Salt stress is a major abiotic factor that limits wheat production worldwide. However, this threat is increasing significantly because soil salinity affects approximately 20% of the irrigated agricultural land globally, leading to significant yield losses by impairing plant growth and photosynthetic efficiency. This study aimed to identify single-nucleotide polymorphisms (SNPs) associated with salt tolerance in wheat core collections during the heading stage under saline stress conditions. Chlorophyll content, a physiological indicator of salt tolerance at heading, and soil electrical conductivity (EC) were measured in 609 accessions and a Salt Tolerance Index (STI) was subsequently constructed. Genome-wide association studies (GWAS) were performed using a 35 K SNP chip to identify significant marker-trait associations. Three models (MLM, FarmCPU, and BLINK) were employed for the GWAS, with FarmCPU and BLINK demonstrating superior power over the MLM in controlling false positives. GWAS results revealed four significant SNPs (AX-94929101, AX- 94615611, AX-94510535, and AX-94411611) located on chromosomes 3D, 5D, and 7D. AX-94510535 exhibited significant phenotypic differences based on SNP genotype, suggesting its potential as a marker for STI. Furthermore, the identified candidate genes, TraesCS3D02G218100, TraesCS5D02G059500, and TraesCS5D02G175000, were implicated in biological processes such as DNA replication, cell death, and photosynthesis.

Given that soil salinity significantly limits plant growth and production in agricultural land, research on salt stress is of particular agricultural relevance. In this study, for the purposes of functional screening of genes involved in salt stress responses, we selected approximately 651 transgenic Arabidopsis lines (157 independent full-length) from a transgenic Arabidopsis population overexpressing full-length Brassica rapa cDNAs. Initial screening indicated that the transgenic lines of 12 genes showed apparent salt tolerance phenotypes when exposed to NaCl at a concentration of 125 mM, among which, two genes (BrATL30 and BrZHD10) were selected for detailed characterization. The T₃ progeny of these transgenic lines exhibited accelerated seed germination, often accompanied by faster root growth and higher survival rate, compared with wild-type plants under salt stress. Additionally, in order to examine the agricultural potential of the two selected B. rapa genes, we constructed BrATL30- and BrZHD10-overexpressing Brassica napus transgenic plants (BrATL30-OX and BrZHD10-OX), which showed apparent high salt stress-tolerant phenotypes compared with wild-type plants. Furthermore, we found that the basal expression of several salt- and abiotic stress-responsive genes was higher in transgenic plants than in wild-type plants. Taken together, this study will provide two valuable functional genes related to salt stress tolerance.

In order to investigate salt-tolerant sorghum germplasms that can grow in saline soil from newly reclaimed land, we measured a well-established germination rate, and growth characteristics including leaf number, height, and root length in salt-treatment conditions (0.3, 0.6, 0.8, and 1.2%) and untreated control. The highly salt-tolerant sorghum line was confirmed using PCA (principal component analysis) analysis and fuzzy comprehensive evaluation method. Germination rate gradually decreased at doses higher than 0.3%, but the germination rates reached about 70% in IT124115, IS1041, Dansusu4ho, and Dansusu2ho germplasms. At 0.6% salt-treatment condition, the germination rates ranged from 35% to 100%. Only seven germplasms (IT103274, IT101381, IT104110, Dansusu4ho, IS20740, IS22720, and IS27887) had germination rates exceeding 50% at 0.8% salt-treatment. At 1.2% salt-treatment IT124115, IT028385, and IS1041 withered. The total number of leaves decreased similarly for both germplasms at salt levels below 0.6%, and sweet sorghum leaf count was more susceptible than grain sorghum at doses higher than 0.8%. In addition, the height of both germplasms was severely reduced even at low salt concentrations, whereas grain sorghum exhibited a greater sensitivity to salinity stress in terms of root length, while sweet sorghum had longer roots at low concentrations when compared with the untreated control. PCA analysis and fuzzy comprehensive evaluation showed that 29 sorghum accessions could be divided into 3 groups based on the germination rate and morphological traits. Especially, sweet sorghum accessions showed a different pattern of PCA plot when compared with the grain sorghum, and salt tolerance could be divided into 5 groups using MFV in terms of their traits. Taken together, the results from this work will contribute to the development of domestic agriculture utilizing marginal land such as reclaimed land by selecting elite sorghum germplasms that have a high salt tolerance and capacity.