerant soybeans by 40.65–58.87% and 38.51–50.46%, respectively, and the MDA content by 19.33–30.36% and 16.94–37.48%, respectively. Selenium supplementation also reduced the content of Na+ in salt-sensitive and salt-tolerant soybeans and improved K+ absorption in soybeans, which increased the K+/Na+ ratio. Moreover, high-throughput sequencing of the 16S ribosomal RNA gene demonstrated that selenium application optimized the rhizosphere microecology structure of salt-tolerant and salt-sensitive soybean varieties and enhanced functional genes related to lipid metabolism, energy metabolism and cell motility of rhizosphere microorganisms. In summary, selenium application improved the salt tolerance of the two soybean varieties by enhancing the physiological resistance to salt stress and optimizing the structure and function of the rhizosphere microbial community.

Soybean miR159 Family Members Function in Plant Responses to Low Phosphorus, High Salinity, and Abscisic Acid Treatment

“…MIR159 expression is induced in peanut by salt stress, and miR159 regulates the expression of its target genes [26]. In addition, miR159 in different tissues of S. portulacastrum is involved in plant responses to high-salt stress [27]. In the current study, qRT-PCR results showed that MIR159 responds to high-NaCl concentrations in soybean (Figure 4).…”

“…MiR159 responds to high-salt stress in S. portulacastrum [6,27]. We therefore used qRT-PCR to measure the transcript levels of MIR159 family genes in leaves and roots of soybean plants subjected to short-term (6 h) treatment with 200 mM NaCl.…”

“…Eight miRNAs associated with salt tolerance have been identified in peanut (Arachis hypogea): miR159-1, miR159-2, miR159-3, miR164-2, miR167-3, miR319-1, miR319-2, and miR211-1 [26]. A study of the responses of salt tolerance related miRNAs to high-salt habitats in the mangrove companion plant Sesuvium portulacastrum showed that miR159 is involved in the responses of different tissues to high-salt stress [27], whereas the responses of soybean (Glycine max) MIR159 genes to abiotic stress and their roles in abiotic stress responses are unclear. It is well known that soil salinity and drought are common threats to crops.…”

Genome-Wide Identification and Expression Analysis of Salt-Tolerance-Associated NAC Family Genes in Cyclocarya paliurus

“…Salt stress is a detrimental environmental factor known to impede plant growth and development significantly [23]. To circumvent the deleterious effects of such stress, plants have evolved complex regulatory mechanisms that include the modulation of gene expression [3,24,25]. Notably, the impact of salt stress on the NAC gene family in Cyclocarya paliurus, a species of considerable ecological significance, remains underexplored.…”