Integrative 16S rRNA and transcriptome analysis reveals the molecular mechanisms underlying salt- tolerant germination in highland barley (Hordeum vulgare var. coeleste Linnaeus) seeds
Year: 2025
Type: article
Abstract: Salt stress is a critical abiotic factor that impairs crop seed germination and limits agricultural productivity. Elucidating the mechanisms governing salt tolerance is essential for development of salt-tolerant crop varieties. In this investigation, 217 accessions of highland barley ( Hordeum vulgare var. coeleste Linnaeus ) were evaluated. Germination assays conducted under 200 mmol/L and 500 mmol/L NaCl conditions identified a salt-tolerant variety 37 and a salt-sensitive variety 44. By integrating transcriptome sequencing, 16S rRNA sequencing, and Na + /K + content analysis, we systematically investigated the molecular mechanisms underlying salt-tolerant germination in highland barley seeds. Our findings revealed that the salt-tolerant variety 37 maintained a high germination rate of 98% under 500 mmol/L NaCl stress, with lower Na + accumulation (4.24 g/kg) and a lower Na + /K + ratio (2.59) compared to the salt-sensitive variety 44 (Na + accumulation: 4.89 g/kg, Na + /K + ratio: 3.62). Analysis of 16S rRNA sequencing data showed a significant increase in the abundance of the endophytic bacterium Brevundimonas in salt-tolerant variety 37 under high-salt conditions, which was positively correlated with K + content. In contrast, the dominant bacterium Rhodococcus in salt-sensitive variety 44 exhibited a positive correlation with Na + content and the Na + /K + ratio. Transcriptome sequencing identified 1,467 and 1,644 differentially expressed genes (DEGs) in salt-tolerant variety 37 and salt-sensitive variety 44, respectively. Pathway enrichment analysis indicated that DEGs in salt-tolerant variety 37 were primarily associated with “potassium ion homeostasis” and “response to oxidative stress”. Weighted gene co-expression network analysis (WGCNA) identified 5 co-expression modules, among which the MEyellow module was correlated with Na + content (r = 0.59). Ten core genes were identified, including WRKY transcription factor ( HORVU.MOREX.r3.3HG0268090 ) and receptor protein kinase (RPK; HORVU.MOREX.r3.4HG0331910 ). A total of 174 HvRPK genes were identified, distributed across 7 chromosomes with a predominant localization on chromosome 2. These genes exhibited functional conservation and were involved in salt stress signaling pathways. Phylogenetic, collinearity, and cis-element analyses further supported their regulatory role in salt stress responses. This study clarifies the key mechanisms underlying salt-tolerant germination in highland barley seeds, providing valuable insights and genetic resources for the molecular breeding of salt-tolerant crops.
Source: Frontiers in Plant Science
Authors: Panrong Ren, Yan Qiao, Jie Wang
Institutions: Longdong University, Hangzhou Normal University
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: gold
Estimated APC paid: $3,801
OpenAlex ID: W4415959144