Transcriptional profiling of two contrasting genotypes uncovers molecular mechanisms underlying salt tolerance in alfalfa

Abstract

Alfalfa is an important forage crop that is moderately tolerant to salinity; however, little is known about its salt-tolerance mechanisms. We studied root and leaf transcriptomes of a salt-tolerant (G03) and a salt-sensitive (G09) genotype, irrigated with waters of low and high salinities. RNA sequencing led to 1.73 billion high-quality reads that were assembled into 418,480 unigenes; 35% of which were assigned to 57 Gene Ontology annotations. The unigenes were assigned to pathway databases for understanding high-level functions. The comparison of two genotypes suggested that the low salt tolerance index for transpiration rate and stomatal conductance of G03 compared to G09 may be due to its reduced salt uptake under salinity. The differences in shoot biomass between the salt-tolerant and salt-sensitive lines were explained by their differential expressions of genes regulating shoot number. Differentially expressed genes involved in hormone-, calcium-, and redox-signaling, showed treatment- and genotype-specific differences and led to the identification of various candidate genes involved in salinity stress, which can be investigated further to improve salinity tolerance in alfalfa. Validation of RNA-seq results using qRT-PCR displayed a high level of consistency between the two experiments. This study provides valuable insight into the molecular mechanisms regulating salt tolerance in alfalfa.

Morphological, physiological, biochemical, and transcriptome studies reveal the importance of transporters and stress signaling pathways during salinity stress in Prunus

“…These observations indicate that auxin, SA, and ABA may play critical signaling roles in response to salinity stress in Prunus . Additionally, in salt-sensitive versus salt-tolerant comparisons, a significantly higher number of DEGs were observed in leaves than roots, suggesting a more critical role of hormonal signaling in leaf during salinity stress 32 .…”

“…Forty-one genes were selected randomly for qRT-PCR analysis to validate RNA-Seq data (Supplementary Tables S4 & S5 ). qRT-PCR assays were performed as described previously 32 . RNA samples that were used for RNA-Seq library preparation were also used for qRT-PCR analyses.…”

Morphological, Physiological, Biochemical, and Transcriptome Studies Reveal The Importance of Different Component Traits During Salinity Stress in Prunus

“…These observations indicate that auxin, SA, and ABA may play critical signaling roles in response to salinity stress in Prunus. Additionally, in salt-sensitive vs. salt-tolerant comparisons, a signi cantly higher number of DEGs were observed in leaves than roots, suggesting a more critical role of hormonal signaling in leaf during salinity stress 29 . 32 .…”

“…Forty-one genes were selected randomly for qRT-PCR analysis to validate RNA-Seq data (Supplementary Tables S5 & S6). qRT-PCR assays were performed as described previously 29 . RNA samples that were used for RNA-Seq library preparation were also used for qRT-PCR analyses.…”

Deciphering Molecular Mechanisms Involved in Salinity Tolerance in Guar (Cyamopsis tetragonoloba (L.) Taub.) Using Transcriptome Analyses

“…During salinity stress, plant stress hormones [abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA), and ethylene] and plant growth hormones [auxin (IAA), gibberellins (GA), and cytokinin] play modulatory roles (positive and negative) with intricate crosstalk that contribute to plant growth adaptation during salinity stress. In response to salinity, differential expression of genes associated with phytohormone biosynthesis, signaling, and transport mechanisms have been reported in different plant species, which could be important determinants for salinity tolerance [ 17 , 18 , 19 ].…”